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HP Saw 438A User's Manual

1. 6 14 0698 3450 0751 0444 0757 0442 0757 0444 0757 0442 0757 0463 0757 0463 2100 2655 2100 2655 0698 3451 0698 3451 0698 3160 0698 3160 0698 0083 0698 0083 2100 2655 2100 2655 0698 0084 0698 0084 0757 0465 0757 0465 0698 3154 0757 0200 0757 0460 2100 2030 0757 0460 0698 3154 0757 0200 0757 0279 0757 0280 0757 0422 0698 3446 0699 2624 0699 2623 0698 3441 0698 3441 0698 3441 0698 3441 0360 0535 0360 0535 0360 0535 0360 0535 9 Cc O 0 6 w W O A OHM e 4 0 O OOH ce Q0 O DG E Oo T O m O 1 Ai op ei ta en bei rei re ot bg E a ri ESET 0 debo n o de amp bei bei bei ei oad Table 6 3 Replaceable Parts continued Description RESISTOR 42 2K 4 195 125W TF TC 0 100 RESISTOR 42 2K 4 196 125W TF TC 04 100 RESISTOR 12 1K 4 196 125W TF TC 0 100 RESISTOR 10K 4 195 125W TF TC 0 100 RESISTOR 12 1K 4 196 125W TF TC 0 100 RESISTOR 10K 4 195 125W TF TC 0 100 RESISTOR 82 5K 1 125W TF TC 04 100 RESISTOR 82 5K 1 125W TF TC 6 100 RESISTOR TRMR 100K 10 TKF TOP ADJ 1 TRN RESISTOR TRMR 100K 10 TKF TOP ADJ 1 TRN RESISTOR 133K 1 125W TF TC 0 100 RESISTOR 133K 1 RESISTOR 31 6K 1 RESISTOR 31 6K 4 196 RESISTOR 1 96K 1 RESISTOR 1 96K 4 196 125W TF TC 0 100 RESISTOR TRMR 100K 10 TKF TOP ADJ 1 TRN RESISTOR TRMR 100K 10 TKF TOP ADJ 1 TRN RESISTOR 2 15K 1 125 W TF TC 04 100 RESISTOR 2 15K 1 125W TF TC 04 100
2. E pap L238N02 DEL i TR Lee AC Seu KG A PM ASL ND c H PAOLA E G83 013148 ECO mz crio unes ksze 2 Bong i 5 GRAGWS EE ANA SISSVEO ASt A aput Ir ut New AZT YMO d uan A Se HERR E AS 30NV a 34180 HOSNAS HK UBS Amt EZ 1 SONS vikra 39NVU 228 SUL tH Diz Byk HI U g2blUe i 46 193 US209 zg Lom TP CIG dr Sch i Soe ere iv POL k i 1823 UOSN3S 0 d Did E Je I Noea 01123138 13NN VHO amem E i d s DS b E IUOSNIS iNOHZ 1 laneo JEO 7 2 4 3 ioo peii Rod 4 3198 NEON o SRO EEEE erat Lyte 320N oo 2131 W AZ A J9NVE 8 i3NNVHO HJiji TGMY 1SHid WAZ 3 18 LU H B L ERA A A O E 000 do 0000000 n n m m m m m momo WOSNXIS O d DIV 13NN H2 8938 ve 00 NOIE 310 GRY Gl31HS 34140 kosas H Sifu tH LA SHOLLOSNNOS Ww GEYRO 1h i yN a dja Old CNG SiSSvHS LNG d HOSNSS 5083 L3 GND 073185 UD5N38 Old Or iNQHi OM Ier 31081 34180 wOSNaS f Hp BAGH WALES rr Ea lt 1 wu iR O03 54 REG Li BA regm UN 1 Y m p YOSN3S Did Q 4 RZ d ED JE Ej KOSNIS ge n zit i do NOI 93KN09 260 SO 180 SE me E H 32 ADH ZH 0220 H vao QNO SESS Ho Nee GAD BBMOd Ly 39NVH BNISIAOO 3ONYUO ael H z nr WOTIJA Y 3a k pim CNY lm S37BYO SEH to i i WG ER 0a TER 8 13349 3015439 NO MMOHS 34v Nana O LO
3. UV MI S 4 o 9 No 9 09v 1 928 Gast i 318Y3 gi AG ECH 003 so s r D PIEG EGBT ga amp 211k8 od ZD p ra K IA dOi MITA dOl 431A SDL Pir SSHT E e 83114 aago AST ty Fete ciasY senaz LE irae Se Oi et 3 SC adog L gan ii 8 L i06Y ENEE eb wo 068 a t S osf L H38W N NOLLYNSIS30 MS M i i yy T DI f a Ierd i 30343436 Hori 91 so ile or tes pis Ad SE3SHRN BYE 2 LIMQUID GRLYHOZINE 510 3 bod 3 GNY HOLSISNYHE tf 2 2i Ar 7 e arteriis en ugy e X3IA di A3 A o0l BO M n Deeg 313 i t i QBYDS S dO 80GY E Sy317 14 SS d MO HOLOSLIG JS Hd SDONOBHONAS Lengt edgy pe vm 7 j LEG SE I sa o9 TUE sl A g 831308 o 9 05 8 9 Fd 0r 8 v En T9817 AN FAST PSY A Ki HOLYNNALLY S H r8 67 IR PY stata 680 UL TEE uer Di KK gg INIYO ECK HEI d i geh e GLS a Er Wal Sep UTS Het g y KAIA JOL SET 7 SCH Liber Sen E c lac wani adoece OC i 10003 BrE Hoe sen Te l i SCH g anto o P RS Lg a acd tee Tatas 4 e St y sry DAT E rj E 101 ASS EZE 5 mo 5 EGE 10506 8 23 oF TAS VE CE PEEL by at D i 4 ord soot ep f tse Es BSG are Est Pes 0 29 C 5 5 E gt bar 9 ANOLOYS 3Hi LY AW1ENSUIO re D sda ezo t E H Kg em BNINNGH iY3H N3HK 0380 N9UYA AST G d GJI3TIGNY En S i SUOR i lt SI LYHL HOi23NNOZ 3903 GEYDR i g S S EE lIn3uI3 GAINES QL SU343U 93 2 03141140 Y SS d
4. 4 1 0 3 24 3 13 Remote Operation Hewlett Packard Interface eo A SE 3 28 3 14 HP IB Compatibility 3 28 3 15 Reimote Mode s o 1 1 1 1 3 28 8 16 Local Mode c s enad a 3 29 o e ue ODA w BS 3 29 3 18 T rn on Default Conditions 3 30 3 19 Data Messages 3 30 3 20 Receiving the Data Message 3 31 3 21 Sending the Data Message 3 34 3 22 Receiving the Clear Message 3 40 3 23 Receiving the Trigger Message 3 40 HP 438A Contents 3 25 Receiving the Local Message 3 26 Receiving the Local Lockout Message 3 27 Receiving the Clear Lockout Set Local Message 3 28 Receiving the Pass Control Message 3 29 Sending the Require Service Message 3 30 Sending the Status Byte Message 3 31 Sending the Status Bit Message 3 32 Receiving the Abort Message 3 33 HP IB Syntax and Characteristics Ee Er ced im AS Uo Se AA Cal Fact r cia dBm WATT Logarithmic Le ir Units Error Messages EYE Error Displays w 4 322 8 60 63 wok Go IH P IB Output Format 6x a S EtrorMesBAEeS Lus X acm R GG Gm do WG Filters 206 ovx Goa Includes AUTO FILTER aud MNL L Filter uno MAC A A Sip Si ora HE Examples o cor Go Ae tees Preset xn 6 nox we hee Se Re es a IUE 4 633 AA Cee eed eh eds me fed Recorder Output Gel OP A Y ae el e owe Mo 4 eS s ED Sensor A and Sensor
5. WEEEZ LING ONISSIDOYA TYHANYJ Did YB AA AN O A A AAA 6 A amp A ama A mm A A R A A R A E say zm ma Km tm AEON d mtem HA HE AYA mm mm OND 145910 HG 14907 XN Vos 3658 JSCAS Gi 5935 59 778939 S pni ves 298HFe i aeu t 5 i y 32493 i dSJAS UL j 2 Sdage b 935 gio Us id uer IET ceo i dSCA Lo vero lt h ri E 9938 EE 52 00 A j State SU3A H6 S3HOLYI a we LYTdSIG VIVO WeavidSiQ Vi G ed Did AGONY O d ge ag KE TE We En 7777 0108 8tr00 LINA SWISS sf bm ere eem vn A TT et WA M WN M ind DEE m E DEEN W D E e AAAA M m ME iQv oov H i LY E ZAN GAN Fiz is 61 901 dY lTVEINJO EN O74 suonea2o 1uauoduio2 Ajquassy yun Burss8001d jenuadg O d 97 8 ANBA EI z R 3 EN p XS ENG iU PRADA E i A18W3SSV V V8 t dH HP 438A Service Sheets 5 Lee 0 55050 05050505000 000000000 9 Service Sheet 5 Display Assembly Troubleshooting General These procedures will isolate a problem to one of the following areas u Display LEDs m Anode Data Display Drivers m Cathode Data Display Drivers m Data Display Drivers Test Equipment RE HP 1725A Fault Isolation Procedure 1 Turn the power meter OFF 2 Set switch A3 1 on the A3 assembly to 0101 LSB The switch closest to the edge of the printed circuit board is the least signific
6. electrolytic LED light emitting diode ENCAP encapsulated LE e A idee ed low frequency EXT A tee so external Te get acta adw long EE EE farad LH left hand FET fieid effect transistor EM aere EE limit RB erdene n na eis flip flop LIN linear taper used in Parts PH cen Een Se aes flat head List EILOH uu Soo Sed fillister head Vine ees dation skate gan linear FM frequency modulation LK WASH leck washer BBC VAT reus t front panel WO ciis low local oscillator FREQ Rs frequency LOG logarithmic taper used PAD oii gue eden fixed in Parts List Bees cei e dads tnt gram IGE vee Pa vOS logrithm ic GE vg ere ava germanium LPP ess low pass filter GH2 ivit eeu gigahertz LV dais inert low voltage GL hes disco AA glass EECHER metre distance GRD vo eee eee ground ed WL A ante det ea millampere House nar apt an sed tek ele henry MAX ud entes maximum B oe Sayers sima pi hour M w wy opa cze megohm NOTE All abbreviations in the Parts List appear in uppercase A ROEE Z eiectron tube VR voltage regulator breakdown diode W cable transmission path f wire Ad E ENN SE utes socket Y crystal unit piezoelectric or quartz Z tuned cavity tuned circuit MEG meg 109 used in Parts List MET FLM metal film MET OX metallic oxide MF medium frequency microfarad used in Parts List MPG REG manufacturer mg veins AS milligram MHZ xS megaher
7. G 199US aos YLYQ SG HN LHDSIT 935 HA Mu Boo 138_43M0d YLYQ EYE 1HD37 Good GI R en Wa tee oe we we IN s iti T iij i ON 39D FO 2959 dp z GH p SR 5 30 43158010 v gOS l1Yv3d3H CJ SN 9 vo ED eat Nemme V1 VO AV1dS 1 OI USINDN emm Ett AYTGSIO vate e Y AA 26009 9 P00 ATONASSY AVIASIO CY suojeo07 yusuoduiog Ajquassy ejdsig 82 8 amb 3018 11013819 NO 310N ATEWASSV CV a n 1 veg Sogp NG 10 vaa 134 Y Ke V8EP dH HP 438A Service Sheets 6 Service Sheet 6 Input Amplifier Circuits Troubleshooting Note E General The procedures for checking the Input Amplifier Circuits are given below The Fault Isolation Procedure should be used if the problem has not been isolated to a particular circuit If the problem is known to be in a particular circuit go directly to the troubleshooting for that circuit Whether performing the Fault Isolation Procedure or the troubleshooting for a particular circuit always do the Power Supply Checks first Test Equipment OSANOSCENE Se dE Ae HP 1725A Voltmeter Lasso de oO send Ou da dii E ed bee Moe A us HP 3456A Hange Callbratof asis caia HP 11683A Fault Isolation Procedure Power Supply Checks 1 Verify the voltages at the following test points AAD PO ceris eech 15 Vdc 0 75 Vdc
8. quon i C HB eee i i i 13530 fo mag agit SE AS 398005 iN3HHDO 31V dido 9N 10032 oinv 2100 8 Ed 3508 LNOO Nm HOLY TT L980 YY O mm Ne YARANA e d CY LOY OGY MO SROSNYTISOS IM K Ehe OND 2 HOLA Alt vEECZ 93 J 1dnY NIV vor ONY TYLIDIC wal S 7H GE Jiv s ith win Fi ia N 0 2N LIDD ed 0009 8 500 ATEWISSY HalilTdWY NIYW SV O d HP 438A A5 ASSEMBLY Figure 8 38 P O Main Amplifier Assembly Component Locations HP 438A Service Sheet 8 nee es Service Sheet 8 P O Main Amplifier Assembly Troubleshooting General The following procedures will help to isolate a a problem to one of the following circuits m Range Attenuators a Variable Gain Amplifier m Gain Attenuator Buffer a AC Gain Stage u Synchronous Phase Detector x Low Pass Filter m Sensor Resistor Selection a Analog Digital Input Multiplexer u Reference amp Ramp Start Gate u Ramp Generator u Comparator Test Equipment OSEUIOSCODE elt ssl NO e ee HP 1725A Digital Voltmeter cies opea Sonel Z d RR di HP 3456A SIBI tUe Analyzer za M d uas ead de OZ WA Mes HP 5005B lange AAD LALOR et i ta ER VE UP aaa HP 11683A Fault Isolation Procedure 1 Set up the equipment as follows Power Meter PRESET Calibrator Range 1 mW Function Calibrate Polarity
9. If A5U24 pin 14 is correct select MNL Filter 0 and verify that removing the jumper from A5TP16 makes no difference in the reading at A5U24 pin 14 If moving the jumper does make a difference replace A5U21 Connect a jumper from the 5 volt supply ASTP7 to ASTP12 and measure the voltage at A5U24 pin 12 If the voltage at A5U24 pin 12 is equal to the 5 volt supply select MNL Fiiter 9 and verify that removing the jumper from A5TP12 makes no difference in the voltage at A5U24 pin 12 If moving the jumper does make a difference or if A5U24 pin 12 was not equal to the 5 volt supply replace A5U21 At this point the Filter Switch has been fully verified The following steps will check the Slow and Fast Filters 13 Verify that the voltages at ASTP12 and ASTP16 are approximately equal to 0 6 times the peak voltage at A5TP19 plus or minus 0 3 volts If the voltages at ASTP12 and A5TP16 are incorrect replace A5U24 If the voltage at ASTP12 or A5TP16 is incorrect the problem is more likely to be with the resistors and capacitors associated with the defective filter Analog Digital Input Multiplexer Test 1 Compare the waveform at A5TP11 with Figure 8 50 1V DIV E 10 ms DIV Figure 8 50 Analog to Digital Converter Input 8 117 Service Sheet 8 8 118 HP 438A The voltage levels at points A B C and D on Figure 8 50 should be as indicated below Point A should be the same as A5U19 pin 6 Point B
10. 9 1 8 S 1 8 weeg oneluayos synon jddns 19Mog O d 29 8 21NBI4 E9 01V O d 6V O d CL GER D 6 9 SS asvo Pw 79 o MIIA WOLIOS M2 IA 1001 Y 3018 2 ne a o JGONY y JSYD JOCHLYO MJIA dOl 31YD Quvog MIIA 10819 WO1108 LOBY 0 9081 1690 9281 1090 928 v 20 7881 NOI IYNDISIQU JoN3udd3H SHJGWNN iuYd lifiguiO Q31vVH93iNI ONY HOISISNYHI CHA c in 8 2 6 2dL S310N HYYDVIQ OLIVA3HOS 803 2 9 318V1 Ol u3d38 1 S3LON UL 19945 anlag YEEEZ AlddAS Hu3wOd VEEP e me E IIA A AM emp SEENEN sw pt wywi AA G Y a E vm AAA ee vm iuo i UHR Eloo TT TAG W TOUINGO HOLY1N93U HIN nee ond HOL W 9 AlddfS NVd Dee ge MEL oe sa OLY O d pul ONE I t I UOP Donn Sor Lt i rie ge 110 Wasi fk E m A ud so USL gm Es soi SLE 0 0 m Su mees i zn 1 E z o LUD AST Sec Y GMO H Ome HOLYOIGNI sa NOI193108d gt E Ze I e ve sf el qu3uuno A VU HOLYTNOJH ASI emma i y 1 A Ld X N6 GD 118 Rd l A ae esa A 0189 210 T 607 voos Y i f O d Did Sg M re A 39018 i m ASE ASL ASi i i HOLVOIGNI NO 103 LOHd l m NN we HE Let GUNS ME HO LV 10038 ASL Ae 90009 8600 ATBWASSY 103NNOOU3IN AlddNS H3MOd OLY O d 60009 8 700 AT18N3SSY n m OIV1f93U 6Y O d Suone2o1 yuauodwioy Ajquiassy Jojejnbay 719 8 aunbig Ad WASS
11. Data Output Format Output format when no other talk mode has been defined D DDDDESNNCRLE SIGNED S DIGIT MANTISSA zl duc LINE FEED CARRIAGE RETURN INDICATES EXPONENT FOLLOWS EXPONENT MAGNITUDE EXPONENT SIGN Output format for Learn Mode 1 program code LP 1 Up to 128 ASCII characters EOI Output format for Learn Mode 2 program code LP2 30 bytes EOI Output format for identification program code 71 D HP438AVERx xx EOI Output format for Status Message program code SM 23 ASCII characters EOT Output format for Service Request Mask Value program code RV 1 byte EOI Return to Local Front panel key if not locked out HP 438A Operation Status Byte Rozas MET e Service RQS Bit Over Under Measurement Entry Error Cal Zero Data Ready Request Require imi Complete Condition Service Notes The condition indicated in bits 1 5 must be enabled by the Service Request Mask to cause a Service Request Condition The mask is set with the 1 program code followed by an 8 bit byte The value of the byte is determined by summing the weight of each bit to be checked The RQS bit bit 7 is true when any of the conditions of bits 1 5 are enabled and occur Bits remain set until the Status Byte is cleared Complete HP IB capability as described in IEEE Std 488 1978 and ANSI Std MC1 1 SH1 AH1 T5 TEO L4 LEO SR1 RLI PP1 DC1 Co Tabie 3 7 HP 1
12. 1 count Zero set Digital settability of zero Description After the power meter is initially zeroed the change in the digital readout is monitored as the power meter is stepped through its ranges This test also takes drift and noise into account since drift noise and zero carryover readings cannot be separated HP 438A POWER ME Equipment RODEO oes ok d x Poa ed ex bad Eu A HP 11683A POWEY SENSOR ui en oe ad duties tara HP 11730A Procedure 1 Connect the equipment as shown in Figure 4 1 2 Set the power meter controls as follows LINE Sacre a vd dude trado EEN ON SA rr PRESET 3 Set the range calibrator switches as follows EUNGTION Eos itii ae eth o a TZN STANDBY DINE oe hs II s Gene shat RPM CC OR tng ak MA PEE ON 4 Press the power meter s switch and wait approximately 15 to 17 seconds for the display to reappear and stabilize Verify that the reading is 6 4 0 06 Performance Tests Note Y HP 438A The power meter is now zeroed on range 1 most sensitive 5 Press MNL RANGE 1 ENTER 6 After the power meter reading has stabilized verify that the indication is within the limits shown Power Meter Actual Actual Mus Range Results A Results B 0 06 pW 0 06 pW 0 001 mW f 0 01 mW 0 1 mW A 7 Repeat steps 5 and 6 by entering 8 Repeat steps 2 through 7 for Channel B by pressing B in step 2 9 Repeat steps 2 through 7 for Channel A a
13. 8 10 8 11 8 12 8 13 8 14 Specifications Supplemental bar cienstios E Additional Supplemental Characteristics Ee Service Accessories Fuse Ratings and Part Numbers Allowable HP IB Addresses Major Operating Characteristics RE Message Reference Table Learn Mode 1 Output Format Response to a Clear Message and PRESET Response to a Trigger Message The Status Byte and Service Request Mask HP IB Codes to Parameter Summary Error Messages PRESET Conditions Performance Test Record Factory Selected Components Post Repair Adjustments Tests and Checks Part Numbers for Restored Assemblies Reference Designations and Abbreviations Replaceable Parts Code list of Manufacturers Etched Circuit Soldering Equipment Power Displayed for 1 mW Power alerones Test Switch Pattern Data Bus Test Pattern Extended Test Mode Error Wasare HP IB Commands in Extended Test Mode Memory Data Bus Buffer Signatures Memory Data Bus Buffer Signatures Chip Select Signatures Chip Select Signatures Chip Select Signatures Chip Select Signatures Address Bus Signatures 1 7 1 9 1 10 1 11 i 11 2 7 3 3 3 25 3 37 3 42 3 42 3 45 3 47 3 57 3 69 4 11 5 2 9 2 6 3 6 4 6 6 6 25 8 4 8 25 8 33 8 35 8 52
14. 8 84 HP 438A Example 3 While performing the Fault Isolation Procedure it is observed that segments d and e of displays A2DS1 through A2D58 come on at the same time This would indicate that the SEG4 and SEGS lines are shorted together Check the connections and traces for the SEG4 and SEGS lines If a short is not found check the logic levels at A3U40 pins 2 and 9 If pins 2 and 9 are at different logic levels replace A3U41 If pins 2 and 9 seem to be shorted they are at the same logic level go to Service Sheet 1 and perform signature analysis troubleshooting If signature analysis is normal replace A3U40 When troubleshooting is complete reset switch A351 to all ones m wn ij m dr MM et M V zz 98 8 58 8 weibeig onewayos Sinoro Aeidsig J9UEg yuos4 62 8 BND ev Ci 8 00006000 ost 2 316A MOLD AJIA dO Sl ei il B GZW fi gigOzv 3880 0681 ats a i 10s6 05bi G 6910 086 riit i 156 890 C 6i USSNDN LEYS linoBl2 QsivED3Iis GHY G LSISNYJ NGIZYNS S3C a3oN3H333E 34308 AV1dSIC E germ i a 5 i ag E l z H i P M3i JOL gsG 802v G2iO3NNOS LON 38 os D l i Sid 134208 L12N905 3G Z Nid Ni 3H TEM AVIdSED 30 gt Nid S23M9OS Nid bi Girl 3iU3 N 38 Pim 158 HIY SN J Qi 3AYH SAVIASIG 850 HODORHi 0S3 Sji u wyabyiG JI YWJKOS HW d 2 9 1IEWI Ci Ud3s3H SZLON B
15. Additional information for setting the internal switches is located in sections 2 and 8 The power meter s HP IB address can be set from the front panel as follows a Set power meter s LINE switch from OFF to ON while pressing and holding the key b Release the key 3 29 Operation 3 18 Turn on Default Conditions 3 19 Data Messages 3 30 HP 438A c Enter the desired HP IB address in decimal 0 30 and then press the key d To display the current HP IB address setting in the front panel display press and hold the key Listen Only Mode The power meter is placed in Listen Only mode when its HP IB address is set to 40 The Listen Only mode is provided to allow power meter to accept programming from devices other than controllers Talk Only Mode The power meter is placed in Talk Only mode when its HP IB address is set to 50 In this mode the instrument is configured to send data messages whenever the bus is in the data mode attention control line ATN false Several HP IB parameters are reset at turn on The parameters and their default conditions are listed below m HP IB Local Mode a Unaddressed m Service Request Mask cleared m Status Byte cleared m Free Run Trigger Mode a GT2 Trigger with Delay response to Trigger message x Parallel Poll data line unassigned m Display Enable active The power meter communicates on the interface bus primarily with Data messages Data messages consist of o
16. HP 438A Sensor A B and Sensor B A indications The middle block of annunciators on the front panel display indicate the measurement mode A B or B A and the measurement units dB or Comments Cal factor range filter limits and offset are set separately for each sensor Ratio measurements can be displayed relative to a stored reference In REL mode readings are displayed in either dB or percent Changing the measurement mode causes the contents of the digital filter to be discarded The filter buffer then starts filling up with values from the new measurement mode The power meter displays the average of the accumulated readings Ratios where the denominator is equal to zero cause Error 27 log error to be displayed Logarithmic measurement units dB cannot be used if the ratio is negative To do so would cause Error 27 log error to be displayed Related Sections CAL FACTOR dBm WATT Logarithmic Linear Units Error Messages Filters Limits OFFSET Range REL SET A and SET B STORE and RECALL 3 81 Set A and Set B HP 438A a OD OE Set A and Set B 3 82 Description SET A and SET B are used to select the channel on which measurement parameter changes are to be made Measurement parameters consist of the following Cal Adj reference calibration factor Cal Factor Filters Limits Offset Range Zero SET A and SET B allow measurement parameters to be set for one channel whi
17. Operating and Service Manual HP 438A Power Meter SERIAL NUMBERS Attached to the rear panel of the instrument is a serial number plate The serial number is in the form 0000A00000 and 0000U00000 The first four digits and the letter are the serial number prefix The last five digits are the suffix The prefix is the same for identical instruments it changes only when a configuration change is made to the instrument The suffix however is assigned sequentially and is different for each instrument This manual applies to instruments with serial numbers prefixed 3008A or 3017U and above For additional important information about serial numbers see Instruments Covered By This Manual in Chapter 1 This manual does not contain any backdating information If backdating information is required for operating or repairing your HP 438A with serial prefix 2822A or 2839U and below you must purchase manual part number 00438 90015 UJ HEWLETT PA PACKARD HP Part No 00438 86039 HEWLETT PACKARD Ltd 1997 Station Road West Lothian Scotland EH30 9TG Printed in UK NOTICE The information contained in this document is subject to change without notice HEWLETT PACKARD MAKES NO WARRANTY OF ANY KIND WITH REGARD TO THIS MANUAL INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE Hewlett Packard shall not be liable for errors contained herein or direct indirect
18. blue numbers and all blue lettering are related and set the power meter into its entry mode When a blue key is pressed the display will show that a Ent enter response is required Also some of the keys have a two letter mnemonic near them This two letter mnemonic will be used in remote programming of the power meter Simplified Operating Instructions The instructions located on the foldout provide a quick introduction to front panel operation of the power meter These instructions are designed to rapidly acquaint the new user with basic operating procedures and therefore are not an exhaustive listing of all power meter functions Detailed Operating instructions The detailed operating instructions provide the operating reference information for the power meter user 3 4 Operation 3 4 Remote Operation 3 2 HP IB 3 5 Operator s Maintenance Warning o HP 438A The power meter is capable of remote operation via the Hewlett Packard Interface Bus HP IB Instructions pertinent to HP IB operation cover considerations and instructions specific to remote operation including capabilities addressing input and output formats the status byte and service requests At the end of the discussion is a complete summary of all codes For continued protection against fire hazard replace the line fuse with a 250V fuse of the same rating only Do not use repaired fuses or short circuited fuseholders Operator s maintenanc
19. 1 H 1 1 1 1 ary v 2d D D d d 80008 96700 AT8NSSSY 193NNOOH3INI AlddfiS H3MOd otv O d TRAW 21870 L E I Banda ZH OP 096 D SEN mat E r MORE I 1 2YA 025 005 Lo SE AAA ONY 2H 99 39 KA e La ava ora de Aa Tlel ozz o2 00 EF 2 310 5 9v110A INIT LL y Lzx tuxxJ BIL 404 III A022 iie k rz 4 306 28 38i Ee bP O 096 5 ATONISSY Y3MOS 3N11 LA 310Y1803 JI AUANNI TYNOSU3G Snoikas 33940 OTAI SIOCITCA SnOUdYZYH 353Hi SY3HY 353HLl Oi ALIWIXGHd NI SNINUOM N3HM 71643HY2 ATAKAULXZ 38 C3193NNDJ SI 318Y9 U3MOd IHE UJASN3HN OSLU3NNDJ L SI 378Y9 BANGA FHL U3ASNGHKM 3 INUOR BRIT 3Hi LY LNAS3Ud SI 39Y1104 SNIYM N TNH YA 38Y1104 SAOGHYZYH H38NYU suoye3o7 yuguoduiog Ajquassy 10jejnGag gs g amb 3dIS LIf3819 NO 310N AG Nisi 512 ATBW3SSV 6V V8 v dH HP 438A Service Sheet 10 Service Sheet 10 P O Power Supply Circuits Troubleshooting Note General The following procedures will help to isolate a problem to one of the following circuits m 15 Volt Supply m 15 Volt Supply m 12 Volt Fan Supply Test Equipment OSO CODE cc ced ibas oido t tps can scelestus HP 1725A Digital Voltmeter 0o shoe od end RE RE RUE ERU Mittal HP 3456A Fault Isolation Procedure 1 Verify that the following voltages are at the points indicated SOUP CL EIS a 15 0 75 Vdc ATP ASV ca siters 15
20. 125W TF TC 0 100 RESISTOR 11K 0 1 125W TF TC 04 25 RESISTOR iK 4 196 125W TF TC 0 100 RESISTOR 100K 1 125W TF TC 0 100 RESISTOR 10K 1 125W TF TC 0 100 RESISTOR 100K 1 125W TF TC 0 100 RESISTOR 10K 1 125W TF TO 0 160 RESISTOR 11K 0 025 05W PN TC 0 10 RESISTOR 111 11 0 025 05W PN RESISTOR 100K 1 125W TF TC 0 100 RESISTOR 10K 1 125W TF TC 0 4 100 RESISTOR 10K 1 125W TF TC 04 100 RESISTOR 14 7K 1 125W TF TC 0 4 100 RESISTOR 14 7K 1 125W TF TC 0 100 RESISTOR 14 K 1 125W TF TC 0 106 RESISTOR 14 7K 1 125W TF TC 0 100 RESISTOR 23 7K 1 125W TF TC 0 100 RESISTOR 23 7K 1 125W TF TC 0 100 RESISTOR 23 7K 1 125W TF TC 0 100 RESISTOR 23 7K 1 125W TF TC 0 100 RESISTOR 237 1 125W TF TC 0 100 RESISTOR 215 4 196 125W TF TC 0 100 RESISTOR 10K 4 196 125W TF TC 0 100 RESISTOR 215 1 125W TF TC 0 100 RESISTOR 1 47K 4 196 125W TF TC 0 100 RESISTOR 68 1K 4 196 125W TF TC 0 1006 RESISTOR 100K 4 196 125W TF TC 0 100 RESISTOR 82 5K 4 196 125W TF TC 0 100 RESISTOR 196K 1 125W TF TC 0 100 RESISTOR 162K 1 125W TF TC 0 4 100 RESISTOR 9 09K 1 125W TF TC 0 4 100 RESISTOR 19 6K 1 125W TF TC 0 100 RESISTOR 38 3K 1 125W TF TC 0 100 RESISTOR 75K 1 125W TF TC 0 100 CCF 55 1 T 1 CCF 55 1 T 1 COF 55 1 T 1 CCF 55 1 T 1 CMPF 55 1 CMF 55 1 H8 CCF 55 1 T 1 PTF 56 7 CCF 55 1 T 1 H8 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T
21. 1820 2130 1820 2130 1820 2130 00438 60034 1813 0130 00438 60004 0180 2139 0180 2139 0160 4554 0160 4554 0180 2139 0180 2139 0180 2206 0180 2206 0160 0160 0160 0160 0180 0228 0180 0228 0180 0228 0180 0228 0180 0374 0180 0374 0180 0229 0160 3439 0160 3439 0160 4554 1901 0895 1901 0895 1901 0895 Q CQ rm WB W NY A cd d ne mn D 4 0 HN sa zl Bb da m P En On gt W M m to W Table 6 3 Replaceable Parts continued Description IC LCH TTL LS ADDRESSABLE 8 BIT IC LCH TTL LS ADDRESSABLE 8 BIT IC DCDR TTL LS BIN 2 TO 4 LINE DUAL IC FF CMOS D TYPE POS EDGE TRIG IC COMPARATOR GP DUAL 14 PIN DIP P IC GATE TTL LS NAND QUAD 2 INP IC INV TTL LS HEX 1 INP IC FF TTL LS J K NEG EDGE TRIG IC TRANSCEIVER TTL LS BUS OCTL IC FF TTL LS D TYPE POS EDGE TRIG COM IC DRVR TTL BUS HEX IC DRVR TTL BUS HEX 1C ENCDR TTL LS PRIORITY 8 TO 3 LINE IC SWITCH CUR QUAD 16 PIN DIP P IC SWITCH CUR QUAD 16 PIN DIP P IC SWITCH CUR QUAD 16 PIN DIP P CABLE AY MICRO CLOCK OSCILLATOR XTAL 16 0 MHZ 0 05 BD AY AMPL INPUT CAP FXD 10uF 20 60 V WT SLG TA ELCTLT CAP FXD 10uF 20 60 V WT SLG TA ELCTLT CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 10uF 20 60 V WT SLG TA ELCTLT CAP FXD 10uF 4 209 60 V WT SLG TA ELCTLT CAP FXD 60uF 10 6 V TA CAP FXD 60uF 10 6 V TA CAP FXD 8200pF 10 200 V POLYE FL CAP FXD 8200pF 10 200 V POLYE FL CAP FXD 22uF 10
22. 4 115 IN ID WASHER LK HLCL NO 4 115 IN ID WASHER LK HLCL NO 4 115 IN ID WASHER LK HLCL NO 4 115 IN ID WASHER LK HLCL NO 4 115 IN ID WASHER LK HLCL NO 4 115 IN ID HEATSINK RECT HEAT SINK COMPOUND SIL RESISTOR 147 1 125W TF TC 0 100 IC V RGLTR ADJ POS 1 2 37V TO 3 PKG IC V RGLTR ADJ POS 1 2 32V TO 3 PKG HP 438A Mfr Manufacturer Code Part Number 00438 60008 SA105C103MA AH SA105C103MA AH 150D105X9035A2 DYS SS5117 5117 R712 KFS2 M3 KFS2 M3 KFS2 M3 KFS2 M3 KFS2 M3 KFS2 M3 974 307 974 307 974 307 974 307 974 307 974 307 3 332070 5 3 332070 5 3 332070 5 3 332070 5 3 332070 5 3 332070 5 00438 20021 120 CCF 55 1 T 1 LM317K LM338K HP 438A 00438 60009 0180 0291 0160 0163 0160 0161 0180 0291 0160 0161 0160 4554 0180 0291 0160 0127 0160 3638 0160 6437 0180 0491 0180 1743 0180 0291 1901 0028 1901 0028 1901 0418 1901 0028 1901 0418 1901 0028 1901 0028 1901 0050 1901 0050 1901 0028 1901 0418 1990 0486 1990 0486 1990 0486 1990 0486 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0515 0925 0515 0925 0535 0004 0535 0004 1205 0011 1205 0353 W O o nm m O O O A Ct w Go Qi m 310 2 OQ m G to t 4Q O nm D YW M W M gt w LECT Table 6 3 Replaceable Parts continued Reference HP SIM Description Designation Part No A9 BD AY REGULATOR CAP FXD luf 1
23. 6040 0239 0698 3438 1826 0423 1826 0677 3 DO M r go gt BA HR M Ge de qe M UAA C 0 CO 60 0 VY A D W g Ci Qty D wi Feel o bei El Sech o Sei edo peo Ten je Fe bh Fei MPO Fb Fi k r Fi kl o bei o bei Fi bah Fei bel Tei m M th ki del o bei ei Fi cl bei Table 6 3 Replaceable Parts continued Description BD AY RECTIFIER CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 1uF 10 35 V TA DIODE PWR RECT 400V 750MA DO 29 DIODE PWR RECT 400V 750MA DO 29 DIODE CT RECT 200V 15A SCREW MACH M3 X 0 5 14MM LG PAN HD SCREW MACH M3 X 0 5 14MM LG PAN HD SCREW MACH M3 X 0 5 14MM LG PAN HD SCREW MACH M3 X 0 5 14MM LG PAN HD SCREW MACH M3 X 0 5 14MM LG PAN HD SCREW MACH M3 X 0 5 14MM LG PAN HD THREADED INSERT NUT M3 X 0 5 1 5 MM LG THREADED INSERT NUT M3 X 0 5 1 5 MM LG THREADED INSERT NUT M3 X 0 5 1 5 MM LG THREADED INSERT NUT M3 X 0 5 1 5 MM LG THREADED INSERT NUT M3 X 0 5 1 5 MM LG THREADED INSERT NUT M3 X 0 5 1 5 MM LG INSULATOR FLG BSHG NYLON INSULATOR FLG BSHG NYLON INSULATOR FLG BSHG NYLON INSULATOR FLG BSHG NYLON INSULATOR FLG BSHG NYLON INSULATOR FLG BSHG NYLON CONNECTOR SGL CONT SKT 04 IN BSC SZ RND CONNECTOR SGL CONT SKT 04 IN BSC SZ RND CONNECTOR SGL CONT SKT 04 IN BSO SZ RND CONNECTOR SGL CONT SKT 04 IN BSC SZ RND CONNECTOR SGL CONT SKT 04 IN BSC SZ RND CONNECTOR SGL CONT SKT 04 IN BSC SZ RND WASHER LK HLCL NO
24. A4TP10 segue EVE 15 Vdc 0 75 Vdc The 15 volt and 15 volt supplies should be within 0 05 volts of each other but of opposite polarity If the measured voltages are not as shown troubleshoot the circuits shown on Service Sheet 10 Channel A and B Verification 2 Connect the oscilloscope to A4U2 pin 10 and set the instruments as follows Power Meter PRESET Calibrator Range 100 mW Polarity Normal Function Calibrate Oscilloscope 5 volts div 1 ms div Connect the calibrator to channel and compare the waveform on the oscilloscope with the one in Figure 8 30 Set the power meter to channel B connect the calibrator to channel B and compare the waveform on the oscilloscope with waveform in Figure 8 30 If both signals are good the A4 assembly is operating properly 8 87 Service Sheets 6 8 88 Note Y 2V DIV 1 ms DIV Figure 8 30 Selected Amplifier AC Signal HP 438A If the power meter did not pass the Instrument Accuracy Performance Test and the Ranges 4 and 5 Shaper Adjustment for Channels A and B did not help to bring the instrument into tolerance the components listed below could be causing the problem Channel A Range 4 Channel A Range 5 Channel B Range 4 Channel B Range 5 A4CR1 A4CR3 A4R24 A4R26 A4VR1 A4VR2 A4R28 A4R34 A4CR2 A4CRA A4R25 A4R27 A4VR3 A4VR4 A4R29 A4R35 If only one channel is bad perform the following tests in the order given a Ampli
25. A4U1 and A4U2 A4U3 Pin 8 gt 14 Vdc If the voltage is not correct check A4R5 A4C8 A4U3 and A4U4 Pin 4 14 Vdc If the voltage is not correct check A4R6 A4C2 A4U3 and A4U4 v6 8 6 8 iugiberg ONEUESYJ SMIRI soyydury Jaduj egg amb EN O d 5o o H I o sio ni MIA 40i W in dOL Geva ker Linowis So or i p o o o ae a 80 D i MELA dOL air dOl Guvot DNH 80819 o oy o Go 9 8 3 8 3 NAI GOL Mii OL Quvos IbvvY 1in3s13 Neal Sg RK ST ent D n JUON SI gt SOND LC NG iVNSTS 3G 306303434 SKO1193NNOS UNCOYO Guy 35 1 104 l1IROHUI2 GBZYYSJAKI Kid 0090 928 B5IOi SZB iv 0 SZ28t 439WRN NO LYNG iuva 108383 SH38MA N iuw d 4In2Uuig OGJivHOlik ONY HOLS ISNYEL ESCH EON 9 A DEET 9 18948 20 4198 NY 3AYH EM GHY 2 SITBYG DNIESAO wIete N3islidHY iNdRI vere E ee a V NEES m EH HE TTT TE tee EE Wh Hh MNOS ums rernm rer De A M A POE AGE i H 3O08INCO yal M d CTO ASS 4 I5 zr i 1 ee eres n S LEN i E ME f Y T3NNYSO i eem i ETA ore Qa RATE ty n SORT 7 SNOI103NN02 qus 01140 Et CE Xt m ee Gen 19 zs nm QBvno ouvorvis Uu ls ONO SIS9 Y82 ARE 280 mun E devonvis E DEJ A i 2103019 ONGOY Y Ho WwHOOL euer zg afd geen 080
26. Amplifier Section or Power Supply Section A symbol with a check mark and a number is used to show the order of the checks This symbol is shown on the block diagram to locate the section that the trouble shooting relates to The checks start with the Power Supply Section move on to the Controller Section and then to the Amplifier Section The checks are easy to perform and provide key information In most instances the checks isolate a failure to a major assembly The comments associated with each procedure summarize the known information as a result of passing or failing the check Test Equipment Srt qp Pr HP1740A Power Sensor LOr ais TE CIR S HP 8480 series Sensor Cable breede HP 117304 Ranee AAP ALOE La cnet ede puc qiu AERA UU ades HP 11683A Digital Voltmeter DVM usa dro EE de HP 3456A 8 21 Service Sheet BD1 HP 438A Figure 8 6 Power Meter Service Position 8 22 HP 438A Service Sheet BD1 Power Supply Section Z 1 Procedure To perform the line check remove the power meters top and bottom covers Unscrew the three captive screws holding the A3 CPU Assembly and the two captive screws holding the A5 Main Amplifier Assembly Swing the hinged printed circuit boards out to the service position See Figure 8 6 showing this position After the covers are removed and the assemblies are in the service position connect the line power cable Press the LINE key to the ON position The normal indications are 1 The fa
27. CMF 55 1 05524 CMF 55 1 05524 CCF 55 1 T 1 05524 CCF 55 1 T 1 05524 CCF 55 1 T 1 CCF 55 1 T 1 HP 438A Table 6 3 Replaceable Parts continued Replaceable Parts Reference HP Fd ke Description Mfr Manufacturer Designation Part No Code Part Number 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 1826 0547 1826 1019 1826 0547 1826 1019 1826 0600 1902 3002 1902 3002 1902 3002 1902 3002 8159 0005 8159 0005 8159 0005 8159 0005 8159 0005 8159 0005 8159 0005 8159 0005 8159 0005 8159 0005 00438 60040 00438 60005 0180 0291 0180 0291 0180 0197 0160 4554 0160 6294 0160 4554 0160 0127 0160 2290 0160 3336 0160 3336 0160 3336 0180 0197 0180 0197 0180 0197 0180 0197 0 0 0 Q 0 3 6 3 6 9 3 3 3 3 0 0 0 d d O 0 0 0 0 8 00 00 00 08 m m m JM MN gt NS 00 W W On bees dM M deo Sec ss E Fei deno bi e St pok pi F bi R de d be e Re Fal Fei es bh e Fb Ph ONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT IC OP AMP LOW BIAS H IMPD DUAL 8 PIN ANALOG SWITCH 4 SPST 16 CERDIP IC OP AMP LOW BIAS H IMPD DUAL 8 PIN ANALOG SWITCH 4 SPST 16 CERDIP IC OP AMP LOW BIAS H IMPD QUAD 14 PIN DIODE ZNR 2 37V 5 DO 7 PD 4W TC 074 DIODE ZNR 2 37V 5 DO 7 PD 4W TC 074 DIODE ZNR 2 37V 5 DO 7 PD 4W
28. If the instrument is holding the SRQ bus control line true issuing the Require Service message bit position 6 in the Status Byte and the bit representing the condition causing the Require Service message to be issued will both be true The bits in the Status Byte are latched but can be cleared by removing the causing condition and then reading the Status Byte or by receiving the Clear Status CS program code The power meter responds to a PPE PPD PP1 Parallel Poll Enable PPE bus PPC PPU command by sending a bit on a controller selected HP IB data line B Abort Yes The power meter stops talking and IFC T5 TEO L3 listening LEO Complete HP IB capability as defir 2d in ANSI IEEE Standard 488 1 is SH1 AH1 T5 TEO L3 LEO SR1 RL1 PP1 DC1 DTI CO 1 Commands control lines and interface functions are defined by ANSI IEEE Standard 488 1 Knowledge of these may not be necessary if your controller s manual describes programming in terms of the twelve messages in the HP IB Message column 3 27 Operation 3 13 Remote Operation Hewlett Packard Interface Bus 3 14 HP IB Compatibility 3 28 3 15 Remote Mode HP 438A The power meter can be operated through the Hewlett Packard Interface Bus HP IB HP IB is Hewlett Packard s implementation of ANSI IEEE Standard 488 1 and the identical ANSI Standard MC1 1 Bus compatibility programming and data formats are described in the following paragraphs
29. LINE switch to ON If the power cable is not plugged in follow these instructions On the rear panel 1 Check the line voltage switch for correct voltage selection 2 Check that the fuse rating is appropriate for the line voltage used see Figure 2 1 Fuse ratings are printed on the rear panel 3 Plug in the power cable On the front panel press the LINE switch to ON Turn On Configuration The power meter turns on to the same control settings it had before line power was removed An exception to this is that it always turns on in the local mode In addition some HP IB default conditions are enabled Refer to Turn on Default Conditions later in this section When the power meter is turned on it will execute a power up sequence which will be followed by an automatic RECALL 0 The power up sequence will run some self test routines to verify the operation of ROM RAM and display circuits If any self test failures occur an error message will be reported to the user on the front panel display If for some reason RAM content was lost this error will be reported and all storage registers initialized to put the power meter into the PRESET state Storage location 0 is also set to the PRESET state when a RAM error occurs This means the power meter will be in the PRESET state when it begins operation The internal HP IB address switch is read only when the memory content is lost In all other cases the HP IB address that
30. Note i 3 12 HP IB Checks Description HP 438A 19 Observe the rng and FLt number difference because of the sensor being used Several combinations of keys can be exercised at this time to further familiarize yourself with the front panel operation These procedures check the power meter s ability to process or send the HP IB messages described in Table 3 2 Only the power meter a power sensor a controller and an HP IB interface are needed to perform these checks These procedures do not check that all the power meter program codes are being properly interpreted and executed by the instrument However if the power up sequence and front panel operation are good the program codes in all likelihood will be correctly implemented The validity of these checks is based on the following assumptions 1 The power meter performs properly when operated via the front panel keys that is in local mode This can be verified by the Basic Functional Checks in this section 2 The bus controller properly executes HP IB operations 3 The bus controller s interface properly executes the HP IB operations If the power meter appears to fail any of these HP IB checks the validity of the above assumptions should be confirmed before attempting to service the instrument The select code of the controller s HP IB interface is assumed to be 7 The address of the power meter is assumed to be 13 its address set at the factory
31. Safety Considerations Safety Considerations Warning Y This product and related documentation must be reviewed for familiarization with safety markings and instructions before operation This product is a Safety Class I instrument provided with a protective earth terminal Before Applying Power Verify that the product is set to match the available line voltage and the correct fuse is installed Safety Earth Ground An uninterruptible safety earth ground must be provided from the main power source to the product input wiring terminals power cord or supplied power cord set Any interruption of the protective grounding conductor inside or outside the instrument or disconnecting the protective earth terminal will cause a potential shock hazard that could result in personal injury Grounding one conductor of a two conductor outlet is not sufficient protection In addition verify that a common ground exists between the unit under test and this instrument prior to energizing either unit Whenever it is likely that the protection has been impaired the instrument must be made inoperative and be secured against any unintended operation if this instrument is to be energized via an autotransformer for voltage reduction make sure the common terminal is connected to neutrai that is the grounded side of the mains supply Servicing instructions are for use by service trained personnel only To avoid dangerous elec
32. The RCDR output is disabled OV during dual sensor and relative measurements This dc voltage ranges from 0 to 1 0 Vdc For each of the Power Meter s five ranges 1 0 Vdc corresponds to a full scale indication The output impedance is 1 ko some uses of the RCDR output include recording swept measurements on an X Y recorder leveling input for external ALC or monitoring output power on a strip chart recorder A setup for recording swept measurements is shown in Figure 3 7 HP 438A POWER METER SWEEP OSCILLATOR DEVICE UNDER TEST ER ee EE SWEEP DUT X Y RECORDER X AXIS FREQUENCY Y AXIS POWER Figure 3 7 Test Setup For Recording Swept Measurements Comments Cal factor and offsets have no effect on the recorder output The most stable results are obtained on ranges 3 4 and 5 Use MNL RANGE when using the RCDR output to prevent the power meter from changing ranges while outputting data Related Sections Range REL Relative Measurements SENSOR A and SENSOR B 3 73 Rel HP 438A L 02 e A Rel 3 74 Relative Measurements Description Relative mode permits any measurement result to be compared in dB or 96 to a reference value Pressing the REL key enters or exits relative mode Once relative mode has been entered the first reading is saved as a reference value Successive measurements are displayed relative to the reference valu
33. bi ei ei ri en bai bi a ka ba bi ba ba ba a b F r bi r pb ri ki rh ei Fi ba bi bd Ia ra Table 6 3 Replaceable Parts continued Description HEAT SINK SGL PLSTC PWR CS WASHER LK HLCL NO 4 115 IN ID WASHER LK HLCL NO 4 115 IN ID WASHER FL MTLC NO 4 125 IN ID WASHER FL MTLC NO 4 125 IN 1D PIN EXTRACTOR BUSHING HEAT SINK COMPOUND SIL THY RISTOR SCR VRRM z 400 THYRISTOR SCR VRRM 400 RESISTOR 1 47K 4 196 125W TF TC 0 4 100 RESISTOR 1K 1 125W TF TC 04 100 RESISTOR TRMR 1K 10 TKF SIDE ADJ 1 TRN RESISTOR 1K 4 196 125W TF TC 0 100 RESISTOR iK 1 125W TP TC 0 100 RESISTOR 619 1 125W TF TC 0 4 100 RESISTOR 68 1 4 196 125 W TF TC 0 100 RESISTOR 9 09K 1 125W TF TC 0 100 RESISTOR 422 1 125W TF TC 0 4 100 RESISTOR 422 4 196 125W TF TC 0 100 RESISTOR 4 22K 1 325W TF TC 0 4 100 RESISTOR 316 1 125W TF TC 0 4 100 RESISTOR 7 5K 1 125W TF TC 0 100 RESISTOR 7 5K 1 125W TF TC 0 100 RESISTOR 75 1 125W TF TC 0 4 100 RESISTOR TRMR 1K 10 TKF SIDE ADJ 1 TRN RESISTOR 1 47K 1 125W TF TO 0 100 RESISTOR 1 47K 4 176 125W TF TC 0 100 IC V RGLTR FXD POS 14 7 15 3V TO 220 PKG IC V RGLTR ADJ NEG 1 2 37V 3 TO 220 PKG DIODE ZNR 5 6V 5 DO 35 PD 4W TC 046 DIODE ZNR 47V 5 PD 1W IR 5UA BD AY MOTHER CAP FXD 75 10 15 V AL ELCTLT CAP FXD 2200uF 75 10 50 V AL ELCTLT CAP FXD 680uF 100 10 50 V AL ELCTLT CAP FXD 0 22uF 80 20 200 V CER X5V CAP FXD 0 1uF 10 35 V
34. ei2i 028 gie p gi 1999 r69 bi gag gePot 9492 928 5200 008 ilvG vS5BI A d L RQ TNO TSO ANY 39710A Witt S06 SUR i NYMi O3N 3UOW Si i S 3431 91901 i S199U45 HAJS ATSMISSV EY LON 3uv 2 SJ2 N HYdbviG DiiVW3H2S tds 2 9 381 30 ibv4 m rrr er A Ma MATE file as mare UT S Me A mem wom A am mur wredna aa m 356v 01 43359 8333N8 5 Nawa CI Vj VC mmm AUORSHA TOTT EY eee ey HA erre Li SEI CNA a e Lk C S cia ver Ee MEM n DAME MAM Ofi Zi RA A gaj y EEN uy nm v p l 13iV18 SOMO nyy cals cl 45 c Si g E A Ags jo ojo SE 1 ojalas ltd keck best L 0071 n D OU iNO vara 518 H 833308 3NI1 TOBLNOO seg GNY S538Q0V 2 318VN3 dlHO AVE i ew SIEM cu e Much R NR aloju r fa y Y gt Y Y I oom ru MA AA ALKN 9813939014 WB1832 D 350 mesh mel 3 imo E 9 o am sio mis wem LO MH ONY YS mu KSE EAR KEE ryj I ESI EDT od i EUN y K m 43836 i fe mm LL B3MOd 1383H RI i 3 KOdN ob 4 300036 10U1NOO We NY SSJUGGY i 1 i Lim 5281 1EYAS 8 DAYE nde BE Le ACUN T z t J 13930 Ty N 9 WI Ez i z M ripe P urb i ven E Ka aka E e 21 alk w d
35. 0 0 0 0 0 0 If a RAM failure occurs the test will flash LED s for bits DO D1 indicating a problem with A3U12 or fash LED s for bits D2 D3 when A3U13 has a problem RAM 1 A3U12 RAM 2 A3U13 How many times the test was executed and passed OOO OG O co o E 8 35 Service Sheet BD2 8 36 Note Y HP 438A Signature Analysis Check Set the switch to decimal 1 This is a check that uses programmed signatures as a method of troubleshooting Correct signatures at the peripheral interface adapter PIA for the analog input output give a high confidence factor that a major portion of the digital circuitry is working Signature Multimeter Control Settings FUNCTION WNE SIGNATURE NORM TORES EE TTE POLAD EA eege CLOCK START STOP Signature Multimeter Pod Connections Connect START ST SP green to A3TP9 STRT 2 STOP 2 STOP QUAL red to A3TP9 STRT 2 STOP 2 CLOCK yellow to A3TP6 CLK SA black to A3TP7 GND The normal indication is to have valid signatures at the analog I O input output peripheral interface adapter A3U21 Valid signatures at A3U21 the analog I O input output peripheral interface adapter Version 5 0 is used on 00438 60103 boards which require a single EPROM 00438 80036 Version 2 0 is used on 00438 60003 boards which require 2 EPROM s 00438 80037 and 00438 80038 In order to use the following signatures to repair your A3 board you must have one of the preceed
36. 0 volts If pin 2 is incorrect check for an open trace to TP4 or verify that TP4 is grounded If pin 2 is 0 volts replace U28 2 Verify lines D0 D7 at U19 are as shown in Table 8 18 Table 8 18 Data Line Logic Levels TTL Logic U19 Pin 31 30 29 28 21 26 25 24 Co pm CO B B RA E d If there is activity on the data lines verify that Ul pin 19 is a TTL high If pin 19 is correct replace U1 If pin 19 is incorrect replace U37 If there is no activity on the data lines and the logic levels are incorrect verify that the Service Function Switch A351 is set to the proper position When set to the proper position U3 pins 4 6 8 and 11 are TTL highs If pins 4 6 8 and 11 are incorrect set the switch to all Is or replace the switch If pins 4 6 8 and 11 are correct replace U3 3 Verify that U19 pins 2 4 and 40 are TTL highs If pins 2 4 and 40 are not TTL highs replace R9 4 Verify there is a 2 MHz clock signal at TP6 If TP6 does not have a 2 MHz clock check for an 8 MHz clock at U19 pin 38 If the 8 MHz clock is present replace R16 or U19 If the 8 MHz signal is not present check the Clock circuit 8 61 Service Sheets 1 4 8 62 Note E HP 438A 5 Verify that U19 pin 3 isa TTL high If pin 3 is not a TTL high or there is a signal present verify there is a TTL low at U38 pin 13 If U38 pin 13 is correct temporarily ground U38 pin 10 and verify that U38 pi
37. 0544 1820 1199 1820 1997 1820 1216 1820 1997 1826 0574 1820 2024 1826 1021 1826 1019 1826 1019 1826 1019 1826 0600 1826 0600 1826 1019 1826 1460 1826 1460 1826 0471 1902 0680 1902 0947 1902 0680 00438 60035 0 0 0 0 0 0 0 0 0 0 1 2 7 7 2 7 9 3 2 2 7 d i 7 3 T 6 3 0 6 6 6 9 9 6 1 1 2 7 9 H 1 CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT IC OP AMP GP 8 PIN DIP P IC OP AMP LOW DRIFT 8 PIN TO 99 D A 10 BIT 16 CBRZ CMOS IC FF TTL LS D TYPE POS EDGE TRIG PRL IN D A 8 BIT 16 CERDIP BPLR IC FF TTL LS D TYPE POS EDGE TRIG PRL IN IC COMPARATOR PRCN 8 PIN TO 99 IC COMPARATOR PRCN 8 PIN TO 99 IC OP AMP LOW DRIFT 8 PIN TO 99 D A 8 BIT 16 CERDIP BPLR IC FF TTL LS D TYPE POS EDGE TRIG PRL IN IC V RGLTR V REF FXD 2 5V 8 DIP C PKG IC INV TTL LS HEX 1 INP IC FF TTL LS D TYPE POS EDGE TRIG PRL IN IC DCDR TTL LS BIN 3 TO 8 LINE 3 INP IC FF TTL LS D TYPE POS EDGE TRIG PRL IN IC OP AMP LOW DRIFT 8 PIN TO 99 IC DRVR TTL LS BUS OCTL ANALOG MULTIPLEXER CHNL 16 DIP P ANALOG SWITCH 4 SPST 16 CERDIP ANALOG SWITCH 4 SPST 16 CERDIP ANALOG SWITCH 4 SPST 16 CERDIP IC OP AMP LOW BIAS H IMPD QUAD 14 PIN IC OP AMP LOW B
38. 1 CCF 55 1 T 1 CCF 55 1 T 1 140 140 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 OCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 1 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 6 17 Replaceable Parts Table 6 3 Replaceable Parts continued HP 438A Reference HP m Description Mir Manufacturer Designation Part No Code Part Number A5R50 A5R51 A5R52 A5R53 A5R54 A5R55 A5R56 A5R57 A5R58 A5R59 ASR60 ASR61 A5R62 A5R63 A5R64 A5R65 ASR66 A5R67 A5R68 A5R69 A5R70 A5R71 A5R72 A5R73 A5R74 A5R75 A5R76 ASR77 A5R79 A5R80 A5R8l A5R82 A5R83 A5R84 ASTP1 ASTP2 ASTA A5TP4 ASTPS ASTP6 ASTI ASTPS8 ASTP9 6 18 0757 0444 0698 3162 0757 0280 0811 3350 0811 3349 0811 3348 0698 3455 0757 0274 0757 0442 0698 6360 0757 0199 2100 3109 0757 0440 0757 0123 0699 0148 0699 1172 0698 3160 0698 3136 0698 3450 0757 0278 0757 0280 0699 0148 0698 3156 0757 0465 0698 3449 0757 0465 0751 0441 0698 3150 0757 0419 0757 0280 0757 0465 0757 0280 0757 0442 0698 3156 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 O M vn gt M O 2 cO e O W W W W W
39. 2N2907A A3Q6 1853 0281 9 1 TRANSISTOR PNP 2N2907A SI TO 18 PD 400MW 2N2907A A3Q7 1853 0281 9 1 TRANSISTOR PNP 2N2907A SI TO 18 PD 400MW 37 2N2907A A3Q8 1853 0281 9 1 TRANSISTOR PNP 2N2907A SI TO 18 PD 400MW 2N2907A A3Q9 1853 0281 i9 1 TRANSISTOR PNP 2N2907A SI TO 18 PD 400MW 2N2907A A3Q10 1853 0281 9 1 TRANSISTOR PNP 2N2907A SI TO 18 PD 400MW 2N2907A A3Q11 1853 0281 9 1 TRANSISTOR PNP 2N2907A SI TO 18 PD 400MW 2N2907A A3Q12 1853 0281 9 1 TRANSISTOR PNP 2N2907A SI TO 18 PD 400MW 2N2907A A3Q13 1853 0281 9 1 TRANSISTOR PNP 2N2907A SI TO 18 PD 400MW 2N2907A A3Q14 1853 0281 9 1 TRANSISTOR PNP 2N2907A SI TO 18 PD 400MW 2N2907A A3Q15 1853 0281 9 1 TRANSISTOR PNP 2N2907A SI TO 18 PD 400MW 2N2907A A3Q16 1853 0281 9 1 TRANSISTOR PNP 2N2907A SI TO 18 PD 400MW 2N2907A A3Q17 1853 0281 9 1 TRANSISTOR PNP 2N2907A SI TO 18 PD 400MW 2N2907A A3Q18 1853 0281 9 1 TRANSISTOR PNP 2N2907A SI TO 18 PD 400MW 2N2907A A3Q19 1853 0281 9 1 TRANSISTOR PNP 2N2907A SI TO 18 PD 400MW y 2N2907A A3Q20 1854 0477 7 1 TRANSISTOR NPN 2N2222A SI TO 18 PD 500MW 2N2222A A3R1 1810 0280 8 1 NETWORK RES 10 SIP 10 0K OHM X 9 MSP10A01 A3R2 1810 0280 8 1 NETWORK RES 10 SIP 10 0K OHM X 9 MSP10A01 A3R3 0698 7283 4 1 RESISTOR 90 9K 1 05W TF TC 0 100 5 CMP 50 2 A3R4 0698 7268 5 1 RESISTOR 21 5K 1 05W TF TC 04 100 CMF 50 2 A3R5 0698 7268 5 1 RESISTOR 21 5K 1 05W TF TC 0 100 CMF 50 2 A3R6 0698 7212 9 1 RESI
40. 3 19 mW 10 mW 9 90 mW 10 10 mW 30 mW 31 3 mW 31 9 mW 100 mW 99 0 mW 101 0 mW dBm Mode 20 dBm 19 96 dBm 20 04 dBm 10 dBm 9 96 dBm 10 04 dBm Rel Mode 0 01 dBm 0 01 dBm Power Reference Prf 0 981 mW 1 019 mW Adjustments 5 1 Introduction 5 2 Safety Considerations Warning o 5 3 Equipment Required 5 4 Factory Selected Components This section contains adjustments and checks that ensure proper performance of the power meter Adjustments are not required on any fixed periodic basis and normally are performed only after a performance test has indicated that some parameters are out of specification Performance tests should be completed after any repairs that may have altered the characteristics of the instrument The test results will make it possible to determine whether or not adjustments are required Allow 60 minutes for the power meter to warm up and then remove the top and bottom covers also loosen the screws holding the A3 CPU Assembly and A5 Main Amplifier Assembly for access to the test and adjustment points To determine which performance tests and adjustments to perform after a repair refer to paragraph 5 6 Post Repair Adjustments This section contains a warning that must be followed for your protection and to avoid damage to the equipment being used Adjustments described in this section are performed with power applied to the instrument and with protective covers removed Maintenanc
41. 3994 2 Rack Mounting Flange Kit HP part number 5062 3974 When rack mounting with a support shelf and slide kit order 1 Shelf HP part number 5062 3996 2 Slide Kit HP part number 1494 0064 In addition to the rack mounting hardware a front handle assembly two provided is also available for the power meter Order front handie kit Option 907 HP part number 5061 9688 Rack mounting information is provided with the rack mounting kits If a kit was not ordered as an option or an accessory with the power meter it may be purchased through the nearest Hewlett Packard office Refer to Mechanical Options or Mechanical Equipment Available in section 1 2 15 Environment The instrument should be stored in a clean dry environment The foliowing environmental limitations apply to both storage and shipment Temperature 2c PE QE E ER Acad etd d aa at rte gps 55 to 75 C Hamidi Le ee een lt 95 relative ALADO aa lt 15 300 metres 50 000 feet HP 438A Installation 2 16 Packaging Tagging for Service If the instrument is being returned to Hewlett Packard for service please complete one of the blue repair tags located at the end of this manual and attach it to the instrument To minimize repair time be as specific as possible when describing the failure Keep the following two items in mind when describing the failure i Describe what makes you think the instrument is failing An example might be Power meter
42. 4 Factory Selected Parts 6 5 Parts List Backdating 1 6 6 Parts List Updating Change Sheet 6 7 Illustrated Parts Breakdown 6 8 Ordering information Y Note 6 2 HP 438A Parts marked with an asterisk are factory selected parts The value listed in the parts list is the nominal value Refer to sections 5 and 6 of this manual for information on determining what value to use for replacement Parts marked with a dagger 1 are different in power meters with serial number prefixes lower than the one that this manual applies to directly Production changes to power meters made after the publication date of this manual are accompanied by a change in the serial number prefix Changes to the parts list are recorded by serial number prefix on a MANUAL CHANGES supplement Also parts list errors are noted in the ERRATA portion of the MANUAL CHANGES supplement Most mechanical parts are identified in Figure 6 1 through Figure 6 3 These figures are located at the end of the replaceable parts table To order a part listed in the replaceable parts table include the Hewlett Packard part number with the check digit and the quantity required Address the order to the nearest Hewlett Packard office The check digit will ensure accurate and timely processing of your order To order a part that is not listed in the replaceable parts table include the instrument model number instrument serial number description and
43. 8 9 3 4 5 6 7 8 9 In auto filter mode the average of the last four values entered into the filter is compared to the average of the entire filter If the difference between the two averages is greater than 12 5 the contents of the digital filter are set to zero The filter then starts storing new measurement values and power meter displays the average of accumulated power readings This feature shortens the settling time of the power meter when the input power changes substantially Only one digit is allowed for MNL FILTER data entries If a second digit is entered it replaces the one that is already there The O decimal point and keys are ignored PRESET sets both sensor A and sensor B to auto filter mode Related Sections PRESET Range SET A and SET B STORE and RECALL 3 63 Limits Limits 3 64 HP 438A Description The limits checking function allows the power meter to monitor the power level on each sensor and to indicate when that power is outside preset limits High and low limits can be set and the limits checking function is enabled only via remote programming Limit values are entered in dBm and need not be the same for each sensor Allowable values range from 299 999 to 299 999 dBm Values entered outside this range cause the limit to be set to the minimum or maximum value as appropriate When the limits checking function is enabled the power meter uses the last high and low limit
44. 9 NEAR TERMINATION P O TWISTED PAIR WITH 8 OF OTHER WIRE OF TWISTED PAIR P O TWISTED PAIR WITH 7 P O TWISTED PAIR WITH amp SHIELD CONNECT ATN TO EARTH SRO GROUND IFC NDAC NRFD DAV EO D104 D103 DIO2 DIOL ISO METRIC THREAD M3 5 x 6 CRO RIBBON 73 CONNECTOR o Gir Logic Levels The Hewlett Packard Interface Bus Logic Levels are TTL compatible i e the true 1 state is 0 0 Vdc to 0 4 Vdc and the false 0 state is 2 5 Vdc to 5 0 Vdc Mating Connector HP 1251 0293 Amphenol 57 30240 Mating Cables Available HP 10833A 1 metre 3 3 ft HP 10833B 2 metres 6 6 ft HP 10833C 4 metres 13 2 ft HP 10833D 0 5 metre 1 6 ft Cabling Restrictions 1 A Hewlett Packard Interface Bus system may contain no more than 2 metres 6 6 ft of connecting cable per instrument 2 The maximum accumulative length of connecting cable for any Hewlett Packard Interface Bus system is 20 0 metres 65 6 ft Figure 2 3 Hewlett Packard Interface Bus Connection Installation 2 10 2 14 Storage and Shipment HP 438A 2 13 Rack Mounting The power meter may be rack mounted using Hewlett Packard sub module cabinets If it is desired to rack mount one power meter by itself order half module kit HP part number 5062 3972 If it is desired to rack mount two power meters or another HP product with the same physical dimensions side by side order the following items 1 Lock Link Kit HP part number 5062
45. A1MP10 5041 2849 5041 2849 AIMP11 5041 2848 5041 2848 A1MP12 5041 2886 5041 2886 AIMP13 5041 2838 5041 2838 AIMP14 5041 0309 5041 0309 A1MP15 5041 2846 5041 2846 AIMP16 5041 2852 5041 2852 A1MP17 5041 2847 5041 2847 A1MP18 5041 2853 5041 2853 AL1MP19 5041 2845 5041 2845 A1MP20 5041 2855 5041 2855 A1MP21 5041 2843 5041 2843 A1S1 5060 9436 5580 9436 A182 5060 9436 5560 9436 A1S3 5060 9436 5560 9436 A184 5060 9436 5560 9436 A155 5060 9436 5560 9436 A186 5060 9436 5560 9436 A1S7 5060 9436 5560 9436 A1S8 5060 9436 5560 9436 A1S9 5060 9436 5560 9436 A1S10 5060 9436 5560 9436 A1S11 5060 9436 5560 9436 A1512 5060 9436 5560 9436 A1813 5060 9436 5560 9436 A1S14 5060 9436 5560 9436 A1515 5060 9436 5560 9436 A1S16 5060 9436 5560 9436 A1S17 5060 9436 5560 9436 Table 6 3 Replaceable Parts Description Mfr Code BD AY KEY 28480 SOCKET IC DIP 16 CONT DIP SLDR KEY A KEY B KEY B A KEY 1 4 BLANK KEY ZERO KEY CAL ADJ KEY FACTOR KEY OFFSET MNL KEY STORE KEY REL KEY DBM WATT KEY LCL KEY SHIFT KEY 1 4 BLANK KEY AUTO RANGE KEY RANGE KEY FILTER KEY MNL FILTER KEY RECALL KEY PRE SET KEY OSC SWITCH PB SPST NO MOM SWITCH PB SPST NO MOM SWITCH PB SPST NO MOM SWITCH PB SPST NO MOM SWITCH PB SPST NO MOM SWITCH PB SPST NO MOM SWITCH PB SPST NO MOM SWITCH PB SPST NO MOM SWITCH PB SPST NO MOM SWITCH PB SPST NO MOM SWITCH PB SPST NO MOM SWITCH PB SPST NO MOM SWITCH PB SPST NO MOM SWITCH PB SPST NO MOM SWITCH PB SPST NO MOM SWITCH
46. All front panel functions are programmable via HP IB except setting the LINE switch and activating the key The key is not programmable because the shifted functions have their own program codes Additional functions are available in remote operation only A quick test of the power meter s HP IB interface is described in this section under HP IB Functional Checks These checks verify that the power meter can respond to or send each of the applicable bus messages described in Table 3 2 For more information about HP IB refer to ANSI IEEE Standard 488 1 or the identical ANSI Standard MC1 1 the Hewlett Packard Electronic Systems and Instruments catalog and the booklet Improving Measurements in Engineering and Manufacturing HP part number 5952 0058 The power meter s complete bus compatibility as defined by IEEE Standard 488 and the identical ANSI Standard MC1 1 is described at the end of Table 3 2 Table 3 2 also summarizes the power meter s HP IB capabilities in terms of the twelve messages in the HP IB Message column Remote Capability The power meter communicates on the bus in both remote and local modes In remote most of the power meter s front panel keys are disabled exceptions are the LINE switch and the key Front panel displays however remain active and valid In remote the power meter can be addressed to talk or listen When addressed to listen the power meter responds to the Data Trigger Clear SDC Remote and Lo
47. Aug 9 2 ay sDuipee 19mod au Jo 01721 3U AejdSip 0 pueuluioo eui Sazet pue epow 40sues a qnop Sy 0 1919W 49 00 ay 198 ejdsip ortuuaeo 10 Jea uij e Bulluem Jasn aut uo Buipuadap syun jugweinseal au sa 560 puewuwoo siu U31N3 Y LLYM wep SA iN SIS RSR GZ 8 4 v a 1 329 be Nam d LN SE S geg A ABB epow J9mod a Re g iguueuo Ae dsip y ur ja aw ay ind 01 RASOWY 2 0 E Ed f pueuluoo aui sejeriur pue 8UUEUJ JAIE H313NN HRMOd Vett 732 E iosuas abuis y se g Jauueyo sj29 9g v a a peinseaui Si BAI J8MOd 19410 SULOS 0 BAI EIAs SIA 19 M0d pue pojqeua SI apo aAijeies Jal aul S30 dS 13H Slu8tu819U1 qp L00 ut GP 66 66H 0166 66 S S12S410 10 oDue ou P9 99 9S auueyo 91 10 JaS JO UP 19 U9 ULI Jasn au pue spow Anua jasyo au s19 u3 92u919 9J 19M0d MU dU 01 paje1q eo Huieg 01 10110 pesajua aq ULI 10198 uOIl eiquea 390319431 e pue 9poui uoneJgie2 ey sig ua Jaja Jamod aut epoul Jemod y jeuueuo ejdsip y ui laqatu 84 1nd 0 pueuiuloo BUJ sajeliiui pue J3UUBUD 3AIJIL iosues ajfuls au se y jauueyo s 9a 89 uogjeutu 0 suo jo oDue1 34 Ul uone201 Jalsi a s BJ03S e 191U9 ULI 198N 94 pue 9AInoe sauooeq epow Aqua 2149uinu 9181s JUSUINISU 910js 8U S19 u3 v 38018 te 138440 1 rav wa 8 1 v UO BUIQUIOO 10SU8S 18 8W sofueuo JajaweJed 101 Jamod ay SO19Z jey eunno e sajeniul pot g Ja ua ay OL 19 9LU Jamod 8U 19S
48. Cause the system to accept the next number sent and use it as the variable gain amp setting for channel B Valid range of numbers are 0 15 l To set the Zero DAC to the value 152 using BASIC type DUTPUT 713 ZDA152EN Do not include any spaces in the command string 2 Version 5 0 is used on 00438 60103 boards which require a single EPROM 00438 80036 Version 2 0 is used on 00438 60003 boards which require 2 EPROM s 00438 80037 and 00438 80038 In order to use the following signatures to repair your A3 board you must have one of the preceeding versions of EPROM 8 53 Service Sheets 1 4 8 54 Note Y HP 438A Signature Analysis Mode Checks In most cases the Signature Analysis procedures will isolate a problem to the component level Next to each check in parentheses is the component being checked and the Service Sheet where the component is located The procedures must be done in the order shown All checks up to and including Miscellaneous Checks must be done Test Equipment Signature Analyzer ANE dE EXTA FR EXT eRe een us HP 5005B o pop vue Pa Exam RE d ebd Ede qa dba tdt d Stes HP 1725A Free Run Signature Analysis General Free Run Signature Analysis is to be used to verify operation of the following w Data Bus a Address Decoding Address Bus w The contents and operation of ROM The signatures represent firmware for ROM s with HP part number 00438 80036 A3U9 version 5 0 or wit
49. Check that the SRQ annunciator is on and that the response to the parallel poll is 4 indicating that the power meter issued the Status Bit message Description Series 200 300 BASIC Unconfigure the power meter from responding to a SEND 7 LISTEN parallel poll 13 CMD 5 SCG 18 Place the power meter in parallel POLL MODE PPOLL 7 Check that the SRQ annunciator is on and that the response to the parallel poll is 0 indicating that the power meter is no longer configured to respond to a parallel poll To turn the SRQ annuciator off set the LINE switch to OFF then to ON 3 23 Operation 3 24 Trigger Message HP 438A This check determines whether or not the power meter responds to a lrigger message This check assumes that the power meter is in remote mode Description Series 200 300 BASIC Send a Data message to place the 10 OUTPUT 713 TRO Power Meter in the Trigger Hold mode Send the Trigger message 20 TRIGGER 713 30 V 10 40 ENTER 713 V Address the power meter to talk and store the data in variable V Display the value of V Check that the power meter s RMT and TLK annunciators are on and that the controller displays the same value as the one shown in the power meter s display Note that the power meter displays data using engineering notation The controller may display the same value using a different format HP 438A Operation All p
50. FXD 0 33uF 5 50 V POLYC MET CAP FXD 0 01uF 10 200 V POLYE FL CAP FXD 0 1uF 10 200 V POLYE FL CAP FXD 3300pF 10 200 V POLYE FL CAP FXD 0 18uF 10 80 V POLYE FL CAP FXD Q 1uF 4 196 100 V POLYP FL CAP FXD 30pF 5 300 V MICA DIODE SWITCHING 80V 200MA 2NS DO 35 CONN POST TYPE 100 PIN SPCG 2 CONT CONN POST TYPE 100 PIN SPCG 20 CONT CONN POST TYPE 100 PIN SPCG 26 CONT CONNECTOR RF SMB M PC 50 OHM INDUCTOR RF CH MLD 100UH 5 RIVET SEMITUB OVH 123D A 188LG HINGE RIVETED TRANSISTOR PNP SI PD 625MW FT 200MHZ TRANSISTOR PNP SI PD 625MW FT 200MHZ TRANSISTOR J FET 2N4391 N CHAN D MODE TRANSISTOR PNP SI PD 625MW FT 200MHZ TRANSISTOR NPN SE PD G25MW FT 200MHZ TRANSISTOR PNP Si PD 625MW FT 200MHZ TRANSISTOR NPN SI PD 625MW FT 200MHZ TRANSISTOR J FET 2N4393 N CHAN D MODE TRANSISTOR PNP 2N2905A SI TO 39 PD 600MW NETWORK RES 10 SIP 10 0 OHM X 9 RESISTOR 3 16K 1 125W TF TC 0 100 NETWORK RES 10 STP 10 0K OHM X 9 RESISTOR 6 19K 0 1 125W TF TC 04 25 RESISTOR 316 1 125W TF TC 0 100 RESISTOR 1 21K 1 125W TF TC 0 100 HP 438A Mfr Manufacturer Code Part Number CD15ED300J03 CD1I5ED300303 HEW 249 HEW 249 HEW 249 HEW 249 150D684X9035A2 DYS 150D684X9035A2 DYS SA305C104M A AH HEW 249 HEW 249 HEW 249 HEW238T HEW 249 HE W238T HEW 238T HEW238T HEW 238T HE W860 CD15ED300JO3 65806 077 3592 6002 3593 6002 5164
51. GNYB ZH 022 See OOE Che e EIA NL ONY e RECH SBLON Wat eM d 39Y1S NIVO DY HOLVYANSLLY ZONYH H04 2 8 338Yi OL Yisde m me m A A mt WON HA WH S3 OR EEN M A A A M uA 8 190945 anlag 80508 82700 ATBWZSSY dial lay NTYW SV 078 suoneso7 yuauodwo0y Ajquassy sayydury ulew Sv O d 25 8 ania ATANISSV SV V8 t dH HP 438A Service Sheet 9 Service Sheet 9 P O Power Supply Circuits Troubleshooting General The following procedures will help to isolate a a problem to one of the following circuits a 5 Volt Digital Supply m 5 volt Display Supply a Transformer F1 a Line Power Assembly U1 Test Equipment RE HP 1725A Digital Voltmeter nay oso vA aN een oes us ema a EARS ES HP 3456A Fault Isolation Procedure 1 Verify that the following voltages are at the points indicated A9TPA 5V Digital 5 0 05 Vde A9TP3 5V Display See Figure 8 55 If both both supplies are incorrect check to see if both the plus and minus 15 volt supply indicators are illuminated If they are not illuminated perform the Total Power Failure Test If there is a problem with the 5 Volt Digital Supply perform the 4 5 Volt Digital Supply Test If there is a problem with the 4 5 Volt Display Supply perform the 5 Volt Display Supply Test 5 Volt Di
52. HP IB codes normally used by the operator to control the power meter are given in Table 3 6 HP IB Code to Parameter Summary All front panel keys except and have corresponding program codes Lower case alpha characters are interchangeable with upper case characters The number 0 and the letter O are not interchangeable Numeric data can be entered in fixed floating point or exponential format All measurement parameter entries must be terminated with the program code EN This is equivalent to pressing the key in local mode All frequency entries must be terminated with HZ KZ MZ or GZ For DUTY CYCLE DY CAL FAC KB and CAL CL the percent sign 76 can be used in place of EN Turning Off Functions When operating in local mode OSC reference oscillator and REL relative mode toggle on and off with successive keystrokes In remote mode these functions do not toggle on and off Instead a specific program code is required to turn off each function Use RLO to turn off REL mode and OCO to turn off the reference oscillator Hold Range When the power meter is addressed to listen and receives program code RH Range Hold it switches from auto range to manual range using the current auto range value If the power meter is already in manual range mode no action is taken No range number is entered with this program code 3 31 Operation 3 32 HP 438A Hold Filter When the power meter is addressed to lis
53. Manufacturer Designation Part No Code Part Number 1901 0895 1252 3487 1252 3489 1252 3488 1252 3488 1252 3487 1250 1255 1252 3487 1252 3488 1252 3488 1251 8248 1252 3487 1251 0600 1251 0600 1251 0600 1251 0600 9100 3922 9100 3922 9100 2247 9100 3922 9100 3922 1854 0810 1854 0810 1854 0810 1853 0459 1853 0459 0811 1557 0757 0346 0757 0346 0698 3447 0757 0346 0757 0346 0698 3447 0698 3450 0698 3450 0757 0465 0757 0465 0698 3156 0698 3156 6757 0459 0757 0459 0698 3159 0698 3159 en Qo tO tO C O m AA HM o cO tO U W L BMW dO o Wb A a A O OC O O O mp m D DIODE SCHOTTKY SM SIG QSCH1186 CONN POST TYPE 100 PIN SPCG 5 CON T 87499 104 CONN POST TYPE 100 PIN SPCG 3 CONT 87499 102 CONN POST TYPE 100 PIN SPCG 4 CONT 87499 103 CONN POST TYPE 100 PIN SPCG 4 CONT 87499 103 CONN POS T TYPE 100 PIN SPCG 5 CONT 87499 104 CONNECTOR RF SMB M PC 50 OHM 51 051 0000 CONN POST TYPE 100 PIN SPCG 5 CONT 87499 104 CONN POST TYPE 100 PIN SPCG 4 CONT 87499 103 CONN POST TYPE 100 PIN SPCG 4 CON T 87499 103 CONN POST TYPE 100 PIN SPCG 26 CONT 3593 6002 CONN POST TYPE 100 PIN SPCG 5 CONT 87499 104 CONNECTOR SGL CONT PIN 1 14 MM BSC SZ SQ 16 06 0034 CONNECTOR SGL CONT PIN 1 14 MM BSC SZ SQ 16 06 0034 CONNECTOR SGL CONT PIN 1 14 MM BSC SZ SQ 16 06 0034 CONNECTOR SGL CONT PIN 1 14 MM BSC SZ SQ 16 06 0034 INDUCTOR FIXED Z 1200 OHMS 120 TO 650 14067 INDUCTOR FIXED Z gt 1200 OHMS 120 T
54. No 135 8690 0167 Tip Temp 390 440 C Ungar Division 735 825 F Eldon Ind Corp Compton CA 90220 Ungar PL113 8690 0007 A Lu Soldapullt by Edsyn Co 8690 0060 Van Nuys CA 91406 Soldering Tool Soldering Heat Staking Soldering Tip Soldering Unsoldering Soldering Tip Heat Staking Shape Chisel HP 5020 8160 or modified Ungar PL11 De Solder Aid To remove Suction Device molten solder from connection Must not dissolve etched Freon 8500 0232 circuit base board Rosin flux Solvent To remove excess flux from soldered area before application of protectiove coating 8090 0607 Component Rosin flux core high tin replacement content 63 37 tin lead 18 Circuit board guage AWG 0 040 in repair wiring diameter preferred 1 For working on circuit boards for general purpose work use No 555 Handle 8690 0261 and No 4037 Heating Unit 473 563 W HP 8690 0006 tip temperature of 850 900 F and Ungar No PL113 i chisel tip 8 4 HP 438A 8 16 Troubleshooting 8 18 After Service Safety Checks Service 8 17 Service Related Error Messages The power meter generates error messages to indicate operating problems incorrect keyboard entries or service related problems The error message is generally cleared when the error condition is removed Refer to Service Sheet 2
55. ON ON ON iter ARTE NT DH ES A A E 3 UO 9 zn cote 47 0286 HAH word uS NYOS OUYOSADN uy Gs see TSG 136 Gi 59 zd p wo 5 457 KGR PE EE d ER 340930 i i A j Nos H 3 3 J 1 G ml AY 3dSIC Mew HOLY AVIJSIO VIVO 318Yv553U0Q0vV m EA WR M ELA d bdo e TU S UR 7 rsa i H A oe ge e j uoip e 30d LISO St el ugly ra A HEI 780 Ss3uQav ONY Kg X 83440 _ VIVO JJONY Jg E oy CAN GAN 9 14 EE 161 06 are OF AR wed 2 2 gt 6 NE CR A rhein bre AGS JHL NO Eau 7 sde WCO 11 SEY tO RDDOSHI O29 J3YD ZLEG 3179 1180 3140 0180 31D74158 E1 H 2 7 Zomme ig LLY BE Z 1 f ZAW v NYOS GHYO AJ ONY w AVIG IQ VIVO JGOHLYO vid O i 9O1VNV Lindl ORISSJOCHR lYUl1N32 Die VBE 37 8300030 yy S838GGVv 0 1 0109 8t000 LIN 9NISS3OOHd IVHINGO EY O d iSYM H suone20 juauodwog Ajquiassy yun Durssa2oJd eUII O d vz 8 enbi4 REA ZER ZSR VAST pope ASH m n ANS 35 XA d 4 4 0 j T rad ji ZAB RY BA NZD ATBWaSSV V V8 V dH 08 8 6 8 urejBejq oneueuas sino WAG Aejdsiq 12 8 Sandia Y 1 O d 9g 2 9 S E 2 i Gl 28 f amp GL El 6 St 91 i gi 8 9H2tY x 850 Ot B DS
56. P O A5 Main Amplifier Assembly Component Locations V1 9 ww Se oux de e W RC cae xpo d P O Main Amplifier Circuits Schematic Diagram 5 Volt Display Supply Waveform 8 45 8 48 8 48 8 49 8 51 8 72 8 73 8 73 8 75 8 75 8 77 8 77 8 79 8 77 8 85 8 85 8 88 8 90 8 93 8 93 8 98 8 100 8 100 8 101 8 103 8 103 8 106 8 106 8 107 8 107 8 108 8 110 8 110 8 112 8 112 8 114 8 115 8 117 8 119 8 119 8 122 xi Contents l HP 438A 8 55 5 Volt Display Clock 2 aa eee 8 123 8 56 Rectifier Assembly Component Locations 8 124 8 57 P O Interconnect Assembly Component Locations 8 125 8 58 Regulator Assembly Component Locations 8 127 8 59 P O Power Supply Circuits Schematic Diagram 8 127 8 60 P O Interconnect Assembly Component Locations 8 132 8 61 Regulator Assembly Component Locations 8 133 8 62 P O Power Supply Circuits Schematic Diagram 8 133 8 63 Internal Top View ooo Ux Eee IE 8 136 8 64 Internal Bottom View ces 8 137 8 65 Power Reference Oscillator Assembly Component Test Point and Adjustment Locations 8 139 8 66 Power Reference Oscillator Schematic Diagram 8 139 xii Tables 1 1 1 2 1 3 Recommended Test Equipment 1 5 2 1 2 2 3 1 3 2 3 3 3 4 3 5 3 6 3 7 3 8 3 9 4 5 1 9 2 6 1 6 2 6 3 6 4 8 1 Schematic Diagram Notes 8 3 8 4 8 5 8 6 8 T 8 8 8 9
57. PB SPST NO MOM SWITCH PB SPST NO MOM O W m h NW gt M a w GG 0 so 2 A c3 A cd M coo EE cd coc co d NOW uo W 6 6 HP 438A Table 6 3 Replaceable Parts continued Replaceable Parts Reference HP 7 Deseription Mfr Manufacturer Designation Part No Code Part Number A1S18 A1519 A1520 A1821 ATW4 A 5060 9436 5060 9436 5060 9436 5060 9436 00438 60033 00438 60002 1990 1076 1990 0587 1990 0587 1990 0665 1252 0242 0380 0059 00438 80006 00438 60031 1200 1617 1200 1617 1200 1617 1200 1617 1200 1617 1200 1617 1200 1617 1200 1617 1200 1616 1200 1616 1200 1616 1200 1617 1200 1617 1200 1616 1200 1616 00438 60103 1420 0314 0180 2815 0180 2620 0160 4554 0160 4554 0180 1745 0160 4554 0160 4554 0160 4554 0160 0574 0180 2617 Z o o 0 0 G a X M pa e FF M da 3 om KY Pd W ka WDNR NN OD a b o pad kat Set e o o o pd ek ri Re pb Re tab A RA pa ek M a M M ra M MH e de eM je bb had red rd Feb m Fi SWITCH PB SPST NO MOM SWITCH PB SPST NO MOM SWITCH PB SPST NO MOM SWITCH PB SPST NO MOM CABLE AY KEY BD BD AY
58. POWER REF Display will show a power level HP 438A POWER METER SOOO OA a b en QUO Oo mum POWER SENSOR Figure 3 3 Front Panel Checks Setup 1 6 Press ZERO Wait approximately 15 seconds for the zeroing routine to finish Verify that display shows With a walking decimal point Observe that the POWER REF OSC LED is off during this routine 7 Press CAL ADJ The power meter will display Ent and annunciators 96 100 0 CF A and rcF are on Enter the REF CAL FACTOR shown on the power sensor using blue numeric keys and the key for a decimal point Press ENTER The power meter will display with a walking decimal point and annunciators A A Wait approximately 5 seconds for the CAL ADJ routine Observe that during CAL ADJ the POWER REF OSC LED will be turned off and on 8 Press CAL FACTOR The power meter will display Ent 96 100 0 CF A and 1 150 Enter the CAL FACTOR at 50 MHz Press ENTER The CF displayed will be the one used in the measurments 9 Turn on POWER REF OSC The display will now read 1 888 3 with annunciators WATT A 100 0 CF and A on 10 Press dBm WATT Display will change to 8 op dBm 3 14 HP 438A il 12 13 14 15 16 Lf 18 Operation Press B Repeat steps 4 through 10 for channel B inputs Remove sensor from POWER REF OSC Connect the equipment as shown in FIGURE 3 4 The pow
59. PT CONNECTOR SGL CONT TML TS PT IC TRANSCEIVER TTL LS BUS OCTL IC DRVR TTL LS BUS OCTL IC DRVR TTL LS BUS OCTL IC FF TTL LS D TYPE POS EDGE TRIG COM IC FF TTL LS D TYPE POS EDGE TRIG COM jc FF TTL LS D TYPE POS EDGE TRIG COM IC TRANSCEIVER TTL LS BUS OCTL PROM PROGRAMMED IC DRVR TTL LS BUS OCTL iC 64K SRAM 150 NS CMOS IC FF TTL LS J K NEG EDGE TRIG IC DRVR TTL LS BUS OCTL IC INTERFACE XCVR MISC UNKNOWN IC INTERFACE XCVR MISC UNKNOWN IC DRVR TTL LS BUS OCTL IC MPU CLK FREQ 2 MHZ ENHANCED 6800 IC 8 BIT 16 BIT SYSTEM TIMING CONTROLLER 1C PERIPHERAL INTERFACE ADAPTER CLK 2MHZ IC PERIPHERAL INTERFACE ADAPTER CLK 2MHZ IC DCDR TTL LS BIN 2 TO 4 LINE DUAL IC DRVR TTL BUS HEX IC DRVR TTL BUS HEX ic DRVR TTL BUS HEX IC DCDR TTL LS BIN 3 TO 8 LINE 3 INP PAL PROGRAMMED IC GPIB TALKER LISTENER IC DRVR TTL LS BUS OCTL Replaceable Parts Mfr Manufacturer Code Part Number CMF 50 2 CMF 50 2 7650045 90B07S SN74LS245N SN74LS244N SN74LS244N SN74LS377N SN74LS377N SN74LS377N SN74LS245N 00438 80036 SN74LS244N HM6264ALP 15 SN74LS112AN SN74LS244N DS75161AN DS75160AN SN74LS244N MC68B09P AM9513APC MC68B21P MC68B21P SN74LS156N SN7407N SN7407N SN7407N SN74LS138N 00438 80013 P8291A SELECTED SN74LS244N 6 11 Replaceable Parts Reference HP SE SE Part No 6 12 1820 1729 1820 1729 1820 1281 1820 1753 1826 0175 1820 1197 1820 1199 1820 1212 1820 2075 1820 1858 1820 0668 1820 0668 1820 1851
60. RESISTOR 100K 1 125 W TE TC 0 100 RESISTOR 100K 1 125W TF TC 04 100 RESISTOR 4 22K 1 125W TF TC 6 4 100 RESISTOR 5 62K 1 125W TF TC 0 100 RESISTOR 61 9K 1 125W TF TC 0 100 RESISTOR TRMR 20K 10 TKF TOP ADJ 1 TRN RESISTOR 61 9K 1 125W TF TC 0 100 RESISTOR 4 22K 1 125W TF TC 0 100 RESISTOR 5 62K 1 125W TF TC 0 100 RESISTOR 3 16K 1 125W TF TC 6 100 RESISTOR 1K 1 125W TF TC 04 100 RESISTOR 909 1 125W TF TO 0 100 RESISTOR 383 1 125W TE TC 0 100 RESISTOR 2 61K 0 1 125 W TF TO 0 4 25 RESISTOR 2 58K 0 1 125W TF TC 0 25 RESISTOR 215 1 125W TF TC 0 4 100 RESISTOR 215 1 125W TF TC 04 100 RESISTOR 215 1 125W TF TC 0 100 RESISTOR 215 1 125W TF TC 0 100 CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT 125W TF TC 0 100 128W TF TC 0 100 125W TF PC 0 100 125W TF TC z04 100 HP 438A Mfr Manufacturer Code Part Number CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 82PR100K 82PR100K CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 82PR100K 82PR100K CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 82PR20K CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 05524
61. TEMPER HP 1725A Senate EES HP 5005B AEG KW Ee HP 11683A Fault Isolation Procedure Power Supply Checks 1 Verify the following voltages are at the points indicated ASTERO e ae vA EAQUE 15 0 75 Vde DOLE eset ra pU 15 0 75 Vdc ADRES Sere ee eee P 5 0 05 Vdc The 15 volt and 15 volt supplies should be within 0 05 volts of each other but of opposite polarity If the measured voltages are not as shown above troubleshoot the power supply circuits on Service Sheet 9 5 Vdc or 10 15 Vdc and 15 Vdc Problem Isolation Using Signature Analysis 1 Turn the power meter OFF 8 95 Service Sheet 7 8 96 crt 8 HP 438A On the A3 assembly set A3S1 to signature analysis mode A351 is the red switch assembly When the switches are set towards the front panel of the power meter they are set to 1 The switch closest to the edge of the printed circuit board is the least significant bit LSB To set signature analysis mode set the switches as follows 0001 LSB Connect the signature analyzer pod to the A3 assembly as follows Signature Analyzer Pod A3 Assembly CLK A3TP6 START STOP A3TP9 QUAL A3U6 Pin 9 GND A3TP7 Set the controls on the signature analyzer as follows ICE st esta pe ese et peo RE IE falling edge SAM cosas sand wehbe wie wade eer RT ERN Md rising edge SEO is cha stereo ide STRE Se ater eee ee falling edge Turn the power meter ON V
62. TRIM SIDE 3 1 2 6 24 HP 438A Manufacturer Part Number 02037 02037 05524 05524 03123 04568 03123 05524 05524 05524 05524 05524 05524 05524 05524 05524 05524 05524 03418 03418 03285 03406 02037 02037 03746 03746 02440 05769 04939 04637 01932 28480 28480 28480 02010 75915 02805 05879 28480 28480 28480 28480 28480 CCF 55 1 T 1 CCF 55 1 T 1 140 89PR2K 140 CCF 55 1 T 1 CMF 50 2 CCF 55 1 T 1 CMF 50 2 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CMF 55 1 T 9 16 06 0034 16 06 0034 AD741CH LM301AH 1N827 54 713 011 X5V 502Z 54 713 011 X5V 502Z 820 BC 3002 26 500220 00438 60010 00438 60047 0160 4065 SA105C103MAAH 312001 MDL 3 8 31 221 1020 5021 8413 00438 00018 00438 20035 5041 8803 5001 0538 HP 438A Replaceable Parts Designation Part No D Code Part Number MP6 5062 3914 8 1 28480 5062 3914 5062 3864 28480 5062 3864 1460 1345 00359 00438 00019 28480 5041 8801 28480 3160 0483 10938 0624 0458 05610 2190 0016 04805 2950 0043 04605 6960 0133 04507 6960 0024 03480 5021 5831 28480 00438 00012 28480 00438 00017 28480 00438 20020 28480 00438 20023 28480 5040 688
63. Table 3 8 Error Messages continued Error Message Action Required Display CF Error Entered cal factor is out of range Re enter value between 1 0 and 150 0 D Error Entered offset is out of range Re enter value between 99 99 and 99 99 rg Error Entered range number is out of Re enter range number between 1 and 5 range FL Error Entered filter number is out of Re enter filter number between 0 and 9 1 range re Error Entered recall register number is Re enter register number between D and 19 1 out of range Error Entered storage register number Re enter register number between 1 and 191 is out of range rCF Err Entered reference cal factor is Re enter CAL ADJ value between 50 0 and 120 02 out of range rCL Fail Continuous memory failure Refer to footnote below Ad Error Entered HP IB address is out of Re enter HP IB address between range 0 30 range 40 49 or 50 59 HP IB data without valid prefix Check then re enter valid prefix with data Invalid HP IB code Check then re enter correct HP IB code Hardware Errors Service related errors Refer to Service Related Errors in section 8 Service 1 This error indication is cleared after two seconds or by selecting any function The selected function will be executed When the error is cleared the parameter that caused the error remains unchanged from its previous value 2 Error 57 occurs when the instrument is turned on and the internal RAM c
64. Ted Ra det an d Gane ous oe eure dese falling edge Qual tee uua catur tu atu eg LO 3 Set switch A3S1 to 0001 The least signifiant bit is the switch that is closest to the edge of the printed circuit board When the switches are set towards the front panel of the instrument they are set to one Turn the instrument off then back on again HP 438A Service Sheets 1 4 4 Verify the signatures for 5 volts and ground are as shown below Rev 5 0 Rev 2 0 45 volts A3TP8 9UCF 7PUO Ground 0000 0000 If Signature Analysis Mode will not run perform the Signature Analysis Mode Troubleshooting under Miscellaneous Checks Note 5 Verity the signatures in Table 8 19 Table 8 19 Microprocessor Data Bus Buffer Signatures Pin Signal Number Name If all signatures are correct perform the Miscellaneous Tests If any signature is incorrect move the QUAL line to Ul pin 1 set QUAL to High and verify the signatures for 5 volts version 2 0 A988 version 5 0 F039 and ground 0000 are as shown Verify the signatures in Table 8 20 Table 8 20 Microprocessor Data Bus Buffer Signatures Fi Sina Number Name If any signature was incorrect replace U1 Service Sheets 1 4 8 64 HP 438A If all the signatures were correct set QUAL to LO and verify the signatures in Table 8 21 Table 8 21 Microprocessor Data Bus Buffer Signatures Pin ae If any signature is incorrect re
65. Test Mode Error Messages LED Display Description D3 D2 D1 D0 0001 0010 0011 0100 0101 0110 001 11 1000 1001 1010 1011 1100 1101 The power meter thinks that there is no sensor connected If a sensor is connected the problem could be caused by a bad sensor sensor cable or Sensor Resistor Selection circuit see Service Sheet 8 The Zero DAC was set to its maximum value 255 but a valid zero could not be achieved This would indicate that the voltage at the A D converter was too high gt 140mV for the Zero DAC to correct This could happen if power is applied to the sensor during ZEROing or if there was a failure in the Amplifier Section see BD3 The Zero DAC was set to its minimum value 0 but a valid zero could not be achieved This would indicate that the voltage at the A D converter was too low lt 140 mV for the Zero DAC to correct This could happen if there was a failure in the Amplifier Section see BD3 After the Zero DAC was set the digitally filtered voltage on RANGE 1 was not between 140 and 140 mV After the Zero DAC was set the digitally filtered voltage on RANGE 2 was not between 140 to 140 mV After the Zero DAC was set the digitally filtered voltage on RANGE 5 was not between 140 to 140 mV With Offset DAC set to 64 the offset voltage is not between 0 and 750 mV or with the Offset DAC set to 192 the offset voltage is not less
66. V1 Vi 11 Disconnect the DVM negative input lead from the Vrf connector on the test power meter Reconnect it to test power meter chassis ground Observe the DVM reading Record the reading as Vcomp V comp 12 Calculate the power reference oscillator output level Prf from the following formula Prf 2Veompl Vi Vo Vd V 4R CalibrationF actor Where Pr power reference oscillator output level Vcomp previously recorded value Vi previously recorded value VO previously recorded value R previously recorded value Calibration Factor value for thermistor mount at 50 MHz traceable to the National Bureau of Standards 13 Verify that Prf is within the limits shown in the following table Record the reading Actual 0 981 mW 1 019 mW 4 10 HP 438A Performance Tests Table 4 1 Performance Test Record Hewlett Packard Company Tested by u Model HP 438A Power Meter Serial Number Slee eee NIE RR ERIE Date Paragraph Test Minimum Actual Maximum Number Result Result Result 4 8 Zero Carryover Power Meter Range 0 06 uW 0 06 pW 0 1 pW 0 1 uW 0 001mW 0 001 mW 0 01 mW 0 01 mW 0 1 mW 0 1 mW Instrument Accuracy Watt Mode 3 pW 3 13 pW 3 19 pW 10 pW 9 90 pW 10 10 pW 30 pW 31 3 yW 31 9 pW 100 pW 99 0 pW 101 0 pW 300 pW 0 313 mW 0 319 mW 1 mW 0 995 mW 1 005 mW 3 mW 3 13 mW
67. ZAA HP 438A Service Sheet BD3 RONN UN 1 Service Sheet BD3 Amplifier Section Principles of Operation General As shown on the block diagram the A4 Input Amplifier Assembly and the A5 Main Amplifier Assembly are the major physical components The Amplifier Section can be divided into the following five functional sections 1 The connected power sensor Not shown on the block diagram refer to the Power Sensor Operating and Service Manual 2 The input amplifier circuits Service Sheet 6 These circuits are on the A4 Input Amplifier Assembly 3 The digital I O and DAC circuits Service Sheet 7 These circuits are all contained on the A5 Main Amplifier Assembly 4 The amplifier detector and comparator circuits Service Sheet 8 These circuits are all contained on the A5 Main Amplifier Assembly 9 The 1 mW 50 MHz Power Reference circuits Service Sheet 11 Connected Power Sensor and Input Amplifier Circuits The connected power sensors determine the frequency range dynamic range and measurement accuracy of the combined power sensor and power meter A simplified block diagram of the interconnection between the power sensors the two channels of the input amplifier and the monitoring circuits in the main amplifier is shown in Figure 8 12 The basic operation of these circuits is described in the following paragraphs The power sensor dissipates the RF input power into a 50 or 75 ohm impedance and generates a
68. a current regulation diode Indicates a voltage regulation diode Indicates a Schottky hot carrier diode Multiple transistors in a single package physical location of the pins is shown in package outline on schematic Identification of logic families as shown in this case ECL Indicates an opto isolator of a LED and a photoresistor packaged together The resistance of the photoresistor is a function of the current flowing through the LED HP 438A Service y 1 Table 8 1 Schematic Diagram Notes 4 of 8 DIGITAL SYMBOLOGY REFERENCE INFORMATION input and Output indicators Implied Indicator Absence of polarity indicator see below implies that the active state is a relative high voltage level Absence of negation indicator see below implies that the active state is a relative high voltage level at the input or output E Polarity Indicator The active state is a relatively low voltage level Dynamic ndicator The active state is a transition from a relative low to a relative high voltage level Inhibit Input Input that when active inhibits blocks the active state outputs of a digital device Analog Input Input that is a continuous signal function e g a sine wave Polarity Indicator used with Inhibit Indicator Indicates that the relatively low level signal inhibits blocks the active state outputs of a digital device Output Delay Binary output changes state only after the referenced i
69. accuracy plus 0 5 verification system error plus 0 2 transfer error 1 9 maximum error The power reference oscillator can be set to 0 7 using the same equipment and following the adjustment procedure To ensure maximum accuracy in verifying the power reference oscillator output the following procedure provides step by step instructions for using specified Hewlett Packard test instruments of known capability If equivalent test instruments are used signal acquisition criteria may vary and reference should be made to the manufacturer s guidelines for operating the instruments Note 1 The power meter may be returned to the nearest Hewlett Packard office y to have the power reference oscillator checked and or adjusted Refer to section 2 Packaging 4 8 HP 438A Performance Tests H owen HP 438A POWER METER METER ns eg E DIGITAL VOLTMETER POWER REF 1 88 mW HARE 58 Miz THERMISTOR MOUNT Figure 4 3 Power Reference Level Test Setup Equipment Test Power Metra deco A ta Sereda OKA e HP 432A Thermistor Mount wicker ee Y dan ols HP 478A Option H75 H76 Digital Voltmeter UVM eo Seege et ood HP 34564 Procedure 1 Set the DVM to measure resistance Connect the DVM between the Vrf connector on the rear panel of the test power meter and pin 1 on the thermistor mount end of the test power meter interconnect cable 2 Round the DVM reading to two decimal places Record this value as
70. analyzer is set up properly Rev 5 0 Rev 2 0 5 volts A8TP8 9UCF 9UCF Ground 0000 0000 5 Verify the signatures in Table 8 38 If all of the signals are correct continue with step 6 8 110 HP 438A Service Sheet 8 Table 8 38 Gain Attenuator Buffer Signatures Number Name H26A A857 5PAG SAAC AFFU 3P63 8FCP U992 If any signatures are incorrect check the Digital I O circuits on Service Sheet7 If the Digital I O signatures are correct replace A5U16 6 Verify the signatures in Table 8 39 Table 8 39 A D Input Multiplexer Signatures Pin Signal Sigmatures Number Name A5U19 1 387H 387H CPOU CPOU U5PU U5PU If all of the signatures are correct the circuit is operating normally If any of the signatures are incorrect continue troubleshooting on Service Sheet 7 Reference Ramp Start Gate and Ramp Generator Test 1 Check A5U8 pin 2 for a 5 Vp p digital waveform If there isn t any signal perform signature analysis troubleshooting on Service Sheet 1 2 If the voltage at A5TP8 is not equal to 2 5 0 05 Vdc replace A5U12 3 If the voltage on A5U17 pin 6 is not between 6 and 8 Vdc replace A5U17 A5R59 A5R61 A5R62 or A5R64 4 If the voltage on A5U8 pin 3 is not equal to 1 8 0 1 Vdc replace ASR66 or R67 5 Compare the waveform at A5U8 pin 7 with Figure 8 45 8 111 Service Sheet 8 HP 438A 5 ms DIV Figure 8 45 Ramp Start Gate Waveform If t
71. any of the signatures are incorrect continue with the troubleshooting for Service Sheet 3 3 If troubleshooting is complete disconnect the signature analyzer and reset switch A351 to all ones Auto Zero DAC and Buffer Test 1 Using the oscilloscope compare the waveform at A5U10 pin 4 to the waveform shown in Figure 8 34 If the displayed waveform is the same as Figure 8 34 the circuit is operating properly If the Fault Isolation Procedure is being performed and the circuit is operating properly go to the Offset Removal DAC Buffer and Gain Compensation Test If the displayed waveform is not the same as Figure 8 34 measure the voltage at the collector of A5Q1 The measured voltage should be 6 2 0 4 Vdc If the measured voltage is not as stated continue with the Stable Current Source Test If the measured voltage is correct go to step 2 20 mV DIV 2 ms DIV Figure 8 34 Auto Zero DAC Test Signal 2 Performs steps 1 through 6 of the Fault Isolation Procedure 3 Verify the signatures in Table 8 34 8 98 HP 438A Note 45 Service Sheet 7 Table 8 34 Zero BAC Buffer Signatures Pin A5U11 Signatures If any signature is incorrect replace A5U11 If all signatures are correct replace A5U10 4 If troubleshooting is complete disconnect the signature analyzer and reset A3S1 to all ones Offset removal DAC Buffer and Gain Compensation Test i Connect the oscilloscope to A5U3 pin 15 2 Compare the
72. bias network defective A4R8 A4R12 A4R14 A4R9 A4R13 A4R15 m A4U1 A4U3 is defective The dc voltage at A4TP3 A4TP1 is too low m Shorted or leaky A4C13 A4C14 u DC bias network defective A4R8 A4R12 A4R14 A4R9 A4R13 A4R15 w A4U1 A4U3 is defective 8 89 Service Sheets 6 8 90 HP 438A 220 Hz Buffer Test Check for a signal 220 Hz 10 Vp p at A4J8 pins 1 3 and A4J9 pins 1 3 If only one signal is bad replace A4U5 and or the associated resistors A4R53 A4R56 If more than one signal is bad check for a signal 220 Hz 10 Vp p at A4TP5 and A4TP6 If either signal is bad continue with the 220 Hz Multivibrator Test If the signals are both good replace A4U5 and or the associated resistor s A4R53 A4R56 220 Hz Multivibrator Test Check A4TP5 and A4TP6 for a square wave of 220 Hz 20 Hz and 10 Vp p If the signals are good the Multivibrator is working normally If only one of the signals is bad then the problem is A4Q2 if A4TP5 was bad or A4Q3 if A4TP6 was bad If both signals are bad the problem is one of the transistors A4Q1 A4Q5 Figure 8 31 shows signals and voltages which are present when the multivibrator is operating normally 2VIDIV 1ms DIV A404 and A405 Base Waveform Figure 8 31 Multivibrator Waveforms HP 438A Service Sheets 6 A402 and A403 Base Waveform Figure 8 31 Multivibrator Waveforms continued Channel Selection Circuitry Test Select ch
73. continue with the Address Bus Signatures Note E Address Bus Signatures 1 Set the controls on the signature analyzer as follows SEALY Site coins EE rising edge STOP RM CE falling edge EE falling edge 2 Verify the signatures in Table 8 14 8 58 HP 438A Service Sheets 1 4 Table 8 14 Address Bus Signatures If all signatures are correct continue with step 3 If any signature is incorrect verify the signatures in Table 8 15 Table 8 15 Address Bus Signatures Pin Sia Number Name If any signature is incorrect continue with step 3 If all signatures for pins 8 through 15 are correct replace U18 3 Verify the signatures in Table 8 16 Table 8 16 Address Bus Signatures 7 Sigua Number Name The probe should blink indicating signal activity Service Sheets 1 4 8 60 HP 438A If any of the signatures are correct verify the signatures in Table 8 17 Table 8 17 Address Bus Signatures Signal Name soo PA8 If all of the signatures are correct replace U30 If the signatures in Table 8 15 or Table 8 17 are incorrect perform Free Run Mode Troubleshooting If Free Run Mode Troubleshooting is normal replace U19 If the Address Bus signatures are correct perform the Memory Data Bus Tests Reset Power Fail Test Voltage Checks 1 Ensure the power meter is turned on 2 Verify that U19 pin 37 is a TTL high If the measured voltage is correct go to the Tim
74. current rating are used for replacement Do not use repaired fuses or short circuited fuseholders To do so could create a shock or fire hazard eg eg Some printed circuit boards contain devices that may be damaged if the board is removed or installed while the power is on Verify that the LINE switch is OFF or that the power cord is unplugged before you remove or install a printed circuit board After removing MOS devices from sockets store the devices with the pins in conductive foam This will prevent accidental damage from a static discharge Test equipment and test accessories required to maintain the power meter are listed in Table 1 3 Recommended Test Equipment Equipment other than that listed may be used if it meets the critical specifications listed 8 10 Service Tools Equipment recommended for use when changing components on printed circuit boards is listed in Table 8 1 The following unique service tools will make servicing of this instrument much easier Pozidriv Screwdrivers Many screws in the power meter appear to be Phillips type but they are not To avoid damage to the screw heads Pozidriv screwdrivers should be used The Pozidriv No 1 size can be HP 438A Service ordered as HP part number 8710 0899 and the Pozidriv No 2 size can be ordered as HP part number 8710 0900 Tuning Tools For adjustments requiring non metallic tuning tools use the blade tuning tool HP part number 8710 0033 or he
75. dc voltage proportional to the RF input power level The 220 Hz multivibrator provides the 220 Hz drive signals to the power sensors which are modulated by the dc voltage The resulting sensor output is a 220 Hz signal that is proportional in amplitude to the RF input power level and is in phase with the 220 Hz reference signal that is applied to the synchronous phase detector in the power meter s main amplifier The shaping feedback circuit serves to reduce the gain of the input amplifier at higher power levels This reduction in gain is required to offset the improved efficiency of the power sensing elements at the higher power levels The sensor resistor input to the sensor resistor circuit in the main amplifier is used by the controller to determine which model power sensor is connected to an input channel Note that any two HP 848X series power sensors can be connected to the power meter The controller is able to adjust the individual channel input to the 8 41 Service Sheet BD3 8 42 HP 438A connected power sensor and provide the correct measurement result for each channel If the Option 002 rear panel input ports are present the controller can determine if more than one power sensor is connected to the same channel input For example if power sensors are connected to both the front panel and real panel A inputs error message 33 ZinPutS is displayed The output from the auto zero DAC on the main amplifier is set by the
76. default condition at turn on Refer to Triggering Measurements with the Data Message discussed earlier in this section Note i Hardware Errors NOT available via the Status Message v AAaaBBCCccDDddEF GHI JKLM CR LF gt SENSOR B FILTER MEASUREMENT UNITS ACTIVE ENTRY CHANNEL MEASUREMENT ERROR CODE SEE TABLE 3 8 ENTRY ERROR CODE CSEE TABLE 3 8 OPERATING MODE SENSOR A RANGE SENSOR B RANGE m SENSOR A FILTER LINE FEED CARRIAGE RETURN SENSOR 8 LIMITS STATUS SENSOR A LIMITS STATUS LIMITS CHECKING STATUS GROUP TRIGGER MODE TRIGGER MODE REL MODE STATUS OSC STATUS Figure 3 6 Status Message Output Format 3 40 HP 438A gt Mode 00 Sensor A 01 Sensor B 02 A B 03 B A 04 A B 05 B A 06 Zeroing A 07 Zeroing B 08 Cal A 09 Cal B 10 Ext Cal A 11 Ext Cal B Codes Used in Status Message Operation Ecce pu s Le ales e Ium Range Filter Measurement Units 0 Watts 00 0 izHold 1 GT1 zEnabled 1 0Over high limit 2 Under low limit Over high limit and under low limit 3 41 Operation HP 438A Table 3 4 Response to a Clear Message and PRESET Sensor A CAL ADJ 100 096 CAL FACTOR 100 096 OFFSET 0 00 dB Filter AUTO Range AUTO Low Limit 0 000 dBm High Limit 0 000 dBm Sensor B CAL ADJ CAL FACTOR OFFSET Filter Range Low Limit High Limit Display OSC Entry Channel Measu
77. disconnect the signature analyzer and reset switch A351 to all ones Miscellaneous Buffer Test 1 Perform steps 1 through 6 of the Fault Isolation Procedure 2 Connect the QUAL line from the Signature Analyzer Timing Pod to A3U6 Pin 2 and verify the signatures in Table 8 37 If all signatures are correct the circuit is operating properly If the Fault Isolation Procedure is being performed and the circuit is operating properly go to the Cal Oscillator Control Test If any of the signatures are incorrect replace the integrated circuit associated with the bad signature s HP 438A Service Sheet 7 Stable Current Source Verify that the voltage at the base of A5Q1 is 3 6 0 4 Vdc less than the 15 volt supply If the measured voltage is not as stated replace A5VR2 or A5R6 Verify that the voltage at the collector of A5Q1 is 6 2 0 4 Vdc If the measured voltage is not as stated replace A5Q1 and A5V R3 If the measured voltage is as stated A5Q1 is operating properly Verify that the voltage at the collector of A5Q2 is 6 2 0 4 Vdc If the measured voltage is not as stated replace A5Q2 and A5VR1 H the measured voltage is as stated A5Q2 is operating properly Cal Oscillator Control Test Monitor the voltage at the collector of A5Q5 With the oscillator turned on the voltage should be within 0 2 volts of the 15 volt supply With the oscillator off the voltage should be 0 volts If either voltage is incorrect
78. filter mode There is no front panel indication when the power meter is auto ranging Comments PRESET sets both sensor A and sensor B to AUTO RANGE If you are only interested in power readings in one range manual range can be used for faster readings Use manual range when using the rear panel RCDR output so that the power meter does not change ranges while outputting data The recorder output provides a 0 to 1 Vdc output for each range Pressing the key when the power meter is already in auto range mode causes the instrument to step down one range if possible There is a 20 overlap on ranges If the power reading can be displayed on either range the power meter stays on the lower range In linear mode this provides a means for down ranging to obtain greater resolution in borderline situations For example with an HP 8481A power sensor measuring a power level of 1 153 mW the range could be either range 4 1 to 10 mW or range 3 0 1 to 1 2 mW with 20 overrange The display in range 4 would read 1 15 mH but in range 3 would read 1 152 mH Related Sections Error Messages PRESET Recorder Output SET A and SET B HP 438A Recorder Output ni aaa Recorder Output Description The rear panel RCDR output produces a dc voltage that corresponds to the power level in Watts of sensor A or sensor B depending on the measurement mode Only single sensor power measurements produce a valid dc output voltage at the RCDR output
79. following five power supplies are isolated to reduce the unwanted interaction in the power meter 1 The 5 V digital power supply 2 The pulsed 5 V display power supply This power supply is enabled by the CPU timer circuit 3 The 15 V analog power supply 4 The 15 V analog power supply 9 The 10 4 V power supply for the fan Because of the high precision requirements the power meter uses separate grounding points for each type of digital and analog signal Grounding is very important B GND is the chassis or earth ground point that is connected to the protective earth terminal of the power receptacle B GND is defined as a point at the rear panel RCDR BNC connector See Figure 8 5 for a simplified diagram of the distribution of the grounds used on the different boards The grounds are defined as follows 1 The main instrument ground at the RCDR BNC connector 2 The A GND is defined as the ground at the sensor bulkhead that is supplied to the input being measured The A GND is not a true ground but a reference for the signal being amplified through the bandpass amplifiers The A GND is created on the A5 Main Amplifier Assembly and applied to the A4 Input Amplifier Assembly A detailed explanation of the creation of the A GND is provided on Service Sheet 8 3 The B GND is the low current analog ground It is applied directly to the main amplifier from the main instrument ground It is used on the main amplifier filters a
80. line NKCO NKC7 corresponding to the suspected switch For example monitor NKC7 U43 pin 4 for the key When the key is not pressed the line should be a TTL high When the key is pressed a TTL signal should be on the line If the TTL signal does not appear replace the switch If the signal does appear replace U43 or U22 Addressable Display Latch Verify that there is a signal on U31 pins 4 through 7 and 9 through 12 and on U32 pins 4 and 5 If all signals are incorrect ensure that there is a signal on U33 pin 1 If there isn t a signal on pin 1 perform Free Run Signature Analysis following this procedure If the signal is on pin 1 check for a signal on U33 pins 4 and 5 If signals are present on pins 4 and 5 check the logic level on U32 pin 15 If the level is a TTL low perform the Signature Analysis Mode Checks at the beginning of this procedure If the level is a TTL high check the signatures for PB1 PB3 using the Signature Analysis Mode Checks Cathode Data Display and Keyboard Scan PIA Check If outputs for U31 are bad check U31 pin 14 for a TTL signal and U31 pin 15 for a logical high If the clock signal is absent replace U33 If the reset is held low check the Reset Power Fail circuit on Service Sheet 2 If the Reset Power Fail circuit is operating properly replace U15 If the conditions on pins 14 and 15 are correct replace U31 If the outputs for U32 are bad check U32 pin 14 for a clock signal and U32 pi
81. main signal Heavy dashed line with arrows indicates path and direction of main feedback Indicates stripline i e RF transmission line above ground Wiper moves toward cw with clockwise rotation of control as viewed from shaft or knob Numbered Test Point measurement aid provided Encloses wire or cable color code Code used is the same as the resistor color code First number identifies the base color second number identifies the wider stripe and the third number identifies the narrower stripe e g denotes white base yellow wide stripe violet narrow stripe A direct conducting connection to earth or a conducting connection to a structure that has a similar function e g the frame of an air sea or land vehicle A conducting connection to a chassis or frame Common connections All like designation points are connected Letters off page connection e g AKM Number Service Sheet number for off page connection e g 12 Number only on page connection 8 7 Service o y HP 438A Table 8 1 Schematic Diagram Notes 3 of 8 SCHEMATIC DIAGRAM NOTES Indicates multiple paths represented by only one line Letters or names identify individual paths Numbers indicate number of paths represented by the line Coaxial or shielded cable Relay Contact moves in direction of arrow when energized Indicates a pushbutton switch with a momentary ON position Indicates a PIN diode Indicates
82. must be in place The tests are designed to verify published instrument specifications Perform the tests in the order given and record the data on the test card and or in the data spaces provided at the end of each procedure 4 1 Performance Tests 4 5 Calibration Cycle 4 2 4 6 Abbreviated Performance Test 4 7 Test Procedures HP 438A This instrument requires periodic verification of performance to ensure that it is operating within specified tolerances The performance tests described in this section should be performed at least once each year under conditions of heavy usage or severe operating environments the tests should be more frequent Adjustments that may be required are described in section 5 Adjustments Refer to section 3 Operation for a Basic Functional Checks test It is assumed that the person performing the following tests understands how to operate the specified test equipment Equipment settings other than those for the power meter are stated in general terms It is also assumed that the technician will select the power sensor cables adapters and probes required for test setups illustrated in this section HP 438A Performance Tests REA NAAA 0000 4 8 Zero Carryover Test Specification Electrical Performance Limits Conditions Characteristics Accuracy 0 5 full scale Most sensitive range Decrease percentage by factor of 10 for each higher range
83. normal indication is This display will show na CH A if a power sensor is not connected and PLERSE 8 if a power sensor is connected but has not been zeroed If a problem is detected in the extended test mode an error number will be displayed The explanation of these errors and their relationship to the zeroing and calibration routines will be given on Service Sheet 1 Manual Display Check Set switch to decimal 5 This will enable a manual test of the front panel displays Repeated pressing of the key will light each LED segment and annuciators The normal indication is All segments of the large LED s all of the smaller number eights and all of the annunciators will light one at a time as the A key is pressed Continue to press until the sequence starts to repeat If any of the displays fail to light refer to Service Sheets 4 and 5 8 33 Service Sheet BD2 8 34 Automatic Display Check Set switch to decimal 4 This check is similar to the manual HP 438A display check except the displays are lighted and sequenced through automatically The normal indication is At turn on all displays will be lit This will be followed by a walking through turn on of each LED segment large and small Then the annunciators will be turned on in two groups If any of the displays fail to light refer to Service Sheets 1 3 4 and 5 Keyboard Manual Check Set the switch to decimal 3 Each front panel key can be pressed and a corr
84. not as shown in Figure 8 15 at test point A4TP3 or A4TP4 depending on which channel is active Refer to A4 Input Amplifier Assembly on Service Sheet 6 SERES bom 0 05V DIV CH SU RR UR T ES NE E d M ABRE RARI E cm E o des 1 ms DIV Figure 8 15 Selected Amplified AC 2 The phase detector drive is not as shown in Figure 8 16 at test point A4TP5 or A4TP6 Refer to A4 Input Amplifier Assembly on Service Sheet 6 1ms DlV Figure 8 16 Phase Detector Drive If the RAMP END signal is wrong and steps 1 and 2 are correct go to Service Sheet 8 If the RCDR signal is wrong and steps 1 and 2 are correct go to Service Sheet 7 05 8 69 8 weber 19019 uon2as Jandy 1 8 angia EOS 107 507 RA E AAA H EZE OVO NIYO 33 NOTIYSN3dMOS Neva hore 833408 d j wc ai 138440 le t NOI VSNIANOO YK WZ Lits 138340 j P gt a i 4 i s 33 HW OS Bu QU 1 i T WE 033308 i38 B2MOd i 30Uhos v0 OB IS384n0 RSE 219 1 JINI JZIE THN OS 15 980 ZEW 06 Dt SR G8 2 97 ofl zu 3 323109 i SROZNY TT ZOSTA boron tb ET OTW BB LNOG HRS cag GNS dny 043 Gire gOSN3S H BAKE Ji e i NO 193338 YOSNIS i8 INNYHD BOiS1S3e YHOSN3S KW 21910 B SO lest Rn HOLVEYAKOD x078
85. of V4 Typical Calulations 1 ACCURACY DVM Measurements Vcomp 0 018 V Vo 0 023 R 0 03 Math Assumptions 0 01 EFFECTIVE EFFICIENCY CAL NIST 0 5 MISMATCH UNCERTAINTY 0 1 Source amp Mount SWR lt 1 05 lt 0 7 2 MATH ASSUMPTIONS Pap 2Vcomp V Vo t V V URNEFFECTIVE EFFICIENCY Assume Vg Vi V1 Vo V4 Vo V4 2Vi Vo Want Vo Vi Therefore error V1 2ViVo Vo Vo V4 2Vg 2V4Vo 2Vo Vi Vo If 2Vo V1 Vo lt lt 2Vcomp V1 Vo That is if Vo lt lt Vcomp then the error is negligible 5 12 HP 438A For example If Vcomp 4 volts and Vo 400 pV then the error is lt 0 01 typically Vo can be set to 50 pV Derivation of the formula for V4 Vo 2Vcoy pP Vi Vo 3 V2 V PRF URNEFFECTIVE E EFFICIENCY Desired PRp 1 mW 107 W Therefore 10 3 2Vcowp Vi Vo V2 V2 UR EFFEGTIVE EFFICIENCY Let 4R EFFECTIVE EFFICIENCY 107 K Substitute IN Vg for Vo V4 see Math Assumptions under Accuracy Then 0 Vi Vo 2Vcomp Vi Vo K or Vi Vo Veomp y Vcomp K Adjustments 5 13 Replaceable Parts 6 6 1 Introduction 6 2 Abbreviations 6 3 Replaceable Parts Note List This section contains information for ordering parts Table 6 1 ists part numbers for restored assemblies Table 6 2 lists abbreviations u
86. or loss in the measurement system For example to add an offset of 20 dB press Single sensor and difference measurements are displayed in units of Watts or dBm Ratio and relative measurements are displayed in either percent of dB Press to toggle from one measurement unit to another The Power Meter can store up to 19 instrument configurations for recall at a later time For example to store an instrument configuration in storage register 10 press STORE CAL ADJ ZERO dBm WATT RECALL OFFSET dBm WATT recalls an intrument configuration stored in register 3 and changes the Power Meter to the recalled parameters Operation 3 10 3 6 Turn On Instructions Warning o Caution y 3 7 Turn On Note HP 438A Before the instrument is switched on all protective earth terminals extension cords autotransformers and devices connected to it should be connected to a protective earth grounded socket Any interruption of the protective earth grounding will cause a potential shock hazard that could result in personal injury Only 250V normal blow fuses with the required rated current should be used Do not use repaired fuses or short circuited fuseholders To do so could cause a shock or fire hazard p O cmm 0 0 Before the instrument is switched on it must be set to the voltage of the power source or damage to the instrument may result Turn On Procedure If the power meter is already plugged in set the
87. power meter changes accordingly Table 3 3 shows the information contained in the string and the order in which it is sent i HP 438A Operation Table 3 3 Learn Mode 1 Output Format Output from Power Meter Trigger Mode TRx Measurement Mode AP BP AR BR AD or BD Sensor A Parameters AE Cal Factor KB xxx x EN Offset OS sxx xx EN Range RA or RM x EN Filter FA or FM x EN Low Limit LL sxxx xxx EN High Limit HL sxxx xxx EN Sensor B Parameters BE Cal Factor KB xxx x EN Offset OS sxx xx EN Range RA or RM x EN Filter FA or FM x EN Low Limit LL sxxx xxx EN High Limit HL sxxx xxx EN Active Entry Channel AE or BE LG or LN Measurement Units OCO or OC Reference Oscillator Status GTx Group Trigger Mode Limits Checking Status LMO or LM1 Carriage Return Line Feed EOI 1 s indicates sign x indicates a single digit Learn Mode 2 After receiving the program code LP2 Learn Mode 2 and when addressed to talk the power meter sends 2 ASCII characters and 2 followed by a string of 28 8 bit binary bytes The last byte is sent with EOI bus line true thus terminating the message This binary data can then be stored in the controller s memory The most straight forward way to program the system controller is to use a loop to read 30 binary characters and store them in an array Learn Mode 2 requires a contr
88. seconds for the power meter zeroing process Set the range calibrator function switch to calibrate On the power meter press CAL ADJ CL 100 then ENTER This procedure allows the power meter to calibrate using an external reference the range calibrator output Adjust 220 Hz A4R43 for the maximum front panel reading 5 7 Adjustments 5 11 Ranges 4 and 5 Shaper Adjustment Channel A and B Reference Description Equipment Procedure HP 438A TTT eme Service Sheet 6 Ranges 4 and 5 Shaper circuits are adjusted for proper gain HP 4384 POWER METER RANGE E CALIBRATOR 1003000 o enu D A Figure 5 4 Ranges 4 and 5 Shaper Adjustment Setup Range TEE Wok IER panes HP 11683A 1 Connect range calibrator to channel A input connector 2 Set the range calibrator controls as follows A E a E a O Ed ON RANGE occa wacka aaa ouod d ERE uada tus 1 mW FUNCTION Sena ad Eten STANDBY POLARITY trio executes NORMAL 3 Turn the power meter ON Press PRESET After zeroing the power 5 8 meter set the range calibrator to calibrate then press CAL ADJ 100 and ENTER on the power meter 4 Set the range calibrator range to 10 mW 5 Adjust RNG 4 A4R26 until the power meter reads 14 40 20 01 10 mW Set the range calibrator range to 100 mW Adjust RNG 5 A4R34 until the power meter reads 140 4 0 1 mW Repeat steps 4 through 7 to check that interaction between steps has not caus
89. should be the same as A5U19 pin 12 Point C should be the same as A5U19 pin 5 Point D should be the same as A5U19 pin 4 If the voltage levels at A B C and D are not as indicated in step 2 perform step 5 of the Gain Attenuator Buffer Test If the test is normal replace A5U19 If the voltage levels at points A B C and D are not as shown in Figure 8 50 go to step 4 If the voltage levels are correct perform the A Ground Circuit Test Verify the following voltages A5U19 pin 5 2 5 volts 0 2 volts pin 12 0 0 volts 0 2 volts If either voltage is incorrect perform the Sensor Resistor Selection Test If the voltage at A5U19 pin 4 is not 3 5 0 5 Vdc perform the Fault Isolation procedure to isolate the problem Sensor Resistor Selection Test 1 With no sensor connected verify the following voltages A5U20 pin 3 2 5 0 2 volts pin 6 2 5 0 2 volts pin 11 2 5 0 2 volts pin 14 2 5 0 2 volts If any of the voltages are incorrect replace the appropriate components Verify that A5U20 pins 2 and 7 are equal to 2 5 0 1 volts If the voltages are correct continue with step 4 If the voltage at pins 2 and 7 do not equal 2 5 0 1 volts verify that A5U20 pin 1 is low lt 0 8V and that A5U20 pin 16 is high gt 2 0V If the voltages are correct replace A5U20 If the voltages are incorrect make sure that sensor A is selected If it is continue troubleshooting on Service Sheet 7 Connect t
90. special incidental or consequencial damages in connection with the furnishing performance or use of this material WARRANTY A copy of the specific warranty terms applicable to your Hewlett Packard product and replacement parts can be obtained from your local Sales and Service Office Herstellerbescheinigung Hiermit wird bescheinigt da dieses Gerat System in bereinstimmung mit den Bestimmungen von Postverf gung 1046 84 funkentstort ist Der Deutschen Bundespost wurde das Inverkehrbringen dieses Ger tes System angezeigt und die Berechtigung zur berpr fung der Serie auf Einhaltung der Bestimmungen einger umt Zusatzinformation f r Mef und Testgerate Werden Me und Testger te mit ungeschirmten Kabeln und oder in offenen MeSaufbauten verwendet so ist vom Betreiber sicherzustellen dafdie Funkentst rbedingungen unter Betriebsbedingungen an seiner Grundst cksgrenze eingehalten werden Manufacturer s Declaration This is to certify that this equipment is in accordance with the Radio Interference Requirements of Directive FTZ 1046 1984 The German Bundespost was notified that this equipment was put into circulation and has been granted the right to check the equipment type for compliance with these requirements Note If test and measurement amome is ad with unshielded cables and or used for measurements in open setups the user must ensure that under these operating conditions the radio fre
91. than 0 V This problem is most likely caused by the Offset DAC Buffer or Offset Removal DAC circuits on Service Sheet 7 Offset DAC setting for one or more of the 10 calculated offset voltages would be less than zero or greater than 255 While trying to execute the CAL ADJ procedure a variable gain amplifier setting which would result in a valid CAL voltage 3 18 to 3 85 V at the A D converter could not be achieved A D converter overflowed during the CAL ADJ procedure This could be caused by a failure in the Amplifier Section BD3 or applying too much power to the sensor that is connecting the HP 8484A without the HP 11708A Attenuator The A D converter returned a count proportional to voltage for BGND that was out of range This could be an A D converter problem or a BGND problem 1 V at the recorder output RCDR could not be achieved with a normal setting of the Gain DAC The most likely cause of this problem would be one of the Gain Compensation amplifiers the Gain DAC Buffer or the Gain DAC However an incorrect voltage from the filter output of Service Sheet 8 could also cause the problem When the power meter turned its internal Power Reference Oscillator on and off to make sure that there was a sensor connected the A D converter detected that there was always power applied to the sensor Possibly the sensor was connected to an external reference or the power meter may have been unable to turn off its internal Power Refe
92. the internal bridge resistance R of the test power meter approximately 200 ohms AA 3 Connect the test power meter to the power meter as shown in Figure 4 3 4 Set the power meter LINE switch to ON and the OSC switch off LED off aan a a Pa a a a a a a T a EEE ONE Note i Wait thirty minutes for the test power meter thermistor mount to stabilize before proceeding to the next step 5 Set the test power meter RANGE switch to Coarse Zero and adjust the front panel Coarse Zero control to obtain a zero meter indication 6 Fine Zero the test power meter on the most sensitive range then set the test power meter RANGE switch to 1 mW Note Ensure that DVM input leads are isolated from chassis ground when 3 performing the next step 7 Set the DVM to measure microvolts Connect the positive and negative input leads respectively to the Vcomp and Vrf connectors on the rear panel of the test power meter Performance Tests HP 438A 8 Observe the reading on the DVM If less than 400 microvolts proceed to the next step If 400 microvolts or greater press and hold the test power meter Fine Zero switch and adjust the Coarse Zero control so that the DVM indicates 200 microvolts or less Then release the Fine Zero switch and proceed to the next step 9 Round the DVM reading to the nearest microvolt Record this value as VO V0 10 Set the power meter OSC switch to ON LED on Record the reading observed on the DVM as
93. uoru Xijoud au ejnjnrsuoo 19339 pu sji8tp MOJ JISHA a ejd 18qiunN jenos Y 8 pue V puue pued quo ypa orpexed ur ode synduy S10J09UUO9 OPNE 9 euirg joejuos ZI qu3noadu3 o3e g pu y jouuguo 03 syndut poued eaa 00 uodo avsuosNuas 9 6 uonelado HP 438A PRESET CALIBRATION MEASUREMENT MODES Operation Press to set the Power Meter to the following conditions Measurement Mode Sensor A Reference Oscillator Off Active Entry Channel A Measurement Units Watts REL Mode Off Measurement Parameters set for Sensor A and Sensor B Cal Factor 100 0 Cal Adj 100 0 Offset 0 00 dB Auto Filter Auto Range In addition default conditions are set for some remote only functions Refer to Table 3 5 Response to Clear Message and PRESET Connect the power sensor as shown HP 438A POWER METER E BEBO A Ek Eu POWER SENSOR Press ZERO to zero the Power Meter Each sensor must be zeroed seperately for dual sensor operation CAL ADJ is used only during calibration for entering the sensor s calibration factor at 50 MHz that is the reference calibration factor For example to calibrate the Power Meter to the sensor with a reference cal factor of 98 press CAL ADJ RECALL MNL FILTER dBm WATT The Power Meter can display single sensor A or B dual sensor ratio A B or B A or dual sensor difference A B or B A power measurements In addition measurements can
94. used in B A difference measurements where the sensor B power level is less than the sensor A power level Difference measurements can be displayed relative to a stored reference In REL mode readings are displayed in either dB or percent Changing the measurement mode causes the contents of the digital filter to be discarded The filter buffer then starts filling up with values from the new measurement mode The power meter displays the average of the accumulated readings Related Sections Cal Factor dBm Watt Logarithmic Linear Measurement Units Filters Limits OFFSET PRESET PRESET Range REL Relative Measurements SET A and SET B STORE and RECALL 3 79 Sensor A B and Sensor B A OOOO A E E Sensor A B and Sensor B A 3 80 Dual Sensor Ratio Measurements HP 438A Description SENSOR A B and SENSOR B A cause the power meter to make dual sensor ratio measurements The power meter displays the ratio of the sensors power values in either dB or percent The power value of each sensor includes offsets and cal factors in addition to measured power Also A B sets A as the active entry channel and B A sets B as the active entry channel Procedure To make B A ratio measurements press B A To make A B ratio measurements press the key and then B A Example To make B A ratio measurements LOCAL keystrokes program codes Program Codes AR BR SENSOR A B SENSOR B A
95. values set for each sensor Procedure To set a high limit or a low limit for the active entry channel a Address the power meter to listen b Send a program string in a Data message consisting of program code LL limit low or LH limit high a numeric value and program code EN ENTER To enable the limits checking function address the power meter to listen and then send a Data message with program code LM1 The limits checking function is disabled by program code LMO Example To set sensor A s low limit to 10 dBm and high limit to 20 dBm and to enable the limits checking function LOCAL keystrokes 3 not avallable In local AELL1OENLH2OENLM1 Enable Limits SETA Checking program codes Low Limit High Limit HP 438A Limits Program Codes Parameter Low Limit High Limit Enable Limits Checking Disable Limits checking Program Code LL LH Indications If the limits checking function is enabled and the input power exceeds the high limit or is less than the low limit the out of limits condition is indicated on the front panel by a flashing A or B annunciator depending on the measurement mode The out of limits condition is indicated only for sensors used in the current measurement For dual sensor measurements the out of limits condition is indicated for the sensor s out of limits The out of limits condition can be indicated over the bus by setting the Service Request Ma
96. which may or may not need to be connected for calibration Power Sensor Attenuator HP 8481B disconnected HP 8482B disconnected HP 8481D connected HP 8484A HP 11708A connected HP 8485D connected HP R Q8486D connected HP 8487D connected 1 To calibrate the power sensor to the meter first connect the sensor to the POWER REF output To see if your sensor requires an attenuator for calibration see the list above 2 Press the key and wait for the zeroing routine to finish 3 Press and enter the reference calibration factor Ref CF which is printed on the sensor label If you have a power sensor that does not specify the reference calibration factor assume it to be 100 4 Press and wait for the calibration routine to finish The sensor is now calibrated Operation 3 10 Operator s Checks 3 12 HP 438A 5 To see the results of the calibration first make sure the OSC light is on then press and enter the same reference calibration factor Ref CF that you entered for CAL ADJ Press ENTER The display should now read 1 mi 0 dBm except for the following sensors Power Sensor Display HP 8481B lH HP 8482B 1H HP 8481D i uM HP 8484A i uM HP 8485D i uM HP R Q8486D 1 uM HP 8487D 1 uM Operator s Checks are procedures designed to verify the proper operation of the power meter s main capabilities Two procedures are provided as described below Basic Functional Checks This procedure requires powe
97. 0 35 V TA CAP FXD 0 033uF 10 200 V POLYE FL CAP FXD 0 01uF 10 200 V POLYE FL CAP FXD 1uF 10 35 V TA CAP FXD 0 01uF 10 200 V POLYE FL CAP FXD 0 01uF 20 50 V CER X7R CAP FXD iuF 10 35 V TA CAP FXD 1uF 20 50 V CER Z5U CAP FXD 0 22uF 80 20 200 V CER X5V CAP FXD 1uF 10 50 V CER Y5R CAP FXD 10uF 20 25 V TA CAP FXD 6 1uF 10 35 V TA CAP FXD luF 10 35 V TA DIODE PWR RECT 400V 750MA DO 29 DIODE PWR RECT 400V 750MA DO 29 DIODE PWR RECT 400V 1 5A DIODE PWR RECT 400V 750MA DO 29 DIODE PWR RECT 400V 1 5A DIODE PWR RECT 400V 750MA DO 29 DIODE PWR RECT 400V 750MA DO 29 DIODE SWITCHING 80V 200MA 2NS DO 35 DIODE SWITCHING 80V 200MA 2NS DO 35 DIODE PWR RECT 400V 750MA DO 29 DIODE PWR RECT 400V 1 5A LED LAMP LUM INT 2MCD IP 25MA MAX BVR 5V LED LAMP LUM INT 2MCD IF 25MA MAX BVR 5V LED LAMP LUM INT 2MCD IF 25MA MAX BVR 5V LED LAMP LUM INT 2MCD IP 25MA MAX BVR 5V CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT SCREW MACH M3 X 0 5 10MM LG PAN HD SCREW MACH M3 X 0 5 10MM LG PAN HD NUT HEX DBI CHAM M3 X 0 5 2 9MM THK NUT HEX DBL CHAM M3 X 0 5 2 9MM THK HEAT SINK TO 5 TO 39 CS HEAT SINK SGL PLSTC PWR CS Replaceable Parts Code Part Number 00438 60009 150D105X9035A2 DYS HEW238T HEW 238T 150D105X9035A2 DYS HEW238T SA10
98. 0 75 Vdc The magnitude of the 15V supply should be within 0 05 volt of the 15V supply If both supplies are incorrect check to see if both the 5V Digital and Display indicators are illuminated If they are not illuminated continue troubleshooting on Service Sheet 9 If there is a problem with the 15 Volt Supply perform the 15 Volt Supply Test If there is a problem with the 15 Volt Supply perform the 15 Volt Supply Test 15 Volt Supply Test 1 Connect the oscilloscope or voltmeter to A9TP8 15V If the voltage is not 15 0 75 Vdc continue with step 2 If the voltage is 15 0 75 Vdc the supply is operating normally 2 Disconnect A10J1 and the red lead for the Fan Motor Control Module the lead is on A10 If the voltage is still incorrect continue with step 3 If the voltage returns to normal reconnect A10J1 If the voltage is stili normal the problem is with the Fan or the Fan Motor Control Module If the problem remains disconnect the following cables one at time until the voltage returns to normal 8 131 Service Sheet 10 HP 438A Note ug Remove the cables in the order given Cable Problem Location Related Service Sheets A5J3 Ad Service Sheet 7 A4J2 A4 Service Sheet 6 3 Check A9TP2 15V IN If A9TP2 is gt 20 Vdc replace A9UI If the voltage is incorrect the problem is in one of the following circuits 12V Fan Regulator 15V Regulator Filter capacitors 15V Bridge circuit Crow
99. 0160 3879 0160 3879 0160 2027 0160 3070 0180 0100 0160 2255 0160 3878 0160 0179 0160 3879 0160 7088 0160 7087 1901 0518 1901 0518 0122 0299 1250 1220 00436 80001 9140 0144 00436 80002 R O e O HF OWN M O WH O Om M o sn OY O YN MO W m O O O GG C UG ph Pe b bel Se Fe ee pko M mE th bet bei ee fei CAP FXD 0 01uF 20 50 V CER X7R DIODE PWR RECT 400V 750MA DO 29 DIODE PWR RECT 400V 750MA DO 29 CONN POST TYPE 100 PIN SPCG 8 CONT CONNECTOR SGL CONT PIN 1 14 MM BSC SZ SQ CONNECTOR SGL CONT PIN 1 14 MM BSC SZ SQ CONN POST TYPE 156 PIN SPCG 6 CONT SCREW MACH M3 X 0 5 10MM LG PAN HD NUT HEX DBL CHAM M3 X 0 5 2 9MM THK HEAT SINK SGL PLSTC PWR CS WASHER LK HLCL NO 4 115 IN ID SCREW MACH 4 40 25 IN LG PAN HD POZI WASHER FL MTLC NO 4 125 IN ID SUPPORT BOARD BUSHING HEAT SINK COMPOUND SIL CONNECTOR SGL CONT TML TS PT IC V RGLTR FXD POS 11 5 12 5V TO 220 PKG RESISTOR 0 CWM CONNECTOR PC EDGE 18 CONT ROW 2 ROWS CONNECTOR PC EDGE 18 CONT ROW 2 ROWS 50MHZ OSC BD AN BD AY 50MHZ OSC CAP FXD 0 01uF 20 100 V CER X7R CAP FXD 0 01uF 20 100 V CER X7R CAP FXD 0 01uF 20 100 V CER X7R CAP FXD 300pF 5 500 V MICA CAP FXD 100pF 4 596 300 V MICA CAP FXD 4 7uF 10 35 V TA CAP FXD 8 2pF 3 05 500 V CER CoG CAP FXD 1000pF 20 100 V CER X7R CAP FXD 33pF 4 596 300 V MICA CAP FXD 0 01uF 20 100 V CER X7R CAP FXD 36pF 4 296 300 V GL CAP FXD 200pF 2 300 V GL DIODE SCHOTTKY SM SI
100. 01688 017658 0155 0188 y 31000A NY3 90 qe 108 NOD HO LO OND L8 5 100 L LOLY LNZWNHLSNI LNOHDNOBHL SUQ1V1NDIY 83141103U A No OL 133HS 301AU3S ANI NO NMOHS 38Y S3I JddnS 2 440 83MOd Ab OL ONY ASI INNI AS1 3HL e 133H 391AH3S ALTE NO NMOHS 3UV S31 1ddNS U3MOd 1ndNI 49 AVIdS1G QNY TYLISIG AS 3Hl Z AGE ATBWZSSY HOLY1ND3H 6Y A 1830K3 SINIOd 1853 2 ONY 310N 103NNOOEGINI OLY BY ONY SG3T IO oM Vivo 3 u31Jl103H QV CLA NOILO3S AlddNS u3MOd E SOLYTITOSO 13303 30N383438 ZHW_OS 200 NOI1dO 25 338 BOLYTTIOSO pres ZHW OS 30N383338 Mu ZHN OS 8 TINNYHO 01 lt 8 ge suosn3s V T3NNVHO OL TA Y nm ove l ova ava ONI TOS HOSN3S HOA JEREMI ODU Nivo 7 NOLLYSNIdWOJ 139430 0U37 OLNY HOSNIS 40191838 HOSNIS 200 SOIVUG EE 1AL 1708 ZH 022 34180 80103130 8 TS was 80103130 ZSVHd O Em SE WLIDIG H3X31d u31113 83131 T NIV 90 NY iinW SSYd MOT AE SSYdaNyg 1904 VON311Y EH zygyjywa OZVONILLY 5 SNONOBHONAS gt r 031341 14HY A y nas bdLSYY ino 03193138 TINNVHO dNOD 378YN3 AYTdSIO AS AVidSiQ ZY JOYS BIAIBS 108 udididdWV NEVA SY H3ld3 INY IDdNI yy CEA NOI103S HJI4l TddV Sv Oi ON3 dMYH ie 1vNOIS TOBLNOO NO 1039 1dn883INI SU3G0030 Suvwrdos 29v2831M1 Ba ODIN 1041N09 30V JU3INI 0 1 LNOHDNOEKL dek ONY G Y d GNY gi dH 901vNY G38n STYNDIS ON INL SONNO SS
101. 0333 308533 32N353433 QNDOED EOSN3S Ov GZTUHYS lt tH 932 10343338 vi gy3 O DY HOSNIS i X2Y6G323 f83IZ RV i DOEN EEIE KE 39N383438 ov 338v HYA 0812 BG Lt ONAOHY 40193130 IM HOLYSNI LY i EA OSNIS 39YHd gt ZDMY j 0119313 SNONQEMONAS SE E EK ov GZIdHYG tH 002 ITGWY NTVW Sv O d retreat em X M ATGRA SY U2Ijt1dWV ifldN bY O d NOI O S H3dl 12WV H A180W3SSY El 19848 2914188 08 HP 438A Service Sheets 1 4 TTT eege Service Sheets 1 4 Central Processing Unit Troubleshooting General The following troubleshooting is for Service Sheets 1 through 4 Extended Test Mode allows the power meter to report calibration and zeroing errors Signature Analysis in most cases will isolate a problem to the component level Extended Test Mode Turn off the power meter To put the power meter into extended test mode set A3S1 to decimal 14 as shown in Figure 8 18 Turn on the power meter FRONT PANEL i Figure 8 18 A3S1 Decimal 14 Setting Extended test mode allows for HP IB control of the DAC s and Variable Gain Amplifier When the power meter is in extended test mode the following calibration and zeroing error messages may be displayed on the microprocessor board LED s A3DS1 8 51 Service Sheets 1 4 HP 438A Table 8 6 Extended
102. 047 0160 4065 0160 4554 2110 0001 2110 0421 1250 0083 5021 8413 00438 00018 00438 20035 5041 8803 5001 0538 RESISTOR 1 47K 1 125W TF TC 0 100 RESISTOR 10K 1 05W PN TC 0 4 10 RESISTOR TRMR 2K 10 TKF SIDE ADJ 17 TRN RESISTOR 6 8K 1 05W PN TC 0 10 RESISTOR 7 5K 4 196 125W TF TC 0 4 100 RESISTOR 100K 1 05W TP TC 0 100 RESISTOR 100K 1 125W TF TC 0 100 RESISTOR 100K 1 05W TF TC 0 100 RESISTOR 1K 4 196 125W TF TC 0 100 RESISTOR 1K 4 195 125W TP TC 0 100 RESISTOR 10K 4 196 125W TF TC 0 100 RESISTOR 5 11K 1 125W TF TC 0 4 100 RESISTOR 75 1 125W TF TC 0 100 RESISTOR 1 33K 4 196 125W TF TC 0 100 RESISTOR 50 0 1 125W TF TC 0 4 25 CONNECTOR SGL CONT PIN 1 14 MM BSC SZ SQ CONNECTOR SGL CONT PIN 1 14 MM BSC SZ SQ IC OP AMP LOW NOISE 8 PIN TO 99 IC OP AMP GP 8 PIN TO 99 DIODE ZNR 1N827 6 2V 5 DO 7 PDz 4W DIODE ZNR 8 2V 5 DO 35 PDz 4W TC 065 CAP FXD 5000pF 80 20 0 V CER X5V CAP FXD 5000pF 80 20 0 V CER X5V WASHER LK INTL T NO 8 168 IN ID WASHER LK INTL T NO 10 195 IN ID NUT HEX DBL CHAM 8 32 THD 085 IN THK NUT HEX DBL CHAM 10 32 THD 067 IN THK CAN RECT 72 IN DP OUT 1 959 IN WD OUT 50MHZ OSC BD AY OPTION 002 ONLY FAN ASSY CAP FXD 0 1UF 20 250VAC RMS PART OF Su CAP FXD 0 01uF 20 50 V CER X7R FUSE 1A 250V NTD 1 25X 25 UL PART OF S1 FUSE INCH 375A 250V TD FE UL CONNECTOR RF BNC FEM SGL HOLE FR 50 OHM FRAME FRT 88 1H PANEL FRONT FRAME REAR TRIM STRIP
103. 10 00 0 04 dBm 9 96 dBm____ 10 04 dBm Press the power meter key and verify that the display indicates G op 0 01dB HP 438A Note Performance Tests Range Calibrator Actual Results Setting Max 3 uW 3 13 pW 3 19 uW 10 pW 9 90 pW 10 10 pW 30 pW 31 3 pW 31 9 pW 100 aW 99 0 GW 101 0 pW 300 pW 0 314 mW 0 318 mW l mW 0 995 mW 1 005 mW 3 mW 3 13 mW 3 19 mW 10 mW 9 90 mW 10 10 mW 30 mW 31 3 mW 31 9 mW 100 mW 99 0 mW 101 0 mW It is not necessary to check instrument accuracy in dBm The power meter uses the same internal circuitry to measure power and mathematically converts watts to dBm 4 7 Performance Tests HP 438A eege 4 10 Power Reference Level Test Specification Electrical Performance Limits Characteristics Characteristics Internal 50 MHz oscillator factory set to 0 7 traceable to National Bureau of Standards Power reference 1 0 mW Power reference Worst case Accuracy RSS for one year Description The power reference oscillator output is factory adjusted to 1 mW 0 7 To achieve this accuracy Hewlett Packard employs a special measurement system accurate to 0 5 traceable to the National Bureau of Standards and allows for a transfer error of 0 2 in making the adjustment If an equivalent measurement system is employed for verification the power reference oscillator output can be verified to 1 mW 1 9 1 2
104. 13 Remote message then send a Data message KB 95 EN Check that the power meter s RMT and LSN annunciators are on and that the display indicates the channel A cal factor is set to 95 This check determines whether or not the power meter properly receives the Local Lockout message disabling all front panel keys including Lech This check also determines whether or not the Clear Lockout Set Local message is properly received and executed by the power meter This check assumes the power meter is in remote mode Description Series 200 300 BASIC Send the Local Lockout message LOCAL LOCKOUT 7 Check that the RMT annunciator is on Press the power meter s key The RMT annunciator should remain on Operation 3 20 Clear Message HP 438A Description Series 200 300 BASIC LOCAL 7 Send the Clear Lockout Set Local message Check that the power meter s RMT annunciator is off Description Series 200 300 BASIC Return the power meter to remote mode if the REMOTE 713 remaining checks in this section are to be performed Check that the power meter s RMT annunciator is on This check determines whether or not the power meter properly responds to the Clear message This check assumes that the power meter is in remote mode Description Series 200 300 BASIC Send a Data message to set the cal factor to 98 596 OUTPUT 713 KB 98 5 EN Check that the powe
105. 15 V TA CAP FXD 22uF 10 15 V TA CAP FXD 22uF 10 15 V TA CAP FXD 22uF 10 15 V TA CAP FXD 10uF 10 20 V TA CAP FXD 10uF 10 20 V TA CAP FXD 33uF 10 10 V TA CAP FXD 0 039uF 4 596 200 V POLYC MET CAP FXD 0 039uF 5 200 V POLYC MET CAP FXD 0 01uF 20 50 V CER AFR DIODE SCHOTTKY SM SIG DIODE SCHOTTKY SM SIG DIODE SCHOTTK Y SM SIG HP 438A Mfr Manufacturer Code Part Number 02037 02037 01698 03406 03406 01698 01698 01698 01698 01698 01698 01698 01698 13307 13307 13307 28480 01417 SN74LS259N SN74LS259N SN74LS139AN MM74C74N LM319N SN74LSOON SN74LS04N SN74LS112AN SN74LS245N SN74LS377N SN7407N SN7407N SN74LS148N ULN 2074B ULN 2074B ULN 2074B 00438 60034 H3 102 16 000MHZ 28480 04200 04200 02010 02010 04200 04200 04200 04200 05176 05176 04200 04200 04200 04200 04200 00438 60004 109D106X0060C2 DYP 109D106X0060C2 DYP SA105C103MAAH SA105C103MAAH 109D106X0060C2 DYP 109D106X0060C2 DYP 150D606X9006B2 DYS 150D606X9006B2 DYS HEW238T HEW238T 150D226X9015B2 DYS 150D226X9015B2 DYS 150D226X9015B2 DYS 150D226X9015B2 DYS 150D106X9020B2 DYS 04200 150D106X9020B2 DYS 04200 150D336X9010B2 DYS 05176 HEW 249 05176 HEW 249 02010 SA105C103MAAH 02062 QSCH1186 02062 QSCH1186 02062 QSCH1186 HP 438A Replaceable Parts Table 6 3 Replaceable Parts continued Reference HP Description Mfr
106. 2 the fast filter is active If the number is 3 through 9 the slow filter is active The CPU selects the output of the required filter The low pass filter output that is selected is determined by the digital filter that is selected It is important to understand that the digital filter is not a circuit It is an averaging function that is performed by the software and controlled by the front panel and keys The selection of the slow and fast filters is determined as follows 1 If the digital filter number is 0 1 or 2 the fast low pass filter 45 ms is selected 2 If the digital filter number is 3 through 9 the slow low pass filter 800 ms is selected A detailed description of digital filtering is provided later in this service sheet The output of the low pass filter is buffered and applied to the following two circuits 1 The summing point of the offset removal DAC Service Sheet 7 The use of this output was described previously 2 The Analog Digital Input Multiplexer The Analog Digital Multiplexer can select any one of the following signals as the ADC analog to digital converter input to the comparator HP 438A gt R 05 or Service Sheet BD3 The low pass filter output The front and or rear sensor resistors for sensors connected to channels A or B The B GND 0V The auto zero DAC output this signal is only selected for testing The offset removal DAC output this signal is s
107. 5 Calculate the offset DAC settings to match these new values 6 Find the gain DAC settings required to provide a full scale 1 Vdc output at the rear panel RCDR recorder connector After the power sensor and power meter are correctly zeroed and calibrated they can be used to make power measurements within the specified parameters of the combined instruments Digital Filter Software Routine Digital Filter The most important point to understand about the digital filter is that it is a software routine and not a hardware component It does however have a direct bearing on the selection of the slow or fast low pass filter The selected combination of these two filters determine the speed resolution and stability jitter of the final measurement result The digital filter is an averaging filter The value returned by the digital filter is the average of the last N power readings where N is the HP 438A Troubleshooting Hints Service Sheet BD3 filter length The filter length is determined by two being raised to some power where that power is the filter range number zero through nine The filter number can be manually selected using the front panel key or automatically selected by the software if the key is active The relationship between the selected filter number and the filter length is as follows Filter Filter Length Number Number of Readings 0 1 i The troubleshooting checks on this service sheet are used to n
108. 5003 09 1537 76 R 4012 00438 20029 2N4393 2N2905A MSP10A01 CCF 55 1 T 1 MSP10A01 H8 CCF 55 1 T 1 CCF 55 1 T 1 HP 438A Replaceable Parts Table 6 3 Replaceable Parts continued Reference HP C Qty Description Manufacturer Designation Part No D Code Part Number 1 0757 0439 0698 3441 0757 0123 0757 0279 0698 8638 0698 8638 0699 0842 0757 0420 0699 0148 0757 0296 0699 0924 0757 0280 0757 0465 0757 0442 0757 0465 0757 0442 0811 3351 0811 3348 0757 0465 0757 0442 0757 0442 0698 3156 0698 3156 0698 3156 0698 3156 0698 3158 0698 3158 0698 3158 0698 3158 0698 3442 0698 3441 0757 0442 0698 3441 0757 1094 0757 0461 0757 0465 0757 0463 0698 3453 0757 0470 0757 0288 0698 3157 0698 3161 0757 0462 4 Go o 6 G 6 O Go Oo os 9 6 9 1 6 6 9 9 2 2 2 2 4 4 4 4 9 8 9 8 9 2 6 4 2 3 i 3 9 3 mb bech Ech bei debo bei bebo Sei Sch Fei 0 e ti bi ti ei Fi bah bal eA bai rh r ra bi m eA r Ra bd Tra md m fet F eh F Fa r Fa R ri kd RESISTOR 6 81K 1 125W TF TC 0 100 RESISTOR 215 4 196 125W TF TC 0 100 RESISTOR 34 8K 4 196 125W TF TC 0 100 RESISTOR 3 16K 1 125W TF TC 0 100 RESISTOR 3 16K 0 1 325W TF TCz04 25 RESISTOR 3 16K 0 1 125W TF TC 0 25 RESISTOR 6 19K 0 1 125W TF TC 0 25 RESISTOR 750 1 125W TF TC 04 100 RESISTOR 31 6K 0 1 1W TF TC 0 15 RESISTOR 6 19K 4 195
109. 5C103MAAH 150D105X9035A2 DYS SR835E1085MAAH SR402E224ZA AH FD41Y5R1H105K 199D1112 150D104X9035A2 DYS 150D105X9035A2 DYS SS5117 SS5117 5117 SS5117 85117 01542 HLMP 1301 01542 HLMP 1301 01542 HLMP 1301 01542 HLMP 1301 04055 04055 04055 04055 04055 04055 04055 04055 09908 09908 06691 06691 05792 TXBF 032 025B 02608 6073B 6 21 Replaceable Parts A9MP15 1205 0353 3 A9MP16 2190 0003 ASMP17 2190 0003 A9MP18 3050 0105 A9MP19 3050 0105 A9MP20 5000 9043 A9MP21 5040 6843 A9MP22 08673 20063 A9MP23 ASQ1 A9Q2 A9R1 A9R2 A9R3 A9RA A9R5 A9R6 A9R7 A9R8 A9R9 A9R10 A9R11 A9R12 A9R13 A9R14 A9R15 A9R16 A9R17 A9R18 A9U1 A9U2 A9VR1 A9VR2 6040 0239 1884 0244 1884 0244 0757 1094 0757 0280 2100 2633 0757 0280 0757 0280 0757 0418 0757 0397 0757 0288 0698 3447 0698 3447 0698 3154 0698 3444 0757 0440 0751 0440 0757 0398 2100 2633 0757 1094 0757 1094 1826 0607 1826 0527 1902 0952 1902 0176 noon wo om O A A m WOW m ON 0 O DH ose A10 A10C1 A1002 A10C3 A10C4 A1005 A10C6 A10C7 A10C8 00438 60006 0180 3286 0180 3283 0180 3282 0160 3638 0180 1743 0160 4554 0160 4554 0160 4554 4 1 co W W 6 22 Reference HP CIQty Designation Part No D tO rh Sei ei SE
110. 8 23 Data Bus Test Pattern Bit Pattern Start Test 1 Test 1 Test 1 Test 2 Tests Restart Start Complete Complete Complete 1 RAM 1 A3U12 0 0 RAM 2 A3U13 How many times the test was executed and passed 0 0 0 0 0 0 0 0 oo O c CO O ba m O OO FF EO O O O Oe Fi 0 1 1 1 1 1 1 D4 D7 count in binary For version 5 0 ignore RAM 1 A3U12 not A 3 used If a RAM failure occurs the test will flash LED s for bits DO D1 indicating a proble with A3U12 or flash LED s for bits D2 D3 when A3U13 has a problem 2 Reset A3S1 to 1 0001 If RAM is operating properly perform I O Data Bus Buffer Check I O Data Bus Buffer Check U39 Service Sheet 1 1 Move the QUAL line to U39 pin 19 set QUAL to LO and verify the signatures for 5 volts versions 5 0 and 2 0 2881 and ground 0000 are as shown 2 Verify the signatures in Table 8 24 Note 8 65 Service Sheets 1 4 HP 438A Table 8 24 I O Data Bus Buffer Signatures 5 0 If all the signatures are correct perform the Miscellaneous Checks If any of the signatures are incorrect go to step 3 3 Move the QUAL line to U39 pin 1 set QUAL to LO and verify the signatures for 5 volts version 5 0 7610 version 2 0 H843 and ground 0000 are as shown 4 Verify the signatures in Table 8 25 Table 8 25 1 O Data Bus Buffer Signatures m Sena Number Name 228 F U960 9HHP 5F
111. 8 53 8 55 8 55 8 56 8 56 8 57 8 58 8 59 xiii Contents xiv 8 15 8 16 8 17 8 18 8 19 8 20 8 21 8 22 8 23 8 24 8 25 8 26 8 27 8 28 8 29 8 30 8 31 8 32 8 33 8 34 8 35 8 36 8 37 Address Bus Signatures 4 4 1 1 Address Bus Signatures 1 1 1 Address Bus Signatures pee Data Line Logic Levels 1 1 1 1 1 Microprocessor Data Bus Buffer Signatures Microprocessor Data Bus Buffer Signatures Microprocessor Data Bus Buffer Signatures Meory Data Bus Buffer Signatures Data Bus Test Pattern 1 1 1 4 I O Data Bus Buffer Signatures I O Data Bus Buffer Signatures I O and Display Address Decode Signatures Analog I O PIA Signatures i Cathode Data Display and Keyboard Scan PIA igtatgres ve Aer EUN a 603 Tier A D and Software Signatures Analog I O PIA Signatures Anode Data Display Drivers Voltage Levels Digital I O Signatures w a a ses Digital O Signatures lt s e wia owa Zero BAC Buffer Signatures Offset DAC Buffer Signatures Gain DAC Buffer Signatures Miscellaneous Buffer Signatures HP 8990A 8 59 8 59 8 60 8 61 8 63 8 63 8 64 8 64 8 65 8 66 8 66 8 67 8 68 8 69 8 70 8 70 8 82 8 97 8 97 8 98 8 99 8 101 HP 438A
112. 9 28480 00438 20036 28480 00438 20037 28480 00438 00012 28480 2190 0104 04805 2950 0132 04604 00436 20014 28480 1251 3362 05879 0510 1148 11544 7120 3104 02154 7120 3105 02154 2200 0164 04771 2206 0166 04771 5041 1682 28480 0362 0227 27264 0360 1190 04880 00438 00001 28480 00438 20031 28480 00438 20026 28480 00438 20025 28480 00438 00009 28480 7120 4163 22670 00438 00002 28480 0515 0886 69908 2200 0164 04771 1400 0249 04225 00438 60041 28480 Table 6 3 Replaceable Parts continued Description COVER UTOP PRF COVER BTM U TOP TILT STAND SST REAR PANEL FOOT FULL 1 2MOD FAN GRILLE SCREW TPG 8 16 375 IN LG PAN HD POZI WASHER LK INTL T 3 8 IN 377 IN ID NUT HEX DBL CHAM 3 8 32 THD 094 IN THK PLUG HOLE TR HD FOR 438 D HOLE BRS PLUG HOLE TR HD FOR 688 D HOLE NYL SIDE STRUT SUPPORT CABLE PANEL SUB SCREEN RFI WINDOW LIGHT PIPE 19MM SUPPRT BOT S PNL SUPPRT TOP PNL SUPPORT CABLE WASHER LK INTL T 7 16 IN 439 IN ID NUT HEX DBL CHAM 7 16 28 THD 094 IN THK WASHR MOUNT CONN NUT AUDIO CONN RETAINER PUSH ON KB TO SHFT EXT WIRE MARKER SGL LTR A PLSTC SPR CLP PVC WIRE MARKER SGL LTR B PLSTC SPR CLP PVC SCREW MACH 4 40 188 IN LG UNCT 82 DEG SCREW MACH 4 40 312 IN LG 82 DEG KEY CAP LINE CONNECTOR SGL CONT SKT 1 14 MM BSC SZ SQ TERMINAL SLDR LUG PL MTG FOR 3 8 SOR DECK BOARD SUPPORT PUSHROD SWITCH CLIP PUSHROD SUPPORT AMPLIFIER LABEL WARNING 5 IN WD 1 IN LG AL SHIELD INPUT AMP SCREW MACH M3 X 0 5 6MM LG PA
113. A Table 8 2 Schematic Diagram Notes 1 of 8 Test point symbols Stars are numbered or lettered for casy correlation Interconnection information of schematic diagrams procedures and locator illustrations Circled letter indicates circuit Arrow connecting star to meas Star shown connected to path continues on another urement point signifies no circuit signifies measuring aid schematic diagram Look for measuring aid provided metal post circuit pad etc same circled letter on service provided sheet indicated bv adjacent bold number 3 in this example Plug in connection information Assembiy part number Socket designation for A2 assembly Number indicates Assembly name pin of socket XA2 Assembly designation x Stage name PN A2 DC REGULATOR ASSY 08708 60007 Maus Mid T M E mmm 33 not mounted on assembly A2 SERIES m REGULATOR iil REFERENCE DESIGNATIGHS wiTHMIN OUTLINED were en ASSEMBLIES ARE ABBREVIATED FULL D SIGNATION iN CLUDES ASSEMBLY NUMBER rg RI OF ASSEMBLY Al IS AIR DESIOMATIONS OF CYMER COMPONENTS ARE COMPLETE AS SHOWN d 8 S Non plug in B connection information Solder point EE named REFERENCE DESIGNATION NO PREFIX A2 ASSY Circuit board common Connector symbols within the Dagger indicates borderlines of circuit assemb AS i Cl circuit change See lies signify connections to the 3 o section VII as
114. A5Q6 and A5Q7 with the waveforms in Figure 8 48 If the signal at the collector of A5Q6 is incorrect replace A5Q6 A5R19 or A5R20 If the signal at the collector of A5Q7 is incorrect replace A5Q7 A5R21 or A5R22 If the signal at A5TP19 is not as shown in Figure 8 47 replace A5U26 or A5R38 Low Pass Filters Set up the equipment as described in the Fault Isolation procedure Select MNL Filter 0 If A5U21 pin 8 is a logical low lt 0 8V continue troubleshooting on Service Sheet 7 Verify that A5U21 pin 9 is the complement of A5U21 pin 8 If pin 9 is not the complement of pin 8 replace A5U13 Select MNL Filter 9 If A5U21 pin 8 is high gt 2 0V continue troubleshooting on Service Sheet T Again verify that A5U21 pin 9 is the complement of A5U21 pin 8 If pin 9 is not the complement of pin 8 replace ASU13 At this point the control lines that control the Filter Switch have been verified The following steps will verify that the switch will pass and block a signal 8 Connect a jumper from the 5 volt supply ASTP7 to A5TP16 and measure A5U24 pin 14 The voltage at A5U24 pin 14 should be 8 4 0 4 Vdc HP 438A Note 10 li 12 Service Sheet 8 If the voltage at A5U24 pin 14 is incorrect check the voltage at A5U24 pin 12 If the voltage at A5U24 pin 12 is equal to the 5 volt supply replace A5U24 A5R83 or A5R84 If the voltage is incorrect replace A5U21
115. AC Circuits 8 43 Amplifier Detector Filter and Comparator dlc PLI 8 44 1 mW 50 MHz Power Reference Circuit 8 46 Digital Filter Software Routine Digital Filter 8 46 Troubleshooting Hints 8 47 Power Sensor to First Amplifier Interface Check 8 47 Service Sheet 1 4 General s 4 ee ue A AHS ee wow s 8 51 Extended Test Mode 8 51 HP IB Commands in Extended Test Mode 8 53 Signature Analysis Mode Checks 8 54 Free Run Signature Analysis 1 8 54 Address Bus Signatures 1 4 8 58 Reset Power Fail Test Voltage Checks 8 60 Timing Check 05x X E 0 ux A 8 60 Free Run Mode Troubleshooting 8 61 Data Bus 1655845 31e a ox Sos wee ee 8 62 Miscellaneous Checks a a we 8 71 vii Contents HP 438A Service Sheet 5 General 4 voe Were M Sct ee CU odes 4 8 81 Fault Isolation Procedure 8 81 Service Sheet 6 General zh Ro r Reip DOSE AE A AN A 8 87 Fault Isolation Procedure 8 87 Amplifier Test eats xi EUER vs 8 89 220 Hz Buffer Test omo emm s 8 90 220 Hz Multivibrator Test 8 00 Channel Selection Circuitry Test 8 91 Decoupled Power Supply Test 8 92 Service Sheet 7 General Las w BOZE GR a ah Xa gs WA 8 95 Fault Isolation Procedure 8 95 Digital I O Test sida as 8 96 Auto Zero DAC an
116. B Codes to Parameter Summary HP IB Parameter Code LLL Sensor A minus Sensor B measurement Low Limit SET A Sensor measurement A B ratio measurement Sensor B minus Sensor measurement SET B Channel B measurement B A ratio measurement CAL ADJ Clear Status Byte Display All Display Disable Display Enable DSP OFS ENTER AUTO FILTER Filter Hold MNL FILTER Ignore Group Execute Trigger GET bus command Trigger Immediate response to Group Execute Trigger Trigger with Delay response to Group Execute Trigger CAL FACTOR Log dB or dBm High Limit Disable limits checking function Enable limits checking function Linear Watts or Learn Mode 1 Learn Mode 2 Reference Oscillator off Reference Oscillator on OFFSET PRESET AUTO RANGE RECALL Range Hold Exit REL mode Enter REL mode MNL RANGE Service Request Mask Value Status Message STORE Trigger Hold Trigger Immediate Trigger with Delay Trigger Free Run ZERO Prefix for Service Request Mask identification 1 These commands are fully compatable with the HP 437B Power Meter HP IB command codes 2 Requires numeric entry followed by program code EN 3 47 Cal Adj HP 438A Cal Adj 3 48 Description CAL ADJ is used to calibrate the power meter and any compatible power sensor to a known reference During the calibration cycle the gain of the power meter is adjusted so that the front panel dis
117. C3 6U3U OCHF 89HP F315 If any signature is incorrect replace U39 If all signatures are correct connect the signature analyzer as follows CHOICE MF pp falling edge SAM uo costas IA Sese Reuse la dt asa Cre Eus rising edge ERR CEE Ee falling edge 8 66 HP 438A Service Sheets 1 4 6 Verify the signatures for 4 5 volts version 5 0 and 2 0 9UCF and ground 0000 are as shown 7 Verify the signatures in Table 8 26 Table 8 26 I O and Display Address Decode Signatures A3U27 Pin 11 12 13 14 15 A3U33 Pin 9 10 11 12 If all signatures are correct perform the Analog I O PIA Check If any signature is incorrect replace the integrated circuit associated with the bad signature Analog UO PIA Check U21 Service Sheet 3 1 Connect the QUAL line to U21 pin 23 Verify that the controls on the signature analyzer are set as follows PARODI ES AO E S EAE Tees QUAL Clock LE falling edge E EE rising edge UOP m falling edge Qual TN LO edge 2 Verify the signatures for 5 volts versions 5 0 and 2 0 494F and ground 0000 are as shown 3 Verify the signatures in Table 8 27 8 67 Service Sheets 1 4 8 68 HP 438A Table 8 27 Analog UO PIA Signatures Fs Sia Number Name Lo 5 0 U21 26 ID7 1D6 ID5 ID4 1D3 1D2 ID IDO AAO AA AA AADO AADI AAD2 AAD3 AAD4 AAD5 AAD6 AAD If any signature is incorrect replace U21 If all signatures are corr
118. D NEREK Single Sensor Measurements Sensor A B and Sensor B A Dual Sensor Difference Measurements Sensor A B and Sensor B A Dual Sensor Ratio Measurements Set A And Set B X ug o3 oec ada OAK Store and Recall PEZET ZERO dob oun PERPE Atak ED 4 Performance Tests a iub is Ew 86 W doe thy 4 2 Equipment Required TEC T SAN W Z 4 3 Performance Test Record 4 4 Performance Tests P a e b tates E 4 5 Calibration Cycle ew Boe WA WW 4 6 Abbreviated Performance Test 4 7 Test Procedures Vu dece a bos 4 8 Zero Carryover Test 44 4 ee 4 9 Instrument Accuracy Test 4 10 Power Reference Level Test 3 43 3 43 3 43 3 43 3 44 3 45 3 45 3 46 3 46 3 48 3 51 3 53 3 55 3 55 3 55 3 56 3 60 3 60 3 64 3 66 3 66 3 69 3 71 3 73 3 74 3 76 3 76 3 78 3 78 3 80 3 80 3 82 3 84 3 86 4 1 4 1 4 1 4 1 4 2 4 2 4 2 4 3 4 5 4 8 Contents HP 438A 5 Adjustments 5 1 Introduction ea Mw i ae Se vx ae 5 1 5 2 Safety Considerations 5 1 5 3 Equipment Required 9 1 5 4 Factory Selected Components 5 1 5 5 Interrelated Adjustments 5 2 5 6 Post Repair Adjustments 5 2 5 7 15 Volt Power Supply Adjustment 5 3 5 8 5 Volt Power Supply Adjustment 5 4 5 9 Analo
119. D 1 NORMAL OPERATION DEPRESSED g DEPRESSED 1 NORMAL OPERATION FRONT PANEL 5 5 Adjustments 5 6 HP 438A Turn the power meter ON The instrument should now display LLL uu oo cs Connect the DVM between B GND A5TP2 and 2 5V REF A5TP8 testpoints on A5 Read the DVM Enter the reading to 5 digits 4 decimal places into the power meter by entering the numbers into the keyboard then pressing ENTER Adjust the ADC SLOPE A5R61 so that the display reading is centered about zero The reading may be from 5 00 to 5 00 try to get as close to zero as possible Turn the power meter OFF Return A381 to its original position HP 438A Adjustments EEN 5 10 220 Hz Frequency Adjustment Reference Description Equipment Procedure Service Sheet 6 The 220 Hz is adjusted for maximum power meter readout HP 438A POWER METER RANGE CALIBRATOR Figure 5 3 220 Hz Frequency Adjustment Setup Range Calibrator sex sieut seis i dete VESPERE HP 11683A Turn both the power meter and the range calibrator ON Set the range calibrator controls as follows LINT orbs Meteo E ES pde esi acu Ed E ON RANG osse cM stood cen amba M LE i mW FUNCION opens o beso ER EO eil eai STANDBY EEN oot ortas rem eod vede ede lod pe ae NORMAL Connect the range calibrator output to channel A using the sensor cable Press on the power meter then press ZERO and allow time approximately 15 to 17
120. DISPLAY DISPLAY SOL STA RED DISPLAY NUM SEG 5 CHAR 11 H DISPLAY NUM SEG 5 CHAR 11 H LED LAMP LUM INT 1MCD IF 30MA MAX BVR 5V CONN POST TYPE 100 PIN SPCG 34 CONT SPACER RVT ON 25 IN LG 152 IN ID LABEL INFO CBL AY DISPLAY SOCKET IC DIP 14 CONT DIP DIP SLDR SOCKET IC DIP 14 CONT DIP DIP SLDR SOCKET IC DIP 14 CONT DIP DIP SLDR SOCKET IC DIP 14 CONT DIP DIP SLDR SOCKET IC DIP 14 CON T DIP DIP SLDR SOCKET IC DIP 14 CONT DIP DIP SLDR SOCKET IC DIP 14 CONT DIP DIP SLDR SOCKET IC DIP 14 CONT DIP DIP SLDR SOCKET IC DIP 16 CONT DIP DIP SLDR SOCKET IC DIP 16 CONT DIP DIP SLDR SOCKET IC DIP 16 CONT DIP DIP SLDR SOCKET IC DIP 14 CONT DIP DIP SLDR SOCKET IC DIP 14 CONT DIP DIP SLDR SOCKET IC DIP 16 CONT DIP DIP SLDR SOCKET IC DIP 16 CONT DIP DIP SLDR MICROPROCR BD AY BATTERY 3V 16A HR LITHIUM POLYCARBON CAP FXD 100uF 20 10 V TA CAP FXD 2 2uF 10 50 V TA CAP FXD 0 0luF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 1 5uF 10 20 V TA CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 022uF 20 100 V CER X7R CAP FXD 6 8uF 10 35 V TA 5560 9436 5560 9436 5560 9436 5560 9436 00438 60033 06438 66002 HDSP 3533 HLMP 2620 5082 7415 5082 7415 3431 6202 00438 80006 00438 60031 ICS 314 HGT ICS 314 HGT ICS 314 HGT ICS 314 HGT ICS 314 HGT ICS 314 HGT ICS 314 HGT ICS 314 HGT SEP 20363 01 SEP 20363 01 SEP 20363 01 ICS 314 HGT ICS 314
121. ECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT RESISTOR TRMR 2K 10 TKF SIDE ADJ 17 TRN 05524 COP 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 140 140 140 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CMF 55 1 T 9 CCF 55 1 T 1 89PR2K CCF 55 1 T 1 CCF 55 1 T 1 PTF 56 7 MTR5 50PPM DEG C 200K 0 1 CCF 55 1 T 1 COCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 PTF 56 7 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 85 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 HP 438A Replaceable Parts Table 6 3 Replaceable Parts continued Reference HP Ci Qty Description Designation Part No iD Code Part Number AS TP10 ASTP11 ASTP12 A5TP13 A5TP14 A5TP15 ASTP16 ASTP17 A5TP18 A5TP19 A5TP20 A5U1 A5U2 ABUS A5U4 ABUS A5U6 A5U7 A5U8 A5U9 A5U10 ASUI ABU12 A5U13 A5U14 A5U15 A5U16 A5U17 A5U18 A5U19 A5U20 ABU21 A5U22 A5U23 A5U24 A5U25 A5U26 A5U27 A5U28 ASVRI ASVR2 A5VR3 ASW11 0360 0535 0 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 1826 1460 1826 0471 1826 0921 1820 1997 1820 1934 1820 1997 1826 0098 1826 0026 1826 0471 1820 1934 1820 1997 1826
122. EF OSC SEE A1W4 SEE A2W5 SEE A3W6 CABLE ASSY HP IB LINE SWITCH AY WIRING HARNESS SEE A4W13 SEE A5Wi1i1 OPT 903 18 AWG 3 COND 90 IN LG CABLE AY REAR OPTION 002 ONLY CABLE AY REAR OPTION 002 ONLY CBL AY REF OSC OPTION 002 ONLY WIRING HARNESS POWER SENSOR CABLE 5 FT DELETED WITH OPTION 004 00438 60046 00438 60038 00438 60052 00438 60046 00438 60038 00438 60052 CH7081 00438 60051 00438 60051 00438 60026 00438 60048 11730A 8120 1378 00438 60051 00438 60051 00438 60026 00438 60048 11730A W17 W18 6 26 Replaceable Parts HP 438A FRONT PANEL Y LU a O A lt ep LO a z INTO STAND OFFS Figure 6 1 Front Panel Illustrated Parts Breakdown 6 27 Replaceable Parts HP 438A REAR PANEL MP47 ONLY OPT 002 MP46 ONLY OPT 002 MP91 MP33 J4 OPT ONLY P O W13 J5 OPT ONLY P O W14 J6 OPT ONLY P O W15 MP 16 MP17 MP14 U1 Figure 6 2 Rear Panel Illustrated Parts Breakdown 6 28 HP 438A Replaceable Parts CABINET PARTS Figure 6 3 Cabinet Parts 6 29 Replaceable Parts 30 HP 438A Table 6 4 Code list of Manufacturers Mir Manufacturer Code Name BUEHLER GEBR NACHFOLGER GMBII NIPPON ELECTRIC CO ANY SATISFACTORY SUPPLIER ALLEN BRADLEY CO INC TI INC SEMICOND COMPONENTS DIV SPECT
123. ER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 4 209 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP EXD 0 01uF 20 50 V CER ATR CAP FXD 0 01uF 20 50 V CER XTR CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 80 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R DIODE GEN PRP 35V 50MA DO 35 DIODE SCHOTTKY SM SIG DIODE SCHOTTKY SM SIG DIODE ARRAY DIODE ARRAY DIODE ARRAY LED LAMP ARRAY LUM INT 500UCD LED LAMP ARRAY LUM INT 500UCD CONN POST TYPE 100 PIN SPCG 24 CONT 02010 SA105C103MA AH SA105C103MA AH SA105C103MA AH SA105C103MA AH 838 546 X5E 471K 180D106X9020B2 DYS FD12C0G2D100D 199D1134 SA105C103MA AH SA105C103MAAH SALO5C103MAAH SA105C103MAAH SA105C103MA AH SA105C103MAAH SA105CI03MAAH SA105C103MA AH SA105C103MA AH SA105C103MAAH SA105C103MA AH SA105C103MA AH SA105C103MAAH SA105C103MA AH SA105C103MA AH SA105C103MAAH SA105C103MA AH SA105C103MAAH SA105C103M A AH SA105C103MAAH SA105C103MAAH SA105C103MA AH SA105C103MAAH SA105C103MAAH SA105C103MAAH SA105C103MAAH 303 5082 2835 50825510 TND908 TND908 TND908 HLMP 6204 HLMP 6204 499345 5 HP 438A Replaceable Parts Table 6 3 Replaceable Parts continued R
124. G DIODE SCHOTTKY SM SIG DIODE VVC 82PF 5 C 2 C20 MIN 2 CONNECTOR RF SMC M PC 50 OHM COIL VARIABLE INDUCTOR RF CH MLD 4 7UH 10 COIL 3 1 2 TURNS SA105C103MA AH SS85117 555117 87800 107 16 06 0034 16 06 0034 26 60 1060 5040 0170 08673 20063 120 UAT812UC 1 2007 1 252 18 50 123 252 18 50 123 00438 60010 00436 60011 SR201C103MA AH SR201C103MAAH SR201C103MA AH CD15FD301JO3 CD15FD101JOS3 150D475X9035B2 DYS 301 000 COH0 829C SR201C102MA AH CD15ED330J03 SR201C103MAAH TY06 360G CY06C201G 5082 5509 5082 5509 050 051 0109 220 00436 80001 1025 36 00436 80002 6 23 Replaceable Parts Table 6 3 Replaceable Parts continued Reference HP bag Description Mfr Designation Part No Code G1A1Q1 1854 0247 TRANSISTOR NPN SI TO 39 PDz1W FT 800MHZ G1A1Q2 1854 0810 TRANSISTOR NPN SI PD 625MW FT 200MHZ GIAIRI 0757 0442 RESISTOR 10K 1 125W TF TO 0 100 G1A1R2 G1A1R3 G1A1R4 G1A1R5 GIA1R6 G1A1R7 GIA1R8 G1A1R9 G1A1R10 G1A1R11 G1A1R12 GIA1R13 GiA1R14 GIAIR15 GIA1R16 GIA1TP1 GIA1TP2 G1A1U1 G1A1U2 GiAIVRI GLAIVR2 G102 G1C3 GIMP2 G1MP3 G1MP5 G1MP6 G1MP8 0757 1094 0811 3234 2100 3109 0811 3682 0757 0440 0698 7284 0757 0465 0698 7284 0757 0280 0757 0280 0757 0442 0757 0438 0757 0398 0757 0317 0698 6364 1251 0600 1251 0600 1826 0013 1820 0223 1902 0680 1902 0956 0160 3036 0160 3036 2190 0009 2190 0124 2580 0002 2950 0078 7100 1204 00438 60010 00438 60
125. GUYOBAJA LV Sth y Y f DE Ti BHI k gt i oN 13S3UN BE t NOTIYNSIS3U 33N36333H SNOLLJBNNOJ UNIONS GHY 39Y170A 1102812 O31YH531NI d t 1581 0287 56 t 0285 6PRZ 0Z8T bErE Gast ESE OZS 202 0385 Side USSR oie Big VIA is en HHR Leite W V A WE bu SuagMnN LUYd S310N WYGSYT SIIYW3H2S B04 2 8 JTAYE OL EEN 3108 i g E 2 G ZE void LIQQHIS Q31YH931NI ONY HOISISNYHi ares Dt UIE 84 t AM ore ra D w aiiidng SAG Vivg 0 10 ias TT 8 H pT CN 13413034 18 kir chal Can Rf zm SNOTIYNSTS2U JINGI oM 01 00 B 8 L NOI1039 N UNE sora Boas p Nm 833408 3413038 1 NSNYUL _ p SI88YS 80JAJ8 VIVO Bl dH LINA 9NISS3008d 1VEIN3O LY O d S 0109 88700 suoneoo7 J uauodwo5 Ajqwassy pun Duissadold 2 4439 07 8 anG voice p cd AEN a A18N3SSV V V8 t dH 91 8 62 8 weeg ayewiayos synod Aouio PUL J0ssaoo0Jdoq0l E2 8 ANIA tv O d 18 Se ven a s KI et rin et oi tel gi BEA i LYND SZ 305383338 FL ico BE 62 So o o o 1 l i 1 1 i t 1 A or MM o or d b Dep pl vo pn iq fei 20 math dOi M314 dO M3 dOi W it GkYOe cuvog E 8E LINSHIS 1300819 eeney art Br 8 tle o d o i 1 i o 3 d c abi ocO OL MIA dOi uvog i el St vi sey 1480810 LI Rab S 8Bi OZBi 6i L 0ZBi SliG S al f 51i O281 t i608 8tv20 7382 0684
126. HGT SEP 20363 01 SEP 20363 01 00438 60103 BR 2325 199D1147 199D1134 SA108C103MAAH SA105C103MA AH 150D155X9020A2 DYS SA105C103MAAH SA105C103MAAH SA105C103MAAH SR201C223MA AH 199D1131 6 7 Replaceable Parts Table 6 3 Replaceable Parts ES HP 438A Reference HP S Qty Description Mfr Manufacturer Designation Part No Code Part Number 6 8 0160 4554 0160 4554 0160 4554 0160 4554 0160 3455 0180 0374 0160 3874 0180 2620 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 0160 4554 1901 0376 1901 1085 1901 0539 1906 0275 1906 0275 1906 0275 1990 0933 1990 0933 1252 1276 CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 4 209 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER A7R CAP FXD 470pF 10 1 kV CER X5E CAP FXD 10uF 10 20 V TA CAP FXD 10pF 4 596 200 V CER CoG CAP FXD 2 2uF 10 50 V TA CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 80 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V C
127. HP 438A TTT TTT eege Service Sheet BD1 Overall Block Diagram Principles of Operation General The power meter is a microprocessor controlled dual channel power meter with a built in 1 mW 50 MHz power reference Figure 8 1 shows a simplified overall diagram of the power meter For purposes of explanation and troubleshooting the power meter is divided into the following three functional sections 1 The Controller Section 2 The Amplifier Section 3 The Power Supply Section CONTROLLER SECTION A2 DISPLAY A3 CENTRAL PROCESSING UNIT Ai KEYBOARD i AMPLIFIER SECTION A4 INPUT AMPLIFIER AS MAIN AMPLIFIER ey 94 RCDR i ha wn wat wm d SENSOR B Z 6 POWER SUPPLY SECTION Gi SR MHz REFERENCE OSCILLATOR 11 A8 A9 A10 USED POWER SUP SE Serien gt THROUGHOUT INSTRUMENT 3 18 Figure 8 1 Power Meter Simplified Overall Diagram The Controller Section enables the functions that the user requests by pressing front panel keys local operation or by HP IB program codes remote operation The overall power range and frequency response of the power meter is determined by the power sensors that are connected to channel A and channel D HP 438A Note Service Sheet BD1 Under microprocessor control the analog power inputs from the power sensors are measured and digitized by the Amplifier Section The Controller Section calculates and display
128. IAS H IMPD QUAD 14 PIN ANALOG SWITCH 4 SPST 16 CERDIP IC OP AMP GP 8 PIN DIP P IC OP AMP GP 8 PIN DIP P IC OP AMP LOW DRIFT 8 PIN TO 99 DIODE ZNR 1N827 6 2V 5 DO 7 PD 4W DIODE ZNR 3 6V 5 DO 35 PD 4W TCz 036 DIODE ZNR 1N827 6 2V 5 DO 7 PD 4W CBL AY ANALG INP LM201AN OP 07CJ SELECTED AD7533CD DM74LS374N DAC 08EQ DM74LS374N LM211H LM311H OP 07CJ SELECTED DAC 08EQ DM74LS374N SN74LS04N DM74LS374N SN74LS138N DM74LS374N OPOTDJ SN74L5244N DG508ACJ DG201ABK DG201ABK DG201ABK TLO74ACN TLOT4ACN DG201ABK 04078 LM201AN 04078 LM201AN 02180 OP 07CJ SELECTED 02037 1N827 02037 1N827 28480 00438 60035 6 19 Replaceable Parts Designation A8 A8C1 A8C2 A8C3 A8CR1 A8CR2 A8CR3 A8MP1 A8MP2 ASMP3 A8MP4 ASMP5 A8MP6 A8MP7 A8MP8 A8MP9 A8MP10 ASMP11 A8MP12 A8MP13 sz ASMP14 ASMP15 A8MP16 A8MP17 A8MP18 A8MP19 A8MP20 A8MP21 A8MP22 A8MP23 A8MP24 A8MP25 A8MP26 ASMP 27 A8MP28 A8MP29 A8MP30 A8MP31 A8MP32 A8R1 A8U1 A8U2 6 20 HP Part No 00438 60008 8 0160 4554 0160 4554 0180 0291 1901 0028 1901 0028 1906 0231 0515 1087 0515 1087 0515 1087 0515 1087 0515 1087 0515 1087 0590 1076 0590 1076 0590 1076 0590 1076 0590 1076 0590 1076 1200 0081 1200 0081 1200 0081 1200 0081 1200 0081 1200 0081 1251 2313 1251 2313 1251 2313 1251 2313 1251 2313 1251 2313 2190 0003 2190 0003 2190 0003 2190 0003 2190 0003 2190 0003 00438 20021
129. ISO 39N3Y3338 H3MOd LVLD H3A02 HOLVT1I2SO 39N3H3434 H3M0d LVLO S i i d 13A SV18 A 4018 LINDHID NO 310N 1311 ATAWISSV 200 NOILdO LVZD LVLD 7 Weer dH Service Sheet 11 HP 438A INTERNAL TOP VIEW 4 i AL Figure 8 65 Internal Top View 8 141 Service Sheet 11 HP 438A gt ES wi OPT 002 ONLY wi OPT 002 ONLY W15 OPT 002 AS J2 ONLY MP 73 PIONI AS J 8 G2 OPT 082 Wit ONLY AS J3 AS Figure 8 66 Internal Bottom View 8 142
130. J CAL FACTOR dBm WATT Logarithmic Linear Units Error Messages Filters Limits OFFSET PRESET Range REL Relative Measurements SET A and SET B 3 85 zero HP 438A Zero 3 86 Note Description ZERO is used to adjust the power meter s internal circuitry for a 0 power indication when no power is applied to the sensor Pressing the key automatically zeroes all five of the power meter s ranges For dual sensor measurements each channel of the power meter must be zeroed separately Be sure that no power is applied to the sensor while the power meter is zeroing Any applied RF input power introduces an offset that affects all subsequent measurements Procedure To zero the power meter to the sensor connected to the active entry channel press ZERO Example To zero the power meter LOCAL fkeystrokes um program codes Program Codes Parameter Program Code ZE HP 438A Zero indications The power meter display shows eight dashes and a moving decimal point while zeroing When the zeroing is completed new zero values are stored and the instrument is returned to its previous state Comments Zero the power meter before entering the reference calibration factor The power meter s internal reference oscillator automatically turns off during zeroing If the reference oscillator was on before the zeroing was initiated it will be returned to the on state when zeroing is co
131. L SYMBOLOGY REFERENCE INFORMATION Sequential Logic Functions Cont d mCNTR Counter Array of flip flops connected to form a counter with modulus m m is replaced with a number that indicates the number of states 5 CNTR 10 CNTR etc REG Register Array of unconnected flip flops that form a simple register or latch SREG Shift Register Array of flip flops that form a register with internal connections that permit shifting the contents from flip flop to flip flop ROM Read Only Memory Addressable memory with read out capability only RAM Random Access Memory Addressable memory with read in and read out capability Dependency Notation mAm Address Dependency Binary affecting inputs of affected outputs The m prefix is replaced with a number that differentiates between several address inputs indicates dependency or indicates demultiplexing and multiplexing of address inputs and outputs The m suffix indicates the number of cells that can be addressed Gm Gate AND Dependency Binary affecting input with an AND relationship to those inputs or outputs labeled with the same identifier The m is replaced with a number or letter the identifier Cm Control Dependency Binary affecting input used where more than a simple AND relationship exists between the C input and the affected inputs and outputs used only with D type flip flops Vm OR Dependency Binary affecting input with an OR relationship to those inputs or ou
132. N HD SCREW MACH 4 40 188 IN LG UNCT 82 DEG CABLE TIE 062 625 DIA 091 WD NYL SWITCH PUSHBUTTON LINE ON OFF KIT 00438 00019 5041 8801 08147 PLASTITE 1920 02 28200 10 101 BS 51043 K1105 2673 BLACK 5021 5831 00438 00012 00438 00017 00438 20020 00438 20023 5040 6889 00438 20036 00438 20037 00438 00012 1922 04 76500NP 00436 20014 91 T 422 6 9 669 C8P LETTER A C8P LETTER B A M nm e Mi ba N Na NENA bo RO NN N N o o o oh h d ja pd 5041 1682 02 05 5223 720 380H 00438 00001 00438 20031 00438 20026 00438 20025 00438 00009 ph pi o Mi E 00438 00002 TY 23M 8 00438 60041 eC O 04 W G M W om O W o D m 4 D GG d to HN O gt O Go HF CO HB WD o Oo t u lt MH bi bei A M Fei bel Se 6 25 Replaceable Parts HP 438A Designation Part No Di Code _ Part Number TI 9100 4342 4 9100 4342 0960 0443 0960 0443 00438 60050 00438 60050 00438 60050 00438 60050 00438 60026 00438 60026 Table 6 3 Replaceable Parts continued Description TRANSFORMER LINE MODULE FILTERED PART OF 1 CABLE AY FRONT CABLE AY FRONT CBL AY R
133. Normal 2 Connect the calibrator to channel A Select MNL Filter 2 If A5U13 pin 3 is not a TTL high gt 2 0V continue troubleshooting on Service Sheet 7 Verify that A5U13 pin 4 is the complement of A5U13 pin 3 If pin 4 is not the complement of pin 3 replace A5U13 3 Select MNL Filter 3 If A5U13 pin 3 is not a TTL Low 0 8V continue troubleshooting on Service Sheet 7 Press AUTO FILTER 4 Connect an oscilloscope to A5TP4 Comp out and compare the displayed waveform with Figure 8 40 8 107 Service Sheet 8 HP 438A 1V DIV 10 ms DIV Figure 8 40 Ramp End Waveform If the waveform is correct the circuits on Service Sheet 8 are operating normally If Performance Test 4 9 Instrument Accuracy Test indicates that there is a range to range accuracy problem perform the Range Attenuator Tests If the signal at A5TP4 is not correct perform the following tests in the order given 1 Compare the waveform at A5TP1 with Figure 8 41 If it is incorrect perform the Reference Ramp Start Gate and Ramp Generator Tests If the waveform is normal continue with step 2 1V DIV 5 ms DIV Figure 8 41 Analog to Digital Converter Ramp Waveform 2 Compare the waveform at ASTP18 with Figure 8 42 If the waveform is incorrect perform the Range Attenuator 1 100 and Variable Gain Amplifier Tests If the waveform is normal continue with step 3 8 108 HP 438A Service Sheet 8 1 ms DIV Figure 8 42 Variable Gai
134. O 650 14067 INDUCTOR RF CH MLD 100NH 10 10M100K INDUCTOR FIXED Z gt 1200 OHMS 120 TO 650 14067 INDUCTOR FIXED Z gt 1200 OHMS 120 TO 650 14067 TRANSISTOR NPN SI PD 625MW FT 200MHZ TRANSISTOR NPN SI PDz625MW FT 200MHZ TRANSISTOR NPN SI PD 625MW FT 200MHZ TRANSISTOR PNP SI PD 625MW FT 200MHZ TRANSISTOR PNP SI PD 625MW FT 200MHZ RESISTOR 15 5 3W PWI TC 0 20 RESISTOR 10 1 125 W TF TC 0 100 RESISTOR 10 1 125W TF TC 60 100 RESISTOR 422 1 125W TF TC 0 100 RESISTOR 10 1 125W TF TC 0 4 100 RESISTOR 10 1 125W TF TC 0 4 100 RESISTOR 422 1 125W TF TC 0 100 RESISTOR 42 2K 1 125W TF TC 0 4 100 RESISTOR 42 2K 1 125W TF TC 0 100 RESISTOR 100K 1 125W TF TC 0 100 RESISTOR 100K 1 125W TF TC 0 100 RESISTOR 14 7K 1 125W TF TC 0 100 RESISTOR 14 7K 1 125W TF TC 0 100 RESISTOR 56 2K 1 125W TF TC 0 100 RESISTOR 56 2K 1 125W TF TC 0 100 RESISTOR 26 1K 1 125W TE TC 0 100 RESISTOR 26 1K 1 125W TF TC 0 100 RS 2B CCF 55 1 T 1 CCF 55 1 T 1 COF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 6 13 Replaceable Parts Reference HP C Designation Part No D 0698 3450
135. P 438A The key to understanding the operation of the firmware is to understand that it resides in ROM and is interrupted at 1 ms intervals by hardware generated interrupt During these 1 ms intervals the firmware accomplishes the required configuration changes calculations and updates to perform all of the power meter s defined functions SCAN AND SOFTWARE DEBOUNCE KEYSOARD INPUTS REFRESH DISPLAYED INFORMATION i START AND MONITOR ADC INPUT VALUE TO DIGITAL FILTER WHEN REQUIRED PERFORM TASK 2 PERFORM TASK 1 Figure 8 2 Interrupt Control Routine Flowchart The firmware has the following three main routines 1 The interrupt routine provides synchronous control of all power meter functions 2 The task 1 routine primarily handles user commands both front panel and HP TB A flowchart of the Task 1 routine is shown in Figure 8 3 3 The task 2 routine primarily handles the mathematical calculations for the required measurement results and sets error flags when required A flowchart of the Task 2 routine is shown in Figure 8 4 HP 438A Service Sheet BD1 HP IB PERFORM HP IB FUNCT ION PENDING FUNCTION KEYBOARD PERFORM APPLICABLE COMMAND KEYBOARD COMMAND PENDING ROUTINE NEW FORMAT DATA AND DATA UPDATE DISPLAY INPUT 2 BUFFERS i Figure 8 3 Task 1 Flowchart When the instrument powers up the status byte is set to 0 and a GT2 trigger with delay response to group execute
136. P10A01 4116R 001 681 4116R 001 681 761 3 R220 CMF 50 2 761 3 R220 761 3 R220 CCF 55 1 T 1 CCF 55 1 T 1 MSP10A01 CMF 65 2 CCF 55 1 T 1 CCF 55 1 T 1 CMF 65 2 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 MSP10A01 CMF 50 2 HP 438A Reference HP Ci Qty Designation Part No D 0698 7220 0698 7220 3101 2172 3101 2761 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 0360 0535 1820 2075 1820 2024 1820 2024 1820 1858 1820 1858 1820 1858 1820 2075 00438 80036 1820 2024 1818 3183 1820 1212 1820 2024 1820 3513 1820 3431 1820 2024 1820 2624 1820 2705 1820 2983 1820 2983 1820 1427 1820 0668 1820 0668 1820 0668 1820 1216 00438 80013 1820 2549 1820 2024 9 WoW A Qo A A c 6 W H W W Qo ONY Qo d Qo w e O oO O D O O O O w Table 6 3 Replaceable Parts continued Description RESISTOR 215 1 05W TF TC 0 100 RESISTOR 215 1 05W TP TCz 04 100 SWITCH DIP RKR 4 SPDT 0 05A 30VDC SWITCH DIP SL 7 1A 0 1A 30VDC CONNEC TOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS
137. RA9 Range Attenuator 1 10 100 1 Perform the Gain Attenuator Buffer Test if it has not already been performed Measure the voltage at ASTP7 4 5V using ASTP20 as ground Connect A5TP7 to A5U25 pin 11 Select MNL Range 1 If the voltage on A5U25 pin 10 is not equal to the voltage at A5TP7 0 01 volts replace A5U25 Select MNL range 4 If the voltage on A5U25 pin 10 is not equal to the voltage at ASTP7 divided by 10 plus or minus 0 01 volts replace A5U25 A5R53 A5R54 or A5R55 Select MNL Range 5 If the voltage on A5U25 pin 10 is not equal to the voltage at ASTP7 divided by 100 plus or minus 0 001 Vdc replace A5U25 A5R53 A5R55 AC Gain Stage Test SS Measure the gain of the AC Gain Stage The gain is equal to the voltage at ASTP15 divided by the voltage at A5U23 pin 3 The gain should be about 240 If there is no signal at ASTP15 replace A5U23 If the gain is significantly off 20 check the gains of ASU23A and A5U23B and replace the associated components if necessary The gain of A5U23A should be 27 5 and is equal to the voltage at A5U23 pin 1 divided by the voltage at A5U23 pin 3 The gain of A5U23B is 10 4 and is equal to the voltage at ASTP15 divided by the voltage at A5TP14 Synchronous Phase Detector Test ie 2 Set up the equipment as described in the Fault Isolation procedure Compare the waveform at ASTP19 to Figure 8 47 8 113 Service Sheet 8 HP 438A A The amplitud
138. ROL ELECTRONICS CORP CHEMCENTRAL K D I PYROFILM MOTOROLA SEMICONDUCTOR PRODUCTS UNICORP EG amp G WAKEFIELD ENGR INC MEPCO ELECTRA INC ELECTROVERT INC PANDUIT CORP PRECISION MONOLITHICS INC FAIRCHILD CORP T D R ELECTRONICS INC THERMALLOY CO SPRAGUE ELECTRIC SEMICON DIV CORNING ELECTRONICS MEPCO ELECTRA INC MICRO OHM CORP TRANSITRON ELECTRONIC CORP CORNING ELECTRONICS SIEMENS CORP NATIONAL SEMICONDUCTOR CORP HEWLETT PACKARD CO CORP HQ RCA CORP SOLID STATE DIV MEPCO ELECTRA CORP SPRAGUE ELECTRIC CO BECKMAN INDUSTRIAL CORP LITTLEFUSE INC Address NURNBERG GM TOKYO JP EL PASO TX US DALLAS TX CITY OF IND CA CHICAGO IL US WHIPPANY NJ PHOENIX AZ ORANGE Nj WAKEFIELD MA US MORRISTOWN NJ US ELMFORD NY TINLEY PARK IL SANTA CLARA CA MOUNTAIN VIEW CA US BRISTOL RI DALLAS TX CONCORD NH RALEIGH NC US MINERAL WELLS TX US EL MONTE CA WAREFIELD MA SANTA CLARA CA US ISELIN NJ SANTA CLARA CA PALO ALTO CA SOMERVILLE NJ SAN DIEGO CA NORTH ADAMS MA FULLERTON CA US DES PLAINES IL US MANUAL CHANGES Note This manual does not contain any backdating information If backdating information is required for operating or repairing your HP 438A with serial prefix 2822A or 2839U and below you must purchase manual part number 00438 90015 7 1 Service 8 1 Introduction 8 2 Service Sheets 8 5 Safety Considerations This section contains information required for servicing the power met
139. Related Interface mmand Functions Co l LLO The power meter returns to local mode front panel control It responds equally to the Go To Local GTL bus command and the front panel key Disables all front panel keys including LCL Only the controller can return the power meter to local front panel control The power meter returns to local mode front panel control Local Lockout is cleared when the bus control line goes false The power meter has no controller RLI co capability The power meter sets the SRQ bus SRQ SR1 control line true if one of the following conditions exists and has Pass Control Take Control Require Service been enabled via the Service Request Mask to send the message for that condition data ready cal zero completed entry error measurement error or over under limits 1 Commands control lines and interface functions are defined by ANSI IEEE Standard 488 1 Knowledge of these may not be necessary if your controller s manual describes programming in terms of the twelve messages in the HP IB Message column 3 26 HP 438A Operation Table 3 2 Message Reference Table continued HP IB Message Applicable Response Related Interface Command Functions Status Byte Yes The power meter responds to a SPE SPD T5 Serial Poll Enable SPE bus command by sending an 8 bit byte when addressed to talk
140. SE X0 en NE E ovas E F T e0iS REN Di Zeg i POS G civit i DIEC sora owi LL gv E HM HAE AN Er a 2 bh lo 1 gt a i e Z sa i sd i w 0 J a ch E L aous ain 1 2 1 gt Nm 1089 3008 JOBO Na hre tll i Y33366 HO IMS HO IMS i w NOI LONE w e NO E LONN d Nee 9834308 SSZEJJY Ay ej JOEAGAS t9108 8tP00 LIN ONISSJJOWd IVUINSO tV O d u0118907 juguodwoy Ajquassy un butssad01d je quag O d 22 8 9JnDrJ auvog 40 3018 LINOHI LON A18W31SSV V v8tr dH 84 8 44 8 wwesBerq oneweayos Sun Yid aoejiaja jeJaudueg pue out 6z g ANGLA 80 o I l o rio WIN GOL Malt del O8 OE 22 5 immo SER Y Lin o0 izq o o H t H t o en a d so Di RE m4 Maid dOi Milk dOL WK Zz D2ntv 1lfiou io uo op gud bo o o 3 B H i 1 t i o oe A eo D cH fp MZIA JOL Mala dol Hyo DENG 1380610 l i MR erer eg 8 seres ie La ei HO e DE Le vn d 1 eb sp E Nid EE ESOU ONY 29v 320A lf oklO QaivBOaiNl Dot SJABYS ADIAJS ea R ovv i iua i H H 1411784111 EE E EE EN EEN 1 Zig BBLi Bli Bra TR gizi 255 cert eee sole von H NOI S RO 2 S30 305363438 Qi LYNSESZO 328383336 SH39WAN vd LinOHlO Q3 VH93iN ONY u0JS SNYE M e M HH e V ias ums m TU MM AO tia nm S310N veryovig Ji ivAGHOS 3016YL OL 93439 TAS si epe M rt 5vVN
141. SOR B SENSOR A B and SENSOR B A SENSOR A B and SENSOR B A STORE and RECALL 3 75 Sensor A and Sensor B HP 438A ee NOOO Sensor A and Sensor B Single Sensor Measurements Description SENSOR A and SENSOR B cause the power meter to make single sensor measurements Absolute power is displayed for the selected sensor in either dBm or Watts In addition SENSOR A sets the active entry channel to A and SENSOR B sets the active entry channel to B Procedure To select a single sensor measurement mode press SENSOR A or SENSOR B J Example To select SENSOR A as the measurement mode LOCAL keystrokes program codes Program Codes Program Code SENSOR A SENSOR B Indications The middle block of annunciators on the front panel display indicate the measurement mode and the measurement units The cal factor and offset if any for the selected sensor are also indicated in the front panel display 3 76 HP 438A Sensor A and Sensor B Comments Filter range offset cal factor and limits can be set for the selected sensor PRESET sets the measurement mode to SENSOR A Single sensor measurements can be displayed relative to a stored reference In REL mode readings are dislayed in either dB or percent Changing the measurement mode causes the contents of the digital filter to be discarded Related Sections CAL FACTOR dBm WATT Logarithmiic Linear Units Filters OFFSET PRESET Ran
142. STOR 100 1 05W TF TC 04 100 CMF 50 2 A3R7 0698 7212 G 1 RESISTOR 100 4 195 05W TF TC 0 100 CMF 50 2 6 9 Replaceable Parts Table 6 3 Replaceable Parts continued HP 438A Reference HP i dk Description Manufacturer Designation Part No 5 Part Number A3R8 A3R9 A3R10 A3R11 A3R12 A3R13 A3RI4 A3R15 A3R16 A3Ri7 A3R18 A3R19 A3R20 A3R21 A3R22 A3R23 A3R24 A3R25 A3R26 A3R27 A3R28 A3R29 A3R30 A3R31 A3R32 A3R33 A3R34 A3R35 A3R36 A3R37 A3R38 A3R39 A3R40 A3R41 A3R42 A3R43 A3R44 A3R45 A3R46 A3R47 A3R48 A3R49 A3R50 0698 7236 1810 0280 0698 7268 0698 7268 0698 7268 0698 7269 0698 3460 0698 7236 0698 7212 0698 7220 0698 7220 0698 7220 0698 7220 0698 7220 0698 7220 0698 7253 0757 0317 0698 7260 0698 7260 0698 7236 0698 7220 0698 7212 1810 0273 1810 0265 1810 0265 1810 0247 0698 7232 1810 0247 1810 0247 0698 3430 0698 3430 1810 0411 0757 0984 0698 3430 0698 3430 0757 0984 0698 3430 0698 3430 0698 3430 0698 3430 0698 3430 1810 0273 0698 7220 6 10 RESISTOR 1K 4 196 05W TF TC 0 100 NETWORK RES 10 SIP 10 0K OHM X 9 RESISTOR 21 5K 1 05W TF TC 0 100 RESISTOR 21 5K 4 196 05W TF TC 0 4 100 RESISTOR 21 5K 4 196 05W TF TC 04 100 RESISTOR 23 7K 1 05W TF TC 0 106 RESISTOR 422K 1 125W TF TC 0 100 RESISTOR LK 4 196 05W TF TC 04 100 RESISTOR 100 1 05W TF TC 0 100 RESI
143. STOR 215 1 05W TF TC 0 100 RESISTOR 215 4 196 05W TF TC 0 4 100 RESISTOR 215 1 08W TF TC 0 100 RESISTOR 215 1 05W TF TC 0 100 RESISTOR 215 1 05W TF TC 0 100 RESISTOR 215 1 05W TF TC 0 100 RESISTOR 5 11K 1 05W TF TC 04 100 RESISTOR 1 33K 1 125W TF TC 04 100 RESISTOR 10K 1 05W TF TC 04 100 RESISTOR 10K 1 05W TF TC 0 100 RESISTOR 1K 1 05W TF TO 0 100 RESISTOR 215 1 05W TF TC 0 100 RESISTOR 100 1 05W TF TC 0 100 NETWORK RES 10 SIP 470 0 OHM X 9 NETWORK RES 16 DIP 680 0 OHM X 8 NETWORK RES 16 DIP 680 0 OHM X 8 NETWORK RES 16 DIP 220 0 OHM X 8 RESISTOR 681 1 05W TF TC 0 100 NETWORK RES 16 DIP 220 0 OHM X 8 NETWORK RES 16 DIP 220 0 OHM X 8 RESISTOR 21 5 1 125W TF TC 0 4 100 RESISTOR 21 5 1 125W TF TC 04 100 NETWORK RES 10 SIP 50 0 OHM X 9 RESISTOR 10 1 5W TF TC 0 100 RESISTOR 21 5 4 196 125W TF TC 0 106 RESISTOR 21 5 1 125W TF TC 0 100 RESISTOR 10 1 5W TF TC 04 100 RESISTOR 21 5 1 325W TF TCz04 100 RESISTOR 21 5 1 125W TF TC 04 100 RESISTOR 21 5 1 125W TF TC 09 100 RESISTOR 21 5 1 125W TE TC 0 100 RESISTOR 21 5 1 125W TF TCz04 100 NETWORK RES 10 SIP 470 0 OHM X 9 RESISTOR 215 1 05W TF TC 0 100 05524 CMF 50 2 MSP10A01 CMF 50 2 CMF 50 2 CMF 50 2 CMF 50 2 CCF 55 1 T 1 CMF 50 2 CMF 50 2 CMF 50 2 CMF 50 2 CMF 50 2 CMF 50 2 CMF 50 2 CMF 50 2 CMF 50 2 CCF 55 1 T 1 CMF 50 2 CMF 50 2 CMF 50 2 CMF 50 2 CMF 50 2 MS
144. Sending the Data Message HP 438A Description Series 200 300 BASIC Send the Remote message to the power meter REMOTE 713 Check that both the RMT and LSN annunciators are on Press on the power meter Check that the RMT annunciator is now off but that the LSN annunciator remains on This check determines whether or not the power meter properly issues Data messages when addressed to talk Before beginning this check set the power meter s LINE switch to OFF then to ON Press LCL If an HP Series 200 300 controller is used a short program is required to perform this check Description Series 200 300 BASIC Address the power meter to talk and store its 10 10 output in variable V 20 ENTER 713 V 30 DISP V 40 END Display the value of V Check that the power meter s TLK annunciator is on The controller should display the same value as the one shown in the power meter s display Note that the power meter displays data using engineering notation The controller may display the same value using a different format HP 438A Receiving the Data Message Local Lockout and Clear Lockout Set Local Messages Operation This check determines whether or not the power meter properly receives Data messages Description Series 200 300 BASIC Send the first part of the Remote message REMOTE 7 enabling the power meter to remote Address the power meter to listen completing the OUTPUT 7
145. TA CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 0 01uF 20 50 V CER X7R HP 438A Mfr Manufacturer Code Part Number 02608 6073B 5000 9043 5040 6843 08673 20063 120 1884 0244 1884 0244 CCF 55 1 T 1 OCF 55 1 T 1 82PARIK CCF 55 1 1 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 CCF 55 1 T 1 82PARIK CCF 55 1 T 1 CCF 55 1 T 1 LM340AT 15 LM337T Z30035 10RL 00438 60006 36DE183G015EA2P 36DE1056 674D183 SR402E224ZA AH 150D104X9035A2 DYS SA105C103MAAH SA105CLO3MAAH SA105C103MAAH HP 438A Table 6 3 Replaceable Parts continued Replaceable Parts Reference HP e Ss Description Mfr Manufacturer Designation Part No Code Part Number A1009 A10CR1 A10CR2 10J1 A10J2 A10J3 A10J4 AIOMP1 A10MP2 AIOMP3 AIOMP6 A10MP7 A10MP8 A10MP9 A10MP10 A10MP11 A10TPL A10U1 A10W1 A10XA8 A10XA9 Gi G1A1 G1A1C1 G1A1C4 G1A1C5 G1A1C06 G1A1C7 G1A1C8 G1A1C9 G1A1C10 G1A1C11 GIA1C12 G1A1C13 G1A1C14 G1A1CR1 G1A1CR2 G1A1CR3 G1A1Ji GIA1L1 G1A1L2 G1A1L3 0160 4554 1901 0028 1901 0028 1252 3491 1251 0600 1251 0600 1251 3638 0515 0925 0535 0004 1205 0353 2190 0003 2200 0103 3050 0105 040 0170 08673 20063 6040 0239 0360 0535 1826 0147 8159 0005 1251 8116 1251 8116 00438 60010 00436 60011 0160 3879
146. TC 074 DIODE ZNR 2 37V 5 DO 7 PD 4W TC 074 RESISTOR 0 CWM RESISTOR 0 CWM RESISTOR 0 CWM RESISTOR 0 CWM RESISTOR 0 CWM RESISTOR 0 CWM RESISTOR 0 CWM RESISTOR 0 CWM RESISTOR 0 CWM RESISTOR 0 CWM CABLE AY AMP SIG BD AY MAIN AMPL CAP FXD luF 10 35 V TA CAP FXD 1uF 10 35 V TA CAP FXD 2 2uF 10 20 V TA CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 1000pF 5 50 V CER CoG CAP FXD 0 01uF 20 50 V CER X7R CAP FXD 1uF 20 50 V CER Z5U CAP FXD 0 15uF 10 80 V POLYE FL CAP FXD 100pF 10 50 V CER X7R CAP FXD 100pF 10 50 V CER X7R CAP FXD 100pF 10 50 V CER X7R CAP FXD 2 2uF 10 20 V TA CAP FXD 2 2uF 4 10 20 V TA CAP FXD 2 2uF 10 20 V TA CAP FXD 2 2uF 10 20 V TA 04055 04055 04055 04055 04055 04055 01698 02883 01698 02883 01698 02037 02037 02037 02037 01339 01339 01339 01339 01339 01339 01339 01339 01339 01339 28480 28480 04200 04200 04200 02010 06352 02010 02010 05176 02010 02010 02010 04200 04200 04200 04200 TLO72ACP DG201ABK TLO72ACP DG201ABK TLO74ACN L 2007 1 L 2007 4 L 2007 1 L 2007 1 L 2007 1 L 2007 1 L 2007 1 L 2007 1 L 2007 1 L 2007 1 00438 60040 00438 60005 150D105X9035A2 DYS 150D105X9035A2 DYS 150D225X9020A2 DYS SA105C103MA AH DA13C0G1H102J SA105C103MAAH SR835E105MA AH HEW 238T SAI02A101K AAH SA102A101K AAH SA102A101KAAH 150D225X9020A2 DYS 150D225X9020A2 DYS 150D225X9020A2 DYS 150D225X9020A2 DYS 6 15 Repl
147. The Status Byte will be affected by the events that occur during the new measurement cycle Trigger immediate TR1 When the power meter receives the trigger immediate program code it makes one measurement in the shortest possible time The instrument then waits for the measurement results to be read While waiting the instrument can process most bus commands without losing the measurement results However if the instrument receives GET Group Execute Trigger new measurement cycle will be executed Once the measurement results are read onto the bus the power meter reverts to the hold mode Measurement results obtained via trigger immediate are normally valid only when the instrument is in a steady settled state Trigger with Delay TR2 Triggering with delay is identical to trigger immediate except the power meter inserts a settling time delay before taking the requested measurement This settling time is a function of the selected range and filter and is sufficient to produce valid accurate measurement results 3 33 Operation 3 21 Sending the Data 3 34 Message HP 438A Free Run TR3 This mode is identical to local operation and is the mode of operation in effect when no other trigger mode has been selected The measurement result data available to the bus is constantly being updated as rapidly as the power meter can make measurements Entry into remote from local via the key sets the power meter to the free run mo
148. This is followed by a shorter fiash of all dashes When the self test is finished the power meter will display no CH A or E WATT A or B Error 31 or 22 and flashing A or E Since the power meter stores the last active parameters in storage location 0 this stored information is what will be recalled and displayed during power up This is the reason for the A or B information being displayed 1 Verify that the power up internal diagnostics are exercised without any error messages other than na CH A ERROR 31 or no CH E ERROR 22 depending on which channel was active during power down 2 Press PRESET This sets the parameters for channel A and B to Cal Factor 100 0 Offset 0 00 dB Low Limit 0 00 dB High Limit 0 00 dB Auto Filter Auto Range 3 13 Operation HP 438A 3 Set the power meter to the following conditions Measurement Modes e sd ERR E tA AGE n even Sensor A Reference Oscillator A ee ae Sed DOR TIAM D OFF Active Entry Channel ex esci LAU WAS WN ZA A Measurement Units EE Watt Limits Gee AE OFF Rel Moder ibas OFF Group Execute Trigger Mode Trigger with Delay GT2 ds urs evade as Esse QUA PEE UL OP UN d Free Run 4 Connect a power sensor with associated cable to channel A input as shown in Figure 3 3 The error message should disappear and display will show either a power level or PLERSE amp and Error 15 Annunciators WATT A 100 CF and A on 5 Connect the power sensor to 1 mW
149. This particular select code address combination that is 713 is not necessary for these checks to be valid However the program lines presented here must be modified for any other combination These checks can be performed together or separately Any special requirements for a check are described at the beginning of the check HP 438A Initial Setup Equipment Remote and Local Messages and LCL Operation The test setup is the same for all of the checks Connect the equipment as shown in Figure 3 5 HP 438A POWER METER CONTROLLER POWER SENSOR Figure 3 5 HP IB Functional Checks Setup HP B Controller venerar HP 9000 Series 200 300 BASIC 2 0 Power Sensor 42 teca dues bou oA EL DERE REGA ZI a HP 848x series This check determines whether or not the power meter properly switches from local to remote control from remote to local control and whether or not key returns the instrument to local control Before beginning this check set the LINE switch to OFF then to ON Description Series 200 300 BASIC Send the Remote message by setting the Remote REMOTE 713 Enable bus contro line REN true and addressing the power meter to listen Check that the power meter s RMT and LSN annunciators are on Description Series 200 300 BASIC Send the Local message to the power meter LOCAL 713 Check that the power meter s RMT annunciator is off but its LSN annunciator is on 3 17 Operation
150. V 9 JONVY INM 13SJ4d Uu pue uo s10 ej1250 92919j91 YLOg suJn A84 si pe eisul st 200 uondo Gau HO pue UO 10104280 eguejajel Jemod ay sun y AH IN uv319 epow Aue ey Buifja9ueo 103 197 pue H31N3 palojue SI Aejdsip ay ul uorneunuojur USUM t LLYM uoneuiquio9 193941 Josuas aui Duijejqueo 10 pesn ZHI 0G je Mu SI euBis ay pue JojOauu00 N ad epoui abues one WEP ein dSQ pateidsip si lesjJo 3S0 wyo ys e SI jndjno esualajal 1amod ay Ue 18jua 0 jeuueyo pajoajas aui sosnej pare no eo e IIUM 134 6 YNO O SINGU pa ejdsip 338 43M0d G JONVY OLAV 9uauinu 40 Shay SNOVA jurod Ewop ay 10 g 13S sufis pue 10 v 138 aie SAQy 8l BADR S opow Ajqua ejep y uauA uoneue dxa parjiduiis eui ui euo eui 0 uonoun Aiepuooas e SAEY SASY au sasauiuaJed ui SIOqWAS 10 s19119 AG p9M0 10 91 sjoqe deo Asy ejeuM seoejd ul pue pajje3a1 aq ueo usaJauju U NOJU 0197 suomneoo 19151091 aDe10 s ur uonguojul 6 TIv038 810 98UU09 OIPNE 19EJU09 Z 9jeuigj gt nones ii A eesti TUS zs EE PRESSE x WEE ynon ese g pue y jeuueuo 01 sjndui eu 8 EX UO pau21iMs SI 49 aui ou 0 19M0d AJEWII 8 pue v Ni 3017 pe1nseoui 3q 01 S 3A8 1900 OM 10 a0U8JeJJIP 8U pue g y 01721 101 SMOE siu s ex Y 8 pue g v ey jo uoipbunj peius e sajqeug 131HS PUBLWILUOD SNG e WOJ 15020 EJO Ut LOU JI 9poui LOO eu 0 1938 19 0d au suinjag A81N3 HV319 191 Wid SI 19pJ0 0121 ay pue g SI jeuueyo
151. V source are such that they are equal but opposite in sign The 5V D digital is measured and adjusted second before the other adjustment procedures are started Make adjustments only in the order specified Table 5 2 lists the adjustments related to repairs or replacement of any of the assemblies Table 5 1 Factory Selected Components Dasis of Selection If the reference power is outside the range of 1 000 0 0007 mW Table 5 2 Post Repair Adjustments Tests and Checks Assembly Repaired Related Adjustment or Reference Al Keyboard A Display A3 Central Processing Unit A4 Input Amplifier AS Main Amplifier AS Rectifier 9 Regulator G1 50 MHz Reference Oscillator 5 2 Performance Test Service Sheet None None 5 7 5 8 5 9 5 7 5 8 5 10 5 11 5 7 5 8 5 9 4 10 4 11 4 12 4 13 5 7 5 8 4 8 4 9 5 7 5 8 5 7 9 8 5 12 5 13 HP 438A Adjustments y 5 7 15 Volt Power Supply Adjustment Reference Description Equipment Procedure Service Sheet 10 The 15 volt supply is measured then the 15 volt supply is measured and adjusted so that the supplies are equal in amplitude but of opposite sign DIGITAL VOLTMETER Figure 5 1 Power Supply Adjustments Setup Digital Voltmeter DVM weet ar Votes a e VR ade CR HP 3456A 1 Remove the top and bottom covers of the power meter Loosen the screws that secure the A3 CPU Assembly Turn the instrument ON a
152. YV Gu VP dH HP 438A Service Sheet 11 Service Sheet 11 Power Reference Oscillator Circuits Troubleshooting General Before trying to troubleshoot the G1A1 Assembly verify the presence of 15 Vde and 15 Vdc on the circuit board If the 15 volt supply is not correct troubleshoot the Cal Oscillator Control and Miscellaneous Buffer on Service Sheet 7 If a defect in the G1A1 Assembly is isolated and repaired the correct output level 1 mW 0 7 must be set by a very accurate power measurement system Hewlett Packard employs a special system accurate to 0 5 and traceable to the National Institute of Standards and Technology NIST When setting the power level a transfer error of 0 2 is introduced making the total error 0 7 If a system this accurate is available it may be used to set the proper output level Otherwise Hewlett Packard recommends returning the power meter so it can be reset at the factory Contact your nearest Hewlett Packard office for more information 50 MHz Oscillator Malfunctions of the oscillator circuit will occur as a wrong output frequency or as an abnormal output level The voltage at GIAITP2 will indicate if the ALC loop is trying to compensate for an incorrect output level l Modulation of the 50 MHz signal or spurious signals which are part of j the output may be caused by defects in GLAIR9 GIA1R10 GI1AIRI11 or G1A1C3 in the ALC loop ALC Loop and Power Supply Isolating p
153. Z TIS 13NNVHQ meme e uvas im ONY EP OM Le S316VO 40 Luyd 38v m SAB HARD MT atg E 296 NO LEO AYHL S3Ni7 BOLSISJE EOSNJS YNOF FHL 3ONVE got SE te AMOLOVE JRL iY AB I OWIO DNINND x ON i dYHS _ us Meno ccc AG ID ty Sa iv3k NaH 035 Si LYEL HOI02NWOO 3903 vans ee t E Then p Ue I GBYOS 1302810 GILNIBS hok em Y TANNYHO USPS EVA NR 9 9 1vW3H28 BOJ ZB 318V Of BATE Cl I eebe EE EE EE EE EE ERN ER EZR 3i0N 0009 8 00 A1dN3SSvV E3iJgiddMv IN NI PY O d HP 438A A4 ASSEMBLY FREQ Y Figure 8 32 Input Amplifier Assembly Component Locations HP 438A eee ae a al Service Sheet 7 Service Sheet 7 P O Main Amplifier Assembly Troubleshooting Note WS General The following procedures will help to isolate a problem to one of the following circuits Digital I O u Miscellaneous Buffer u Cal Oscillator Control m Auto Zero DAC and Buffer u Stable Current Source m Offset Removal DAC Buffer and Gain Compensation A5U9 m Gain DAC Buffer and Gain Compensation A5U2 The Fault Isolation Procedure should be used if the problem has not been isolated to a particular circuit If the problem is know to be in a particular circuit go directly to the troubleshooting for that circuit Whether performing the Fault Isolation Procedure or the troubleshooting for a particular circuit always perform the Power Supply Checks and the Digital I O Test first Test Equipment OSA DE
154. ZHGGY z 7 2 m Z HOSS300Bd QUO HA Sa 39v 3823INI QUVOBA33 30V dU3lNi AYIASIO LINO DNISSJOOGd TVUINJO EV OBYOBAJX LV 2 4 NOILO3S H3110HLNOO HP 438A Service Sheet BD2 Service Sheet BD2 Controller Section Principles of Operation General As shown on the block diagram the A3 Central Processing Unit CPU is the major physical component of the controller The controller can be divided into the following five functional sections 1 The data input output circuits Service Sheet 1 These circuits consist of the Al Keyboard Assembly the A11 HP IB Interface Assembly and part of the A3 CPU Assembly 2 The microprocessor and memory circuits Service Sheet 2 These circuits are all contained on the A3 CPU 3 The timer and peripheral interface adapter PIA circuits Service Sheet 3 These circuits are all contained on the A3 CPU 4 The display drivers Service Sheet 4 These circuits are all contained on the A3 CPU 5 The front panel display circuits Service Sheet 5 These circuits are all contained in the A2 Display Assembly The CPU controls the rest of the instrument by using the following three buses to enable address and transfer data to the other sections of the instrument 1 The control bus is derived from part of the address bus and hardware generated signals such as power fail or free run These signals are used to enable specific digital circuits when they are requir
155. aceable Parts Reference HP C Qty Designation Part No iD A5C17 A5C18 A5C19 A5C20 A5C21 A5C22 A5C23 A5C24 A5C25 A5C26 A5027 A5C28 A5C29 A5C30 A5C31 A5C32 A5C33 A5C34 A5C35 A5C36 ASCR1 A5J1 A5J2 A5J3 A534 ASLI ASMP1 A5MP2 ASQI A5Q2 A5Q3 A5Q4 A5Q5 A5Q6 A5Q7 A5Q8 A5Q9 A5R1 A5R2 A5R3 A5R4 A5R5 ASR6 6 16 0160 2199 0160 2199 0160 3762 0160 3702 0160 3402 0160 3661 0180 0373 0180 0373 0160 4557 0160 3402 0160 3439 0160 3661 0160 0160 0160 4325 0160 0161 0160 0168 0160 0155 0160 2291 0160 7136 0160 2199 1901 0050 1251 8935 1251 8106 1251 8248 1250 1377 9140 0210 0361 0009 00438 20029 1853 0459 1853 0459 1855 0420 1853 0459 1854 0810 1853 0459 1854 0810 1855 0414 1853 0314 1810 0280 0757 0279 1810 0280 0699 0842 0698 3444 0757 0274 2 CG or a OW oA NY ON tO C to QC o P e 7 2 3 0 7 8 8 i 5 9 3 3 2 3 2 3 2 4 9 8 0 8 9 1 ex Table 6 3 Replaceable Parts continued Description CAP FXD 30pF 5 300 V MICA CAP FXD 30pF 5 300 V MICA CAP FXD 0 68uF 5 50 V POLYC MET CAP FXD 0 027uF 5 50 V POLYC MET CAP FXD 1uF 4 596 50 V POLYC MET CAP FXD 0 1uF 5 50 V POLYC MET CAP FXD 0 68uF 4 109635 V TA CAP FXD 0 68uF 10 35 V TA CAP FXD O luF 20 50 V CER X7R CAP FXD luF 4 595 50 V POLYC MET CAP FXD 0 039uF 5 200 V POLYC MET CAP FXD 0 1uF 4 596 50 V POLYC MET CAP FXD 8200pF 10 200 V POLYE FL CAP
156. ach sensor Registers 1 through 19 are available for storing instrument configurations Registers 0 through 19 are available for recall Register 0 always contains the previous power meter configuration Thus RECALL 0 provides a way to recover from an entry error Procedure To store an instrument configuration press STORE enter a number from 1 to 19 and then press ENTER To recall an instrument configuration press RECALL enter a number from 0 to 19 and then press ENTER Example To recall an instrument configuration that has been stored in register 2 LOCAL Ff unction x keystrokes Functlon NE program codes HP 438A Store and Recall Program Codes Program Code RECALL STORE ENTER Indications When the stored contents of a register are recalled the power meter changes to the recalled parameter values The power meter executes a RECALL 0 at power up This places the power meter in the same state that it was in when power was removed The Cal Adj value reference calibration factor for each sensor can be stored and recalled but the internal calibration settings are not stored PRESET has no effect on the storage registers 1 through 19 Register 0 however is set to the PRESET conditions when the key is pressed Storage register 0 is set to the PRESET state when a continuous memory error Error 57 occurs High and low limits cannot be stored Related Sections CAL AD
157. al replace R28 or R27 If there is a signal replace U20 HP IB Interface Check U29 Service Sheet 1 1 Move the QUAL line to U29 pin 8 set QUAL to LO and verify the signatures for 5 volts versions 5 0 and 2 0 P95U and ground 0000 are as shown 2 Verify the signatures in Table 8 30 Table 8 30 Analog I O PIA Signatures Pin T 1 NR 1 T 2 NR 2 1DO ID D2 ID3 ID4 1D5 1D6 1D7 If any of the signatures are incorrect replace U29 U17 or U16 If all of the signatures are correct perform the Miscellaneous Checks 8 70 HP 438A Note E Service Sheets 1 4 Miscellaneous Checks The Miscellaneous Checks provide troubleshooting for the following areas u Keyboard Priority Encoder U43 Service Sheet 1 m Addressable Data Display Latch U31 and U32 Service Sheet 3 u Signature Analysis Mode Troubleshooting Service Sheets 1 4 The display circuits must be operating properly to perform the Keyboard Priority Encoder test Keyboard Priority Encoder Perform the Manual Keyboard Check on Block Diagram 2 If the power meter doesn t display OO at power ON perform Free Run Signature Analysis and the Signature Analysis Mode Checks If the indication for one key is incorrect the problem is either the switch for that key U43 or U22 To determine where the problem is set the oscilloscope to gt 0 5 ms division and 1 V division look at the column
158. amp de d P O Central Processing Unit Assembly Component Locations xtate SIDA SV ete e canon eh a Timer and Peripheral Interface PIA Circuits Schematic Diagram 2 ona es P O Central Processing Unit Assembly Component Jh 3 4 9s ce dede a Bs Oe ee X rug Display Driver Circuits Schematic Diagram Display Assembly Component Locations Front Panel Display Circuits Schematic Diagram Selected Amplifier AC Signal Multivibrator Waveforms Input Amplifier Assembly Component Locations Input Amplifier Circuits Schematic Diagram Auto Zero DAC Test Signal Offset Removal DAC Test Signal After Gain Aon DTOSBIOD Jus o 6 e exe wide HOGER MU Offset Removal DAC Test Signal Before Gain Compensation y we dG WOK A Recorder Output Test Signal P O Main Amplifier Assembly Component Locations P O Main Amplifier Circuits Schematic Diagram Ramp End Waveform 4 4 2 1 1 Analog to Digital Converter Ramp Waveform Variable Gain Amplifier Waveform AC Gain Stage Waveform Analog to Digital Converter Input Waveform Ramp Start Gate Waveform Analog to Digital Converter Ramp Waveform Synchronous Phase Detector Output Waveform Phase Detector Drive Waveforms Phase Detector Control Waveform Analog to Digital Converter Input A Ground Circuit Showing Feedback Path
159. and electrically The procedures for checking electrical performance are given in section 4 Performance Tests If the contents are incomplete if there is a mechanical defect or if the instrument does not pass the performance tests notify the nearest Hewlett Packard office If the shipping container is damaged or the cushioning shows signs of stress notify the carrier and the Hewlett Packard office Keep the shipping material for the carrier s inspection 2 1 installation 2 3 Preparation for Use 2 2 Warning DG Caution Y HP 438A 2 4 Power Requirements To avoid the possibility of hazardous electrical shock do not operate this instrument at line voltages greater than 126 5 Vac with line frequencies greater than 66 Hz Leakage currents at these settings may exceed 3 5 mA This is a Safety Class product that is it is provided with a protective earth terminal An uninterruptible safety earth ground must be provided from the main power source to the product input wiring terminals through the power cable set or supplied power cord set Whenever it is likely that the protection has been impaired the instrument must be made inoperative and secured against any unintended operation If this instrument is to be energized via an external autotransformer for voltage reduction make sure the common terminal is connected to neutral that is the grounded side of the line Mains supply The power meter requires a p
160. annel A and verify the following A4U2 Pin 1 Logical high gt 2 0 volts Pin 16 Logical low 0 8 volts A4U4 Pin 1 Logical low 0 8 volts Pin 16 Logical high gt 2 0 volts Select channel B and verify the following A4U2 Pin 1 Logical low 0 8 volts Pin 16 Logical high gt 2 0 volts A4U4 Pin 1 Logical high gt 2 0 volts Pin 16 Logical low lt 0 8 volts If any level is incorrect troubleshoot the Miscellaneous Buffer A5U14 on Service Sheet 7 Service Sheets 6 8 92 HP 438A If only one channel is bad set the power meter to that channel This procedure will assume that channel A is bad but all of the steps will be applicable to channel B Be sure to use the test points and values shown in parentheses when troubleshooting channel B With an oscilloscope check to see that the signal at A4U2 A404 pin 14 is equal to the signal at A4U2 A4U4 pin 10 0 1 volts and that the voltage at A4U2 A4U4 pin 6 is equal to the voltage at A4U2 A4U4 pin 7 0 1 volts If either case is not true replace A4U2 A4UA If A4U2 A4U4 pin 6 equals A4U2 A4U4 pin 7 0 1 volts but the voltage does not equal 0 volts 0 05 volts replace A4U1 A4U3 Decoupled Power Supply Test Check for the proper voltages at the following points A4U1 Pin 8 gt 14 Vdc If the voltage is not correct check A4R2 A4C7 A4U1 and A4U2 Pin 4 lt 14 Vdc If the voltage is not correct check A4R3 A4C1
161. ant bit LSB When the switches are set towards the front panel of the instrument they are set to 1 3 Turn the power meter ON 4 A manual test of the front panel displays is now enabled All front panel displays will be illuminated Repeated pressing of the A key will light each LED segment and annunciator Below is the normal indication as the A key is pressed The front panel will be blank then all segments of the large LEDs all of the smaller number eights and all of the annunciators will light one at a time as the A key is pressed Continue to press the key until the sequence starts to repeat If only one segment of a single seven segment display is defective or only one LED of one LED bar display is defective replace the appropriate display Note E 5 Once the defective segment LED or display has been identified trace the lines for the component in question back to Service Sheet 4 6 Use the voltage levels in Table 8 31 and the procedure in step 7 to determine if the problem is with the Cathode Data Display Drivers or the Anode Data Display Drivers A The voltage levels for A3U25 A3U26 A3U41 and A3U42 are a TTL u low lt 0 8V when the display is illuminated and gt 4 5 volts when the display is of Note 8 81 Service Sheets 5 Note cont d 8 82 HP 438A The voltage levels in Table 8 31 are valid only when the entire front panel is illuminated When switch A3S1 is set to 1101 a
162. arrow down a malfunction to one of the following assemblies A4 Input Amplifier Assembly A5 Main Amplifier Assembly and G1 50 MHz Reference Oscillator The major part of this service sheet is the A5 Main Amplifier Assembly and its schematic diagrams are on Service Sheets 7 and 8 The A4 Input Amplifier Assembly schematic diagram is on Service Sheet 6 and G1 50 MHz Reference Oscillator schematic diagram is on Service Sheet 11 The checks will cover selected inputs and outputs of these major assemblies The checks attempt to verify a good interface between the power sensor and the input amplifier so that the zeroing loop is completed and that analog to digital conversion ADC is being accomplished by the CPU and main amplifier connections Test Equipment A A CM HP 1740A Power Sensor Eege ere peas is ea iet HP 8480 series Sensor Caley qe ta R AL e Ee d HP 11730A Digital Voltmeter DVM pasitos HP 3456A Power Sensor to First Amplifier Interface Check Assuming at this point that BD1 Amplifier v 3 has been completed and the comparator output RAMP END signal was incorrect or that the RCDR rear panel recorder BNC output is not 1 Vdc Connect power sensor to channel A or channel B and the 1 mW POWER REF The normal indication is 8 47 Service Sheet BD3 HP 438A The display should read 1 888 2 WATT mW and channel A or B depending on the active channel If any abnormal indication occurs 1 The selected amplified ac is
163. ational test is included in section 3 under Basic Functional Checks If the performance tests are to be considered valid the following conditions must be met a The power meter must have a 1 hour warm up for all specifications b The line voltage for all instruments must be 100 120 220 or 240 Vac 5 10 and the line frequency must be 48 to 66 Hz The power meter has the additional capability of operating on line frequencies of 360 to 440 Hz but the line voltage is limited to a nominal 100 or 120 Vac c The ambient temperature must be 0 C to 55 C Equipment required for the performance tests is listed in Table 1 3 Recommended Test Equipment Any equipment that satisfies the critical specifications given in the table may be substituted Results of the performance test may be tabulated in Table 4 1 Performance Test Record The Performance Test Record lists all of the performance test specifications and the acceptable limits for each specification If performance test results are recorded during an incoming inspection of the instrument they can be used for comparison during periodic maintenance or troubleshooting procedures The test results may also prove useful in verifying proper adjustments after repairs are made The performance tests given in this section are suitable for incoming inspection troubleshooting or preventive maintenance During any performance test all shields and connecting hardware
164. bar circuit Transformer secondary 15 Volt Supply Test 1 Connect an oscilloscope to A9TP7 If the voltage is 15 0 75 Vdc the supply is operating normally If the voltage is incorrect continue with step 2 Note al Adjust the magnitude of the 15 volt supply to within 0 05 volts of 1 the 15 volt supply 2 Disconnect A10J1 and the red lead for the Fan Motor Control Module the lead is on A10 If the voltage is still incorrect continue with step 3 If the voltage returns to normal reconnect A10J1 If the voltage is still normal the problem is with the Fan or the Fan Motor Control Module If the problem remains disconnect the following cables one at a time until the voltage returns to normal Note Remove the cables in the order given Cable Problem Location Related Service Sheets A543 A5 Service Sheet 7 A4J2 A4 Service Sheet 6 8 132 HP 438A Service Sheet 10 a 3 Check A9TP5 15V IN If A9TP5 is 20 Vdc replace A9U2 If the voltage is incorrect the problem is in one of the following circuits 12V Fan Regulator 15V Regulator Filter capacitors 15V Bridge circuit Crowbar circuit Transformer secondary 8 133 Service Sheet 10 HP 438A A10 ASSEMBLY NOTE ON CIRCUIT SIDE wn ES SC B ju 05 Ger a i 4 ats Soe SE Be AUR ott EE 4 SOG RA 7 e Figure 8 60 P O Interconnect Assembly Component Locations 8 134
165. be displayed relative to a reference measurement SENSOR To display the Sensor A power measurement on the front panel press 4 Single sensor measurements are display in dBm or Watts To display the ratio of Sensor A divided by Sensor B press A B Ez 3 7 Operation MEASUREMENT PARAMETERS HP 438A Ratio measurements are displayed in dB or To display the difference between Sensor A and Sensor B press A B a Difference measurements are displayed in dBm or Watts REL Press to enter and exit relative mode Once relative mode has been entered the first power reading is saved as a reference Successive measurements are displayed relative to the reference The REL annunciator in the front panel display lights when the Power Meter is in relative mode Measurement parameter can be set for each sensor Blue keys indicate parameters that have selectable values Values are selected in a Blue Key Data ENTER format Data consists of digits 0 through 9 and the decimal point Pressing any blue key activates the data functions of the corresponding keys SET A and SET B SET A and SET B allow measurement parameters to be entered for Sensor A and Sensor B For example to designate channel A as the active entry channel press SET A Any measurement parameters that are entered will apply to Sensor A only regardless of the measurement mode displayed on the front panel CAL FACTOR The calibration factor i
166. ber and description of a mechanical part find the part in one of the figures in section 6 or section 8 The part in the figure will be labeled with its reference designator Look up the reference designator in Table 6 3 Replaceable Parts The power meter has a mixture of Unified National inch and metric screws The metric screws are defined by Industrial Fasteners publication IFI 500 and are identified in the replaceable parts list as metric M Unified National screws have a dull steel gray appearance and the metric screws have a shiny silver appearance Do not use a metric screw in a Unified National nut thread damage will result 8 13 Test Point and Adjustment Locations Most test points and adjustments are indicated on individual circuit board assemblies Test points and adjustments can also be found on the component locator diagrams adjacent to the assembly chematic diagrams Service HP 438A 8 14 Service Aids on Printed Circuit Boards The service aids on the printed circuit boards include test points indicator LEDs reference designators adjustment names and assembly part numbers 8 15 Other Service Documents Service Notes Manual Changes Supplements Application Notes and other service literature are available from Hewlett Packard For further information contact your nearest Hewlett Packard office Table 8 1 Etched Circuit Soldering Equipment Specification Item Recommended HP Part No Wattage 35W Ungar
167. ble Sets calibration factor for the meter Overrides current value Range 1 150 in 0 1 increments ZERO Key pad entry or programmable Zeros all 5 ranges reference oscillator automatically switched off during zeroing CAL ADJ Automatic key pad entry or programmable Calibrates meter using internal 1 00 mW reference or external reference oscillator Reference Cal Factor settable from 50 096 to 120 096 OFFSET Key pad entry or programmable Range 99 99 to 99 99 dB in 0 01 dB increments Digital Filter Length Keypad entry or programmable Averages power readings from 1 to 512 successive values in increments by factors of 2 1 2 4 256 512 High Low Power Limits Programmable only Activates Service Request and flashing front panel indicator Individual channel values from 299 99 to 299 99 dBm in 0 001 dB increments STORE RECALL Registers Nineteen registers to store complete operating state of meter for later recall REL Key pad entry or programmable Displays all successive measurements relative to the last displayed value when activated Units are in dB or 96 1 9 General Information HP 438A Table 1 3 Additional Supplemental Characteristics EN Meter Noise As a of full scale with constant temperature range 1 measured over a one minute interval and two standard deviations Decrease noise by a factor of 10 for each higher range for all sensors and all filte
168. bserve the front panel seven segment displays and annunciators The normal indications are 1 All front panel indicators are lighted to provide a visual inspection of each front panel display segment and annunciator 2 All the display segments large and small will display the number eight The center three columns and the two right hand columns of annunciators will be lighted J When the power up routine is completed and after a short flash of all dashes the display will show some message defining the next step to be taken This message will be self explanatory 8 23 Service Sheet BD1 HP 438A Abnormal Indication If an abnormal indication occurs 1 If all displays fail to light check the 5V display enable CLK clock at A9TP1 with the oscilloscope The waveform should be as shown in Figure 8 7 2 When only one of the display segments or annunciators fails to light check respective components and display drive circuits Refer to Controller Section Troubleshooting BD2 0 2 ms DIV Figure 8 7 Display Enable Waveform Amplifier Section C 3 As a check of the Amplifier Section two approches can be taken depending on the test equipment available If only a power is available it can be used with the 1 mW POWER REF to set up some known conditions for troubleshooting If the HP 11683A Range Calibrator is available it can used as a variable source for checking the ranges Procedure one Connect a power sensor to channe
169. cal messages When addressed to talk the power meter can issue the Data and Status Byte messages Whether addressed or not the power meter responds to the Clear DCL Local Lockout Clear Lockout Set Local and Abort messages In addition the power meter may issue the Require Service and Status Bit messages Local to Remote Changes The power meter switches to remote operation upon receipt of the Remote message The Remote message has two parts a the remote enable bus control line REN is set true and b the device listen address is received once while REN is true When the power meter switches to remote the front panel RMT annunciator turns on The power meter s control settings remain unchanged with the local to remote transition HP 438A 3 16 Local Mode Note 3 17 Addressing Operation Local Capability In local the power meter s front panel controls are fully operational and the instrument will respond to the Remote message Whether it is addressed or not it will also respond to the Clear Local Lockout Clear Lockout Set Local and Abort messages When addressed to talk the instrument can issue Data messages and the Status Byte message Whether addressed or not the instrument can issue the Require Service and Status Bit messages Remote to Local Changes The power meter always switches from remote to local whenever it receives the Local message GTL or the Clear Lockout Set Local message The Clear Loc
170. ce the reference cal factor has been entered the instrument goes through its calibration routine and the display shows eight dashes and a moving decimal point Comments The reference calibration factor which is entered via CAL ADJ is used only during calibration Calibration factors entered via CAL FACTOR are used for actual measurements Zero the active entry channel before entering the reference calibration factor The reference calibration factor can be found on the body of the sensor A calibration should be performed whenever the power meter changes power sensors or whenever the ambient temperature changes by more than 5 C PRESET sets CAL ADJ to 100 The gain of the power meter however does not change until a new calibration is performed Pressing and then without entering any data causes the power meter to initiate a calibration using the last entered value for CAL ADJ Any command received during the calibration process aborts the calibration and executes the function of the command received The number entered for CAL ADJ however is stored as the last entered value When using an older HP 8483A Power Sensor enter a reference calibration factor of 9696 even though 10096 may be indicated on the sensor s cal factor label Using this CAL ADJ value compensates for mismatch between the 75 ohm sensor and the 50 ohm reference oscillator Newer HP 8483A Power Sensors have the correct reference cal factor 9696 or les
171. ciency over the frequency range of the power sensor Pressing the key enables entry of the calibration factor for the sensor connected to the active entry channel A chart of CAL FACTOR versus Frequency is printed on each sensor and an accompanying data sheet Calibration factor is entered in percent Valid entries for CAL FACTOR range from 1 0 to 150 0 Front panel numeric entry allows up to 4 digits After the first four digits are entered succeeding digits are ignored Only one digit to the right of the decimal point is accepted Data entered over the bus in remote mode is rounded to the required resolution Procedure Cal factor is entered separately for sensor A or sensor B To enter the cal factor for the active entry channel press CAL FACTOR enter the cal factor in percent and then press ENTER Example To enter a cal factor of 99 ck trokes eystrokes 3 8 KBSSEN program codes Program Codes Parameter CAL FACTOR ENTER Program Code Cal Factor 3 52 HP 438A Indications When the key is pressed the front panel display shows EHT _ After a number has been entered and the key has been pressed the display returns to its previous mode The front panel displays the value of the calibration factor s used in the current measurement Comments During actual measurements calibration factors entered via CAL FACTOR are used The reference calibration factor w
172. circuit microcircuit ABBREVIATIONS EMI cuotas ASA eumd centimetre BEZ sp eise heterodyne DIA ee digital to analog HEX own ew hexagonal A pith aire decibet HD uot eee stas head dBm decibel referred to 1 mW HDW onines hardware d needs direct current HE sed high frequency deg degree temperature HG VL reete mercury interval or difference o A seen high US degree plane angle HP Hewlett Packard 9C degree Celsius centigrade HPP sS high pass filter 9E vsus degree Fahrenheit HR hour used n Parts List w vou erus degree Kelvin HEN Zeie ee ms high voltage DEPC deposited carbon Ho om cA iar ee Bae oe Hertz DET wal eek etches detector IC assu integrated circuit diam cer cer eres diameter ID ose never inside diameter DIA diameter used in Parts IP intermediate frequency List IMPG impregnated DIFF AMPL differential ino E eset lt inch amplifier INGD 12 aie obi inncandescent div See alec ate eg ed division INGL os cad ge include s DPDT u 65000 double pole INP nad SAAS aes input double throw INS snot dasz GA insulation DR a ea drive INT cb ea LECCE S internat DSB es double sideband Kg ow eve ttr kilogram DTL diode transistor logic Ipae kilohertz DVM iiiv digital voltmetet KO cM PL kilohm ECL emitter coupled logic EM acs dba dee Gack Bhat Ss kilovolt EMF electromotive force Iiis eeu c ewe ees pound EDP electronic data processing LO inductance capacitance ELECT
173. controller and in conjunction with stored values in the software is used to remove any dc offset voltage associated with the individual power sensors y HP BBX emm HP Q SELECTED AMPLIFIED AC 228 Hz SAMPLED AC 1S8V Y Figure 8 12 Simplified Power Sensor and input Amplifier Diagram The controller sets the miscellaneous buffer on the main amplifier to connect the following signal paths for the selected input channel 1 The amplified ac output 2 The sensor resistor input 3 The sensor ground reference to the A GND circuit on the main amplifier The power sensor and the A4 Input Amplifier Assembly function together to amplify the modulated 220 Hz signal by a factor of approximately 600 HP 438A Service Sheet BD3 Digital UO and DAC Circuits The digital I O circuits interpret the control signals from the CPU central processing unit controller and set the input amplifier and the main amplifier to the correct configuration to perform the required measurement The outputs from the digital I O circuits are stored in the flip flop registers of the miscellaneous buffer the zero DAC Digital to Analog Converter buffer and the gain attenuator buffer Figure 8 13 is a simplified block diagram of the zeroing loop When the key is pressed or the HP IB program code ZE is given the software zeroing routine is initiated The auto zeroing DAC output is used to zero the input from the power se
174. cription Series 200 300 BASIC Send a Data message to set the Service Request OUTPUT 713 Mask to 4 USING 2A B 91 4 OUTPUT 713 RM 15 EN Send a Data message containing an entry error This causes the Require Service message to be sent Check that the power meter s SRQ annunciator is on Description Series 200 300 BASIC Read the binary status of the controller s HP IB 10 V 0 interface and store the data in variable V in this 20 STATUS 7 2 V step 7 is the interface s select code and 2 is a status register for bus control lines Display the value of the SRQ bit in this step 6 is the SRQ bit for the controller numbered from 0 30 DISP SRQ BIT V 6 40 END Check that the SRQ value is 1 indicating that the power meter issued the Require Service message HP 438A Status Bit Message Operation This check determines whether or not the power meter sends the Status Bit message This check can be performed in either local or remote mode If the power meter s SRQ annunciator is off perform the first part of the Require Service message check before beginning this check Description Series 200 300 BASIC Configure the power meter to respond to a parallel SEND 7 LISTEN poll with positive true logic on HP IB data line 13 CMD 5 SCG 10 DIOS Place the power meter in parallel poll mode causing it to send the Status Bit message
175. cs 4a E 4 4 3 1 3 4 Remote Operation HP IB 3 2 3 5 Operator s Maintenance 3 2 PRESE is 14 3 WH ee MACA 3 7 CALIBRATION uy ve e Xx eS 3 7 MEASUREMENT MODES 3 7 SENSOR cta ete aoa ee ae A Rue e uS 3 7 REL A cake oe ee e e die 3 8 MEASUREMENT PARAMETERS 3 8 SET A and SEL DB e Ka Imm 3 8 CAL PACTOR 447 8 ae as b A A 3 8 A y ud 4 RR are oat ae BAW ses eas 3 8 RANGE e p bk 4 ceo WR A 6 s d 3 9 OPIOBI cisco x G EA O 3 9 MEASUREMENT UNITS 2 3 9 STORE and RECALL ao rodos w GG 3 9 3 6 Turn On Instructions 3 10 dale Purn ON A a be a a eats 3 10 3 8 Error Messages 14 1 1 1 1 11 3 11 3 9 Power Reference and Calibration 3 11 3 10 Operator s Checks 3 12 Basic Functional Checks 3 12 HP IB Functional Checks 3 12 3 11 Basic Functional Checks 3 13 3 12 HP IB Checks 4 44 duum des eun 3 16 TOA Se Dy Vox ue wok Xue CSS MUR em vs 3 17 Remote and Local Messages and LCL 3 17 Sending the Data Message 3 18 Receiving the Data Message 3 19 Local Lockout and Clear Lockout Set Local Messages 3 19 Clear Message vi gd de Ses Z Hh ee ok 3 20 Abort Message vox a eae aa KO A 3 21 Status Byte Message 3 21 Require Service Message 1 1 1 1 1 3 22 Status Bit Message 3 23 Trigger Message
176. d Buffer Test SE 8 98 Offset removal DAC Buffer and Gain Compensation Test 8 99 Gain DAC Buffer and Gain Compensation Test 8 100 Miscellaneous Buffer Test 8 102 Stable Current Source 1 14 8 102 Cal Oscillator Control Test 8 102 Service Sheet 8 General e deste abe cece ais Oh st yk mie a 8 105 Fault Isolation Procedure 8 105 Gain Attenuator Buffer 1 8 108 Reference Ramp Start Gate and Ramp Generator PO ut ubl gd ds dedo he ok CUN aud 8 109 Range Attenuator 1 100 8 110 Variable Gain Amplifier 8 111 Range Attenuator 1 10 2100 8 111 AC Gain Stage Test 8 111 Synchronous Phase Detector Test 8 111 Low Pass Filters wada er w Eo da 8 114 Analog Digital Input Multiplexer Test 8 115 Sensor Resistor Selection Test 8 116 A Ground Circuit Test 8 117 Service Sheet 9 General cS ra WY Se E w 8 121 Fault Isolation Procedure 8 121 5 Volt Digital Supply Test 8 121 5 Volt Display Supply Test 8 122 Total Power Failure Test 8 123 vill HP 438A Contents Service Sheet 10 General Ap T secte aer gece sae do BB oe S aj A 8 129 Fault Isolation Procedure 8 129 15 Volt Supply Test 1 1 1 8 129 15 Vol
177. d MNL RANGE Description The power meter divides each sensor s power range into 5 ranges of 10dB each Range 1 is the most sensitive lowest power levels and Range 5 is the least sensitive highest power levels Range 5 can be less than 10 dB if the sensor s power range is less than 50 dB The range can be set either automatically or manually for the active entry channel AUTO RANGE automatically selects the correct range for the current measurement MNL RANGE enables the range to be selected manually Valid range numbers are 1 through 5 Only one digit is permitted for range entries If a second digit is entered it replaces the first digit Another feature of the power meter is the hold range mode Hold range provides a means of switching from auto range to manual range while retaining the current auto range setting Procedure To select auto range press AUTO RANGE To select manual range press MNL RANGE J enter a numeric value and then press ENTER To select hold range mode press the MNL RANGE key and then the ENTER key Example To select range 3 manually LOCAL er unctione keystrokes RANGE Funct Lon program codes 3 71 Range 3 72 HP 438A Program Codes z Program Code S RA Parameter AUTO RANGE MNL RANGE Hold Range ENTER indications The MNL annunciator on the front panel display lights when the power meter is in manual or hold range mode or manual or hold
178. d Overall Diagram 8 14 8 2 Interrupt Control Routine Flowchart 8 16 8 3 Task 1 Flowchart ss oh Gos ROK RG 8 17 8 4 Fask 2 Plowcehaft sono GG ABW ees 8 18 8 5 Simplified Power Supply Growiding CN do us es 8 21 8 6 Power Meter Service Position o 8 22 8 7 Display Enable Waveform EN 8 24 8 8 Ramp End Waveform sss r 8 25 8 9 Overall Block Diagram ees NE 8 27 8 10 Service Function Switch 8 32 8 11 Controller Section Block Diagram 8 39 8 12 Simplified Power Sensor and n Amplifier Diagram 2 e mc Ei 9o BK oh 8 42 8 13 Simplified Zeroing Block Dip 2 P 8 43 HP 438A 8 14 8 15 8 16 8 17 8 18 8 19 8 20 8 21 8 22 8 23 8 24 8 25 8 26 8 27 8 28 8 29 8 30 8 31 8 32 8 33 8 34 8 35 8 36 Contents Simplified Analog to Digital A D Converter Block Diagram yh le E ata deos ado A Selected Amplified AC 1 1 1 Phase Detector Drive 1 1 1 1 Amplifier Section Block Diagram A351 Decimal 14 Setting Keyboard Assembly Component Locations Central Processing Unit Assembly Component Locations e de GOA A PA SS Data Input Output Circuits Schematic Diagram P O Central Processing Unit Assembly Component Locations a Ge Res ok NE GS Se d Microprocessor and Memory Circuits Schematic Diagram 3 od BO eo A et
179. d non operating environment Temperature humidity shock and vibration type tested to MIL T 28800B Class V requirements Safety Meets requirements of TEC 348 5 9 kg 13 lbs 89mm H x 213mm W x 418mm D 3 5 H x 8 4 W x 16 8 inches D 3 5 H x 8 4 W x 16 8 inches D Net weight Dimensions FIA and IEC racking standards 35H x 0 5 W x 17D 213mm e LB din 418mm R 5 16 8in 3 REA t i2mm C8 5in 2 FRONT VIEW Sa B 75in 2 12mm Y Sin Note For ordering cabinet accessories the module sizes are 3 1 2H 1 2MW and 17D HP 438A General Information Table 1 2 Supplemental Characteristics Zero drift of sensors As a of full scale 1 hour at constant temperature after 24 hours warmup Decrease percentage by a factor of 10 for each higher range Sensors HP 8481A 8481B 8481H 84824 8482B 8482H 8483A 8485A R8486A Q8486A W8486A and 8487A Sensors HP 8484A 8481D 8485D 8486D and 8487D Measurement speed lt 0 1 of full scale on range 1 lt 2 0 of full scale on range 1 Over HP IB and free running trigger Single channel 20 readings per second Dual channel Channel switching delay Power reference 2 readings per second 200 ms Frequency 50 MHz nominal SWR 1 05 maximum Connector Type N female Meter adjustments CAL FACTOR Key pad entry or programma
180. dc perform the Stable Current Source Test If troubleshooting is complete disconnect the signature analyzer and reset switch A351 to all ones Gain DAC Buffer and Gain Compensation Test 1 Connect an oscilloscope to the RECORDER OUTPUT on the rear panel of the power meter 2 Compare the waveform on the oscilloscope with the waveform in Figure 8 37 3 If the displayed waveform is the same as Figure 8 37 the Gain DAC Buffer and Gain Compensation circuits are operating properly If the Fault Isolation Procedure is being performed and the circuits are operating properly go to the Miscellaneous Buffer Test If the displayed waveform is not the same as Figure 8 37 connect the oscilloscope to A5U3 pin 15 and compare and display to Figure 8 35 If the displayed waveform is not the same as Figure 8 35 perform the Offset Removal DAC Buffer and Gain Compensation Test If the displayed waveform is the same as Figure 8 35 go to step 5 50 mV DIV gy 72 E Figure 8 37 Recorder Output Test Signal 8 101 Service Sheet 7 8 102 HP 438A 5 Perform steps 1 through 6 of the Fault Isolation Procedure 6 Verify the signatures in Table 8 36 Table 8 36 Gain DAC Buffer Signatures A5U4 Signatures pum eus sc If any signatures are incorrect replace A5U4 If all the signatures and the waveform at A5U3 pin 15 are correct replace A5U3 and A5U2 w l If troubleshooting is complete
181. de A local command from the controller does not return the power meter to free run mode Program Order Considerations Although program string syntax is virtually identical to keystroke order some program order considerations need highlighting Trigger Immediate and Trigger with Delay When either of the trigger program codes TR1 or TR2 is received by the power meter a measurement is immediately initiated Once the measurement is completed some bus commands can be processed without aborting the measurement However any HP IB program code sent to the power meter before the triggered measurement results have been completed will abort the trigger Thus trigger codes should always appear at the end of a program string and the triggered measurement results must be completed before any additional program codes that affect measurement are sent ZERO and CAL ADJUST Zero the power meter before performing a calibration adjustment to avoid inaccurate measurement results OFFSET and Display Offset The display offset program code DO is only valid when it immediately follows the program code for OFFSET OS When the Power Meter is addressed to listen and receives the program string OS DO EN a Data message the offset that causes the power meter display to read 0 dB or dBm 1 000 mW or 100 depending on the measurement units and measurement mode is entered The power meter sends Data messages when addressed to talk The instrument re
182. delay terminal thin film transistor thread through titanium tolerance trimmer transistor transistor transistor logic MULTIPLIERS Abbreviation T G M k da d TR D n p f a Prefix Multiple 1012 10 tera giga mega 10 kilo 10 deka 10 deci 107 centi 107 milli 195 1078 107 107 12 19715 197 18 micro nano pico fernto atto NOTE All abbreviations in the Parts List appear in uppercase Vp p VSWR VTO television television interference traveling wave tube micro 108 used in Parts List microfarad used in Parts List ultra high frequency unregulated voltampere volts ac variable voltage controlled oscillator volts dc volts dc working used in Parts List volts filtered variable frequency oscillator very high frequency volts peak volts peak to peak volts rms voltage standing wave ratio voltage tuned oscillator vacuum tube voltmeter volts switched working inverse voltage wirewound without yttrium iron garnet characteristic impedance Replaceable Parts HP 438A Designation Part No D Part Number Al 00438 60001 1 1 00438 60001 A1J1 1200 0507 ICN 163B 53 G30 AIMP1 5041 2839 5041 2839 AIMP2 5041 2840 5041 2840 AIMP3 5041 2842 5041 2842 A1MP4 5041 0309 5041 0309 AIMPS5 5041 2841 5041 2841 AIMP6 5041 2850 5041 2850 A1MP7 5041 2851 5041 2851 A1MP8 5041 2854 5041 2854 A1MP9 5041 2844 5041 2844
183. displays MO SEHSUR when a power sensor is connected to the input port 2 If the failure only occurs under certain conditions explain how to duplicate the failure An example might be Power meter will not make measurements in ranges 4 and 5 Original Packaging Containers and materials identical to those used in factory packaging are available through Hewlett Packard offices Mark the container FRAGILE to encourage careful handling In any correspondence refer to the instrument by model number and full serial number Other Packaging The following general instructions should be used for repackaging with commercially available materials 1 Wrap the instrument in heavy paper or plastic If shipping to a Hewlett Packard office or service center complete one of the blue tags mentioned above and attach it to the instrument 2 Use a strong shipping container A double wall carton made of 2 4 MPa 350 psi test material is adequate 3 Use enough shock absorbing material 75 to 100 mm layer 3 to 4 inches around all sides of the instrument to provide a firm cushion and prevent movement in the container Protect the front panel with an appropriate type of cushioning material to prevent damage during shipment 4 Seal the shipping container securely 5 Mark the shipping container FRAGILE to encourage careful handling Operation 3 1 Introduction 3 2 Operating Characteristics 3 3 Local Operation T
184. e If a new measurement mode is selected while relative mode is enabled REL is disabled and the reference value is lost Procedure Press to toggle in and out of relative mode Press to alternate between dB and percent Example To enter relative mode and make relative measurements assuming that the Power Meter is not in relative mode LOCAL Keystrokes lt E program codes Program Codes Program Code Enter REL Mode Exit REL Mode HP 438A Rel indications When the power meter is displaying a relative measurement the REL annunciator on the front panel display lights The displayed value is the measurement result relative to the reference in dB or Comments Relative measurements cannot be output via the rear panel RCDR output If the reference is zero or negative power the measurement result can be displayed in dB as long as the measured power does not change signs that is positive to negative or vice versa while REL mode is on If the measured power does change signs while displaying dB in REL mode Error 27 illegal logarithmic operation occurs If a negative reference is used the ratio indication will be displayed in absolute value The reference value is stored if the power meter is in REL mode when the instrument configuration is saved The reference value once set cannot be read Related Sections dBm WATT Logarithmic Linear Measurement Units SENSOR A and SEN
185. e should be performed only by trained personnel who are aware of the hazards involved When the maintenance procedure can be performed without power the power should be removed Most of the adjustment procedures include a list of recommended test equipment and the test equipment is also identified on the test setup diagrams If substitutions must be made the equipment used must meet the critical specification listed in Table 1 3 in section 1 Factory selected components are identified on the schematics and parts lists by an asterisk which follows the reference designator The nominal value of the selected component is shown Table 5 1 lists the reference designator the service sheet where the component is shown the value range and the basis for selecting a particular value Adjustments 5 5 Interrelated Adjustments 5 6 Post Repair Adjustments Note Reference Service Range of Designator Sheet Values GIA1R2 11 82502 with GIA1VR2 5 11 V between 0 C and 55 C and if the GIAIR2 G1A2VR2 combination combination Zener or is 8250 5 11 V then change the G1A1R2 GIA1VR2 combination to G2A1R2 14700 with 14700 8 25 V However if the GLAIR2 GLAIVR2 combination is G2A1VR2 8 25 V already 1470Q 8 25 V then a problem exists elsewhere Option 002 Zenet HP 438A The 15V adjustment on the A9 Regulator Assembly should be the first item checked during any adjustment procedure The 15V source and the 15
186. e appropriate program code When the power meter is addressed to talk it will output data for the selected function The output format for these functions is described in the following paragraphs Service Request Mask Value is explained later under Sending the Service Request Mask Value 3 35 Operation 3 36 HP 438A Learn Modes In addition to being able to store front panel setups in its own registers the power meter has two learn modes that use the controller s memory One learn mode allows the power meter to send instrument configurations to the controller s memory The second learn mode is a subset of the first and transfers only information that can be stored in a STORE RECALL register Whenever data is being transferred between controller and power meter it must do so in uninterrupted strings If a data string is broken or interrupted the data could be lost or offset and misinterpreted by the power meter An offset of data bytes can persist until EOT is read Learn Mode 1 After receiving an LP1 program code Learn Mode 1 and when addressed to talk the power meter sends a string of up to 128 ASCII characters containing information on the instrument configuration The last character is sent with EOI bus line true thus terminating the message This data can then be stored in the controller s memory for future use When the power meter is addressed to listen the ASCII data string can be returned to the power meter The
187. e consists of replacing defective fuses The primary power fuse is located within the tine Power Module Assembly Refer to Figure 2 1 for instructions on how to change the fuse If the instrument does not operate properly and is being returned to Hewlett Packard for service please complete one of the blue tags located at the end of this manual and attach it to the instrument Refer to section 2 for packaging instructions HP 438A Operation Table 3 1 Major Operating Characteristics 70 dBm to 44 dBm Auto or Manual 1 through 5 ranges the power range of each sensor is divided into five parts Power Range Sensor Dependant Power Sensor Range HP8481B 0 to 44 dBm 1 mW to 25 W HP8482B 0 to 44 dBm 1 mW to 25 W HP8481H 10 to 35 dBm 100 pW to 3 W HP8482H 10 to 35 dBm 100 4W to 3 W HP8481A 30 to 20 dBm 1 pW to 100 mW HP8482A 30 to 20 dBm 1 pW to 100 mW HP8485A 30 to 20 dBm 1 pW to 100 mW HP8483A 75 Q 30 to 20 dBm 1 pW to 100 mW HP R Q8486A 30 to 20 dBm 1 uW to 100 mW HP8481D 70 to 20 dBm 100 pW to 10 pW HP8484A 70 to 20 dBm 100 pW to 10 pW HP8485D 70 to 20 dBm 100 pW to 10 pW HP R Q8486D 70 to 20 dBm 100 pW to 10 pW HP8487D 70 to 20 dBm 100 pW to 10 pW 100 kHz to 33 0 GHz Frequency Range Sensor Dependent Zeroing Calibration o
188. e of the waveform should be equal to the peak amplitude 3 of the signal at A5TP15 If the amplitude of the waveform does not equa the peak amplitude of the signal at A5TP15 check A5R26 A5R27 and A5T38 Note so NI MI IN LM y ERE E E MR RR RAE ERUNT NEN 08 0 IE ee eee 1ms DIV Figure 8 47 Synchronous Phase Detector Output Waveform If the signal is correct the circuit is operating properly If the signal is incorrect go to step 3 3 If the signal appears to be only half wave rectified check for an open A5R26 4 If the signal at ASTP19 is equal to the signal at ASTP15 compare the waveform at ASTP10 with Figure 8 48 5V DIV Eque EE EE L3 T0101 d ipd bu 1 ms DIV A5TP10 Waveform Figure 8 48 Phase Detector Drive Waveforms 8 114 HP 438A Service Sheet 8 Paro Oa ee BEER We e ee EJ a pu Ee desse LI bells KI eS LE p EM E Jm LI SV DIV OV 1 ms DIV Collector of A5Q6 BEM SIS RS BENE KKM EE KAMERA ZR Collector of A5Q7 Figure 8 48 Phase Detector Drive Waveforms continued If the signal is incorrect continue troubleshooting on Service Sheet 6 5 Compare the signal at A5U26 pin 3 with Figure 8 49 8 115 Service Sheet 8 8 116 Note uy HP 438A 1V DIV 2 ms DIV Figure 8 49 Phase Detector Control Waveform If the signal is correct check for an open A5R27 If the signal is incorrect compare the signals at the collectors of
189. e service position these switches can be set to several positions corresponding to some diagnostic routines The routines can either be for manual or automatic tests of the digital circuitry A351 can be loaded on the printed circuit board in either of the two positions shown in Figure 8 10 UEPRESSED G DEPRESSED 1 NORMAL OPERATION DEPRESSED DEPRESSED 1 NORMAL OPERATION FRONT PANEL Figure 8 10 Service Function Switch HP 438A Service Sheet BD2 Table 8 4 Test Switch Pattern Normal Operation Extended Test Mode Manual Display Check Automatic Display Check Keyboard Manual Check Memory Check RAM Signature Analysis A to D Adjustment Service Function Switch Checks In normal operation with the switch in the all ones or normal operating position the power up routine can be executed This diagnostic performs a check of ROM RAM and displays as was mentioned earlier However by changing the least significant bit LSB from a zero to a one on the switch an extended test mode can be accessed Extended Test Mode Check Set the switch to decimal 14 This enables an extended test mode for the calibration and zeroing errors reporting routine This position also allows for HP IB control of the DACS digital to analog converters as well as a check of the variable gain amplifier The checking of the DACS and the variable gain amplifier will be performed at the service sheet level of troubleshooting The
190. e this mating connector The rear panel interface connector for the Hewlett Packard Interface Bus is a 24 pin connector The HP IB mating connector is shown in Figure 2 3 Part numbers for mating connectors are included in the figure Note the two securing screws are metric 2 10 Mating Connectors Coaxial Connectors The front panel output POWER REF 1 00mW 50 MHz and the rear panel Option 002 OSC power reference oscillator output connectors require 50 ohm type N male mating connectors The rear panel RCDR recorder output signal connector requires a 50 ohm BNC male mating connector Both types must be compatible with the specifications of US MIL C 39012 The power reference oscillator connectors are designed to be used with power sensors that have Type N connectors 2 11 Operating Environment The operating environment is specified to be within the following limitations Temperature ses oue uei pede po EC Ee 0 C to 55 C O lt 95 relative E E lt 4570 metres 15 000 feet 2 12 Bench Operation The instrument cabinet has plastic feet and fold away tilt stands for convenience in bench operation The plastic feet are designed to ensure proper stacking with other instruments in similar housings and the tilt stands raise the front of the power meter for easier viewing of the front panel HP 438A installation SIGNAL GROUND P O TWISTED PAIR WITH 11 SHOULD BE GROUNDED P O TWISTED PAIR WITH 12 P O TWISTED PAIR WITH
191. e to or destruction of part or all of the product Do not proceed beyond a CAUTION sign until the indicated conditions are fully understood and met General Information CCC EI CC AICC CIT TT ET NS CT BN CL RIIIE Introduction This manual contains information required to install operate test and service the Hewlett Packard 438A Power Meter The power meter is shown in FIGURE 1 1 with all of its externally supplied accessories This manual also documents Option 002 which adds the capability of rear panel sensor inputs and a second reference oscillator output This section of the manual covers the instrument description options accessories specifications and other basic information The remaining sections cover the following information Section 2 Installation Section 3 Operation Section 4 Performance Tests Section 5 Adjustments Section 6 Replaceable Parts Section 7 Manual Changes Section 8 Service Two copies of the operating information are supplied with the power meter One copy is in the form of an Operating Manual and is simply a copy of the first three sections of the Operating and Service Manual It should remain with the instrument for use by the operator The other copy provided is the Operating and Service Manual which should be retained by the technicians responsible for the periodic servicing of the instrument Additional copies of either manual may be ordered through your nearest Hewlett Packard sales office The part n
192. e use of an extension cord power cabie without a protective conductor grounding Grounding one conductor of a two conductor outlet is not sufficient protection This instrument is equipped with a three wire power cable When connected to an appropriate ac power receptacle this cable grounds the instrument cabinet The type of power cable plug shipped with each instrument is determined by the country of destination Refer to Figure 2 2 for the part numbers of these power cables Cables are available in different lengths and some with right angle plugs to the instrument Check with you nearest HP service center for descriptions and part numbers for these cables 2 4 HP 438A HP 8122 1351 BS 1363A PLUG NEUTRAL LINE UNITED KINGDOM HP 8129 1378 NEMA 5 15P HP 8129 2956 DHCR 187 PLUG DENMARK HP 8120 1369 NZSS 198 AS 3112 PLUG HP 8120 1575 IEC 326 014 IEC 83 STD 81 SABS 164 REPUBLIC OF SOUTH AFRICA and INDIA Installation HP 8129 1689 CEE 7 STO SHT VII DIN 49441 VDE 8628 CONTINENTAL EUROPE HP 8120 2194 SEV 1911 1958 24587 TYPE 12 PLUG NEUTRAL SWITZERLAND HP 8120 4753 MITI 41 9682 PLUG NEUTRAL JAPAN NOT INTERCHANGEABLE WITH 8128 1378 Figure 2 2 Power Cable and Line Mains Plug Part Numbers installation 2 6 HP 438A 2 8 HP IB Address Selection and Configuring The address can be selected from the front panel and stored in RAM When shipped from the fac
193. e zeroing and calibration software routines is contained in Service Sheet 3 When power is applied to the instrument it goes through its pretest routine and the reset power fail resets the CPU to a predetermined hardware configuration The CPU then retrieves the last front panel setup stored in RAM and establishes the required measurement configuration This controlled restart ensures that the power meter always starts operation from a known configuration When power is turned off or lost the combined action of the reset power fail and RAM chip enable circuits protect the data stored in the RAM This is accomplished by immediately disabling the input output functions of the RAM and applying the battery voltage to the Vcc input of the portion of RAM used for data storage when power is off The input output functions are disabled to prevent any false data from HP 438A Service Sheet BD2 being stored while the power level is dropping The required restart data is always present in RAM The service function switch and buffer can select and initiate diagnostic programs that are used when troubleshooting the power meter A list of the available diagnostic programs and instructions on how to run them are contained in the troubleshooting section of this service sheet Timer A D PIA and Latch Circuits The two main purposes of the timer A D or ADC analog to digital converter circuit are to time the A D conversion in the A5 Main Amplifier A
194. ear panel in parallel with the front panel inputs and a rear panel connector for an additional power reference oscillator If Option 002 was not initially ordered with the power meter the option can be added by ordering the Option 002 retrofit kit HP part number 00438 60044 Option 004 deletes the two HP 11730A Sensor Cables normally supplied with the power meter Refer to paragraph 1 12 Cables in this section for other cables available 1 8 Mechanical Option A mechanical option kit is available containing hardware and installation instructions for adding handles to the meter To obtain front handle kit Option 907 order HP part number 5061 9688 HP 438A 1 9 Accessories Supplied 1 10 Accessories Available General information The accessories supplied with the power meter are shown in Figure 1 1 The line power cable will be supplied in one of several configurations depending upon the country of destination for the original shipment from the factory Refer to Power Cables in section 2 of this manual Two power sensor cables HP part number 11730A are supplied 1 11 Rack Mounting Kits These kits are very useful when the power meter is to be rack mounted It permits access to internal circuits and components and access to the rear panel is possible without removing the instrument from the rack Rack mounting one power meter Order HP part number 5062 3972 This kit includes one rack flange and one extension ada
195. ect perform the Cathode Data Display and Keyboard Scan PIA Check Cathode Data Display and Keyboard Scan PIA Check U22 Service Sheet 3 1 Move the QUAL line to U22 pin 23 set QUAL to LO and verify that the signatures for 5 volts versions 5 0 and 2 0 A20U and ground 0000 are as shown 2 Verify the signatures in Table 8 28 HP 438A Service Sheets 1 4 Table 8 28 Cathode Data Display and Keyboard Scan PIA Signatures Pin Sigal Number Nm se 0 The probe should blink indicating signal activity If all signatures are correct perform the Timer A D and Software Check If the signatures for pins 4 5 6 or 9 were incorrect perform the Miscellaneous Checks If the signatures for any other pins were incorrect replace U22 Timer A D and Software Check U20 Service Sheet 3 1 Move the QUAL line to U20 pin 10 set QUAL to LO and verify the signatures for 5 volts versions 5 0 and 2 0 HFC3 and ground 0000 are as shown 2 Verify the signatures in Table 8 29 8 69 Service Sheets 1 4 HP 438A Table 8 29 Timer A D and Software Signatures Pin Bags Number d i UC82 UC82 CUOP 0000 FCUF 6AUA H5U4 U2F5 Verify the signal at U20 pin 2 is 2 kHz and U20 pin 3 is 1 kHz If the signatures and frequencies are correct perform the HP IB Interface Check If any signature or frequency is incorrect verify that 4 MHz is at U20 pin 6 If there isn t a sign
196. ed a shift in settings Repeat the procedure for channel B of the power meter by making connection to channel B from the range calibrator Repeat the above procedure starting with step 3 except press on the power meter Adjust RNG 4 SHP A4R27 and RNG 5 SHP A4R35 as in steps 5 and 7 above HP 438A Adjustments 5 12 Power Reference Oscillator Frequency Adjustment Y Note Reference Description Equipment Procedure Adjustment of the Power Reference Oscillator frequency may also affect the output level of the oscillator Thus after the frequency is adjusted 50 0 0 5 MHz the output level should be checked as described in section 4 A procedure for adjusting the output to the specified level is provided in the next paragraph Service Sheet 11 Variable inductor G1A1L1 is adjusted to set the power reference oscillator output frequency to 50 0 10 5 MHz HP 438A POWER METE POWER REF 1 08 mV 59 MHz Figure 5 5 Power Reference Oscillator Frequency Adjustment Setup Frequency Couiteriss2 co ia EEG HP 5328A Option 031 1 Connect the equipment as shown in Figure 5 5 and set up the counter to measure frequency 2 Set the power meter LINE switch to ON in and the POWER REF OSC switch to off LED off 3 Set the power meter POWER REF OSC switch to on LED on and observe the indication on the counter f the counter display reads GH 40 5 MHz no adjustment of the power reference oscillator frequ
197. ed to perform their designated functions 2 The address bus controls access to the ROM and RAM It also supplies inputs to the control decode circuits 3 The data bus transfers information throughout the controller Note that the data bus is buffered at the data inputs to the microprocessor at the ROM and RAM outputs at the HP IB circuits and at the I O interface These buffers provide the required signal strength to drive the associated circuits They also help to isolate problems and aid in locating a malfunction when one occurs Data Input Output Section The A1 Keyboard Assembly is used during local operation to select the measurement configuration of the power meter When a key is pressed the keyboard priority encoder in the CPU encodes and stores this information in the cathode data display and keyboard scan PIA Peripheral Interface Adapter When the PIA is enabled this information is transferred to the microprocessor and the appropriate changes to the instrument are initiated 8 29 Service Sheet BD2 8 30 HP 438A The All HP IB Assembly is used during remote operation to interface the HP IB to the HP IB interface management and transceiver circuits on the CPU These circuits manage the exchange of the bi directional information between the CPU and the HP IB The HP IB assembly also contains the manual HP IB address switch The output from this switch is applied to the HP IB address buffer on the CPU Note that the pr
198. eference HP Qty Description Mfr Manufacturer Designation Part No Code Part Number A3J2 1252 3489 CONN POST TYPE 100 PIN SPCG 3 CONT 87499 102 A3J3 1251 8106 7 1 CONN POST TYPE 100 PIN SPCG 20 CONT 3592 6002 A3J4 1200 1205 6 1 SOCKET IC DIP 16 CONT DIP DIP SLDR 2 641610 2 A3J5 1251 8601 17 1 CONN POST TYPE 100 PIN SPCG 34 CONT 3594 6002 A3J6 1251 8935 JO 1 CONN POST TYPE 100 PIN SPCG 2 CONT 65806 077 A3MP1 1400 1210 7 1 HOLDER BAT 1 WD BH906 A3MP2 1200 0688 7 1 SOCKET IC DIP 14 CONT DIP DIP SLDR DILB14P 308T A3MP3 1200 0654 17 2 SOCKET IC DIP 40 CONT DIP DIP SLDR DILB40P 308T A3MP4 0340 0944 3 1 INSULATOR IC NYLON BLACK 814 060 A3MP5 1200 0567 1 3 SOCKET IC DIP 28 CONT DIP DIP SLDR DILB28P 308T A3MP6 00438 20029 9 3 HINGE RIVETED 00438 20029 A3MP7 0403 0179 0 3 BUMPER FOOT ADH MTG SJ 5012 BLK A3MP8 2190 0731 19 3 WASHER FL NM NO 4 115 IN ID 26 IN OD A3MP9 3050 0891 71 3 WASHER FL MTLC 3 0 3 3 MM ID 6 85 MM OD A3MP10 0515 0168 4 3 SCREW MACHINE ASSEMBLY M3 5 X 0 6 6MM LG A3MP11 0361 0009 5 3 RIVET SEMITUB OVH 123DIA 188LG 531 R 4012 A3Q1 1853 0281 9 1 TRANSISTOR PNP 2N2907A SI TO 18 PD 400MW 2N2907A A3Q2 1853 0281 9 1 TRANSISTOR PNP 2N2907A SI TO 18 PD 400MW 2N2907A A3Q3 1853 0281 9 1 TRANSISTOR PNP 2N2907A Si TO 18 PD 400MW 2N2907A A3Q4 1853 0281 9 1 TRANSISTOR PNP 2N2907A SI TO 18 PD 400MW 2N2907A A3Q5 1853 0281 9 1 TRANSISTOR PNP 2N2907A SI TO 18 PD 400MW
199. elected during the zeroing routine The gain DAC output this signal is only selected during the calibration routine The Analog to Digital Converter ADC in the power meter consists of the following three parts 1 2 3 The ramp generator and comparator circuits in the main amplifier The timer A D and software interrupt circuit in the CPU The software routine that controls these circuits START RAMP COUNTER OUT TIMER A D TG MICROPROCESSOR CPU COMPARATOR MAIN AMPLIFIER Figure 8 14 Simplified Analog to Digital A D Converter Block Diagram Figure 8 14 Simplified A D Converter Block Diagram shows the relationship between the CPU and the main amplifier circuits The method of digitizing the input signal is identical for all input signals The sequence is as follows ER The selected signal from the analog digital input multiplexer is applied to the ADC input of the comparator The CPU generates the start ramp signal This signal is applied simultaneously to the timer A D in the CPU and the ramp generator in the main amplifier The timer A D starts counting at a 4 MHz rate Using the 2 5 V reference input the ramp generator produces a positive linear ramp 8 45 Service Sheet BD3 8 46 HP 438A 5 When the ramp voltage equals the ADC input voltage the comparator sends the ramp end signal to the timer A D circuit in the CPU The counter is stopped at the count that represents
200. ency is necessary If it is not within these limits adjust the power reference oscillator frequency as described in steps 4 and 5 4 Remove the power meter top cover and loosen the screws holding the A3 CPU Assembly Swing the assembly out The screwdriver adjustment is accessible through a hole in the deck 5 Adjust GLAILI to obtain a 54 88 0 5 MHz indication on the counter Adjustments 5 13 Power Reference Oscillator Level Adjustment Reference Description Note i Equipment Procedure HP 438A Service Sheet 11 The power reference oscillator is factory adjusted to 1 0 mW 0 7 using a special measurement system accurate to 0 5 traceable to the National Institute of Standards and Technology and allowing for a 0 296 transfer error To ensure maximum accuracy in readjusting the power reference oscillator the following procedure provides step by step instructions for using specified Hewlett Packard instruments of known capability If equivalent instruments are used signal acquisition criteria may vary and reference should be made to the manufacturer s guidelines for operating the equipment The power meter may be returned to the nearest HP office to have the power reference oscillator checked and or adjusted Refer to section 2 Packaging POWER HP 438A POWER METER METER en ty 1 CEJ DIGITAL VOLTMETER rro E Boose POWER REF 1 62 mW i 58 MHz THERMISTOR MOUNT Fi
201. ent unit annunciators and the table above Comments Logarithmic units cannot be used with a measured value that is zero or negative If the value is zero or negative Error 27 illegal logarithmic operation will be displayed With REL mode off logarithmic units cannot be used to display A B difference measurements where the SENSOR A power level is less than the SENSOR B power level Likewise with REL mode off logarithmic units cannot be used to display B A difference measurements where the SENSOR B power level is less than the SENSOR A power level PRESET sets the measurement units to Watts linear units With no power applied to the sensor the displayed power in single sensor measurement mode dirfts both negative and positive about zero If the power meter is in logarithmic mode negative drift results in a log error Error 27 This is normal and does not require corrective action Related Sections Error Messages PRESET REL Relative Measurements SENSOR A B and SENSOR B A HP 438A D Error Messages Error Messages Description The power meter generates error messages to indicate operating problems incorrect keyboard or HP IB entries and service related problems Error messages are grouped as follows Errors 01 through 49 These are measurement errors which indicate that not all conditions have been met to assure a calibrated measurement Measurement errors can usually be cleared by readjust
202. er It includes block diagrams with theory and troubleshooting schematic diagrams schematic diagram notes and after service safety checks The pages in the last part of this section are called the service sheets SS They contain block diagrams schematic diagrams supplemental diagrams and associated information 8 3 Block Diagrams The block diagrams and related service information are found on Service Sheets BD1 BD2 and BD3 BD1 is an overall block diagram that shows the major functional sections of the power meter It serves as an index to the more detailed information on the succeeding service sheets and is the starting point for most troubleshooting procedures BD2 shows the Controller Section with connections to BD3 the Amplifier Section 8 4 Schematic Diagrams The schematic diagrams and their associated information are presented in Service Sheets 1 through 11 These diagrams in functional groupings are designed to aid in understanding the principles of operation and to aid in troubleshooting the power meter Refer to the paragraph entitled Trouble shooting for additional information 8 6 Before Applying Power Verify that the instrument is properly set to operate from the available line voltage and that the correct fuse is installed An uninterrupted safety earth ground must be provided from the main power source to the instrument input wiring terminals power cord or supplied power cord set 8 7 Warnings and Caut
203. er meter will display a power level Annunciators WATT B 100 096 CF and B are on Press to display dBm The power meter will now display the loss through the power splitter This number will be used as an offset to get the power level displayed back to 1 mW Annunciators B MNL 100 096 CF and B are on Press The power meter display reads Ent annunciators show dB 0 00 B and 99 99 Key in a number equivalent to power loss through power splitter using the blue keys representing the numbers and the key for the decimal point Press ENTER n alternative is to just press which is in the blue key mode This takes the loss in dB through the splitter and uses it as the offset to return to a display of 1 mW HP 438A POWER METER 11667A POWER SPLITTER Figure 3 4 Front Panel Checks Setup 2 Press to return to channel A as the active channel Repeat step 15 for channel A Press B A Press to display the ratio in 96 The above checks have been using the AUTO RANGE and AUTO FILTER modes To check the two MNL manual keys for RANGE and the FILTER Press MNL RANGE The power meter will display Ent Annunciators rng 3 1 5 and A will be on for channel A Annunciators rng 1 1 5 and B will be on for channel B Press MNL FILTER The power meter will display Ent Annunciators FLt 1 0 9 and A will be on for channel A Annunciators FLt 7 0 9 and B will be on for channel B Operation 3 16
204. erify the signatures for 5 volts and ground are as shown below Rev 5 6 Rev 2 0 5 volts A3TP8 9UCF 94CF Ground 0000 0000 If the signatures are incorrect go to Service Sheet 1 and begin troubleshooting using signature analysis Perform the following tests in the sequence given to determine the problem circuit w Digital I O Test u Auto Zero DAC and Buffer Test u Offset Removal DAC Buffer and Gain Compensation Test u Gain DAC Buffer and Gain Compensation Test m Miscellaneous Buffer Test a Cal Oscillator Control Test Disconnect the signature analyzer and reset switch A3S1 to all ones Digital I O Test L 2 Perform steps 1 through 6 of the Fault Isolation Procedure Verify the signatures in Table 8 32 HP 438A Service Sheet 7 Table 8 32 Digital I O Signatures Signal DS 80 20 so 9 85PP H16U 52AA 66PF If all signatures are correct the Digital I O circuits are operating properly If the Fault Isolation Procedure is being performed and the Digital I O circuits are operating properly go to the Auto Zero DAC and Buffer Test If any signature is incorrect verify the signatures in Table 8 33 Table 8 33 Digital I O Signatures A5U18 A5U15 Digital I O lso 20 so 29 If ali signatures are correct replace the integrated circuit A5U15 or A5U18 that was associated with the incorrect signatures from Table 8 32 8 97 Service Sheet 7 HP 438A If
205. erify the signatures in Table 8 9 Table 8 9 Memory Data Bus Buffer Signatures If all signatures are correct replace U8 If any signature is incorrect verify the Chip Select signatures 8 55 Service Sheets 1 4 8 56 HP 438A Chip Select Signatures 1 Set the controls on the signature analyser as follows Start ee E t eee es dnd rising edge EE rising edge Clock Em falling edge 2 Verify the signatures in Table 8 10 Table 8 10 Chip Select Signatures Pin Number Signal NETTEN E U28 16 NRAME 5 STAT2 STOP2 18 NSWE 19 NROMIE 20 NMEME 21 NIRT 22 NIOE 23 NADS If all signatures are correct and you have version 2 0 continue with step 3 If you have version 5 0 proceed to step 4 If any signature is incorrect verify the signatures in Table 8 11 Table 8 11 Chip Select Signatures Pin Number Signal qe R NW NFREERUN BS BA PA12 DAIN PA14 PA13 NPWR FAIL PA11 PA10 If the signature for pin 2 is incorrect verify that A3TP4 is grounded or look for an open trace If the signature for pin 10 is incorrect perform the troubleshooting for the Reset Power Fail circuit If any other signature is incorrect replace U19 HP 438A Service Sheets 1 4 If all signatures are correct replace U28 3 Applies to version 2 0 only Verify the signatures in the table below Chip Select Signatures If all signatures a
206. ering offset values Pressing OFFSET DSP OFS and then ENTER automatically enters the offset necessary for the power meter s display to indicate 0 00 dB or dBm for logarithmic units or 10096 or 1 00 mW for linear units depending on the measurement mode Existing offsets are taken into account in the calculation of the display offset value Procedure To enter an offset for the active entry channel press OFFSET enter a value between 99 99 and 99 99dB and then press ENTER To enter the offset necessary for the power meter to display 0 00dB or dBm 10096 or 1 00 mW depending on the measurement mode press GFFSET GSP OFS and then ENTER Examples To add a 20dB offset to channel B assuming that channel B is the active entry channel LOCAL Function ew ennen Data amma Jm Evan R Keystrokes 2 g OS2GEN Function program codes Data HP 438A Offset The next example uses the display offset function to compensate for the coupling factor of a directional coupler Connect sensor A to the coupler s test port and connect sensor B to the coupler s incident port To enter the correct offset for sensor B to read the power emerging from the directional coupler correcting for any main line insertion loss as well as coupling factor LOCAL 47 Sensocr Function sc ge Function ntect Keystrokes DP UPS BPOSDOEN om TT program codes Functlon Function P
207. eset HP IB address that is selected on the switch is only read by the CPU if the current HP IB address set from the front panel and stored in RAM is lost Microprocessor and Memory Circuits The microprocessor and memory circuits with their associated busses form the kernel of the CPU The microprocessor reads the permanently stored programs in the ROM and uses these instructions to control the operation of the power meter During troubleshooting this kernel can be isolated and exercised by grounding A3TP4 FREE RUN prior to applying power The clock and timer interrupt circuits provide the synchronization required for correct operation of the CPU The address and control decode circuits derive the digital control signals from part of the address bus and hardware monitoring inputs This process is described in detail on Service Sheet 2 These control signals are used to enable different digital circuits when required by the microprocessor The RAM is used for temporary data storage while the power meter is operating However combined with the reset power fail RAM chip enable and the battery circuits part of the RAM is used to store data when the power meter if turned off The following information is retained when power is turned off 1 The current front panel setup 2 Any other front panel setup that has been saved using the key or the HP IB program code ST 3 The current zeroing and calibration data Additional information on th
208. esponding number will be displayed 01 through 21 starting with key A Refer to the following list A B B A SHIFT SET A SET B PRE SET ZERO AUTO RANGE CAL ADJ MNL RANGE CAL FACTOR AUTO FILTER OFFSET MNL FILTER OSC STORE RECALL REL dBm WATT LCL 01 02 03 04 05 06 07 Hog Hog i e Go 09 HH ug g oi ug a UI cr 20 01 HP 438A Service Sheet BD2 The normal indication is The display shows GE at turn on This increments to gi when the key is pressed and so on through the keyboard as each key is pressed up to 21 for the key When a key is pressed and the number doesn t change to the number corresponding to that key then either the key or associated circuitry could be the problem Refer to Service Sheets 1 3 4 and 5 Memory RAM Check Set the switch to decimal 2 The front panel display is blank during this check To verify the check is being run observe the anode data bus bits ADO through AD7 LED s on the A3 CPU Assembly near A3S1 At the next power up there will be a momentary rcl recall Fail error message since information in memory was written over during this test routine The normal indications are The data bus bit pattern changes as shown in Table 8 5 Table 8 5 Data Bus Test IEEE Ee Bits LLL BitPattem ssid Pattern Start Test 1 Test 1 Test 1 Test 2 Tests Restart Start cepe ee Complete 0 1 0 1 1 1 0 H 0 1 0 1 0 0 H 0 0 0 0 H 0 0 0
209. essage The power meter does not respond to the Pass Control message because it cannot act as a controller 3 43 Operation 3 44 Note HP 438A 3 29 Sending the Require Service Message The power meter sends the Require Service message by setting the Service Request SRQ bus control line true The instrument can send the Require Service message in either local or remote mode When the power meter is sending the Require Service message the front panel SRQ annunciator lights The Require Service message is cleared when a serial poll is executed by the controller or when a CS clear status program code is received via a Data message There are five conditions that can be enabled to cause the Require Service message to be sent These conditions which are enabled by the Service Request Mask are described below Data Ready When the power meter has a data point requested by a trigger command Cal Zero Completed When the power meter has completed a calibration or zeroing cycle Entry Error When a number is entered that is out of the allowable range for the selected parameter Measurement Error When the power applied to the sensors is incorrect for the current instrument configuration Over Under Limits When the limits checking function is enabled and the measured power is greater than the high limit or lower than the low limit Service Request Mask The Service Request Mask determines which bits can set the Stat
210. et its outputs will be in their inactive states Toggle Input When active causes the flip flop to change states Set Input When active causes the flip flop to set Reset Input When active causes the flip flop to reset J Input Analogous to set input K Input Analogous to reset input Data Input Always enabled by another input generally a C input see Depen dency Notation When the D input is dependency enabled a high level at D will set the flip flop a low level will reset the flip flop Note strictly speaking D inputs have no active or inactive states they are just enabled or disabled Count Up Input When active increments the contents count of a counter by ra counts m is replaced with a number Count Down Input When active decrements the contents count of a counter by m counts m is replaced with a number Shift Right Down Input When active causes the contents of a shift register to shift to the right or down m places m is replaced with a number Shift Left Up Input When active causes the contents of a shift register to shift to the left or up m places m is replaced with a number NOTE For the four functions shown above if m is one it is omitted The following functional labels are to be used as necessary in symbol build ups to ensure rapid identification of device function Service HP 438A Table 8 1 Schematic Diagram Notes 7 of 8 DIGITA
211. eter It measures power in the range of 70 to 44 dBm over the frequency range of 100 kHz to 26 5 GHz using the existing Hewlett Packard 8480 series power sensors A 1 00 mW 50 MHz POWER REF reference is available for calibrating the meter to the sensor s sensitivity The meter displays power in the following modes dBm dB Rel relative watts and Rel per cent relative The measured ratio and difference of two inputs can be displayed The power ratio is displayed in either dB or while the power difference is displayed in either watts or dBm The ratio or difference power readings of a single sensor input are displayed relative to a stored reference Also displayed are the possible error states of the meter Zeroing calibration and offsets are capabilities of the meter that can be set either locally by the front panel keys or remotely over the Hewlett Packard Interface Bus HP IB When these routines are finished the meter resumes measuring and displaying the input power The meter has both manual and automatic ranging In the AUTO RANGE mode the meter automatically switches through its five ranges and in the MNL RANGE manual range mode one of the five ranges can be selected Memory capacity for saving up to 19 front panel settings is built into the meter and can be accessed by using STORE and RECALL 1 7 Electrical Options Option 002 provides the additional capability of having two power input connectors on the r
212. eter key and wait for the readout to reappear Verify that the reading is 4 85 0 06 uW 5 Set the range calibrator FUNCTION switch to CALIBRATE f Press the power meter key then press the key to get minus sign then press ENTER The minus sign indicates use of an external reference source If the minus sign is not used there will be a HO REF error on the display Verify that the power meter display reads 1 8868 20 006 mW The range calibrator output level is adjustable in 5dB increments Thus the 3 uW 30 pW 300 pW 3 mW and 30 mW legends on the RANGE switch are approximations The true values for these settings are 3 16 31 6 and 316 uW 3 16 mW and 31 6 mW It may be necessary to re zero the meter before each measurement 8 10 11 12 13 14 Set the range calibrator RANGE switch to the positions shown in the following table For each setting verify that the power meter autoranges properly and that the display is within the limits shown Set the range calibrator RANGE switch to STANDBY Connect the calibrator to channel B Press the power meter channel k and repeat steps 4 through 6 to test channel B Set the power meter dBm WATT switch to the dBm position and verify that the display changes to the dBm mode and that the indication is within 20 00 0 04 dBm 19 96 dBm__ MD D4 dBm Set the range calibrator RANGE switch to 10 dBm Verify that the power meter displays
213. etween task 1 and task 2 and that it pass control to the task that was not interrupted This allows both tasks to have an equal amount of execution time independent of what each is working on This method of sharing execution time ensures that a high level of HP IB activity does not slow down mathematical calculations nor does mathematical activity slow down the HP IB response time When task 1 is executing it performs the following functions 1 Determine if any HP IB function is pending and if it is perform it These functions can consist of sending or receiving data over HP IB or executing Il P IB commands 2 Determine if any keyboard command is pending and if it is perform it All key functions have individual routines that are performed each time the key is pressed 3 Determine if there is new data available This data can be an updated measurement result new power meter configuration or an error message If there is new data the display data buffers are updated and the new information is displayed when the display is refreshed during the Interrupt routine When task 2 is executing it performs the following functions 8 18 HP 438A Note Y Service Sheet BD1 1 Gets the last measurement result from the software digital filter This output is the average output of the digital filter at that time A detailed explanation of the digital filter is contained in Service Sheet BD3 2 Checks to determine if any error c
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215. f the power meter to power sensor sensitivity Calibration Factor Power Reference Compensation for mismatch and effective efficiency i mW at 50 MHz dBm dB Relative Watts and Relative Dual Inputs Ratio in dB or Difference in dBm or Watts Compensation for gains or losses in test system Power Display Ratio and Difference Offset Digital Filtering Auto or Manual filters 0 through 9 A filter length or number of readings is determined by two being raised to some power where that exponent is the filter number Memory 19 registers for store and recall of front panel information A twentieth register is used for recall of power down information 1 When using an older HP 8483A that specifies adjusting to 0 96 mW note that the following procedure should be used 1 Set REF CF to 0 96 times the Ref Cal Factor on the label 2 The power meter will automatically adjust to 1 000 mW Note that the cal factor value for 50 MHz power measurements should be read for the plotted data on the sensor body No special procedure is necessary for these measurements 3 3 S E Sainjed j Jaueg 1uo14 perdus L e amb paj29jas AU say ySno4u euo SUOIPUOD PNEJ8p 0j 19 EWONE SI SJAJJ euiu Jo Aio Due 30001 jo aue Jamod e 19 u9 U O Jasn ay pue aie g pue y 9UUByo 10 SJojeuleJed ay pue 19111 OJNE ay s191ue jouueuo poai2a os ay 9Anoe setuodaq epow Aus 9ueunu ey 9j8 S jesald e oui qnd SI 18 8W JaMoOd 8U 2 uaria OLA
216. factory repaired and tested assemblies are available only on a trade in basis therefore the defective assemblies must be returned for credit For this reason assemblies required for spare parts stock must be ordered by the new assembly part number Table 6 1 Part Numbers for Restored Assemblies Part Number Description i Restored Assembly New Assembly Central Processing Unit Assembly 00438 69103 00438 60103 Main Amplifier Assembly 00438 69005 00438 60005 1 When ordering extra assemblies for spare parts stock use new assembly part number only Restored orders require return of the defective part 2 If you have a 00438 68003 or 00438 60003 you must order a 00438 60105 kit for replacement Replaceable Parts HP 438A Table 6 2 Reference Designations and Abbreviations 1 of 2 A a eR E SL Ses assembly AT cuz attenuator isolator termination B Ae uer is fan motor BT wi otis kt E wk battery Qi ua Gig A EN ane a capacitor CP Gaps xm ns coupler CR diode diode thyristor varactor DC 2s directional coupler DL l0 delay line DS annunciator signaling device audible or visual lamp LED DAA A AA ampere E alternating current ACCESS accessory ADI Scie Reed es adjustment AID Ln analog to digital AF tree audio frequency AFC automatic frequency control AGC automatic gain control Bi a aluminum ALC automatic level control AM amplitude modulation AMPL 020 SSG amplifier APC auto
217. fier Test b Channel Selection Circuitry Test c 220 Hz Multivibrator Test If both channels are bad perform the following tests in the order given a Decoupled Power Supply Test b 220 Hz Multivibrator Test c Channel Selection Circuitry Test d Amplifier Test HP 438A Note i Service Sheets 6 Amplifier Test This test assumes channel A is bad Use the test points shown in parentheses when troubleshooting channel B 1 Verify the voltage at A4TP4 A4TP2 is 0 volts If the voltage is not 0 volts replace A4U1 A4U3 2 Verify the following conditions are found at A4TP3 A4TP1 AC ouo po 4 TOO TU da 12 Vp p 0 2 volts SANTE 0 9 Vdc 0 2 volts Freguenty Gd EET 220 Hz 20 Hz If the signals are correct continue with the Channel Selection Circuitry Test If the signals are incorrect check the following list of possible problems and causes a Voltage at A4TP3 A4TP1 is approximately 12 Vdc m Open cable between A4J5 A4J7 and J2 J3 w A4U1 A4U3 is defective Open in main feedback path A4R20 A4R21 A4R22 A4R23 a DC bias network bad A4R8 A4R12 A4R14 A4R9 A4R13 AAR15 Voltage at A4TP3 A4TP1 is 0 9 Vdc no AC u Open cable between A4J8 A4J9 and J2 33 Power meter should indicate Error 31 32 m 220 Hz Oscillator or Buffers are defective Perform 220 Hz Buffer Test The dc voltage at A4TP3 A4TP1 is too high u Shorted or leaky A4C9 A4C10 u DC
218. filter setting Procedure The filter length is set for the active entry channel For dual sensor measurements the filter length should be set for each sensor To automatically select the filter length press AUTO FILTER To manually select the filter length press MNL FILTER enter a number 0 9 and then press ENTER The filter length is the result of 2 being raised to the power of the filter number To select hold filter mode press MNL FILTER and then ENTER 3 61 Filters 3 62 HP 438A Example To manually set the filter length to 128 filter number 7 LOCAL ger Funct fan ow 45 Data 4 emEnter n keystrokes AUTO FILTER GATA 7 Function program codes Data Program Codes Parameter Program Code AUTO FILTER FA MNL FILTER FM Hold filter FH ENTER EN indications The MNL annunciator on the front panel display lights when the power meter is in manual filter or m nual range mode There is no front panel indication when the power meter is in auto filter mode Comments By manually selecting a filter length that is significantly longer than the auto filter mode default length the resolution of the display can be extended to five digits in Watts or to 0 001 in dBm on some power ranges The range setting and filter number required for high resolution is defined in the following table HP 438A Filters for High Resolution High resolution not available 8 9 5 6 7 8 9 4 5 6 7
219. for further troubleshooting when a ROM or RAM error message appears Service error messages from the power up diagnostic are 61 through 66 These errors are displayed when a problem with ROM or RAM has been detected A list of the errors follows 61 A3U9 ROM address 8000H through 09FFFH 62 A3U9 ROM address 0A000H through OBFFFH 63 A3U10 ROM address 0C000H through ODFFFH 64 A3U10 ROM address 0E000H through OFFFFH 65 A3U12 RAM address 800H through OFFFH 66 A3U13 RAM address 0 through 7FFH Visually inspect the interior of instrument for any signs of abnormal internally generated heat such as discolored printed circuit boards or components damaged insulation or evidence or arcing Determine and remedy the cause of any such condition Using a suitable ohmmeter check the resistance from the instrument enclosure to the ground pin on the power cord plug The reading must be less than one ohm Flex the power cord while making this measurement to determine whether intermittent discontinuities exist Check any indicated front or rear panel ground terminals that are marked using the above procedures Check the resistance from the instrument enclosure to the line and neutra tied together with the power switch ON and the power source disconnected The minimum acceptable resistance is two megohms Replace any component which results in a failure Check the line fuse to verify that a correctly rated fuse is installed 8 5 Service HP 438
220. from 90 to 126 Vac sources or from 198 to 252 Vac sources The number visible in the window on the module indicates the nominal line voltage 100 120 220 or 240 Vac to which the instrument must be connected Verify that the line voltage selection card and the fuse are matched to the power source to be used Refer to Figure 2 1 Line Voltage and Fuse Selection Table 2 1 lists the ratings and HP part numbers for the replaceable fuses Selection of Operating Voltage Slide cover and rotate FUSE PULL to left Select line Mains voltage by orienting PC board with desired voltage on left side Push board firmly into module slot Rotate FUSE PULL back into normal position and re insert fuse in holders using caution to select correct fuse value Figure 2 1 Line Voltage and Fuse Selection 2 3 Installation HP 438A Warning For protection against fire hazards the line fuse should be a 250V normal blow fuse with the correct current rating Table 2 1 Fuse Ratings and Part Numbers Line Voltage Part Number 100 120V 2110 0001 220 240V 2110 0421 1 0A 250 V 0 375 A 250 V 2 7 Power Cable Warning o Before connecting this instrument the protective earth terminal of the instrument must be connected to the protective conductor of the Mains power cord The Mains plug shall be inserted only in a socket outlet provided with a protective earth contact The protective action must not be negated by th
221. function of the part and the number of parts required Address the order to the nearest Hewlett Packard office Within the USA it is better to order directly from the HP Parts Center in Mountain View California Ask your nearest HP office for information and forms for the Direct Mail Order System HP 438A 6 9 Recommended Spares List 6 10 Restored Assemblies Reference Designation Replaceable Parts Stocking spare parts for an instrument is often done to ensure quick return to service after a malfunction occurs Hewlett Packard prepares a Recommended Spares list for this instrument The contents of the list are based on failure reports and repair data Quantities given are for one year of parts support A complimentary copy of the Recommended Spares list may be requested from your nearest Hewlett Packard office When stocking parts to support more than one Signal Generator or to support a variety of Hewlett Packard instruments it may be more economical to work from one consolidated list rather than simply adding together stocking quantities from the individual instrument lists Hewlett Packard will prepare consolidated Recommended Spares lists for any number or combination of instruments Contact your nearest Hewlett Packard office for details Table 6 1 lists assemblies within the instrument that may be replaced on an exchange basis thus affording a considerable cost saving Exchange
222. g to Digital Converter Slope Adjustment 5 5 5 10 220 Hz Frequency Adjustment 5 7 5 11 Ranges 4 and 5 Shaper Adjustment Channel A and 4 i50 E E Rond 6 o TE 5 8 5 12 Power Reference Oscillator Frequency Adjustment 5 9 5 13 Power Reference Oscillator Level Adjustment 5 10 6 Replaceable Parts 6 1 Introduction a a e A A ee 6 1 6 2 Abbreviations s w s a w w o xo x 6 1 6 3 Replaceable Parts List 6 1 6 4 Factory Selected Parts 6 2 6 5 Parts List Backdating f 6 2 6 6 Parts List Updating Change Sheet 6 2 6 7 Illustrated Parts Breakdown 6 2 6 8 Ordering Information 6 2 6 9 Recommended Spares List 6 3 6 10 Restored Assemblies 1 1 6 3 7 Manual Changes 8 Service 8 1 Introduction 4 6 Gd BK vov M a 8 1 8 2 Service Sheets 1 1 1 1 4 1 8 1 8 3 Block Diagrams wada ea det 8 1 8 4 Schematic Diagrams 1 1 1 8 1 8 5 Safety Considerations 8 1 8 6 Before Applying Power 8 1 8 7 Warnings and Cautions 8 1 8 8 Recommended Test Equipment and ee 8 2 8 9 Service Tools Aids and Information 8 2 8 10 Service Tools 8 2 8 11 Assembly Locations 8 3 8 12 Parts and Cable Locations 8 3 8 13 Test Point and Adjustment Locations 8 3 8 14 Service Aids
223. ge REL Relative Measurements SET A and SET B STORE and RECALL 3 77 Sensor A Band Sensor B A HP 438A T q_ A AAA AA TH mmm ime Sensor A B and Sensor B A Dual Sensor Difference Measurements Description SENSOR A B and SENSOR B A cause the power meter to make dual sensor difference measurements The power meter displays the numerical difference of the power values of both sensors The power values for sensors and B include all offsets and cal factors that have been set for each individual channel Measurement results are displayed in either dBm or Watts In addition A B sets A as the active entry channel and B A sets B as the active entry channel Procedure To make a difference measurement press the key and then select A B or B A as desired Example To select B A measurement mode LOCAL Keystrokes program codes Program Codes Program Code SENSOR A B SENSOR B A 3 78 HP 438A Sensor A B and Sensor BR A Indications The middle block of annunciators on the front panel display indicate the measurement mode either A B or B A and the measurement units either dBm or Watts Comments Cal factor offset range limits and filter are set separately for each sensor Logarithmic units dBm cannot be used in A B difference measurements where the sensor A power level is less than the sensor B power level Likewise logarithmic units cannot be
224. gital Supply Test 1 Connect the oscilloscope or voltmeter to A9TP4 5V Leave the power meter turned off 2 Adjust A9R3 5V ADJ fully counterclockwise disconnect A10J1 and turn the power meter on 3 If AQTP6 is 210 Vdc continue with step 4 If the voltage is incorrect the problem is probably the 4 5 Volt Bridge circuit the transformer secondary the filter capacitors or the crowbar circuit 4 Try to adjust A9R3 until A9TP4 reaches 5V H this cannot be accomplished replace A8U2 Otherwise reconnect A10J1 and make sure the voltage at A9TP4 is 5 volts If the voltage is incorrect the probiem is located on the A3 or A5 assemblies Continue with step 5 8 123 Service Sheet 9 HP 438A 5 To isolate the problem to a particular board disconnect the following cables one at a time until the voltage at A9TP4 returns to normal Cable Problem Location Related Service Sheets A3J2 A3 Service Sheets 1 4 A3J6 A3 Service Sheet 4 A5J2 A Service Sheets 7 and 8 When the problem has been isolated to a particular board refer to the related service sheets and try to identify the defective component s 5 Volt Display Supply Test 1 Connect an oscilloscope to A9TP3 Compare the waveform in Figure 8 54 with the waveform on the oscilloscope be tes ag SR DAR I eler SEE PEB EGER 200 us DIV Figure 8 54 5 Volt Display Supply Waveform If the signal is incorrect disconnect A3J6 If the signal is now correct there i
225. gure 5 6 Power Reference Oscillator Level Adjustment Setup Test Power Meter vio aisle eua d te ae copa dee HP 432A Thermistor MOM ation va Lb p D ee ha HP 478A H75 H76 Digital Voltmeter DVM eege tio exe ton a KE HP 3456A 1 Set the DVM to measure resistance and connect the DVM between the Vrf connector on the rear panel of the test power meter and pin 1 on the thermistor mount end of the test power meter interconnect cable 2 Round the DVM reading to two decimal places Record this value as the internal bridge resistance R of the test power meter approximately 200 ohms R Internal Bridge Resistance 3 Connect the test power meter to the power meter as shown in ligure 5 5 HP 438A Note 4 5 6 Adjustments Set the power meter LINE switch to ON and the POWER REF OSC switch to OFF Wait thirty minutes for the test power meter thermistor mount to stabilize before proceeding to the next step Set the test power meter range switch to coarse zero Adjust the front panel coarse zero control to obtain a zero meter indication Fine zero the test power meter on the most sensitive range then set the test power meter range switch to 1 mW Ensure that the DVM input leads are isolated from chassis ground when performing the next step 7 10 LL 12 13 Set the DVM to measure microvolts Connect the positive and negative input leads respectively to the Vcomp and Vrf con
226. h part numbers 00435 80037 and 00438 80038 A3U9 U10 version 2 0 To find your firmware version use the HP IB command ID Memory Data Bus Signatures If the Data Bus signatures are normal then the Address Bus does not need to be checked 1 Connect the signature analyzer as shown below Signature Analyzer Pod A3 Assembly Start A3TP11 Stop A3TP11 Clock A3TP6 Ground A3TP7 2 Set the controls on the signature analyzer as shown below FUNCTION uetus anes DUE habita ten can Rota ek NORM CLOCK CE falling edge rr POTENS rising edge SOD Vosa Ro grees MO gu AI SAGE GO falling edge 3 With the power meter off connect a jumper from A3TP4 to ground 4 Ensure that switch A3SI is set to the NORMAL position 1111 The least significant bit is the switch that is closest to the edge of the printed circuit board When the switches are set towards the front panel of the instrument they are set to one HP 438A Service Sheets 1 4 5 Turn the power meter on and use the following signatures to verify that the signature analyzer has been set up properly SED ER 0001 GND EE 0000 Note i If the microprocessor will not go into Free Run perform the Free Run P Mode Troubleshooting near the end of Free Run Signature Analysis 6 Verify the signatures in Table 8 8 If all signatures are correct continue with the Chip Select signatures Table 8 8 Memory Data Bus Buffer Signatures If any signature is incorrect v
227. h present and enabled by the Service Request Mask the bits corresponding to the conditions and also bit 7 the RQS bit are set true and the Require Service message is sent If one or more of the five conditions occurs but has not been enabled by the Service Request Mask the corresponding bits are still set true However if a condition has not been enabled by the mask it cannot cause the RQS bit to be set true Once the power meter receives the serial poll enable SPE bus command it is no longer able to alter the status byte If a bit has been enabled and that condition occurs after the RQS bit has been set true the bit is stored in a buffer and is read the next time the power meter receives the SPE bus command Table 3 6 The Status Byte and Service Request Mask E e a ee SENE DEE EN pu qa Ga wm o us Over Under Measurement Entry Error Cal Zero Data Ready Limit Error Complete After the Status Byte message has been sent it will be cleared if the Serial Poll Disable SPD bus command is received if the Abort message is received or if the power meter is unaddressed to talk Bits stored in the buffer waiting to be read however are not cleared Regardless of whether or not the Status Byte message has been sent the Status Byte and any Require Service message pending will be cleared if a Clear Status CS program code is received by the Power Meter 3 31 Sending the Status Bit Message The power meter sends the S
228. he calibrator to the sensor A input of the power meter If the voltage on A5U20 pin 3 is not equal to 0 10 1 volts check for a bad connection at A5J3 an open cable or an open A5R32 If the voltage on A5U20 pin 2 is not equal to 0 0 1 volts by the voltage on A5U20 pin 3 is equal to 0 0 1 volts replace A5U20 If the voltage on A5U20 pin 7 is not equal to 2 5 0 2 volts replace A5U20 HP 438A Service Sheet 8 A Ground Circuit Test If the voltage from A5TP20 to A4TP4 is 0 0 01 volts the A Ground Circuit is operating properly If the voltage is not 0 0 1 volts check A5U28 A5Q9 and associated circuitry Under normal conditions the voltage at A5U28 pin 6 is 0 7 0 1 Vde Figure 8 51 shows the feedback path for the A Ground Circuit SELECTED INPUT TO A GROUND CIRCUIT FROM SERVICE SHEET 8 SIGNAL REFERENCE GROUND C A GROUND Figure 8 51 A Ground Circuit Showing Feedback Path 8 119 ZC weeg ongtueuas simo sayldwy EN O d ES 8 amb Sv O d p 0 RH la ze 1 dNYHISN s n D A d nas Pun SW 2 310N y QN or Puer AL eee A RA p emus weree 9912 eave mit yae m we em zm mm mm rn rr mee e Fe em I ME E en e em mmer mm mm v O d 20038338 ras S Fi Wi ez YE 9 AGTH Ta INS ONS Y Er WYN De ds dr vocor sE ii 382 E t 1 Did He
229. he waveform is not present at A5U8 pin 7 replace ASUS If the signal is more than 0 7 volts positive replace A5Q3 or A5Ul If the voltage on ATU1 pin 2 is 0 0 01 volts replace A5Q3 6 Compare the waveform at ASTP1 with Figure 8 46 5 ms DIV Figure 8 46 Analog to Digital Converter Ramp Waveform If the signal is correct the circuit is operating properly If the signal is incorrect replace A5Q3 A5U1 A5R77 A5R79 or A5C35 Range Attenuator 1 100 1 Measure the 5 volt supply at ASTP7 using A5TP20 as ground 2 Connect a jumper from A5TP7 to A5U25 pin 3 3 Select MNL Range 3 and measure the voltage at A5U25 pin 2 If the voltage is not equal to the voltage at ASTP7 0 01 volts check A5U25 pin 1 If A5U25 pin 1 is high gt 2 0V perform the Gain Attenuator Buffer Test If A5U25 pin 1 is low 0 8V check A5U25 8 112 HP 438A Service Sheet 8 pin 8 If A5U25 pin 8 is high gt 2 0V replace A5U25 If pin 8 is not high replace A5U13 Select MNL Range 4 If A5U25 pin 2 is not equal to the voltage at A5TP7 divided by 100 plus or minus 0 001 Vdc replace A5U25 A5R23 or A5R24 Variable Gain Amplifier l Measure the AC voltage at A5TP18 and divide it by the AC voltage at A5U27 pin 3 If the calculated value is between 21 and 65 the circuit is operating properly If the gain is not between 21 and 65 perform the Gain Attenuator Buffer Test If that test is normal replace A5U27 A5U22 or A5R46 A5
230. hich is entered via CAL ADJ is used only during the calibration cycle Pressing and then without entering any data sets the calibration factor to 100 PRESET sets the calibration factor of both sensor A and sensor B to 100 Related Sections CAL ADJ PRESET SET A and SET B STORE and RECALL HP 438A dBm WATT dBm WATT Logarithmic Linear Units Description The key can be used to express measurement results in logarithmic or linear units The following table shows which units are applicable to the individual measurement modes Measurement Mode Single Sensor Ratio Difference 1 When REL relative mode is on the measurement is compared to a reference value The reference value is the first value read when REL is activated The dBm WATT key allows any measurement result to be viewed in logarithmic or linear format Procedure Pressing the key alternates the display between the logarithmic and the linear functions When the measurement mode is changed the logarithmic or linear setting of the key remains the same Example If the power meter display reads 1 88 mh to display this value in dBm LOCAL Keystrokes 1 program codes 3 53 dBm WATT 3 54 HP 438A Program Codes Program Code Logarithmic Units dBm or dB Linear Units Watis or 96 indications The status of the key can be determined by observing the current measurement mode the measurem
231. his section provides operating information for the power meter Included in this section are general and detailed operating instructions descriptions of the front and rear panel local and remote operator s instructions and operator s maintenance procedures Table 3 1 briefly summarizes the major operating characteristics of the power meter This table is not intended to be an in depth listing of all operations and ranges but gives an idea of the instrument s capabilities For more information on the power meter s capabilities refer to Table 1 1 Specifications and Table 1 2 Supplemental Characteristics For information on HP IB capabilities refer to the summary contained in Table 3 3 HP IB Message Reference Table Initial Turn On Information Instructions relating to the power meter s turn on procedure are presented to acquaint the user with the general operation of the instrument Information covering front panel operation of the power meter is given in the sections described below To rapidly learn the operation of the instrument begin with Major Operating Characteristics and Operator s Checks Panel Features Front and rear panel features are described in Figure 3 1 and Figure 3 2 The front panel has different colored keys and lettering for different operating modes The key has yellow lettering and relates to the shifted capability of the A B and keys as shown by the yellow lettering next to these keys Blue keys
232. ill return to local lockout the next time it goes to remote No instrument settings are changed by the transition from remote to local When the power meter goes to local mode the front panel RMT annunciator turns off However when the power meter is being addressed whether in local or remote its front panel LSN or TLK annunciator lights The Local Lockout message is the means by which the controller sends the Local Lockout LLO bus command If in remote the power meter responds to the Local Lockout message by disabling the front panel LCL key The local lockout mode prevents loss of system control due to someone accidentally pressing front panel keys If while in local the power meter is enabled to remote that is REN set true and it receives the Local Lockout message it will switch to remote mode with local lock out the first time it is addressed to listen When in local lockout the power meter can be returned to local only by the controller using Local or Clear Lockout Set Local messages or by setting the LINE switch to OFF and back to ON or by removing the bus cable The Clear Lockout Set Local message is the means by which the controller sets the Remote Enable REN bus control line false The power meter returns to local mode full front panel control when it receives the Clear Lockout Set Local message When the power meter goes to local mode the front panel RMT annunciator turns off 3 28 Receiving the Pass Control M
233. ing Check If the measured voltage is incorrect go to step 3 3 Verify that U35 pin 5 is 2 5 Vdc If pin 5 is incorrect check the 5 volt supply R4 and R5 If pin 5 is correct go to step 4 4 Verify that U35 pin 4 is 5 Vdc If pin 4 is correct replace U35 If pin 4 is incorrect go to step 5 5 Verify that U35 pin 7 is 5 Vdc If pin 7 is correct replace C5 or R3 If pin 7 is incorrect go to step 6 6 Verify that U35 pin 10 is approximately 4 2 5 Vdc If pin 10 is correct go to step 7 If pin 10 is incorrect check R10 R11 and C16 7 Verify that U35 pin 9 is gt 2 5 Vdc If the voltage at pin 9 is incorrect check R12 R14 and C15 Timing Check 1 Connect the oscilloscope to U19 pin 37 Connect the oscilloscope s External Trigger Input to A3TP8 2 Set the controls on the oscilloscope as follows Vertical Scale 252 05 se lt 4 Ra Wee siistii 2 volts division Horizontal cale cra Eege AN EDS 20 ms division HP 438A Note E Service Sheets 1 4 Trigger Mode cto E ENSIS d Rd Normal external Trigger Level pts Slightly positive SEET det eb Ur et Ee Positive Edge 3 At turn on the oscilloscope should display a waveform that is at 0 volts for gt 80 ms and then goes to 5 volts The following procedure is to be used if Free Run Mode will not operate Free Run Mode Troubleshooting 1 Verify that U28 pin 14 is a TTL low If pin 14 is correct go to step 2 If pin 14 is incorrect verify that U28 pin 2 is
234. ing the front panel controls or changing the equipment setup Errors 60 through 59 and 90 through 99 These are entry errors which indicate that an invalid keyboard or HP IB entry has been made These errors require that a new entry or function selection be made Errors 60 through 69 These are service errors which provide service related information Service errors are discussed in section 8 of the manual Error Displays Errors are indicated on the front panel The left side of the display shows a brief message eight characters or less indicating the nature of the problem The right side of the display indicates the error code In addition the channel on which the error occurs is indicated in the right side of the display for some errors HP 1B Output Format As long as the front panel display indicates an error condition the instrument sends 9 0000E 40 as the measured data when addressed to talk If an error condition generates SRQ the status byte and status message latch the error until the status message program code SM has been read by the HP IB controller Once the status message has been read the status byte and status message are cleared if the error condition no longer exists If multiple errors occur the status message indicates the most recent error 3 55 Error Messages 3 56 HP 438A If an error condition does not generate SRQ for example the Service Request Mask has been set such that measurement or en
235. ing versions of EPROM HP 438A Service Sheet BD2 Pin Tea ob BETA so 20 If any of the signatures are different from those given troubleshoot the bad signal line by referring to Service Sheet 3 8 37 0t 8 6 8 pe 190 8 109928 ROUD Lpg ainBi4 208 PSS A a o A RA DES mal Je zu i 1 es AvidS ie HA h z ou as iii vive SCH a1evseauogv Mea O DO 8 Pa z d QOAOOQOGOCOCG i ean ruo oe T e G ol 833308 NI ed C 0000000 O m i TEE D j goivi x SC e SM MED US d pe pim ive d Pe gt 7 wd LUCES guy K7 sr Been 74 390Nv e St 70 4 Sam 4 EOS MIS d 3 E RANI DE REN ERE E M m Z TS oan BE i S XTUR3SSV QHYOGA3Y TY S E VET ied aooe Y rsen i jJ ze ZZZZ GUOT77777777222 772272 7PZSZZZZIZIIIZT LLLA EE fdd CY O d Goa o figo EY O d I i h 285 y 4 DRESCH 4 Y eicere 16 98 KE Y s ATI DEO TN A CEE L mg Le Na d 13838 1 P Alo irs E I 3 ERLEA SE 7 164 088 A jm cities i 1 m HEED i 4 O pet i i WNE cz i Z a CLL kL EPIIT STER LINKI EELER En A KZ Sei Ok INOS j AY ony Lutgen ss3ugov Beet 325N E HOLE MS A ae EE A E SEENEN fete Atte NOTLONAS 30iAH35 AG MOLEMS NOL LONG e a A a T a dr ee e ee LUE 30143539 DAD tV Ofd E LINN 9NISS3908d WU IN3O CN O d NOI103S8 H3 770HlNOO iesus AAMAS
236. ions Pay attention to the WARNINGS and CAUTIONS They must be followed for your protection and to avoid damage to the equipment 8 1 Service Warning Caution Y 8 8 Recommended Test Equipment and Accessories 8 9 Service Tools Aids and Information HP 438A AA nn E ZD Maintenance described herein must be performed with power supplied to the instrument and with protective covers removed Such maintenance should be performed on y by service trained personnel who are aware of the hazards involved for example fire and electrical shock Where maintenance can be performed without power applied the power should be removed Any interruption of the protective grounding conductor inside or outside of the instrument or disconnection of the protective earth terminal will create a potential shock hazard and could result in persona injury Grounding one conductor of a two conductor outlet is not sufficient Whenever it is likely that the protection has been impaired the instrument must be made inoperative that is secured against unintended operation Af the instrument is to be energized via an autotransformer for voltage reduction make sure the common terminal is connected to neutral that is the grounded side of the mains supply Capacitors inside the instrument may still be charged even if the instrument is disconnected from the power source Make sure that only 250 volt normal blow fuses with the specified
237. is entered from the front panel is the one saved in RAM HP 438A Note 3 8 Error Messages 3 9 Power Reference and Calibration Note Y Y Operation An internal battery is used to retain data in RAM during off periods The data restores the last control setup that was saved in storage location zero and the other nineteen storage registers Power up error message numbers as well as other error messages displayed on the front panel are listed and explained in Table 3 8 Error Messages As an example ifa ROM or RAM failure occurs the power meter will display an error code number in the range of 61 through 66 depending on the location in memory that has a problem A POWER REF of 1 00 mW at 50 MHz factory set at 0 7 and traceable to the National Institute of Standards and Technology NIST is available at the front panel for calibrating the power meter to the sensor There are two buttons on the front panel dealing with calibration CAL ADJ and CAL FACTOR CAL ADJ is pressed when entering the reference calibration factor for your power sensor and should not need to be reset until another sensor is used CAL FACTOR is pressed when frequency changes To verify calibration on the power meter front panel CAL_ADJ and CAL FACTOR must be the same value Procedure The Calibration Procedure which may appear on the power sensor label does not apply to the HP 438A Power Meter Some sensors come with attenuators
238. ivers The anode and cathode display drivers are used to refresh the front panel display The sequence of the drivers is controlled by the CPU through the anode data display latches and addressable data display latch and drivers Service Sheet 3 Display Assembly The A2 Display Assembly displays the current instrument configuration and the appropriate measurement result or error message 8 31 Service Sheet BD2 Troubleshooting Hints 8 32 HP 438A The troubleshooting checks on this service sheet are used to narrow down a malfunction to one of the following assemblies A1 Keyboard Assembly A11 HP IB Assembly A3 Central Processing Unit CPU Assembly or the A2 Display Assembly The A3 CPU is the major block Its schematic diagrams are on Service Sheets one through four SS1 SS2 SS3 S84 as shown in the lower right hand corner of the solid line boxes The checks will cover changing switch positions of the service function switch A3S1 on the A3 CPU exercising the front panel keys monitoring the front panel displays and checking some signatures When these checks pass it can be assumed that a major portion of the circuitry is functioning Test Equipment Signature Multimeter EE EL i HP 5005B Service Function Switch The service function switch A3S1 contains four single pole double throw toggle switches that are provided to control data bus bits DO through D7 going to the microprocessor With the power meter in th
239. kout Set Local message sets the remote enable bus control line REN false If not in Local Lockout mode the power meter switches to local from remote whenever the front panel key is pressed Local Lockout A local lockout is recommended for purely automatic applications Local lockout disables the key and allows return to local only under program control Return to local can also be accomplished by setting the power meter s LINE switch to OFF then to ON However this technique has some disadvantages a Many of the power meter s parameters are set to default states This may cause the measured power reading to change b There are several HP IB conditions that reset to default states at turn on The power meter interprets the byte on the eight HP IB data lines as an address or a bus command if the bus is in the command mode The command mode is defined as the attention control line ATN being set true and the interface clear control line IFC set false Whenever the power meter is addressed whether in local or remote either the talk TLK or listen LSN annunciator on the front panel turns on The power meter s HP IB address is set in decimal from the front panel HP IB address switches set in binary are located inside the instrument The only time the power meter reads the internal switches however is when the internal RAM contents storing the front panel address setting have been lost for example when the battery fails
240. l Zi i bi Si gi ern E ees t REWA 6295 r 2 62 e m SE SC ECHO Eu Ev Aa m l 1 i o 7 33 ce a gi A Ol Main BOL Oe Ob PREP z LEND to 01 H L slo oo ott A o o b o o H E bod MEE tod i i i E I H I t FIRE H i o or 3 j o va AJA T vilo o DE es ozo Bn 2 es MIA dOl ASIA GOL Maia dOL Mala JOL 08Y06 KME agyog Lb S vngV t LIMSHES B2 S2 venbv LIROKID H 3n o3 R Kona c qo oj Qa 3HOM i i 8 o NYHi DIN 3EOW Si i AZIA AOL i f t GuYOS ma a JOL 1 E age psi 15606 9 6I 10 v Pic vov Tr 1 H DEER Pr Bi TTB oss aq SHZAIYJ AN dE TO aris ic Viv uiv ez ez von FTE YO JOCHIVO BEZ i 21 i G2 amp dis es H 5193 TERA ROT LVR 1S 3G 5 x G Lee EE i FONIU343E i DES DEES Perm 753 ONY 39Vi10 LIT AH LiNOBIG QalvHO31N A amp i i ER 002 0287 a ig 1153 950 008 ee sz veni prr 8581 0081 pennt 7938 3920 ES85 6i lb e Ter ORC to E CL PROTIVNO S3G U 321 Qi inva 30383438 Eege SUSGRON Lave mel H Let n I 1935 NY E i Nep ERES A er ze 835 bb gent ETA DE Strify H Sizle 7538 2929 1938 0935 SELON WvuDvid OI LYNIKO BOY 2 9 318v Ol E3239 340N p 1 Sj99US ODAJOS t E 1035 3 O mai ACE dl woe ostk E 4982 CIA ci JSGAS E E i938 SO NM E cT 95 80223 US Hote gr AVIdS1G VIVO voz 93938 vor Jot e ud TV dSGn64 iTi EFL UT 0 938 5 90 e vor 9 99 H GEE wos i sU E 05997 opt dSGAS IER 1 880As
241. l A and to the POWER REF 1 00 mW 50 MHz Press PRESET Press and wait for routine to finish Press and enter ref cal factor wait for routine to finish Press the POWER REF oscillator key to turn on the 50 MHz signal Press and enter ref cal factor value The normal indication is 1 The display should indicate as shown in Table 8 3 and channel A 8 24 HP 438A Service Sheet BD1 Table 8 3 Power Displayed for 1 mW Power Reference HP 8481B attenuator disconnected 1 000 Watt 1 000 Watt 100 0 3 Watt mW 100 0 3 Watt mW 1 000 3 Watt mW 1 000 3 Watt mW 1 000 3 Watt mW 1 000 3 Watt mW 1 0000 6 u W HP 8582B attenuator disconnected HP 8481H HP 8482H HP 8485A HP 8481A HP 8482A HP 8483A 752 HP 8484A with HP 11708A 50 MHz Reference Attenuator Abnormal Indication If an abnormal indication occurs 1 An error message indicating a faulty sensor Try a second sensor 2 Display shows no RET no power reference Check the plus and minus 15 Vdc power supplies connected to the reference oscillator Refer to A4 Input Amplifier Assembly on Service Sheet 6 3 The COMP OUT comparator out or RAMP END signal at test point ASTP4 is not as shown in Figure 8 8 Refer to Amplifier Section Troubleshooting BD3 4 The RCDR rear panel recorder BNC output is not 1 Vdc Refer to troubleshooting BD3 1V DIV ai BE 5 ms DIV Fig
242. le working in any measurement mode Selecting measurement mode SENSOR A A B or A B automatically sets the active entry channel to channel A Selecting measurement mode SENSOR B B A or B A automatically sets the active entry channel to channel B Procedure To select the active entry channel press for channel A or for channel B Example To designate channel B as the active entry channel LOCAL keystrokes CE program codes HP 438A Set A and Set B Program Codes Program Code Indications When a measurement parameter is being entered an annunciator on the right side of the display lights to indicate the active entry channel Comments PRESET sets the active entry channel to A Related Sections CAL ADJ Cal Factor Filters Limits OFFSET PRESET Range SENSOR A and SENSOR B SENSOR A B and SENSOR B A SENSOR A B and SENSOR B A 3 83 Store and Recall EE Store and Recall 3 84 HP 438A Description The power meter can store instrument configurations for recall at a later time The following information can be stored in the power meter s internal registers Measurement Mode REL mode status on or off Reference value if in REL mode Reference Oscillator status on or off Active entry channel A or B Measurement units logarithmic or linear Cal factor for each sensor Offset for each sensor Range for each sensor Filter for each sensor Cal Adj value for e
243. m 6 6 lt 6 THEN SELECT Sm 15 15 Check for Log or Linear Mode CASE O Units Y CASE 1 Units dB CASE ELSE Units M END SELECT IF Sm 18 18 1 THEN Units Units Rel ELSE Not Rel mode or two channel operation SELECT Sm 15 15 Check for Log or Linear Mode CASE 0 Units WATTS CASE 1 Units dBm END SELECT END IF END 3 39 Operation HP 438A identification This function is used to identify the the power meter s model number and the firmware version After receiving program code ID and when addressed to talk the power meter sends the following string HP438A VERX XX Where HP438A is the instrument model number and VERX XX is the firmware version number 3 22 Receiving the The power meter responds to the Clear message by assuming the Clear Message same conditions as established by PRESET Refer to Table 3 4 The power meter responds equally to the Selected Device Clear SDC bus command when addressed to listen and the Device Clear DCL bus command whether addressed or not 3 23 Receiving the When in remote and addressed to listen the power meter responds to Trigger Message a Trigger message the Group Execute Trigger bus command GET by executing one of the pre programmed codes shown in Table 3 5 If none of the codes has been preprogrammed via a Data message the power meter responds to the Trigger message by executing one settled measurement cycle GT2 which is the
244. mains configured to talk until it is unaddressed to talk by the controller To unaddress the power meter the controller must send the power meter s listen address a new talk address an Abort message or a universal untalk command HP 438A Operation Data Output Format As shown below the output data is usually formatted as a real constant in exponential form first the sign then a digit a decimal point and four digits followed by the letter E and a signed power of ten multiplier The string is terminated by a carriage return CR and line feed LF The power meter sends an EOI with the last byte of each output string 0 DDODEtNNCRLFE SIGNED S DIGIT MANTISSA NE des LINE FEED INDICATES EXPONENT FOLLOWS CARRIAGE RETURN EXPONENT SIGN EXPONENT MAGNITUDE When an error is output to the bus it follows the same format described above As long as the front panel display indicates an error condition the Power Meter sends 9 0000E 40 as the measured data when addressed to talk To determine the error code it is necessary to read the Status Message Refer to the Status Message paragraph below for additional information Exceptions to this format are the data output for the following functions Learn Mode 1 Learn Mode 2 Status Message Identification Service Request Mask Value Each of these five functions is enabled by first addressing the power meter to listen Then the power meter must receive a Data message with th
245. matic phase control ASEN w w ek V assembly AUX O aside mei auxiliary AVE sve e x E dn average AWG American wire gauge BAL Ra Re balance BCD binary coded decimal BDO See aie uie ead ke board BE CU beryllium copper BFO beat frequency oscillator BH EE binder head BKDN 5 c dass os breakdown BP ix Ex bandpass BPP 22 bandpass filter BRS xe aeos anie ee brass BWO backward wave oscillator d EE calibrate cow counterclockwise GER xiu ceramic CHAN l S channel Mas Rex centimeter CMO cabinet mount only COAX sive i499 x3 coaxial COEF essa sA coefficient COM xs ia rana common COMP es composition COMPL e Complete CONN RI dE connector GP ee wae ae Y cadmium plate CRI csv cathode ray tube CTL complementary transistor logic OW AP continuous wave OW de sU Se beans S clockwise REFERENCE DESIGNATIONS E miscellaneous electrical part EE fuse E CEZZE filter Hoobs eb Shee o s wes hardware MY cool DELI circulator J electrical connector stationary portion jack EK uuu pda ia cac NUR aes relay Bide aes an oe nee coil inductor M aris o yty ZOE eee EEN meter MP miscellaneous mechanical part P electrical connector movable portion plug Q siada transistor SCR triode thyristor TU ads ab A SAARE resistor ICD EE thermistor S SS Stitt dated eru switch qeu Abreu transformer EB ER terminal board TO araki et ees thermocouple TP sk Paws od Maer ee test point ASS 06 Sever integrated
246. mpleted To determine whether or not the power meter needs to be zeroed remove any power to the sensor and then read the front panel display If the display does not indicate 0 power the power meter needs to be zeroed Any residual nonzero reading if not corrected will be added to all subsequent measurements resulting in an error This error may be insignificant when measuring moderate to high power values but it can be unacceptable when measuring low power values Error 57 recall fail occurs when the power meter is turned on and the internal RAM contents have been lost This is generally due to battery failure but may also occur when the instrument is powered down while zeroing For best accuracy HP 8484A Power Sensors should be connected to a device with the RF power off before zeroing Zeroing data cannot be stored and recalled but it is remembered when the instrument is turned off PLEASE 0 Error 15 or 16 sensor dependent is displayed when the zero reference drifts negative Related Sections CAL ADJ Error Messages Range STORE and RECALL 3 87 Performance Tests 4 1 Introduction Note i 4 2 Equipment Required 4 3 Performance Test Record 4 4 Performance Tests The procedures in this section test the instrument s electrical performance using the specifications of Table 1 1 as the performance standards All tests can be performed without access to the interior of the instrument A simpler oper
247. n 15 for a logical high If the clock signal is absent replace U33 If the reset is held low check the Reset Power Fail circuit on Service Sheet 2 If the Reset Power Fail circuit is operating properly replace U15 If the conditions on pins 14 and 15 are correct replace U32 8 71 Service Sheets 1 4 HP 438A Verify that there is a signal on U25 pin 6 If there isn t any signal check for a signal on U25 pin 5 If there isn t any signal on pin 5 perform the Signature Analysis Mode Check for U20 Timer A D and Software Check If the signatures for U20 are normal perform Free Run Signature Analysis and the Signature Analysis Mode Checks If there is a signal on U25 pin 5 replace U25 Note The following troubleshooting should only be used if there seems to be C a problem running the Signature Analysis Mode Checks Signature Analysis Mode Troubleshooting Verify that the following three areas are operating properly o Service Function Switch and Service Function Switch Buffer Set the microprocessor to Free Run Mode ground A3TP4 Set A351 to 0001 LSB The least significant bit LSB is closest to the edge of the printed circuit board When the switches are set towards the front panel of the power meter they are set to one Verify that the four bits on A3U3 pins 4 6 8 and 11 are seen on the output A3U3 pins 16 14 12 and 9 of the buffer m Verify the operation of the Reset Power Fail circuit refer to p
248. n 9 goes toa TTL high If pin 9 is incorrect replace U38 If pin 9 is correct replace U38 or U20 6 Verify TP5 is a TTL high gt 3 5 Vdc If TP5 is incorrect replace U19 7 Verify TP11 is a square wave of approximately 15 Hz and 5 volts peak to peak If TP11 is incorrect replace U19 If no failures were found the microprocessor should be in Free Run Mode Data Bus Tests 1 Connect the signature analyzer as described under Free Run Signature Analysis Turn the power meter OFF Remove ROM U9 for version 5 0 or ROMs U9 and U10 for version 2 0 2 Turn the power meter ON Verify that the signature of each data line is either low 0000 or high 0001 If any other signature is seen then one of the RAMs is probably defective If the signatures with the ROM in the circuit were low 0000 or high 0001 then U8 is most likely defective If the data bus signatures are correct then the problem is U9 for version 5 0 or ROMs U9 and U10 for version 2 0 Free Run Signature Analysis must be performed before attempting Programmed Signature Analysis Microprocessor Data Bus Buffer Check U1 Service Sheet 1 1 Connect the signature analyzer to the A3 assembly as follows Signature Analyzer Pod A3 Assembly Start Stop A3TP9 Qual U1 Pin 19 Clock A3TP6 Ground A3TP7 2 Make the following settings on the signature analyzer Function ee Kee e QUAL EE uckaciehs Ee falling edge NATE Pat dw a vire das Ek rising edge SOD de
249. n Amplifier Waveform 3 Compare the waveform at A5TP15 with Figure 8 43 If the waveform is incorrect perform the Range Attenuator 1 10 100 and AC Gain Stage Tests If the waveform is normal continue with step 4 LIT AC cR e a JN ANLE IL VERRE AA ENE UR wi A a a ae Sa 1 ms DIV Figure 8 43 AC Gain Stage Waveform 4 If A5U24 pin 14 is not 3 4 0 4 Vdc perform the Synchronous Phase Detector and Low Pass Filter Tests If the voltage is normal continue with step 5 5 Compare the waveform at A5TP11 with Figure 8 44 If the waveform is incorrect perform the Analog Digital Input Multiplexer and Sensor Resistor Selection Test If the waveform is normal replace A5U7 A5R80 A5R81 or A5R82 8 109 Service Sheet 8 HP 438A 1V DIV D 10 ms DIV Figure 8 44 Analog to Digital Converter Input Waveform Gain Attenuator Buffer 1 Connect the Signature Analyzer as shown below Signature Analyzer Pod 3 Assembly Start Stop A3TP9 Clock A3TP6 2 Set the controls on the signature analyzer as shown below FUNCTION rob A NORM Glok qe T X falling edge DIAIU Ii i edt MOOD TITTEN rising edge A a Rd S Md sn e Rosen falling edge 3 Set switch A3S1 to 0001 LSB The least significant bit LSB is the switch closest to the edge of the printed circuit board When the switches are set towards the front panel of the instrument they are set to one 4 Use the following signatures to verify that the signature
250. n be selected automatically via AUTO FILTER or manually via MNL FILTER For most applications auto filter is the best mode of operation Manual filter mode is useful mainly in specialized applications requiring high resolution or fast settling times In auto filter mode the power meter automatically sets the filter length to satisfy the filtering requirements for most power measurements The filter length depends solely upon the power range in which the power meter is currently operating The following table lists the filter length and filter number for each range when the power meter is in auto filter mode Auto Filter Setting for Each Range Range Filter Length Filter Number 3 60 HP 438A Note Filters When the filtering is selected automatically the resolution is four significant digits for measurements displayed in Watts or percent The resolution is 0 01 dB for measurements displayed in dB or dBm In manual filter mode the filter length is selected by entering a filter number between 0 and 9 Refer to the following table to cross reference filter numbers to filter lengths Filter Number Filter Length 2 3 4 5 6 7 8 9 The filter length is independent of the measurement power range when the filter length is set manually An additional feature of the power meter is the hold filter mode Hold filter mode provides a means of switching from auto filter mode to manual filter mode while retaining the auto
251. n runs indicating line voltage or Mains ac power is present at the transformer that it is being rectified and regulated giving the voltage necessary for the motor control module to drive the dc fan 2 The four red LEDs light emitting diodes on the A9 Regulator Assembly are lighted indicating that the regulated supplies are operating This does not mean that the supplies are within the required tolerances Abnormal Indications If an abnormal indication occurs 1 Check rear panel line fuse 2 Measure the individual regulated supplies Test points and levels are shown on this block diagram The 15 Vdc and 15 Vdc supplies should be equal but of opposite polarity and within 0 05 Vdc of each other Measure 15 Vde 14 25 Vdc to 15 75 Vdc at AOTPS Measure the 15 Vdc at A9TP7 and adjust it if necessary to match the 15 Vdc supply Measure the 5 Vde at A9TP4 and adjust it if necessary to 5 00 0 05 Vdc If the supplies are found to be in error and cannot be adjusted refer to Service Sheets 9 and 10 for more details Controller Section Z 2 If the Turn on and Operator s Checks were completed in section 3 the Controller Section V 2 can be skipped In that case proceed to Amplifier Check 44 3 Procedure To verify the controller power up routine press the LINE key to cycle from the power OFF to power ON condition This will initiate a diagnostic routine stored in ROM This routine is a check of ROM RAM and the displays O
252. nd B when rear panel Option 002 inputs are installed HP 438A Performance Tests 4 9 Instrument Accuracy Test Specification Description Equipment Procedure Electrical Performance Limits Conditions Characteristics Accuracy Instrumentation includes sensor linearity Single channel mode 0 2 Within same calibration range Plus 0 02 dB Outside calibration range Dual channel mode Ratio or difference Multiply single channel specification by 2 1 When operating in range 5 add the corresponding sensor power linearity percentage After the power meter is initially calibrated on the 1 mW range the readout is monitored as the range calibrator is switched to provide reference inputs corresponding to each of the power meter operating ranges HP 438A POWER METER RANGE CALIBRATOR Pai Sarr METER Figure 4 2 Instrument Accuracy Test Setup Range Cahbratot ssi aoa ETE TRAE P NL aya Aue Nees HP 11683A Power Sensor Cable i cis RAGE e PEU HP 117304 1 Connect the equipment as shown in Figure 4 2 2 Set the power meter controls as follows DINE si aos ON SENSOR a aduer E E Eb EN OM beasties A PSD pauta wiv Sena pet dier ER PUT OR US PRESET Performance Tests Note HP 438A Set the range calibrator switches as follows FUNCETO G A a e aa STANDBY POLARITY C xu c ee Sa pares man b eer rd s NORMAL RAND 1mW IS EE ON Press the power m
253. nd allow for warm up 2 Connect the DVM between the 15V testpoint A9TP8 and chassis ground Measure and record the value of the 15 volts The voltage should be between 14 25 and 15 75 Vdc 15 V 3 Connect the DVM between the 15V testpoint A9TP7 and chassis ground Adjust 15V A9R16 until the DVM reading is within 0 05 Vdc of the numerical value from step 2 Ignore the difference in sign for this adjustment 5 3 Adjustments HP 438A ee 5 8 5 Volt Power Supply Adjustment Reference Service Sheet 9 Description The 5 volt supply is measured and adjusted Equipment Digital Voltmeter DVM ccs HP 3456A Procedure 1 See Figure 5 1 Connect the DVM between the 5V testpoint A9TP4 and ground Adjust 5V A9F3 until the DVM reads 5 46 0 05 volts HP 438A Adjustments SEENEN 5 9 Analog to Digital Converter Slope Adjustment Reference Service Sheet 8 Description The Analog to Digital Converter is adjusted for a central reading HP 438A ASTP2 B GNO ASTPS 2 5V REF Figure 5 2 Analog to Digital Converter Slope Adjustment Setup Equipment Digital Voltmeter DVM EE HP 3456A Procedure 1 Turn the power meter OFF Place all 4 switches of A351 to the test position This would be positions where the switches are all opposite to the normal operating position Note A A351 can be loaded on the printed circuit board so that it has one of 9 the two orientations shown DEPRESSED DEPRESSE
254. nd the analog to digital conversion ADC 4 The C GND is the high current main analog ground The C GND is tied to the main instrument ground on the A9 Regulator Assembly and is used on the input amplifier and main amplifier assemblies HP 438A Troubleshooting Hints Service Sheet BD1 5 The D GND is the main digital ground The D GND is tied to the main instrument ground on the A10 Interconnect Assembly and is applied to the A3 Central Processing Unit Assembly CPU From the CPU it is applied to the main amplifier 6 The display ground is the ground for the display drivers The display ground is tied to the main instrument ground on the A10 Interconnect Assembly It is applied to the CPU display driver circuits and used only by the 5 V pulsed power supply B GND MAIN ANALOG LOW CURRENT RECORDER RCOR2 UTPUT BNC CONNECTOR B GND NN B GNO Se INPUT POWER AMPLIFIER _ ASSEMBLY t3 MAIN AMPLIFIER ASSEMBLY Logie CHIPS KG DIGITAL 45V DIGITAL REAR PANEL O GNO DIGITAL CENTRAL PROCESSING ASSEMBLY ZEN DISPLAY PULSED ON amp OFF DISPLAY GND Figure 8 5 Simplified Power Supply Grounding To begin this troubleshooting it is assumed that section 2 Installation Line Voitage and Fuse Selection checks are completed The troubleshooting checks on this service sheet are used to isolate a malfunction to one of the three major sections Controller Section
255. nd the power meter is turned on the entire front panel will be illuminated Table 8 31 Anode Data Display Drivers Voltage Levels A3U25 2 0 5 4 8 10 12 A3U26 2 4 6 8 10 12 A3U41 2 4 6 8 10 12 A3U42 2 12 If the voltage levels are correct go to step i If any of the levels are incorrect check the input of the integrated circuit with the incorrect level If the inputs are correct replace the appropriate integrated circuit If any of the inputs for lines SEGO through SEG18 are incorrect perform signature analysis troubleshooting on Service Sheet 1 If signature analysis does not reveal the problem continue as follows a If the problem is with the inputs for lines SEGO through SEGT replace A3U40 u If the problem is with the inputs for lines SEG8 through SEG18 replace A3U4 A3U5 or A3U11 HP 438A Service Sheets 5 m Verify that a pulsed TTL signal can be seen at the following points A3U24 2 DSO A3U42 4 DS6 4 DS1 6 DS7 6 DS2 8 DS8 8 DS3 10 DS9 10 DS4 12 DS5 If any pin doesn t have a pulsed TTL signal check the inputs for a pulsed T TL signal If there is a pulsed signal on the input replace the appropriate integrated circuit If there isn t any pulsed signal perform signature analysis troubleshooting on Service Sheet 1 m After a problem has been isolated to the Cathode Data Display Drivers or the Anode Data Display Drivers use
256. nducted Susceptibility are within the requirements of RE02 CEO3 RS01 03 and CS01 02 called out in MIL STD 461C and within the requirements of VDE 0871 and CISPR Publication 11 1 When operating in Range 5 add the corresponding sensor power linearity percentage 2 Accuracy does not depend on the meter being in Normal or Relative mode General Information HP 438A Table 1 1 Specifications continued Electrical Characteristics Performance Limits Conditions 1 00 mW Power reference Internal 50 MHz oscillator factory set to 0 7 traceable to National Bureau of Standards 1 2 0 9 Power reference accuracy Worst case RSS for one year General Operating temperature range 0 1055 C Power Requirements 65 V 35 watts 100 120 220 or 240 Vac 5 to 1096 48 to 66 Hz Maximum Line Voltage Line Frequency All specified line voltages may be used 360 to 440 Hz Limited to line voltages of 100 or 120 Vac Power Dissipation 10 VA 8 watts max HP IB Remote Operation All functions except power switch clear entry HP IB address SH1 AH1 T5 TEO L3 LEO SR1 RL1 PPL DC1 DTi CO Compatibility HP IB interface Memory Non volatile Contains complete meter operating state of both channels plus contents of store recall registers Operating an
257. ne or more bytes sent over the bus data lines when the bus is in the data mode ATN bus control line false Unless it is set to Talk Only the power meter receives Data messages when addressed to listen Unless it is set to Listen Only the power meter sends Data messages or the Status Byte message when addressed to talk Virtually all instrument operations available in local mode can be performed in remote mode via Data messages The only exceptions are changing the LINE switch activating the key or changing the HP IB address The power meter may also be triggered via Data messages to make measurements at a particular time HP 438A 3 20 Receiving the Data Message Note E Operation The power meter responds to Data messages when it is enabled to remote REN bus control line true and it is addressed to listen The instrument remains addressed to listen until it receives its talk address an Abort message or a universal unlisten command Data Input Format The Data message string or program string consists of a series of ASCII codes Each code is typically equivalent to a front panel keystroke in local mode Thus for a given operation the program string syntax in remote mode is the same as the keystroke sequence in local mode Example 1 shows a typical program string PRZECL 1 ENOCILGTR2 AM DNE ENTER ZERO LOG CdBm CAL ADJ at 182 REFERENCE OSCILLATOR ON EXAMPLE 1 Typical Program String Program Codes All of the
258. nectors on the rear panel of the test power meter Observe the reading on the DVM If less than 400 microvolts proceed to the next step If 400 microvolts or greater press and hold the test power meter fine zero switch and adjust the coarse zero contro so that the DVM reads 200 microvolts or less Then release the fine zero switch and proceed to the next step Round the DVM reading to the nearest microvolt Record this value as V0 VO Disconnect the DVM negative input lead from the Vrf connector on the test power meter Reconnect the lead to chassis ground Set the power meter POWER REF OSC to ON Record the reading observed on the DVM as Vcomp Vcomp Disconnect the DVM negative input lead from chassis ground Reconnect it to the Vrf connector on the rear panel of the test power meter The DVM is now set up to measure Vi which represents the power reference oscillator output level Calculate the value of V1 equal to 1 mW from the following equation Adjustments HP 438A V Vo Voomp V Vcomp 10 3 4R EFFECTIVE EFFICIENCY Where Vo previously recorded value Vcomp previously recorded value 10 1 milliwatt R previously recorded value EFFECTIVE EFFICIENCY value for thermister mount at 50 MHz traceable to the National Institute of Standards and Technology 14 Remove the power meter top cover and adjust the LEVEL ADJUST potentiometer G1A1R4 so that the DVM reads the calculated value
259. nput m returns to its inactive state m should be replaced by appropriate dependency or function symbols Open Collector Output Output that must form part of a distributed connection Ls c 5 d oda 8 9 Service 3 STATE X Y X Y Functional Labels MUX DEMUX CPU PiO SMI 8 10 HP 438A Table 8 1 Schematic Diagram Notes 5 of 8 DIGITAL SYMBOLOGY REFERENCE INFORMATION Input and Output Indicators Cont d Threestate Output Indicates outputs that can have a high impedance dis connect state in addition to the normal binary logic states Combinational Logic Symbols and Functions AND All inputs must be active for the output to be active OR One or more inputs being active will cause the output to be active Logic Threshold m or more inputs being active will cause the output to be active replace m with a number EXCLUSIVE OR Output will be active when one and only one input is active m and only m Output will be active when m and only m inputs are active replace m with a number Logic Identity Output will be active only when all or noneoftheinputs are active Le when all inputs are identical output will be active Amplifier The output will be active only when the input is active can be used with polarity or logic indicator at input or output to signify inversion Signal Level Converter Input level s are different than output level s Bilateral Switch Bina
260. nsor with no RF signal applied The DAC output is applied to the power sensor is chopped in the sensor then the output from the sensor goes through the entire power meter amplifier chain HP 848X X Be HP 438A LP CHOPPER p FILTER INPUT POWER AUTO ZERO DAC 158 5 ppm C l i I I i I Figure 8 13 Simplified Zeroing Block Diagram The CPU sets the output of the auto zeroing DAC to get the output from the low pass filter Service Sheet 8 as close to zero as possible The remaining offset is computed and stored as a series of 10 values for all combinations of the slow and fast filters and the 5 ranges These values in conjunction with the computed DAC setting are used to determine the zero level for all input signals until the meter is zeroed again The stable current source supplies reference current for the zeroing DAC and the offset removal DAC The offset removal DAC is controlled by the CPU and subtracts the offsets introduced by the amplifier chain to produce the analog recorder output The output of the DAC is summed with the output from the amplifier chain The resulting signal is buffered and supplies the reference current for the gain DAC This circuit is the hardware equivalent of the 10 computed values used by the CPU to determine the correct zeroing adjustments for the measurement that is being made 8 43 Service Sheet BD3 8 44 HP 438A The gain DAC is contr
261. o o RESISTOR 12 1K 1 125W TF TC 0 4 100 RESISTOR 46 4K 1 125W TF TC 0 100 RESISTOR IK 1 125W TF TC 04 100 RESISTOR 10K 0 025 05W PN TC 0 10 RESISTOR 1K 0 025 05W PN TC 0 10 RESISTOR 111 11 0 025 05W PN RESISTOR 261K 1 125W TF TC 0 100 RESISTOR 1 21K 4 196 125W TF TC 0 106 RESISTOR 10K 4 196 125W TF TC 0 100 RESISTOR 10K 4 0 1 125W TF TC 04 25 RESISTOR 21 5K 1 125W TF TC 0 160 RESISTOR 7 5K 1 125W TF TC 0 100 RESISTOR 34 8K 4 196 125W TF TC 0 4 100 RESISTOR 31 6K 0 1 1W TF TCz04 15 RESISTOR 200K 0 1 1W TF TC 504 5 RESISTOR 31 6K 4 196 125W TF TC 0 100 RESISTOR 17 8K 1 125W TF TC 0 4 100 RESISTOR 42 2K 1 125W TF TC 0 100 RESISTOR 1 78K 1 125W TF TC 0 4 100 RESISTOR 1K 4 196 125W TF TC 0 100 RESISTOR 31 6K 0 1 1W TF TC 0 4 15 RESISTOR 14 7K 1 125W TF TC 0 100 RESISTOR 100K 1 125W TF TC 0 100 RESISTOR 28 7K 1 125W TF TC 0 100 RESISTOR 100K 1 125W TF TC 0 100 RESISTOR 8 25K 1 125W TF TC 0 100 RESISTOR 2 37K 1 125W TF TC 0 100 RESISTOR 681 1 125W TF TC 0 100 RESISTOR 1K 1 125W TF TC 0 100 RESISTOR 100K 1 125W TF TC 0 100 RESISTOR 1K 1 125W TF TC 0 100 RESISTOR 10K 1 125W TF TC 0 100 RESISTOR 14 7K 1 125W TF TC 0 100 CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS PT CONNECTOR SGL CONT TML TS P T CONN
262. odulation printed circuit pulse code modulation pulse count modulation pulse duration modulation picofarad phosphor bronze Phillips positive intrinsic negative ABBREVIATIONS cont d peak inverse voltage peak phase lock phase lock oscillator phase modulation PNP positive negative positive part of polystyrene porcelain POS positive position s used in Paris List position potentiometer peak to peak PP peak to peak used in Parts List puls position modulation PREAMPL preamplifier PRF pulse repetition frequency PRR pulse repetition rate picosecand pulse time modulation pulse width modulation peak working voltage resistance capacitance rectifier reference regulated replaceabie radio frequency radio frequency interference round head right hand resistance inductance capacitance rack mount only root mean square round random access memory read oniy memory rack and panel reverse working voltage scatiering parameter second time second plane angle slow blow fuse used in Parts List SCR silicon controled rectifier screw selenium sections semiconductor super high frequency silicon Silver signal to noise ratio single pole double throw spring split ring single pole single throw single sideband stainless steel standing wave ratio synchronize timed slow blow fuse tantalum temperature compensating time
263. olled by the CPU and multiplies the reference signal by some gain such that the recorder output equals one volt for full scale The setting of the gain DAC is determined at the time of calibration The output of the DAC is buffered and applied to the rear panel RCDR recorder output through a 1 kQ resistor Amplifier Detector Filter and Comparator Circuits The settings of the two range attenuators and the variable gain amplifier are controlled by the CPU through the gain attenuator buffer The range attenuators are set to match the front panel selected range if in MNL RANGE mode or the CPU selected range ifin AUTO RANGE mode The variable gain amplifier is set to provide an output from the low pass filter between 3 02 and 3 63 Vdc The setting required is determined during calibration CAL ADJ Calibration is described later The bandpass amplifiers consist of several active stages and RC networks The bandpass response peaks at approximately 230 Hz with 0 degrees of phase shift The synchronous phase detector rectifies the output from the bandpass amplifier by multiplying the input by or 1 Thus the output of the detector is a signal whose filtered dc value is proportional to the true amplitude of the 220 Hz input signal The low pass filter consists of a slow filter and a fast filter The input from the detector is applied to both These filters are related to the digital filter number If the digital filter number is 0 1 or
264. oller that can transfer information in binary form 3 37 Operation HP 438A This string contains the following information Measurement mode REL mode status on or off Reference oscillator status on or off Current reference value ifin REL mode Measurement units Log or Lin Cal Factor for each sensor Offset for each sensor Range for each sensor Filter for each sensor When the power meter is addressed to listen the binary data can be returned to the power meter The power meter changes accordingly Status Message This function enables the power meter s current state to be read under program control After receiving an SM program code Status Message and when addressed to talk the power meter sends a string of 23 ASCII characters followed by carriage return CR line feed LF and EOI The Status Message is updated only after a measurement The Status Message can be interpreted with the information shown in Figure 3 6 3 38 HP 438A Note 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 a b DIM Units 7 DIM Sm 25 PM 713 ENTER Pm Dummy Update Status Message OUTPUT Pm SM ENTER PM Sm Read Status Message t H Check for Rel Mode or two channel operation E Operation In order to obtain Measurement Units E in and dB enter the 9 following program IF m 18 18 2 1 OR VAL Sm 6 6 gt 1 AND VAL S
265. on Printed Circuit Boards 8 4 8 15 Other Service Documents 8 4 8 16 Troubleshooting 8 5 8 17 Service Related Error Messages 8 5 8 18 After Service Safety Checks 8 5 yi d HP 438A Contents 25 BD1 Overall Block Diagram Principles of Operation 4 4 4 1 es 8 14 General 23 w wd od Se GK Ee ure c 8 14 Troubleshooting Hints a ra 1 8 21 BD2 Controller Section Principles of Operation 93 4 8 29 General CEPI t dE eS 8 29 Data Input Output Section 8 29 Microprocessor and Memory Circuits 8 30 Timer A D PIA and Latch Circuits 8 31 Display Drivers a ia da a he Se Des 8 31 Display Assembly eos oz aw ee 8 31 Troubleshooting Hints aa 6 4 11 8 32 Service Function Switch 8 32 Service Function Switch Checks 8 33 Extended Test Mode Check 8 33 Manual Display Check 8 33 Automatic Display Check 8 34 Keyboard Manual Check 1 1 a 8 34 Memory RAM Check 2 5 54 8 35 Signature Analysis Check 1 1 8 36 Signature Multimeter Control Settings 8 36 Signature Multimeter Pod Connections 8 36 BD3 Amplifier Section Principles of Operation 1 4 11411 8 41 General d ieu WC WSW A di 8 41 Connected Power Sensor and Input Amplifier Circuits ox ncs STEP 8 41 Digital I O and D
266. ondition is indicated on the front panel as well as over the bus The out of limits condition is indicated on the front panel by the flashing A and or B annunciator The out of limits condition is indicated only for the sensor s used by the current measurement mode The out of limits condition can be indicated over the bus by setting the Service Request Mask to enable an out of limits condition to issue the Require Service message This condition can also be indicated by reading the Status Message Display Functions The selection of display functions is available only via remote programming During local operation the power meter display is enabled to indicate measurement results error codes entries in progress and instrument status In remote mode two additional display functions are allowed display disable and display all Display Enable DE This function is identical to local operation and is the function in effect when no other display function has been selected This is the display function at turn on This condition is also established by PRESET and the Clear message Display Disable DD This function blanks out the front panel display All readings over the bus remain valid This function is cleared by sending another display function program code DA or DE by PRESET or by the Power Meter receiving the Clear message HP 438A Operation Display All DA This function causes the power meter to turn on all front panel di
267. onditions exist Some error conditions can be cleared by updating the hardware configuration For example the power meter can autorange to a different range as required If the error is cleared task 2 loops back and begins again If the error can not be cleared an error flag is set and the appropriate error message is passed to task 1 3 If no error condition exists the measurement result is formatted and passed to task 1 Fither task 1 or 2 continues to run until the next 1 ms interrupt The interrupt routine is then executed and the sequence repeated for the other task When the power meter is in local operation the keyboard can be used to select the required measurement configuration The instrument remembers the last measurement configuration entered prior to turning off power and returns to that configuration when power is turned on The last measurement configuration that is saved in RAM is battery protected by disabling the write to RAM capability When the power meter is in remote operation with local lockout set all front panel keys except the LINE ON OFF are disabled The measurement configuration is selected by programmed inputs applied through the HP IB Remote operation can only be enabled via HP IB Amplifier Section CZ ZD The Amplifier Section consists of the following assemblies 1 A4 Input Amplifier 2 AS Main Amplifier 3 G1 50 MHz Reference Oscillator In addition Option 002 adds two rear panel sensor inp
268. onnect sensor A to reference oscillator Enter a negative reference cal factor if an external reference source is used If error persists check ouput of reference oscillator Connect sensor B to reference oscillator Enter a negative reference cal factor if an external reference source is used If error persists check ouput of reference oscillator Check sensor A connection to reference oscillator Reference must be 1 mW Check sensor B connection to reference oscillator Reference must be 1 mW Reduce input power to sensor A Reduce input power to sensor B Zero sensor A If error persists check input power Zero sensor B If error persists check input power Select a higher range or reduce input power to sensor A Select a higher range or reduce input power to sensor B Change either the input power offset cal factor or measurement mode 1 This error occurs when the input power exceeds 120 of the full scale power for range 5 and only when the power meter is on range 5 2 This error occurs when the power meter is on manual range and the input power exceeds 12096 of full scale for ranges 1 2 3 and 4 3 Power calculations result in a value that is too large to calculate or display The combination of input power offset cal factor and measurement mode results in a value whose absolute value is greater than 3 4028E4 38 3 57 Error Messages HP 438A Table 3 8 Error Messages continued Erro
269. ontents have been lost This is generally due to battery failure but may also occur when the power meter is powered down during the end of a zero or calibration sequence The error indication is cleared after two seconds or by selecting another function The selected function will be executed Once the error indication is cleared the power meter is configured in the PRESET state and the HP IB address is taken from the value defined on the internal address switch Note Hardware Errors NOT reported via SRQ v 3 59 Filters HP 438A eee ee Filters Includes AUTO FILTER and MNL Filter Description The purpose of filtering is to reduce jitter in the display Measured values are averaged iii with previous values before being displayed The power meter uses a variable digital filter to average power readings The value shown in the display is the average of the last 2N readings where 2N is the filter length and N is the filter number The filter length can range from 1 2 to 512 2 When a new power measurement is input to the filter it is saved and the oldest reading is discarded If the power meter s configuration changes such that the values in the filter are no longer valid for example a change in measurement mode range or filter setting the filter contents are set to zero The filter starts filling up again and the power meter displays the average of the accumulated power readings The filter length ca
270. ormation Table 1 1 Specifications Electrical Characteristics Performance Limits Meter Frequency range 100 kHz to 26 5 GHz 70 dBm to 44 dBm 100 pW to 25W 50 dB total range Sensor dependent Power range Sensor dependent Dynamic range 5 ranges of 10 dB steps for 50 dB total Inputs Channel A and B Multiplexed dual sensors Without digital filtering 1kQ output impedance BNC connector Rear panel output 0 1 volt analog Measurement modes A B A B B A A B B A Watts or dBm Percent or dB Percent or dB Normal or relative al modes Absolute A B A B B A Ratio A B B A Relative Display units Resolution Normal 0 196 full scale 0 01 dB 0 01 dB 0 0196 full scale 0 001dB Auto filter watts or percent dBm or dB Manual filter watts or percent dBm or dB High Accuracy instrumentation includes sensor linearity 0 02 dB Plus 40 02 dB Multiply single channel specifications by 2 0 5 full scale Single channel mode Within same calibration range Outside calibration range Dual channel mode ratio or difference Zero set digital settability of zero Most sensitive range Decrease percentage by a factor of 10 for each higher range one count If using the HP 84844A 8481D 8485D 8486D or 8487D Power Sensors 2 full scale Radiated and Conducted Emissions and Radiated and Co
271. oscilloscope display with Figure 8 35 The de voltage of the waveform is set by the voltage at the SUMMING POINT between A5R15 and A5R71 This waveform was taken with 3 4 Vdc at the SUMMING POINT A voltage other than 3 6 0 6 Vdc may indicate a problem on Service Sheet 8 If the displayed waveform is the same as Figure 8 35 the circuit is operating properly If the Fault Isolation Procedure is being performed and the circuit is operating properly go to the Gain DAC Buffer and Gain Compensation Test If the displayed waveform is not the same as Figure 8 35 compare the waveform at A5U5 pin 4 with the waveform in Figure 8 36 If the waveform at A5U5 pin 4 is correct replace A5U9 and or A5R15 A5R71 A5R17 and A5R16 If the waveform at A5U5 pin 4 is incorrect go to step 3 3 Perform steps 1 through 6 of the Fault Isolation Procedure 4 Verify the signatures in Table 8 35 8 99 Service Sheet 7 HP 438A Table 8 35 Offset DAC Buffer Signatures A5U6 Signatures 50 100 mV DIV 2 ms DIV Figure 8 35 Offset Removal DAC Test Signal After Gain Compensation 500 mV DIV Figure 8 36 Offset Removal DAC Test Signal Before Gain Compensation 3 100 HP 438A Service Sheet 7 If any signature is incorrect replace A5U6 If all signatures are correct measure the voltage on the collector of A5Q1 If the measured voltage is 6 2 0 4 Vdc replace A5US5 If the measured voltage is not 6 2 0 4 V
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273. ower meter operations except setting the LINE switch and setting the HP IB address and remote only functions are bus programmable All measurement results are available to the bus The power meter s response to bus command GET Group Execute Trigger can be programmed The default Condition is Trigger With Delay GT2 If in remote and addressed to listen the power meter makes a measurernent according to the previously programmed setup AH HP IB inputs and outputs are cancelled Table 3 2 Message Reference Table HP IB Message Applicable Response Related Interface Command Functions TEO L3 LEO Remote Yes Remote mode is enabled when the REN RL1 REN bus control line is true Remote mode is not entered however until the first time the power meter is addressed to listen The front panel RMT annunciator lights when the instrument is actually in remote mode When entering remote mode no instrument settings or functions are changed but all front panel keys except CCL are disabled 1 Commands control lines and interface functions are defined by ANSI IEEE Standard 488 1 Knowledge of these may not be i o necessary if your controller s manual describes programming in terms of the twelve messages in the HP IB Message column 3 25 Operation HP 438A HP IB Message Local Lockout Yes Clear Lockout Set Local Table 3 2 Message Reference Table continued Yes
274. ower source of any voltage between 90 and 126 Vac or between 198 and 252 Vac 48 to 66 Hz single phase The power meter has the additional capability of operating with line frequencies of 360 to 440 Hz However operation at line frequencies greater than 66 Hz is limited to a line voltage of 90 to 126 Vac The power consumption is less than 65 VA using either source 2 5 Installation Checklist Before plugging the power meter into the line Mains voltage ensure the following steps are taken 1 Check the line Mains voltage to ensure compatibility with the power meter requirements See paragraph 2 4 Power Requirements 2 Check the line voltage switches on the power meter s rear panel to ensure proper selection for the line Mains voltage See paragraph 2 6 Line Voltage and Fuse Selection 3 Ensure that the fuse rating is appropriate for the line voltage used Fuse ratings are listed in Table 2 1 4 Ensure that the power cable to be used is the required type See paragraph 2 7 Power Cable BEFORE PLUGGING THIS INSTRUMENT into the line Mains voltage ensure that the correct voltage and fuse have been selected 5 Plug in the power cable HP 438A Caution Y installation 2 6 Line Voltage and Fuse Selection BEFORE PLUGGING THIS INSTRUMENT into the Mains line voltage be sure that the correct operating voltage and fuse have been selected A rear panel line power module permits operation
275. pedance 50 Ohms Connectors Type N Range 1 mW Transfer Accuracy 0 2 Input to output SWR 1 05 at 50 MHz Accuracy 0 5 at 50 MHz HP 478A H75 HP 478A H762 1 P Performance Tests A Adjustments T Troubleshooting 2 Calibrated by the National Institute of Standards and Technology NIST for this accuracy Table 1 5 Service Accessories Open end wrench Utica Tool Co Open End Standard SMC connectors Model No OP82 1 4 inch 1 Refer to section 8 Service for applications 2 Utica Tool Company Inc Orangeburg SC 29115 or the nearest Utica Tool Company distributor Conductive polyurethane foam 12 x 12 x 0 25 inches Installation 2 1 Introduction 2 2 Initial Inspection Warning Y This section provides the information needed to install the power meter Included is information pertinent to the initial inspection power requirements line voltage and fuse selection operating environment instrument mounting storage and shipment To avoid hazardous electrical shock do not perform electrical tests when there are signs of shipping damage to any portion of the outer enclosure covers panels and display Inspect the shipping container for damage If the shipping container or cushioning material is damaged it should be kept until the contents of the shipment have been checked for completeness and the instrument has been checked mechanically
276. place U1 If all signatures are correct perform the Memory Data Bus Buffer Check Memory Data Bus Buffer Check U8 Service Sheet 2 1 Move the QUAL line to U8 pin 1 set QUAL to LO and verify the signatures for 5 volts version 5 0 7610 version 2 0 H843 and ground 0000 are as shown 2 Verify the signatures in Table 8 22 Table 8 22 Meory Data Bus Buffer Signatures Pin Signal Number Name TT MENT ee 1 07 If all signatures are correct perform the RAM Check If any of the signatures are incorrect replace U8 RAM Check Version 2 0 U12 and U13 Service Sheet 2 and Version 5 0 U13 Service Sheet 3 HP 438A Service Sheets 1 4 Note For the RAM Check to be valid the Microprocessor Data Bus Buffer i 3 and Meory Data Bus Buffer must be operating properly 1 Set Switch A3S1 to 2 0010 The least significant bit of A3S1 is closest to the edge of the printed circuit board When the switches are set towards the front panel of the power eter they are set to 1 The front panel display is blank during this check To verify the check is being run observe the anode data bus bits ADO through AD LED s on the A3 Assembly near A3S1 At the next power up there will be a momentary rcl recall Fail error message since information in memory was written over during this test routine The normal indications are The data bus bit pattern changes as shown in Table 8 23 Table
277. play reads 1 888 23 1 mW when the sensor is connected to a 1 00 mW reference oscillator Pressing the key enables entry of the reference calibration factor for the active entry channel The reference calibration factor is the sensor s calibration factor at 50 MHz The allowable range of values for CAL ADJ is 50 0 to 120 0 The power meter calibrates to an external reference source if the entered reference calibration factor is negative If the entered reference calibration factor is positive the power meter calibrates to the 1 00 mW internal reference oscillator Procedure Connect the sensor to either channel A or channel B via a power sensor cable and set the active entry channel accordingly Press ZERO Be sure that no RF power is applied to the sensor during the zero routine When the power meter has finished zeroing connect the sensor to the 1 00 mW reference oscillator Press CAL ADJ Enter the reference calibration factor in percent Press ENTER Both channels must be calibrated with their own sensors for dual sensor measurements Example To calibrate a sensor to the power meter with a reference cal factor of 98 5 Function w P nmn Data Y Frenter s LOCAL keystrokes Ga TC 9 8 5 CL98 SEN um program codes Funct lon HP 438A Cal Adj Program Codes Program Code CAL ADJ ENTER Indications After the key has been pressed the power meter will display EHT On
278. pter Rack mounting two power meters Order the following HP part number 5062 3974 two rack flanges and HP part number 5061 9694 cabinet locking hardware Rack mounting one power meter with slides Order the following HP part number 5062 3996 support shelf HP part number 1494 0064 two slides and HP part number 5062 4022 filler panel Rack mounting two power meters with slides Order the following HP part number 5062 3966 support shelf and HP part number 1494 0064 two slides 1 12 Cables Power sensor cables of various lengths are available The model numbers and lengths are listed below HP 11730A 1 5m 5ft HP 11730B 3 0m 10ft HP 11730C 6 1m 20 ft HP 11730D 15 2m 50 ft HP 11730E 30 5m 100ft HP 11730F 61 0m 200ft General Information 1 6 1 13 Recommended Test Equipment HP 438A Table 1 3 lists the test equipment recommended for use in testing adjusting and servicing the power meter If any of the recommended equipment is not available instruments with equivalent critical specifications may be substituted Table 1 1 lists the power meter s performance specifications The following conditions apply to all specifications a The power meter must have a one half hour warm up for all specifications b The line voltage for all instruments must be 100 120 220 or 240 Vac 5 1096 and the line frequency must be 48 to 66 Hz c The ambient temperature must be 0 to 55 C HP 438A General Inf
279. quency interference limits are me at the border of his premises Contents General Information Introduction a a AAN dA he 1 2 Specifications 1 kn uxo ee 1 8 Safety Considerations 1 4 Instruments Covered by this Manual 1 5 Manual Changes Supplement 1 6 Description w w 6 ee a 1 6 Options cow eus M Go 3 e r 1 7 Electrical Options e 1 8 Mechanical Option 1 9 Accessories Supplied 1 10 Accessories Available 1 11 Rack Mounting Kits 1 12 Cables a Que ip do do a 1 13 Recommended Test Equipment Installation 2 1 Introduction ws e Gs i 2 2 Initial Inspection SPE 2 3 Preparation for Use 2 4 Power Requirements 2 5 Installation Checklist 2 6 Line Voltage and Fuse Selection Selection of Operating Voltage 2 7 Power Cable 2 8 HP IB Address Selection and Configuring 2 9 Interconnections 2 10 Mating Connectors 2 11 Operating Environment 2 12 Bench Operation NZ 2 13 Rack Mounting OZZIE 2 14 Storage and Shipment 2 15 Environment 2 16 Packaging 1 1 Kr 1 3 E 1 3 1 4 1 4 1 4 1 4 1 5 1 5 1 5 1 5 1 6 St 2 1 2 2 2 2 2 2 2 3 2 4 2 6 2 8 2 8 2 8 2 8 2 10 2 10 2 10 2 11 Contents HP 438A 3 Operation 3 1 Introduction sp Rue RU e Bd 3 1 3 2 Operating Characteristics 3 1 3 3 Local Operation
280. r Error Message Code Display CALC LIF Underflow error LUF Err Illegal logarithmic operation PER Err Invalid or missing reference value Channel A does not have a sensor connected to it na Ch a Channel B does not have a sensor connected to it no Ch b Both front and rear sensor inputs have sensors connected Option 002 only imPuts Both front and rear sensor B inputs have sensors connected Option 002 only Measurement Errors continued Action Required Change either the input power offset cal factor or measurement mode Change to linear measurement units zero the power meter with no RF input power or increase input power to greater than 0 Watts Exit REL mode Connect a sensor to channel A or change channels assuming a sensor is connected to channel B Connect a sensor to channel B or change channels assuming a sensor is connected to channel A Remove one of the 2 sensors connected to sensor A input Remove one of the 2 sensors connected to sensor B input 1 Power calculations result in a value that is too small to calculate or display The combination of input power offset cal factor and measurement mode results in a value whose absolute value is greater than 1 1755E 38 2 This error is cleared after two seconds or by selection of any other function 3 58 HP 438A Error Messages EN
281. r meter s display indicates the channel A cal factor is set to 98 5 Description Series 200 300 BASIC Send the Clear message setting the cal factor to CLEAR 713 100 Check that the power meter s display indicates the channel A cal factor is set to 100 HP 438A Abort Message Status Byte Message Operation This check determines whether or not the power meter becomes unaddressed when it receives the Abort message This check assumes the power meter is in remote mode Description Series 200 360 BASIC Address the power meter to listen OUTPUT 713 Check that the power meter s LSN annunciator is on Description Series 200 300 BASIC Send the Abort message unaddressing the power ABORTIO 713 meter from listening Check that the power meter s LSN annunciator is off This check determines whether or not the power meter sends the Status Byte message Before beginning this check set the power meter s LINE switch to OFF then to ON and press LCL Description Series 200 300 BASIC Place the power meter in serial poll mode causing SPOLL 713 it to send the Status Byte message Check that the controller s display reads 0 3 21 Operation 3 22 Require Service Message HP 438A This check determines whether or not the power meter can issue the Require Service message set the SRQ bus control line true This check can be performed in either local or remote mode Des
282. r sensors cables and a power splitter It assures the operator that most front panel controlled features are being properly executed by the power meter HP IB Functional Checks These procedures require an HP IB compatible computing controller an HP IB interface and connecting cable The procedures check the applicable bus messages summarized in Table 3 2 The HP IB Checks assume that front panel operation has been verified by performing the Basic Front Panel Checks HP 438A a 000000 3 11 Basic Functional Checks Equipment Procedure Operation The functions of the power meter are checked using power sensors sensor cables and a power splitter These checks provide reasonable assurance that most of the front panel controlled functions are being executed by the power meter Power Sensors 2 a SEV vd vs HP 8480 Series Sensor Cables 2 We wid race RR ARR SERERE EE HP 11730 Series Power SOU cecus ate ced UR eEE YET det KN KE HP 11667A Adapter N m to E Te ao b a ao Vol HP 1250 1528 Adapter APC 3 5 f to E WEE HP 1250 1744 The following procedure was developed using power sensors HP 8485A and HP 8481A Using other sensors such as the HP 8481B will result in different displays Turn on the power meter and observe the power up routine with no power sensor connected to the inputs During power up the diagnostics stored in ROM are executed under microprocessor control and turn on all the display segments and annunciators
283. re correct continue with step 4 If any of the signatures are incorrect verify the signature in the following table Chip Select Signatures Ca mem If the signature is correct replace U7 If the signature is incorrect replace U19 4 Verify the signatures in Table 8 12 Table 8 12 Chip Select Signatures Ne al EE E U15 3 U15 3 NRESET AO Al A2 14 14 NWR U13 22 U13320 NRD U9 22 U9 22 NOE The probe should blink indicating signal activity If all the signatures are correct perform the Signature Analysis Mode Checks If any of the signatures are incorrect verify the signatures in Cable 8 13 8 57 Service Sheets 1 4 HP 438A Table 8 13 Chip Select Signatures Pin Number so 0 0003 0003 8484 FFFF UUUU NRESET 0003 The probe should blink indicating signal activity If the signature for pin 2 is incorrect replace U37 and or R17 If the signature for pin 4 is incorrect replace U36 and or R20 If the signature for pin 6 is incorrect check for a TTL low at U37 pin 8 If pin 8 is a TTL low replace U36 If pin 8 is not a TTL low replace U37 If the signatures for pins 11 13 and 15 are incorrect replace U19 If the signature for pin 17 is incorrect troubleshoot the Reset Power Fail circuit If the Memory Data Bus and Chip Select Signatures are correct perform the Signature Analysis Mode Checks If the signatures are incorrect
284. rement Units Limits Checking REL Trigger Mode Group Execute Trigger Mode Display Function Display Enable Table 3 5 Response to a Trigger Message Program Code Power Meter Response Ignore Group Execute Trigger Trigger Immediate TR1 Trigger with Delay TR2 3 42 HP 438A 3 24 Receiving the Remote Message 3 25 Receiving the Local Message 3 26 Receiving the Local Lockout Message 3 27 Receiving the Clear Lockout Set Local Message Operation The Remote message has two parts First the remote enable bus control line REM is held true then the device listen address is sent by the controller These two actions combine to place the power meter in remote mode Thus the power meter is enabled to go into remote when the controller begins the Remote message but it does not actually switch to remote until addressed to listen the first time No instrument settings are changed by the transition from local to remote When actually in remote the power meter lights the front panel RMT annunciator The Local message is the means by which the controller sends the Go To Local GTL bus command If addressed to listen the power meter returns to front panel control when it receives the Local message If the instrument was in local lockout when the Local message was received front panel control is returned but lockout is not cleared Unless it receives the Clear Lockout Set Local message the power meter w
285. rence Oscillator A failure in the power sensor power sensor cable or Amplifier Section could also cause the problem HP 438A Notes Y Service Sheets 1 4 HP IB Commands in Extended Test Mode The Extended Test Mode also allows the Zero DAC Gain DAC Offset DAC and the Variable Gain Amplifier to be set over HP IB for testing purposes only The Extended Test Mode commands are as indicated in Table 8 7 below Table 8 7 HP IB Commands in Extended Test Mode Cause the system to accept the next number sent and use it as the zero DAC setting for channel A Valid range of numbers are 0 255 Cause the system to accept the next number sent and use it as the zero DAC setting for channel B Valid range of numbers are 0 255 Cause the system to accept the next number sent and use it as the gain DAC setting for channel A Valid range of numbers are 0 255 Cause the system to accept the next number sent and use it as the gain DAC setting for channel B Valid range of numbers are 0 255 Cause the system to accept the next number sent and use it as the offset DAC setting for channel A Valid range of numbers are 0 255 Cause the system to accept the next number sent and use it as the offset DAC setting for channel B Valid range of numbers are 0 255 Cause the system to accept the next number sent and use it as the variable gain amp setting for channel A Valid range of numbers are 0 15
286. replace A5Q4 or A5Q5 Table 8 37 Miscellaneous Buffer Signatures 8 103 901 8 501 8 wesbeig oneueuos synod seysdwy urew O d 6 SY O d pi t uf insino PO uagsooad RER Loew a SO ol H 0 Op o o o o i i o or AA o or tio a gt fen so ai Mila al ia GO M3IA GOL GHYOE 185 CO sinsy ISO LUGDBID so o ud go o o i H 9 4 3 0 4 een E 1 t i 1 i m i B oy b zo pl og fsb M3IA di S in OL cEy09 Nh i 1300939 EE 3a oi o 9 2 2 8 3 E MAJA dQi i cyuvog Sr 2 305v Pas o GE EI SUOR gi DAN _2 BON SL Ce 1 38345 9914438 l DG 8 aniy Wr DY NED A 39003432338 NOTE O3KNO9 ONNOES ONY 39Y1104 L1i8OWIO C31V893iNI 202 0281 Sizgi gze 6631 9281 PTBL DZQ 1661 0295 1986 3281 2v6 9368 0iBQ v6g 55y0 59 EIENEN ROTT RST 1501 ibd i i9NiU3J3U 109919 31YHDSIN NY SOlS 5NvHl 43N89 8v iON 29 aci t 71802 SV SWOTTYRSTS3 AROZOWS 382 XY ABLINOJIO ONINNNY iY3H N3HM 0350 A Hi HOLOINNGS 3902 OdYOS S3iNiEd Oj u3438 93 3 0N WYEDYIO Oiive3HOS 30 2 9 119 Oi Y3438 310N D u334f8 y DYO Ni S BAS LE NC aa Wate iig i NO11VSN3dHOO VIVE 0632 QL9Y p M M A A AAAA zs e VG TYAOWIE LL B uw 8 ASE i 2 E GNO 33
287. reset Preset Description The key sets the power meter to a known state Preset conditions are shown in Table 3 9 Procedure Table 3 9 PRESET Conditions Sensor A and B CAL ADJ 100 0 CAL FACTOR 100 0 OFFSET 0 00 dB Filter AUTO Range AUTO Measurement Mode Sensor A Reference Oscillator OSC Active Entry Channel Measurement Units REL Remote Only Functions Sensors A and B Low Limit High Limit Limits checking 0 000 dBm 0 000 dBm Disabled Free Run Trigger with Delay Display Enable Trigger Mode Group Trigger Mode Display Function To set the power meter to the conditions indicated in Table 3 9 press the key Program Codes The program code for PRESET is PR 3 69 Preset 3 70 HP 438A Comments PRESET does not affect zero and calibration information stored for each sensor Although PRESET sets the CAL ADJ value to 100 0 it does not initiate a calibration using the new value for CAL ADJ PRESET produces the same results as the Device Clear command over the HP IB Storage register 0 is set to the preset condition when a continuous memory error Error 57 occurs Related Sections CAL ADJ CAL FACTOR dBm WATT Logarithmic Linear Units Error Messages Filters Limits OFFSET Range REL Relative Measurements STORE and RECALL HP 438A BEEN Range Range Includes AUTO RANGE an
288. roblems in the ALC Loop and Power Supply circuits may be quickly isolated by measuring dc voltages at the inputs and outputs of the integrated circuits 8 137 OrL B GEL 8 wesBeig WewWayIS Simao 1038jli2sQ 323u049 9H J9MOd v9 8 abla 00 NOildO 1429 LVD Lb YETT Leit tan RONIEJJZE UIROg ZHA 0S Y tv A ant Ma am ES HR INR trier a M erret A a A ns t Heime im m s esen NOTTING ISIC io us 39N3E333 SUSERDN HYS HEED Asy SOLO ISRAEL 00 NOLEdO EA Ke 13433 9014 SU raw OS MW QUO i38 U3ROd ennen STP OY 13A31 ONY 438 OC emen atte US og E 9 hs H3GIA G P VAGOS Ve eviloA Bf E 1429 NOLLYNDISIC 308343334 SYH CNY 290 KOL iGO U wu 232 40a G3iY3 d3H S NOILYNYCJKI SiHi INSNOdMOO 03193738 HOLY 111080 ZHAN Aessen Same JO DY wn AHO10v3 S3iVOIQNL gai WSIY LSY 2 S3iON Wor DILYWIKOS O 2 9 319Yi OL HZABE m m Ot V a e m n r A Ae SHION TE 3i0NI 1T609 9t760 ATSASSSY UOIVITlOSO 3ONGEJJH u3AOd ZHA OS LE 1939S GHAIBS ame mcd EY T 2 3 oT pn M omi ty t 206 ech ot f itAS1 e I QUYORYLS CANES ee ri O eu 8913111280 179 v HS AS mn reng ke xi dTYGNY1 ETE 200 e vm ay o suoneso7 juounsn py pue SO 1591 Juauoduio Ajquiassy IGLO aduasajay JomOd 9 8 eJnDiJ MIIA 3018 MJIALNOUS l YJA09 HOLVITI
289. rocedure following Free Run Signature Analysis o If Free Run Signature Analysis has been performed and all tests are normal A3U1 or A3U19 should be replaced A ASSEMBLY NOTE X ON CIRCUIT SIDE OF BOARD Figure 8 19 Keyboard Assembly Component Locations 8 72 t4 8 2 8 weeg onewayos sinoao indino indu HEG LZ 8 anid ES iu ee MEN NIE NE LN T ditare pa dad aru Re SN EE Ruta ee V O d LIN IN 9 4 J 8 Y M n sr Gre z TINN L 08 eee ei mem tid TOW ex Dor cy i one i ee ui BO OR D 8 go od 8 p pg gt Ce FFAN o 0 d E o o j E 5 ui 338 oa MEE ca Bo ee dq ru poa E pod oi y Er i FETE rut 8538 o of A3 o Ge A33 IE gu dX j H LON SHAR 102 gro Foot Den stoe Bi vid feb es D ru 9343 EY 1 KILA gol X3TA 901 WALA doi mata goi ice lt j zt ua n ceney iria Deep 1INOWIJ Sa pre Ip 104 844 88 ET FE 09 4 89 320 oR rz o Wo on H at ele NLIS LO a9 i o o o o jer E Ce ho XYHX Lon t t MEN i I CS sel 328 i y DEF A i EE I pres Deh wee j3000N3 ALIHOIHd GHYORAJ Hamma LE HH i o o a D wo Ei me oe eo nt i E nu ED oad TU be 3RSN MEJIA doi KBIA gel KAYA Ok A314 GOL E STIR o D o goe B2NEY BYOS B E E d E nim s A we S N LTMDBLO LINDB I TACE zE e uzy sO BSO GD 18 08 me LANE 2 SIs UE FF SY Dez D i E 08 YAYO ep 833308 Sng vivo AS EC Ue 80839084080 1A Ka 1 LE cad btd ie ES Age en seni 3N 10008 06900 A18M3SSY
290. rogram Codes Parameter Program Code OFFSET Display Offset ENTER Indications When an offset is added to a measurement the front panel displays the value of the offset and the dBOS annunciator lights Comments dB offset can be added to a sensor whose display is in Watts The power meter automatically converts the dB offset to Watts and adds that value to the sensor s measured power 3 67 Offset 3 68 Related Sections HP 438A The following equations are used to calculate the value that is entered for the display offset function For measurement modes A B or A B Display Offset of active entry channel a Current OFFSET active entry channel 10 LOG fesihironesenn b Current OFFSET active entry channel 10 LOG LEET c Current OFFSET active entry channel 10 LOG Power active entry channel H the display OFFSET value as calculated above results in an illegal OFFSET entry value the number 333 3 will be displayed The power meter generates Error 51 OFFSET entry error if an attempt to enter the illegal value is made Display offset function ignores REL mode when calculating the offset value PRESET sets both the sensor A and sensor B offset values to 0 00dB The DSP OFS function is only active when it is preceeded by OFFSET dBm WATT Logarithmic Linear Units Error Messages PRESET REL Relative Measurements SET A and SET B STORE and RECALL HP 438A P
291. rs Sensors HP 84814 8481B 8481H 8482A 8482B 8482H 8482A 8485A R8486A Q8486A W8486A and 8487 A Fiker Number Noise 96 6 0 2 4 1 8 0 9 0 7 0 5 0 4 0 3 0 2 0 15 e O GI CO Qd GN A Sensors HP 8484A 8481D 8485D and 8487D Multiply noise levels by 4 for all filters Sensors HP R Q8486D Multiply noise levels by 6 for all filters Settling Time 0 to 99 settled readings over the bus AUTO filter range hold 10 dB decreasing power step Single channel Range Settling Time 1 3 0 s 2 lt 1 0s 3 lt 150 ms 4 5 lt 100 ms Manual filter range hold 10 dB decreasing power step Single channel Filter Number Response Time s 0 10 0 15 O00 A C RA W D r CD RO o Dual channel ratio or difference mode Approximately the sum of the individual response times of each channel plus channel switching delay HP 438A General Information Table 1 4 Recommended Test Equipment Critical Specifications Recommended Model Use Digital Voltmeter Range 0 to 20 Vdc HP 3456A P A T Resolution 0 01 Volt Oscilloscope gt 200 MHz bandwidth HP 1725A T Calibration uncertainty HP 11683A P A T 0 25 Signature Multimeter Qualified Signiture HP 5005B T Analysis Frequency Counter Range 10 Hz to 50 MHz HP 5328A Option 031 P A T Resolution 1 Hz HP 11667A HP 432A Range Calibrator Power Splitter Thermistor Mount Frequency 50 Mhz Im
292. ry controlled switch which acts as an on off switch to analog or binary signals flowing in both directions Dependency notation should be used to indicate affecting affected inputs and outputs Note amplifier symbol with dependency notation should be read to indicate unilateral switching Coder Input code X is converted to output code Y per weighted values or a table The following labels are to be used as necessary to ensure rapid identification of device function Multiplexer The output is dependent only on the selected input Demultiplexer Only the selected output is a function of the input Central Processing Unit Peripheral Input Output Static Memory Interface HP 438A p FF Functional Labels Service Table 8 1 Schematic Diagram Notes 6 of 8 DIGITAL SYMBOLOGY REFERENCE INFORMATION Sequential Logic Functions Monostable Single shot multivibrator Output becomes active when the input becomes active Output remains active even if the input becomes inactive for a period of time that is characteristic of the device and or circuit Oscillator The output is a uniform repetitive signa which alternates between the high and low state values If an input is shown then the output will be active if and only if the input is in the active state Flip Flop Binary element with two stable states set and reset When the flip flop is set its outputs will be in their active states When the flip flop is res
293. s a short somewhere on the A3 assembly Service Sheet 4 shows the related circuits If disconnecting A3J6 does not relieve the problem continue with step 2 2 If the 5V Digital Supply A9TP4 is not 5 0 05 Vde continue troubleshooting with the 5V Digital Supply test 3 Compare the signal at A9TP1 CLK with Figure 8 55 If the signal is incorrect continue troubleshooting on Service Sheet 3 If the signal is correct replace A8U1 8 124 HP 438A Service Sheet 9 200 us DIV Figure 8 55 5 Volt Display Clock Total Power Failure Test 1 Unplug the instrument from the line Mains 2 Remove fuse F1 and check it with an ohmmeter If it doesn t measure zero ohms replace it 3 Verify that the line voltage selection card is in the correct position 4 If everything seems to be correct the problem is in the transformer or line switch assembly i If the line fuse blows repeatedly there may be a problem with the Note 3 Crowbar circuit on Service Sheet 10 8 125 Service Sheet 9 HP 438A A8 ASSEMBLY COMPONENT SIDE CIRCUIT SIDE Figure 8 56 Rectifier Assembly Component Locations 8 126 Service Sheet 9 HP 438A A10 ASSEMBLY Figure 8 57 P O Interconnect Assembly Component Locations 8 127 0 1 8 671 8 weed OREWAUJS SBNIMD NS Jamog Old 6s g aunbiy OLY O d 6V O d BY 5 g o 300NY 5 3819 30041Y2 MBIA dol EU QuvoS RITA 1100410 wolio ZBY to Q as
294. s printed on the label and should be used If an HP 84844 Power Sensor with its associated HP 11708A Reference Attenuator is used the front panel display reads 1 G66 6 instead of 1 888 3 Offset settings are ignored during calibration 3 49 Cal Adj 3 50 HP 438A Error 57 occurs when the instrument is turned on and the internal RAM contents have been lost This is generally due to battery failure but may also occur when the power meter is powered down during calibration or zeroing The error is cleared after two seconds or by selecting any other function Once the error is cleared the power meter is configured to the PRESET state and the HP IB address is read from the internal address switch Because of the variety of sensor power ranges the power meter always auto ranges during calibration After calibration the previous range setting is restored If the CAL ADJ entry is positive the power meter first checks that the sensor is connected to the reference oscillator by turning the oscillator on and off and watching for a power level change on the sensor If the sensor js connected the reference oscillator is turned on for the calibration and returned to its former state upon completion of the calibration Related Section CAL FACTOR Error Messages SET A and SET B PRESET ZERO HP 438A Cal Factor RA AAA 00 Cal Factor Description The calibration factor compensates for mismatch losses and effective effi
295. s the frequency response of the sensor relative to 50 MHz For example to enter a calibration factor of 10076 press CRLJFACTOR ERL ADI ZERO ZERO En MAD FILTER A digital filter averages measurement readings to reduced jitter A filter number 0 through 9 is entered to set the filter length The filter length is the number of readings averaged and is equal to 2 to the power of the filter number that is from 1 to 512 in powers of 2 selects the optimum filter length automatically Because of speed resolution and display considerations the filter can be set manually Measurements with higher filter numbers are slower and more settled measurements with lower filter numbers are faster and have more jitter For example to manually set the filter to 7 filter length of 128 press HP 438A MEASUREMENT UNITS STORE and RECALL Operation RANGE The Power Meter divides the sensor s power range into five ranges of 10 dB each Range 5 may be less that 10 dB if the sensor has a power range of less than 50 dB Range 1 is the most sensitive and range 5 is the least sensitive AUTO RANGE sets the correct range automatically for the current measurement Manual range is used primarily with the rear panel recorder output or when faster readings are required For example to set range manually to Range 3 press MNL RANGE OFFSET dBm WATT OFFSET Offsets can be added to measurements to compensate for gain
296. s the measurement result in the requested units The following discussion explains Figure 8 9 Overall Block Diagram Controller Section YY 2 The microprocessor based Controller Section consists of the following assemblies 1 A1 Keyboard Assembly 2 A2 Display Assembly 3 A3 Central Processing Unit CPU 4 A11 HP IB Assembly The CPU provides the timing calculation and control for the instrument The microprocessor executes instructions stored in the read only memory ROM Data is exchanged between the microprocessor and the other blocks of the CPU over the data bus DO D7 The elements of the CPU are enabled to respond to the data on the data bus by control signals These signals are derived from the address bus A0 A15 by the address and control decoders Data values that must be stored are placed in the random access memory RAM The CPU sends and receives data to and from other assemblies through the keyboard interface HP IB interface and the analog input output 1 0 interface It also sends data to the display through the display interface The display indicates the current status of the power meter This status information can consist of the current measurement configuration and results or one of the error messages contained in Table 3 8 simplified flowchart of the interrupt control routine for the power meter is shown in Figure 8 2 There are no asynchronous interrupts Service Sheet BD1 8 16 H
297. sed in the parts list and throughout the manual Table 6 3 lists all replaceable parts in reference designator order Table 6 4 contains the names and addresses that correspond to the manufacturer s code numbers Table 6 2 lists abbreviations used in the parts list schematics and throughout the manual In some cases two forms of the abbreviation are used one all in capital letters and one partial or no capitals This occurs because the abbreviations in the parts list are always all capitals However in the schematics and other parts of the manual other abbreviation forms are used with both lower case and upper case letters Table 6 3 is the list of replaceable parts and is organized as follows a Electrical assemblies and their components in alphanumeric order by reference designation b Chassis mounted parts in alphanumeric order by reference designation c Mechanical parts The information given for each part consists of the following a The Hewlett Packard part number b Part number check digit CD c Total quantity Qty used in the instrument d Part description e Five digit code that represents a typical manufacturer f Manufacturers part number The total quantity for each part is given only once that is at the first occurrence of the part number in the list The total quantities for optional assemblies are totalled by assembly and not integrated into the standard list Replaceable Parts 6
298. sembly which are separate from J XA2 RI those made through the integral Conducting connection plug part of the assembly to chassis or frame NOT ASSIGNED Asterisk indicates factory selected components See section V Ae Value selected for best operation Value shown is average or most commonly selected value Wire color code Code used MIL STD 681 is the Reference designators deleted same as the resistor color code First number by circuil changes are listed 7 identifies the base color second number the wider here Assembly reference designator s stripe and the third number the narrower stripe Example denotes white base veliow wide stripe violet narrow stripe Large numbers in lower right corners o schematic diagrams are service sheet numbers Thev are provided for con List of all the reference desig venience in tracing inter nations on the diagram connections 8 6 HP 438A Service Table 8 1 Schematic Diagram Notes 2 of 8 ses eon con wm m ERD eg d gemengten 2 AK 12 THIS PAGE SCHEMATIC DIAGRAM NOTES Asterisk denotes a factory selected value Value shown is typical Dagger indicates circuit change See Section VII Tool aided adjustment O Manual control Encloses front panel designation Encloses rear panel designation Circuit assembly borderline Other assembly borderline Heavy line with arrows indicates path and direction of
299. sk to enable an out of limits condition to issue the Require Service Message thus lighting the SRQ annunciator on the front panel Comments PRESET sets both the high and low limits for each sensor to 0 000 dBm and disables the limits checking function Limits are checked against measured power plus offsets By setting the low limit to a value greater than the high limit or setting the high limit to a value less than the low limit a region can be defined An out of limits condition occurs anytime displayed power drifts into this region assuming the limits checking function is enabled If the limits checking function is enabled in remote mode and then the Power Meter is switched to local operation the limits checking function remains enabled High and low limits cannot be stored or recalled Related Sections PRESET Remote Operation HP IB SET A and SET B STORE and RECALL 3 65 Offset Offset 3 66 HP 438A Description Offset values can be entered to each channel to compensate for gain or loss The offset is added to the measured power before the result is displayed Offsets are entered in dB The allowable range of values is 99 99 to 99 99dB in 0 01dB increments Use positive values for gain and negative values for loss Pressing the key and then the key without entering any data sets the offset of the active entry channel to 0 00dB The display offset function provides another method for ent
300. splay LED segments It is used to verify that all display segments are working properly This function is cleared by sending another display function program code DE or DD by PRESET or by the power meter receiving the Clear message At turn on all the display segments light momentarily before the display enable becomes active Triggering Measurements with the Data Message A feature that is only available via remote programming is the selection of free run standby or triggered operation of the power meter During local operation the power meter is allowed to free run outputting data to the display as each measurement is completed In remote three additional operating modes are allowed hold trigger immediate and trigger with delay Hold TRO This mode is used to set up triggered measurements initiated by program codes TR1 TR2 and the Trigger message In trigger hold mode internal settings can be altered by the instrument itself or by the user via the bus The instrument however is inhibited from outputting any data to the front panel display or to the HP IB except as follows The instrument will issue the Status Byte message if serial polled The power meter leaves hold mode when it receives either the free run trigger immediate or trigger with delay program codes or the lrigger message or when it returns to local mode via the key Upon leaving hold the front panel display is updated as the new measurement cycle begins
301. ssembly and supply the 1 ms software interrupt to the timer interrupt latch The 4 MHz input clocks the timer A D circuit The start ramp signal starts the internal counter at the same time as the ramp generator in the main amplifier is started When the measured input signal and the ramp generator output are equal the ramp end signal from the main amplifier stops the counter The counter output is read to the microprocessor under software control The microprocessor uses this data to perform the required computations and displays the results on the front panel A2 Display Assembly The analog I O PIA input output peripheral interface adapter applies the required measurement configuration control signals to the main amplifier The cathode data display and keyboard scan PIA controls the addressable data display latch circuit and the inputs and outputs to the Al Keyboard Assembly The addressable data display latch circuit controls the cathode data display drivers The LED data latch is enabled by the anode data display and LED address decode circuit and controlled directly by the microprocessor The LED lighting patterns are used to obtain circuit information when troubleshooting the instrument Additional information on how to use the LED information is contained in the troubleshooting section of this service sheet The anode data display and LED address decode circuit also selectively enables one of the anode data display latches Display Dr
302. stitute the serial number prefix The last five digits are the suffix The prefix is the same for identical instruments it changes only when a configuration change is made to the instrument The suffix however is assigned sequentially and is different for each instrument The contents of this manual apply directly to instruments having the same serial number prefix es listed under Serial Numbers on the title page An instrument manufactured after the printing of this manual may have a serial number prefix that is not listed on the title page This unlisted serial number prefix indicates that the instrument is different from those documented in the manual If manual changes are needed the manual for this newer instrument is accompanied by a yellow Manual Changes supplement The supplement contains change information that explains how to adapt this manual to the newer instrument In addition to change information the supplement may contain information for correcting errors in the manual The supplement is identified with the manual print date and part number both of which appear on the manual title page For information concerning a serial number prefix that is not listed on the title page or in the Manual Changes supplement contact your nearest Hewlett Packard office 1 3 General Information 1 6 Description 1 6 Options HP 438A The HP 438A Power Meter is a microprocessor controlled dual channel A and B multiplexed m
303. t Supply Test 8 130 Service Sheet 11 General REM I 8 135 50 MHz Oscillator we woke lae 3 8 135 ALC Loop and Power Supply 8 135 Figures WRECZ CC ZE O OZ W OCE EO OE O O Z iene 1 1 HP 438A Power Meter with Accessories Supplied 1 2 2 1 Line Voltage and Fuse Selection 2 3 2 2 Power Cable and Line Mains Plug Part Numbers 2 5 2 3 Hewlett Packard Interface Bus Connection 2 9 3 1 Simplified Front Panel Features sh 3 5 3 2 Rear Panel Features ss 3 6 3 3 Front Panel Checks Setup 1 iO ble ow wg dz 3 14 3 4 Front Panel Checks Setup 2 SE 3 15 3 5 HP IB Functional Checks Setup 3 17 3 6 Status Message Output Format SE 3 40 4 1 Zero Carryover Test Setup S 4 3 4 2 Instrument Accuracy Test Setup hj sk 4 5 4 3 Power Reference Level Test Setup 4 9 5 1 Power Supply Adjustments Setup 5 3 5 2 Analog to Digital Converter Slope Adjustment Setup 5 5 5 3 220 Hz Frequency Adjustment Setup 5 7 5 4 Ranges 4 and 5 Shaper Adjustment Setup 5 8 5 5 Power Reference Oscillator Frequency Adjustment p soe xc 5 9 5 6 Power Reference Oscillator bevel Adjustment Setup 5 10 6 1 Front Panel Illustrated Parts Breakdown 6 22 6 2 Rear Panel Illustrated Parts Breakdown 6 23 6 3 Cabinet Parts UA TI 6 24 8 1 Power Meter Simplifie
304. tatus Bit message if configured to do so as part of the interface s response to the Parallel Poll Enable PPE bus command In order for the power meter to respond to a PPE bus command the instrument must be assigned a single HP IB data line on which to respond by the controller The controller also assigns the logic sense of the bit Both tasks are accomplished by the Parallel Poll Configure PPC bus command If the power meter is sending the Require Service message it will set its assigned status bit true The power meter can send the Status Bit message without being addressed to talk 3 45 Operation 3 46 HP 438A The data line on which the power meter is assigned to respond is cleared by sending the Parallel Poll Unconfigure PPU bus command At turn on the data line is unassigned 3 32 Receiving the Abort Message The Abort message is the means by which the controller sets the Interface Clear IFC bus control line true When the Abort message is received the Power Meter becomes unaddressed and stops talking and listening 3 33 HP IB Syntax and Characteristics Summary Address Set in decimal from the front panel Set the LINE switch to ON while pressing the key Release the key enter the desired address and press the key Factory set to 13 Data input Format Typically the same as front panel keystrokes in local mode All numeric entries sent over the HP IB must be terminated with program code EN for ENTER
305. ten and receives program code FH Filter Hold it switches from auto filter mode to manual filter mode using the current auto filter value If the power meter is already in manual filter mode no action is taken No filter number is entered with this program code Limits The limits checking function allows the power meter to monitor the power present at each sensor and indicate when that power is outside preset limits Enabling the limits checking function and setting limit values are available only via remote programming To set the the limits for a sensor address the power meter to listen and then send a Data message consisting of program code LL limit low or LH limit high a numeric value and program code EN ENTER The allowable range for limit values is 299 999 to 299 999 Values entered that are outside of this range cause the limit to be set to the minimum or maximum value as appropriate Limit values are entered in dBm and converted automatically to Watts when necessary The limits checking function is enabled by program code LM1 and disabled by program code LMO When the limits checking function is enabled it uses the last values set for the high and low limits PRESET and the Clear message sets both the high and low limits for Sensors A and B to 0 000 dBm and disables the limits checking function If the limits checking function is enabled and the input power exceeds the high limit or is less than the low limit the c
306. the value of the ADC input signal This information is used by the microprocessor to compute the measurement value This value can then be used in any other computations required to obtain the final displayed information 1 mW 50 MHz Power Reference Circuit The G1 50 MHz Reference Oscillator provides a 50 0 0 5 MHz output at 1 0 mW 0 7 This output is used during operation to calibrate the individual power sensors used with the power meter It can also be used during the Operator s Check and troubleshooting procedures as a signal source As explained previously the zeroing software routine determines the setting for the auto zero DAC calculates and stores 10 offset values for the 10 combinations of the two low pass filters and the five available ranges For correct calibration the connected power sensor and the power meter must be zeroed prior to calibration The main functions of the power sensor calibration software routine are as follows 1 Verify an appropriate power source and a power sensor are connected to the power meter In some cases the power source is the power meter s 1 mW 50 MHz Reference output 2 Set the range attenuators and the low pass and digital filters to the correct settings for the connected power sensor 3 Set the variable gain amplifier so that the ADC output indicates between 3 02 and 3 63 Vdc 4 Calculate and scale the 10 zeroing offset values to provide more accurate power measurements
307. the following examples as a guide to eliminating the Cathode Data Display Drivers or the Anode Data Display Drivers as the cause of a front panel display problem Example 1 While observing the front panel it is discovered that display A2DS6 is not illuminated but all the other displays are illuminated This fact rules out the possibility that the segment lines are not operating properly Also it is observed that line DS5 activates display A2DS6 the first seven segment display in A2D513 and the B A and REL annunciators Since the first seven segment display in A2DS13 and the B A and REL annunciators are illuminated display A2DS6 must be defective Example 2 While observing the front panel it is discovered that the g segment in all five seven segment displays of A2DS12 and A2DSI3 2 are not illuminated The g segment corresponds to the SEG15 line Since the g segment in all of the displays is not illuminated the problem must be with the Data Display Drivers A3U26 or the Anode Data Display Drivers A3Q7 If the voltage at A3U26 pin 2 is low lt 0 5V replace A3Q7 or the associated components If the voltage at A3U26 pin 2 is high gt 4 5V check A3U26 pin 1 for a TTL low 0 8V If pin 1 is low replace A3U26 If pin 1 is not low go to Service Sheet 1 and begin troubleshooting using signature analysis If signature analysis does not locate the problem replace A3UA4 A3U5 or A3U11 8 83 Service Sheets 5
308. tory the address of the instrument is 13 When an address is stored in RAM and not lost changing the internal HP IB switch will have no effect The address that is stored in RAM can be viewed on the front panel display by pressing local and will be the valid address unless memory is lost Memory lost is indicated by a RCL FAIL ERROR message HP IB addresses from 00 to 30 can be used A list of allowable addresses is given in Table 2 2 Table 2 2 shows the ASCII address codes to decimal equivalents HP 438A Installation Table 2 2 Allowable HP IB Addresses ASCII Address Codes LISTEN TALK Decimal Equivalents SP vd bd StH mg OS SE Co Sara O ao z N eee emen pna 1 Decimal values are equivalent to the last five bits of both talk and listen addresses 2 Decimal 13 is the factory set HP 437b address Use the following procedure to set the HP IB address 1 Turn the instrument off Press and hold the local key while turning the instrument on Wait for the Ent enter address message Release the key Key in the address using the keys representing the numbers QU va W BK 2 7 installation 2 8 HP 438A 2 9 Interconnections The connection from meter to power sensor is made through HP 11730 series sensor cables having circular 12 contact male mating connectors The two front panel connectors Sensor A and Sensor B and the two rear panel Option 002 connectors SENSORS A B requir
309. tputs labeled with the same identifier The m is replaced with a number or the letter the identifier Fm Free Dependency Binary affecting input acting as a connect switch when active and a disconnect when inactive Used to control the 3 state behavior of a 3 state device NOTE The identifier m is omitted if it is one that is when there is only one dependency relationship of that hind in a particular device When this is done the dependency indicator itself G C F or V is used to prefix or suffix the affected dependent input or output HP 438A Service Table 8 1 Schematic Diagram Notes 8 of 8 DIGITAL SYMBOLOGY REFERENCE INFORMATION Miscellaneous E Schmitt Trigger Input characterized by hysterisis one threshold for positive going signals and a second threshold for negative going signals Active ActiveState A binary physical or logical state that corresponds to the true state of an input an output or a function The opposite of the inactive state Enable Enabled Condition A logical state that occurs when dependency conditions are satisfied Although not explicitly stated in the definitions listed above functions are assumed to be enabled when their behavior is described A convenient way to think of it is as follows A function becomes active when it is enabled dependency conditions if any are satisfied and its external stimuls e g voltage level enters the active state Service Sheet BD1
310. tric shock do not perform any servicing unless qualified to do so Adjustments described in the manual are performed with power supplied to the instrument while protective covers are removed Energy available at many points may if contacted result in personal injury Capacitors inside the instrument may still be charged even if the instrument has been disconnected from its source of supply For continued protection against fire hazard repiace the line fuse s only with 250V fuse s of the same current rating and type for example normal blow time delay etc Do not use repaired fuses or short circuited fuseholders Safety Considerations Warning Caution HP 438A Safety Symbols AN Instruction manual symbol The product will be marked with this symbol when it is necessary for the user to refer to the instruction manual see Table of Contents for page references Indicates hazardous voltages mies Indicates earth ground terminal The WARNING sign denotes a hazard It calls attention to a procedure practice or the like which if not correctly performed or adhered to could result in personal injury Do not proceed beyond a WARNING sign until the indicated conditions are fully understood and met Mt T me The CAUTION sign denotes a hazard It calls attention to an operating procedure practice or the like which if not correctly performed or adhered to could result in damag
311. trigger command is executed refer to section 3 for an explanation of the status byte After power up hardware generated interrupts occur every 1 ms Each interrupt causes the interrupt routine to perform the following functions 1 Scan the keyboard inputs to determine if a key has been pressed This subroutine also debounces the keyboard input by verifying that after approximately 10 ms the same key pressed indication is still present 2 Refresh the front panel display information This sequence does not change any information it only allows the display to be refreshed at a rate that provides flicker free operation 3 Start and monitor the analog to digital conversion ADC Once the ADC is started its operation is independent of the software 4 Input the power measurement value to the digital filter when required The digital filter is updated every 50 ms every 50 interrupts This update rate is maintained regardless of the state of the instrument HP IB activity or front panel activity 8 17 Service Sheet BD1 HP 438A GET MEASUREMENT RESULTS FROM DIGITAL FILTER ANY ERRORS FORMAT MEASUREMENT RESULTS FOR TASK 1 UPDATE HARDWARE CONF IGURAT ION AS NEEDED ERROR CLEARED FLAG ERROR STATE TO TASK 1 TO DISPLAY ERROR CONDITION Figure 8 4 Task 2 Flowchart When the interrupt routine is finished it returns to either task 1 or 2 The software logic requires that the returns alternate b
312. try errors do not set the status byte s RQS bit true the status byte and status message latch all entry errors Measurement errors however are latched only if 9 0000E 40 has been sent over the HP IB The status byte and status message are cleared by removing the cause of the error and then reading the status message over the HP IB Error Messages Table 3 8 Error Messages describes all measurement and entry errors The error code front panel error display message and action typically required to remove the error causing condition are given HP 438A Error Display Cannot 4 Cannot dl no CEF Lal Err Cal Err inFut L infFut U L up rng Error Messages Table 3 8 Error Messages Message Power meter cannot zero sensor A Power meter cannot zero sensor B Sensor A is not connected to reference oscillator during calibration Sensor B is not connected to reference oscillator during calibration Power meter cannot calibrate sensor A Power meter cannot calibrate sensor B Input overload on sensor A Input overload on sensor B Sensor A s zero reference has drifted negative Sensor B s zero reference has drifted negative Input power on sensor A is too high for current range Input power on sensor B is too high for current range Overflow error Action Required Ensure that no RF power is being applied to sensor A Ensure that no RF power is being applied to sensor B C
313. tz WOE c2 ea M S millihenry MDO oe OS the es blau mho MIN RI minimum LII Rp minute time e 6 minute plane angle MINAT miniature TAM lie millimetre MOD onse cos modulator MOM momentary MOS eror metal oxide semiconductor Do PEE millisecond MOG flees a cw mounting MTR meter indicating device MV wee cies nae millivolt mVac eataa eseis millivolt ac mNdc ce ee millivolt dc mVpk millivoit peak mVp p millivolt peak to peak mVrms mili volt rms AW ME milliwatts MUX cima ia multiplex MY cok foe a WWE TA mylar BA RS microampere BE Roshan i ore es EVA microfarad pH Sec tai ee eke microhenry pumho oo e micromho A Leg APS we microsecond AM vus Dean endi microvolt MVMAG VEN Her microvolt ac MAE esee microvolt dc ANPE oo 0 microvolt peak Vp p microvolt peak to peak Vrms 122211 microvolt rms map microwatt HP 438A Replaceable Parts Table 6 2 Reference Designations and Abbreviations 2 of 2 nanoampere no connection normally closed negative nanofarad nickel plate normally open nominal norma NPN negative positive negative negative positive zero temperature coefficient not recommended for field replacement not separately replaceable nanosecond nanowatt order by description outside diameter oval head operational amplifier option oscillator peak used in Parts List pulse amplitude m
314. umbers are listed on the title page of this manual 1 1 General Information HP 438A 438A POWER METER CZA HEWLETT PACKARD HP 438A POWER METER POWER SENSOR CABLES LINE POWER CABLE Figure 1 1 HP 438A Power Meter with Accessories Supplied 1 2 HP 438A 1 2 Specifications 1 3 Safety Considerations 1 4 Instruments Covered by this Manual 1 5 Manual Changes Supplement General information Instrument specifications are listed in Table 1 1 These specifications are the performance standards or limits against which the instrument may be tested Supplemental characteristics are listed in Table 1 2 Supplemental characteristics are not warranted specifications but are typical characteristics included as additional information for the user This product is a Safety Class I instrument that is one provided with a protective earth terminal The power meter and all related documentation must be reviewed for familiarization with safety markings and instructions before operation Refer to the Safety Considerations page found at the beginning of this manual for a summary of the safety information Safety information for installation performance testing adjustment and service will be found in appropriate places throughout this manual Attached to the rear panel of the instrument is a serial number plate The serial number is in the form 0000A00000 and 0000U00000 The first four digits and the letter con
315. ure 8 8 Ramp End Waveform Procedure two Connect the range calibrator to the power meter using the HP 11730A power sensor cable Set up the controls to use the range calibrator as a controlled source 8 25 Service Sheet BD1 8 26 HP 438A FUNCTION is danas eis es eR ted STANDBY POLARITY monier io a Vr ERE DORMIT EE TL NORMAL RANGE rd dat cA OE Y Open V S d ERRAT UP rS RU 1mW BINE oaa ueque Bad ed USt dat Rd uc ni eee eed ON 1 Set the power meter control The normal indications are 2 The display should indicate MBA amp MATT micro W 3 Change the range calibrator control setting FUNCION ias enee vere avai CALIBRATE 4 Set the power meter controls Press CAL ADJ E SET A 190 and ENTER The minus sign is needed when an external power reference source is used The display should read 1 888 3 MATT mW and follow the range calibrator as the range is changed Abnorma Indication If an abnormal indication occurs 1 Channel A or channel B problems can be narrowed down by connecting the power sensor to the opposite channel and observing the results 2 The connecting cable from the front panel A or B connector to channel A or B on the amplifier can also be switched at the point where it connects to the A4 Input Amplifier Assembly This indicates a problem with a cable or with the input amplifier analog circuitry Refer to troubleshoot BD3 82 8 22 8 weibeig 20 g E1340 6 8 81NGI4 Laa
316. us Byte s RQS bit true see Table 3 6 When the RQS bit is true the SRQ bus line is also true The Service Request Mask is set by the program code 1 followed by an 8 bit byte a Data message The value of the byte is determined by summing the weight of each bit to be checked Each bit if true enables the corresponding condition to set the RQS bit true At turn on the Service Request Mask is cleared that is set to 0 Sending the Service Request Mask Value a Data Message After receiving an RV program code Service Request Mask value and when addressed to talk the Power Meter will send a single binary word 8 bits that describes the present state of the mask The bit pattern can be interpreted with the information in Table 3 6 This byte is sent with the bus EOI line true thus terminating the message HP 438A le s Weight RQS Bit Require Service Condition Operation 3 30 Sending the Status Byte Message After receiving a Serial Poll Enable SPE bus command and when addressed to talk the power meter sends the Status Byte message The Status Byte message consists of one 8 bit byte in which five of the bits are set according to the conditions described under Sending the Require Service Message The bit pattern of the Status Byte is shown in Table 3 6 Note that bits 6 and 8 are always set to 0 The remaining bit is the RQS bit If one or more of the five conditions described above is bot
317. ut ports in parallel with front panel inputs and a second 50 MHz Reference Oscillator G2 with its output on the rear panel All of the operating functions of the Amplifier Section are enabled and sequenced by the control signals from the CPU As required the correct sensor input is applied through channel A or B of the A4 Input Amplifier Assembly to the A5 Main Amplifier Assembly The primary function of the main amplifier is to selectively attenuate amplify filter and digitize the input signal under the direction of the CPU This allows the CPU to obtain the necessary data to compute and display the measurement results 8 19 Service Sheet BD1 8 20 HP 438A In addition to the primary signal flow other signals such as the power sensor resistor signal can be applied through the multiplexer and digitized The CPU uses the results of these measurements to determine if any changes or corrections are required The 50 MHz Reference Oscillator G1 is enabled by the CPU when either the or entry mode calibration key is pressed The oscillator is turned off manually if the key is pressed again or automatically at the end of the calibration cycle If the optional rear panel reference oscillator is installed both oscillators are turned on and off at the same time Fach oscillator provides an independent 1 mW 50 MHz output that can be used for calibration or as a signal source when troubleshooting Power Supply Section Xy 1 gt The
318. x tuning tool JFD Model No 5284 HP part number 8710 1010 For other adjustments an ordinary small screwdriver is sufficient No matter which tool is used never force any adjustment control against its stops This is especially critical when adjusting variable inductors or capacitors Heat Staking Tool The front panel pushbutton switches have small plastic pins that protrude through the printed circuit board and the pins are then flattened with a heated tool that softens the plastic The heat staking tool is a standard soldering iron with a special tip attached 8 11 Assembly Locations Printed circuit board assemblies are numbered sequentially from front to back For example Al is part of the front panel assembly 8 12 Parts and Cable Locations The locations of individual components on the printed circuit boards and other assemblies are shown adjacent to the schematic diagrams on the appropriate Service Sheet The complete reference designator consists of the assembly designator plus the part designator For example AGRO is resistor R9 on the A6 assembly For specific component descriptions and ordering information refer to Table 6 3 Replaceable Parts Chassis frame and other mechanical parts are identified in Figure 6 1 through Figure 6 3 Mechanical parts have reference designators that begin with the letters MP Mechanical parts such as screws washers and nuts are listed in the replaceable parts list To find the part num
319. ya NIA KOLLGA ENZ S gx on 26 300NY KIIA ROLIDE ciay LATE 90 828F tcr0 9281 NOiiYNSIS3 3JN38343U SHZSHNK LUYS INIBITI Q31YH931NI ONY UDISTSNYHI BYX gr Idi RU B 8 t3 v ts w SNGILYNOSIS30 3083483336 GC NOIJO3S NI NO LYNHOJNE DNELYONOWE IYA Opz 00Z JO J9Y TUA NIT Y u04 A052 Y SLE QYA 923 003 JO 39Y150 INIT Y BOF YO SI bd 30 307WA CE SALON MYHSYIO OILYMEHSS B03 2 8 3718 i OL H343H 7 S310N 6 193uS IMAS RZESZ YZESZ Lekt BNE VETA m m m m ne tHE S Hh Heinsi ee NA mme Reeg EU Isi DX 8 4 H 1 1 H H 1 ve du NEOLYD ONI NO OBLOB da ent YOMO H J cnn 1 AS NJUN A HE R W PY m E I A mM i re St 1 D H H 1 pic 8 1 Li t t D itty LH Jooga su HOLYJIGNI o_NO1LOJLOWHd Woner 1NIBHND d j d DE EE V uum ZZ 60008 82500 aie oo wwa 5 ete Be OP eT BY DK ECG HOLY 10938 eu set ee CN m 6Y Od p em STEN e t NUT i ua ofa 9 d dSUJAG aroga A j snos Noam JOG HQ AS fm AVINSSSY Naa HOLYINDSSH ASt AV 1dS Gw 80508 8759 JI4tL034 av GHS o 1 1 1 r 1 t H t t H H H t H 5 1 H H H H 1 1 1 1 t H r t t H t H a 3 4 1

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