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1. Circuit Desig Code Desig 18 Code i Desig Code 001 6 27 c611 1 2 CR207 Y 23 C002 G 27 C612 1 14 CR208 5 23 6003 K 26 c 701 CR209 y 2 COOL l 26 C702 2 15 CR210 23 C006 29 c801 10 CR212 0 42 C007 0 29 C802 N 8 6008 T 26 c803 Q 9 CR215 18 009 U 27 R 9 CR601 J 8 805 N 7 CR602 J 5 C101 6 26 806 N 5 C102 H 22 6807 R 8 CR701 P 14 C103 F 18 808 R 5 CR702 13 C104 G 18 CR703 2713 C105 H 18 C810 2 CR704 Y 13 C106 K 23 C811 U 7 CR705 108 1 21 813 7 8802 V 5 C109 K 19 818 3 CR803 2 C110 M 24 C815 X 10 CR801 b 2 Cb P 26 c816 xes C112 Q 22 817 Y 5 CR301 Na C113 0 22 c818 3 CR902 92 C115 Q 20 819 Z 6 CR903 0 42 C115 T 20 6820 f 5 9 NS m 23 821 d CR905 NS m 2h 6201 19 05601 30 202 23 5901 11 C203 a 20 6902 0 19 F601 6 16 c204 21 C903 fed i C205 a 18 C901 ji 9 4 J201 b 30 C206 17 C905 g 12 C207 c 18 C906 9 7 U 6 C208 d 17 C907 h 6 C209 21 C908 4 3 K901 K 9 C210 f 2h C909 NS k 26 p101 e 25 C910 NS h 24 P601 H 31 C601 B 28 P602 8 16 C602 B 26 CROO J 26 P603 K 7 C603 D 25 CROO2 L 26 P604 K 4 C604 L 15 CROO3 W 30 P605 g 31 C605 F 13 CR201 U 19 P606 k 31 C606 J 13 CR202 17 C607 J 11 CR203 19 P901 1 C608 L 10 CR20
2. OUT 4 19 2V OUT 2 29 5 UNREG 19 2V OUT 5 LO BAT LED 440 3 14 5v 5 jUNREG COMMON J402 0450 CR403 R405 0403 CR409 3 3 9 HIGHEST SCHEMATIC DESIGNATIONS USED CR4I0 DO MOT RC ALP Trad Ona veg I KEITMULRY iN weraununve CU PVPLANO G 405 8404 a O O NOTES ALL RESISTOR VALUES ARE IN OHMS UNLESS MARKED OTHERWISE 76 8K aw DENOTES POWER SUPPLY COMMON BATTERY PACK Luisa 05 23 ON 4 215 7754 SCHEMATIC PC 404 26758 F G CORIS 1 ast gt 349202 cal EE 2241 P IM erae m er 7 rv arre im Susi nS Yom tI PRO W Dee qwe SV ml i 53108 4 ha Quem iu Se oe E TERRE ID emi ii _ RRAR 5058 erg i Sots in 14 I2 i reu gt Rj ETE deia a _ 3 1 0252 Eum 3
3. Sm mm des am WS am Sho m qa li ub a a USE AND TRIGGER MODE DISABL FIGURE o mo SY T 2 ON RANGE sr CONV ON HANGE TRIGGER MODE DISABLED AUTORANGE O MODE AY TORANGED STROBE ele FIRST INPUT DATA AND CONTROL UPDATE AFTER QUIPUT DATA UPDATE 8 5 TYP REMOTE CONTROL 817 ACCEPTED 3 LUNY N RANCE 4 2 MD CUNY ON 1 5T 5 7 717 ON 3005v RANGE TOGETHER ooo 436 FLAG RESET TRIGGER MODE DISABLE LAST CONY 9 PRODUCED AN e oe QUIPUT DATA UPDATE A RUTUHANGEU STAYS LOW INDICATING UNIT STL AUTORANGING 58 L LUNY QN FINAL HANGE TO ALLOW FOR SETTLING TIME L DATA NOW VALID SETTLED ONE EXTRA L J K L 54 SEE PAGE 1 FOR NOTES ro 2 8 CL 242 gt ofa D POWER SUPPLY 7 TO gt SECTIONS Twas PAGE eo 15 SILTERED 5 10 1 3244
4. 39435 2067 w243 1300 803 0350 LON SNOUVNOIS 243455 74351 SNOUVNOIS3Q 3 viaHOs 15 3HOM TOUINOD 310N30 3532012 310N30 S310830 29 Gava 55380 SQV JOGOIN NI SINWA TV X ISIMM3INLO INVA 551097 SAHO Ni zuv 307V 8 15 5 TIY 93404 4 i ze 20 v 00 TOv 20 905 i 1 1 4 1 I 1 I n 1 H e 062282 Le EST IA rw os md asi 117 La VJix3 IMO 50374135 QUE QWA MON 71 28172138 HOS MOTY 5NISNYHOITY 17415 fy 01 39095 TANTS MO ANDI NI lt 03960094 AMOJ 1541 Bind 0162081 Sav 039NvnOinv 309 0 JANYUCL AW i J 174 10 3009 8198 111534 Wis QIONWNOI Y vivO 104100 7 Tt ie ete 8329213901 03123NM405 LV WHY s Ey eun 300n ne n 380815 039 Dy oe 03104540 300m 8319144 NO ANOJ OH 2222 _ __ _ JINYM NO ANDY JS _ O AA NO ANOD 15 1 NO ARG l
5. 6 04 CB 100 102 CB 100 104 CB 682 105 CEA T0 5 49k 7 68 CB 106 1034 CEA TO 100 70 1 5 0 4 22 0 1 15 49 9 CB 150 102 286566 CEA TO 280 CEA T0 280 72PMR MFF 1 8 6 336k 150 121 10 CB 121 104 0 200 223 10 CR 25 43kK CB 223 104 CB 223 104 200 SERIES Schematic 28656 5 RR 0 589 Var lt 375 R 1 1 84 MtF 7 50 0 1 1 8w 7 50 0 8 1 8 28 0 0 5 1 8W Part of 280408 Part of 280408 20 Potentiometer 0 5W 500 0 Potentiometer 0 5W Thin Film Resistor Network 23 2 RR 14 1 8W MtF 332 0 1 1 8W DLE DLE DLE DLE BEC IRC BEC BEC 1 IRC 72 5 CEA TO 371 MFF 1 8 7 50K MFF 1 8 7 50K MFF 1 8 28 0K 72PMR 20K 72PMR 500 23 2 1 8 332 Digital Multimeter Models 172 173 Keithley Part No R 88 6 04K TF 47 R 76 10K R 76 18K R 76 6 8R R 88 5 H9K 88 7 68 20 20 20 20 20 20 CO 1 gt R 88 280 R 88 280 97 1 R 168 6 336K R 88 150K R 76 470 R 76 470 R 88 200K TF 49 TF 46 R 76 22K R 248 43K R 76 22K R 76 22K 97 5 88 374 R 168 7 SOR R 168 7 50K R 246 28 0K RP 97 20R RP 97 500 TF 56 R 88 23 2K R 168 332K INSTRUCTION MANUAL Digit
6. fa je 4 Br 2 oe 5 222 Die Cmm a J rm 2655 NOISYFANDD N ana a 1 e 1 5 E 5 VRAT VP gas Dem Sia Ww 13002 snam Prva ovo 77 vv mes Y X 2 aii ES 10 22 22 soq ko san 30054 a rasa 55 en re res u ONIN UDQUa JONYH maya Marcel wea AD oli 200m E NE mi E 7 6 ies NO 300014 9e Jii vie AN _ wu TETES 3808 8 28 MN ges rp Wess 1 INN Ovi 8 viva gt 28248E T q 1 9 g gt REMOTE CONTROL 51 5 ui P MISSED PRIOR TO Guittul DATA UPDATE LAST INPUT CONTROL UPDATE TEA bil ETP AL REMOTE BIT TRAN au SEL FLAG dESETS CONTROL Bil INDICATING REMOTE MAS NOT ACCEPTEO BIT JUST MISSED rr m m im ue m EE
7. Interlock Interlock a INSTRUCTION MANUAL THEORY OF OPERATION Digital Multimeter Models 172 173 TABLE 5 1 Continued Summary Of Pushbutton Switching Switch Style Setting Remarks NOTE If DC and R pushbuttons are OUT simultan eously no function will be selected the i input terminals mill be open circuited and the DMM will display 0 The displayed read i ing is meaningless Can be depressed and held IN simultaneously V A Push Push In DMM is set to measure current either AC or DC Not functional when set to 2 i V A Push Push Out DMM is set to measure voltage either or DC I HI LO gt Push Push in DMM is set to low ohms range 07 Push Push Qut DMM is set to high ohms range Only functional when set to 0 in DMM is set for H WIRE ohms measurements Upper pair of terminals are used for volt age sensing Lower pair of terminals are used for ohms source Lower pair of ter minals are useable only in 4 WIRE 2 mode and are open circuited for all other cond itions 2 WIRE 4 WIREz x Push Push Out DMM is set for conventional 2 ohms measurements Upper pair of Terminals 2 WIRE 4 WIRE Push Push must be used Lower pair of terminals are open circuited TABLE 5 2 Gain Chart For AC DC Voltage RANGE CONTROL LINES RANGE ATTENUATION A D GAIN RL H AB 5 3
8. 5 t REFERENCE wu s usa pd 511 i 22 CURRENT SOURCE i es L ase P 9 FROM Clamp i i oua PAGE 1 ZCNE m3 coo 9 D H i AS 8 v t ense 1 aduzo wool Q 2 anoc 5 6 i 7 3 e 1 5v i v FROM ROK POWER 1 77 ANE pase dane PAGE 3 D 39 i lt FROM l 5 5 V DIGITAL SECTION 1 15 29 e PAGE 3 ZONE X 1 Mey PAGE 3 43 AUTO CAL D OSCILLATOR STORAGE A D CONVERTER SECTION Der oem R SATHI Kute INSTRUMENTS LEVEL AMO 73 SECTION 3 ZONE 14 Uerum me ee prem 00000102 28656E em I exez cr 4 LU eon eS i I i 2 ne ONE Ar 3 A Mp B gt Es cf Reis 5 E E 18322 4 e 2013 0094 UPN ATE Bon t m te az ez 3x 2 E
9. FIGURE 39 Waveform For A D Calibration i Adjust potentiometer 8201 AUTO ZERO 2 for a level of 10 0 21 during 2 period j Adjust potentiometer R217 AUTO ZERO A2 for a level of IV 0 2V during Az Period k Repeat steps h i and j until all levels are within IV 0 2V simultaneously l Depress HI LO ohms Set to LO m Release 2 WIRE 4 WIRE Set to 2 WIRE Set range to 6 l Adjust potentiometer R707 9 BIAS for a level of 1 20 2V during AUTO ZERO and AUTO ZERO 2 periods 2 Adjust potentiometer R208 0 3V Ref fora level of IV 20 2V during AUTO CAL ACAL period 3 Repeat steps and 2 until both conditions are met simultaneously 2 Zero and Offset Current Adjustments a Set the DMM to 300 mV DC ranqe b Place a short across INPUT HI and LO c Record the reading on the DMM d Remove the short and connect the Test Circuit H across input and LO e Adjust variable capacitor C203 Input Current to obtain the same reading as in step c to within 2 digits f Remove the Test Circuit and replace the short g Set the DMM to 2 WIRE and LO ohms CC INSTRUCTION MANUAL Digital Multimeter Models 172 173 MAINTENANCE h Set range to 3 i Adjust variable capacitor C205 OHMS zero for a zero reading on the DMM j Set the DMM to 300mV DC k Adjust potentiometer R904 300 mV Zero for a zero reading on the DMM 1 Verify that during the 200 ms INTEG
10. 2 aped kasa a 5 lt EST 5 TuS pions 4 gt 5 m RN ris gt I OLEA E LA DATA NEA 9 pet a A u a o wages vease _ i 2 ira Itn 2291 50 vores T E we Nol La 4 LY TY et 67 23 35 gt a sa c D how x i ARE H sl vm RS oR EX 4 i ER RESISTOR vai UES Qui i OV 8 Cu M gt UNLESS MARKED OTHERWISE F Ls 22 i 5 3 CENE i 2 ALL CAPACITOR VALUES ARE 225 67 MICROFADADS UNLESS MARKED y T PS E OTHERWISE a6 EICCEAMADS I mM i 3 nes e H 3 ELAGNOTES SAME gt i _ 14 77 weuecps ABE CONNEC TES EAT NEUE by 15245 a 4 DEMCTES OPTIONAL CUSTOMER Gas ai i Zt i 5 INSTALLED UP RESSSTCRS P p gt i F c Y c0 Liga 1 e SEE INSTRUCTION MANUAL 9 5 924 uel i i UA BUSS POWER d gt te Fu i i tet JUMPER SELECTION GROUND S COE _ 8 SEE INSTRUCTION
11. v SOURCE DIGITAL SECTION 6 Dd 7 PAGE 3 ZONE 6 6 4906 SS ACTIVE FILTER FROM 591 DIGITAL SECT ON SELF CHECK PAGE 3 ZONE WE it 290v PAGE 3 ZONE A2 o 7 42 15 9 SIGITAL SECTION FASE 3 ZONE 5 FROM 8707 10K R33 DIGITAL SECTION BIAS 200K 4 92 PAGE 3 ZONE 5 R702 30v T ZERO 9 2305 o SIGNAL CONOITIONING SECTION 5 f t NM EO EN ATTENUATOR 8 SAMPLE 2 SwifCH 2 06 T n nim a ee HMS we RRENT 9 REFERENCE RELAY SOURCE DRIVERS OHMS CONVERTER r 5020 2 3244 395982 Fac TORY SELECTED MATCHED SET 70 Gems 3 3244 PAGE 1 ZONE 45 REF FROM PAGE ms TO 5 REF 33444V PAGE 1 ZONE REF X U REFERENCE 332 82 33 100 29v CAL 7 SUPPLY INPUT MUX FROM PAGE 1 R226 49862 D C207 D R2248 T vv j mom 1 ZONE CS 1 i 1 61 i 230 SOK 1 d FROM R230F DIGITAL SECTION oor i i PAGE 3 ZONE 23 8c ABSORBER 2 TRANSIENT _ lt 203 La INPUT CURRENT 0 C204 4 3 3of T
12. EORY OF OPERATION INSTRUCTION MANUAL Digital Multimeter Models 172 173 b DC Volts Input Circuit 1 DC Volts input circuitry is used to attenuate the input if necessary and filter cut unwanted AC signals A combination of attenuation and A D converter gains allows five ranges of DC Volts See Table 5 20n page 5 3 2 There is no attenuation on the 300 m V and 3 V ranges Relay K901 Figure 23 is nown in this position The attenuator is bypassed which allows the input resistance of qreater than 103 ohms 3 Above 3 volts relay K901 switches in the attenuator There are two attentuation levels 2100 with FET switch 0901 off and 1000 with 0901 on 0901 assures AC attenuation of at least 1000 so that normal mode rejection is maintained RL line controls 901 and line controls 0901 See table 5 2 4 Overload protection is assured by the clamp circuit R929 and C907 If a large oltage is applied on the 300 m V 3 V ranges the clamp limits the voltage to 5 V fter R929 R929 absorbs the input voltage As the relay switches in the attenuator L907 keeps the relay voltage from becoming large enough to cause arcing or plazma effects The clamp is essentially an open circuit between 5 Volts Filtering Circuit The OC filter is used in front of the A D Converter on all functions lt is a 3 ole active filter with 3 db frequency of 5Hz and a settling time of less than 300 ms o within 0 01 lt requires an input resista
13. F G ost 2211 73008 5 reem 30075 vas tem RC Duis n owe s 591 2 53108 su ent Tu l ET E pem ee ICT es ma que RRS qap vH H Sie ET Ivas alae w vivo BOU RAND gt x Impr TENE 1 1 poem dieses Tae 4 wee somit Z T _ MERS 2 4 Diti 2 MAL I sine 4 w ee ee M saa i ls A9 two 7 EI i a ti aje 5j 1 m My coss fp cem Tr A ee WM 5 1 a 4 Ld t 15 iY e SE 5 v 30 Be duem 281 re A ee quen ME LAS LL ipii LZ 192 36 PN Sa NES Dc ep rece 145 a Jar t 165 _ LLULL ALL LL ULL Zo Lo Er Eee te 00 2212 ad TALL La La LI 24123 1 ao eei e d A Lad LJ ULL LE D Dada di de LL LE ALL dina e oria dada 4 1210 ow
14. OC dan Ed ss Mai i i i k 1 TO ee j 5 i amp CENTIES MOTEL 1722 a Ct SC mE MAT th e M CBCUIT COMMON i n 5 as 1 2 NO 2507 ij 7 DEMOTES CHASSIS CONNECTION EM la i i m i i i TAA i UNUSED GATES DTMBESMILI uD at iom i i e a Co x Ei EN Qv 1 i 21 EA 1 Dr ee st w V ES t Re m NE i lt Ue 5 1 t 22 pipa 118 7 20 s i i i i 8 DOwN OAT 2 4 ES T i jl PUn EE p H I ew i 2 1 ures NC Ed amp 4 i j 7 2 M IE i i i i i 7 72 fj mares mim 2 04 i i i i i m SEE 416 5 5 E i 280195 b 21004 280 9 ne STROBE i _ _ 3 i us j m 5 gt FUNCTION STROBE j PESE ES E E L r POLARITY ST
15. ZERG 2203 204 THOU 17 DIGITAL SEZTION PAGE 3 ZONE 12 19 AMPLIFIER 82240 DIGITAL SECTION PAGE 3 ZONE 2 2 20 STORAGE 1 2 po A gt 22240 326 27 4 29 8 52246 6 i 565 TROM P3 FROM 200 SECTION DIGITAL SECTION PAGE ZONE PAGE X ZONE K2 pees co 19 SWITCH di VOL TAG DRIVERS vot fAcE urs A D BUFFER INTEGRATOR 2 i DIGITAL SECTION CURRENT N _ COMPARATOR PAGE 5 rion SWITCH CiGiTaL SECTION PAGE 3 ZONE x2 ES 215 T L Sea Q8 Qua cmon Y 200K z aos R225 T 22 09 206 Soe 1 FROM A D BUFFER ZONE 08 t OM DIGITAL SECTION Pace 3 ZONE 43 AUTO ZERO STORAGE T 0022 SEE PAGE 3 FOR NOTES CAPACITOR N TP3O2 hg FROM DIGITAL SECTION PAGE 3 2OME 43 5 et 4 20 amp 2 8005 i 5 81 EM FON TC DIGITAL SECTION 3 ZONE 14 7 14 5 sy TSY 8 200 X 30 SECTION gt 6 4 i i i sv 15
16. 106M L 306 106 1 oub 2023 1095 094 09 1094 0950 29942 292 f oem eocun 2021 ozo 027 man 0 22 SOM 20 41 eno 106 2083 52 vos T rosa 500851 8065 4064 9351 LON SNOIIVNSIS3Q OLLVIN3HDS A B CD E FG H KL MN P QR S TUVWXYZ abcde fg h km n pr AP CR CR R FIGURE 43 Component Layout PC 407 See Table 7 2 REV D 7 3
17. 71015 BOOKS za 30815 39045 exe ie 5 1604 5 3808 15 00d MOLINA 5508 40 Ind b i s som 1 1 9 320642 neva 325 7 0 8015163 441 7704 637715 2 Spa 11 43aQi 62 TYWOlLdO 34040 5 7 x9 vto 531399 o 5 Minted 220 73004 53 0 30 9 m 02086 MQi23wxCo Sissyno 53 0830497 Qu r ms 3 o 50 1203 4 14 35ima puc 9 Q3 evM 553740 0 HA 2 i me SINIYA Cw Z is 5 S 051n M 0 Q3xuvM 553790 ET x9 SPG 3HY 53 HOLSIS3e TTY 7 Fine SS 36 16 53 0 muas 5 5 air V315 53u 1445 x9 8 80nn Aue 71825 5 x9 3200 9 5 3 6 14 8 14 c x9 IN E 1 xj x9 NZOny 1012 x 35044 x NSQUU 7 i 1 2 3 x9 asonu 6 x9 QvOnas 3 v 9 32008 T v A Sonn uin 57 X AN e s n Na az AN 2 i Ei t dE Asona 9 350 Q 1 ponn AS O O 2 om 9 z 2 onu 012 6 FE
18. RCA 700 SERIES Schematic Operational Amplifier 8 pin DIP NAT 8 pin To 5Case NAT Mfr Desig 28656E CA3086 91571 91574 CDAOASAE NES55V 28656E LM308PA 28656E CA3086 LHOO42CH 274040 557445168 26758C U9T7741393 274780 LM308 08028 28656E LM308PA LHOO42CH INSTRUCTION MANUAL Digital Multimeter Models 172 173 Keithley Part No 16 53 1c 144 1c 144 1C 106 10 71 IC 99 51 5 151 4 280903 IC 132 16 127 1C 42 CB INSTRUCTION MANUAL REPLACEABLE PARTS Digital Multimeter Models 172 173 INTEGRATED CIRCUITS U Circuit Mfr Mfr Keithley Desig Description Code Desig Part No 800 SERIES Schematic 286566 801 Operational Amplifier 8 DIP NAT LM301AN C 24 U802 Operational Amplifier 8 DIP NAT LM301AN 1 2 U803 Analog Amplifier 8 pin DIP NAT LF356H 1 152 8900 SERIES Schematic 286568 0901 Linear 8 pin NAT LM308PA 1 99 81000 SERIES Schematic 27902 01001 Quad 2 Input AND 18 DIP RCA CD408 IBE IC 138 01002 Quad 2 Input AND lA pin DIP RCA CD408 IBE IC 138 41003 Quad 2 input 14 DIP RCA CO4OBIBE 16 138 01004 Quad 2 Input AND 18 DIP RCA CD4081BE 138 01005 Quad 2 Input AND 14 DIP RCA CD4081BE 1 138 0
19. XIO GAIN R209 429 000 to 429 001 1 ADJ R901 1000 0 to 1000 1 DC Calibrator output should be adjusted to compensate for dc offset voltage Display should flash alternately between readings 6 16 cc INSTRUCTION MANUAL MAINTENANCE Digital Multimeter Models 172 173 AC Voltage Calibration Depress AC Release V A Depress AUTO MAN Connect the AC Calibrator to the input terminals Set the instrument to the range given in Table 6 12 Set the AC Calibrator for the voltage and frequency given in Table 6 12 Adjust the Control given in Table 6 12 to achieve the display specified TABLE 6 12 Ful Ranae AC Calibration Display Requi red f e M 12 13 15 Oo CO Dw Fw 010 00 mV 1 KHz ADJ R809 to 010 01 mV 1 0000 1 RHz ADJ R803 to 1 0001 100 00 1 KHz ADJ R816 to 100 01 1000 0 20 KHz ADJ C820 C821 to 1000 1 1 0000 20 KHz ADJ C819 to 1 0001 100 00 20 KHz ADJ C817 to 100 01 Repeat these adjustments until both displays are achieved These adjustments are interactive V V 1000 0 KHz ADJ R817 to 1000 1 V V V Ohms Calibration Use test leads supplied with Model 1725 Maintenance Kit Depress 0 Release HI LO Release 2 WIRE 4 WIRE Release AUTO MAN Set the instrument to 30 range Connect a shielded 10 megohm resistor to the upper set of terminals Adjust the 10 MQ ADJ R705 for a reading of 10 000 MQ Depress HI LO
20. 1 235 TVLI9IQ CEE ob x PE Pes REL 493119 P iv m 0 3 10340 23 y 53744 MRS SN VM 211 3 25 NITE e 338 5 21 wim SILYA NEAT Be 2c 2022 geet NORROD BOs 2 lt 839 9 i o oman 63631 4862 I 285492 2 WOVE AS 2431198 9241 335 um A 2096 531Y I 4 11 men m 1 1 i4341V8 la AN i 1 ONINO LINDID L VITII III i 1 1 27 7093 Ta 9099 T 1027 ie I 1992 3012342 AV ISI 5 2 i 03251 lino TIHS 237 k 1 ATddNS AS mCi Ss 3NOZ Z 35vd i m BOLVSVGMCI OL NOIL SOS AL NI SI 1 I som 2 2 3998 035NvH2u3i 925 ONY 37 4402 2303 EN AE xzz cle a SOM QAYIT NOliveidO 01 Ody 7 u3 8sOSGv Zw La 9 hi 9 5 LAr 2 39Yd 5 v lEs 35 40 5 142 0109 Oi h i 1 5094 qu 2099 j 9 9 i 32v W 5 Ri Zx 3 zr 3NCZ
21. rot aw MICE 0006 Fost libi ABD Si FIGURE 4 ALLOWS MANA RAC INT Et USING VP amp Ph PUSHY 1108 NAR EACH PL ab LAL ES Dirt DOWNKAALL MUO TART PUSH CAU MS UPRARGE STRUT MARUR 6 DB 1279 PATA Mes ia OPj RATES ku AS LA 1 113728 Uu LANGE DISCS ANGE 0278 3 TR UFL INS RT 008 CAUM 1128 P OBA Lak BATH RY b CAU ERAT WC Cus S Rub hi VO RAL Sy I D VO KL ima I P W CACSE dade A PU Jed 91 APPR AA NMS lf AR ue Tnt lut BA Sht pr Ups Pare ey n Bottom View Showing Line GENERAL INFORMATION GENERAL INFORMATION INSTRUCTION MANUAL Digital Multimeter 172 173 CONDENSED OPERATING INSTRUCTIONS FUNCTION RANGE ACCURACY INPUT MAX ALLOW SELECTION BELOW IMPEDANCE INPUT DC IN 2 299 99my 001 10 RBELOW3v 600v CONT 9 V A 0UT TO 1200 0Y 1067 107QABOVE 3v 12007 PEAK 3 SEC 50 54 2 20615 REAR PANEL FUSE 01 201615 TOOK 0 15 1000 RMS 6016115 550 DISPLAY BLINKS 300v Arre REAR FUSE Pepi RIN 299 995 0 03 10 300
22. 2 i K 2 7 Cy ATL ae TU UPDATE be COST UA a acre dO GURE 2 Sura uv 7 7 NE OUTPUT E pyet An ME e MM 5 ae SR atomaren ae OUTPUT 3704 ia ASC Ia ar 22 4 Ex t i i kc As wA T Erkost M n Me 21005387 5 4005 LOS Dm umane tane fe samy Beni sec OLD Bane t 2 d OUTPUT bata F t ra 5 e 41 5 tA pond Acto OE 7 1 352458 pea EN 4 EN x TE rw cepe 7 7 Y ner nA IA NOTES ML fup Um 684 acuit lt 8 5 a E i bc pamm jer Le wing 5 9 4 gt DI e OMe mn ws ear que net Perret
23. INTEGRATED CIRCUITS U Circuit Mfr Mfr Keithley Desig Description Code Desig Part No 81100 SERIES Schematic 28019 U1101 Hex Inverters Open Collector Output TEXAS 5 781505 10 141 01102 Hex Inverters Open Collector Output TEXAS SN7LHLSOSN IC 11 U1103 Hex Inverters Open Collector Output TEXAS SN75LSOSN 10 141 01108 Positive NAND Gates and Inverters Totem pole outputs TEXAS SN74LSTAN 1 137 01105 Hex Inverters Open Collector TEXAS 5 781505 1 181 01106 Dual D Type Flip Flop 14 DIP RCA CD4013AE 1C 103 01107 Quad 2 Input l4 pin RCA CDHOOIAE IC 108 01108 COS MOS 8 Stage Static Shift Register 428004 48202248 ii 0402 AE IC 130 U1109 Quad 2 1 AND Mepin RCA CD4081BE IC 138 01110 COS MOS Dual 8 input NAND Gates RCA CD401 2 1 180 U1111 Six COS MOS Hex Inverter RCA CD4O69BE IC 139 VOLTAGE REGULATORS VR Circuit Mfr Keithley Desig Description Code Desig Part No 100 SERIES Schematic 28656E VR101 Zener 9 1V 2 2 2 40 s DIC 1N960B 02 55 VR102 Zener 6 2V 1 4W DIC 1 N827A 02 88 1200 SERIES Schematic 286568 VR201 Zener 6 2V 1 4W Part of matched set 280808 VR202 Zener 9V Part of matched set 280406 VR203 Zener 12V x cox ee ay DIC 18963 07 54 600 SERIES Schematic
24. IRC CEA T0 68 1K R 88 68 1K R807 5000 0 1 1 8W IRC 6 R 241 500 R808 10 1 amp Comp A B C8 106 10 R 76 10M R809 100 Potentiometer 0 5W BEC 72PMR 100K RP 97 100K R810 24 3 0 1 1 8 IRC CEA T0 24 3 R 88 24 3R 8811 15 8 KQ 1 1 8 IRC CEA TO 15 8K R 88 15 84 R812 500 0 1 1 8 IRC MAR 6 R 241 500 R813 3 3 10 1 4W Comp A B 8 332 10 R 76 3 3R ips 10522 of matched set part R 243 R816 500 2 Potentiometer O 5W 72PMR 500 97 500 R817 100 Q Potentiometer 0 5 BEC 72PMR 100 RP 97 100 i Part of matched set part R 243 R820 MA 10 1 4 Comp CB 105 103 R 76 1M 900 SERIES Schematic 28656 R901 100 9 Potentiometer 0 5W BEC 72PMR 100 RP 97 100 R902 2 7 0 102 1 4W Comp A B CB 2R7 10 R 76 2 7 R903 1 1 8W IRC 0 1 R 88 1M R904 200 Potentiometer 0 5W BEC 72PMR 200K RP 97 200K R905 2 7 0 102 1 4W Comp A B CB 2R7 10 R 76 2 7 R906 1 MQ 10 1 4 Comp 105 10 R 76 1M R907 NOT USED R908 NOT USED R909 10 91K2 Part of matched set R 259 R910 99 75K2 Part of matched set R 259 BA 7 2 REPLACEABLE PARTS RESISTORS R Circuit Mfr Mfr Nesig Description Code Desig 900 SERIES Cont
25. Models 172 173 Instruction Manual Contains Operating and Servicing Calibration Information for Models 172 173 1722 and 1728 Publication Date October 1977 Reithley Instruments Inc Instrument Division Cleveland Ohio U S A Document Number 28262 da HASTET INSTRUCTION MANUAL Digital Multimeter Models 172 173 Contains Operating and Servicing Calibration Information For Models 172 173 1722 and 1728 REITH LAY INSTRUMENTS INSTRUCTION MANUAL Digital Multimeter Models 172 173 COPYRIGHT 1976 KEITHLEY INSTRUMENTS INC THIRD PRINTING OCT 1977 CLEVELAND OHIO U S A DOCUMENT NO 28262 REVISION CODE CC CONTENTS Section EN CONTENTS 106 4 ILLUSTRATIONS oue oe c3 24 SPECIFICATIONS DD 201 1 GENERAL INFORMATION i i a Ue ws Q Q GQ 1 1 INTRODUCTION FEATURES WARRANTY INFORMATION CHANGE NOTICE OPTIONAL MODEL 1728 RECHARGEABLE BATTERY OPTIONAL MODEL 1722 DIGITAL INTERFACE TIAL PREPARATION NI GENERAL se do 72 INSPECTION 3 PREPARATION FOR USE da ke PERATING INSTRUCTIONS el GENERAL 2 HOW TO SELECT POWER 3 HOW TO SELECT FUNCTION 4 HOW TO SELECT RANGE 5 HOW TO MEASURE VOLTAGE 6 HOW TO MEASURE CURRENT
26. OPERATING INSTRUCTIONS SECTION 3 OPERATING INSTRUCTIONS 3 1 GENERAL This section provides information needed to operate the Model 172 173 for measurement of voltage current and resistance 3 2 HOW TO SELECT POWER The Model 172 173 may be powered from line voltage or re chargeable nickel cadmium batteries when the Model 1728 is installed The Model 172 173 has a built in line voltage power supply and power cord NOTE The accessory Model 1728 Rechargeable Battery Pack may be ordered at the time of purchase of the Model 172 173 or may be purchased and field installed at a later time if so desired The Model 1728 features plug in wiring and as a result no modifications need to be made to the Model 72 173 chassis a How to Operate from Line Power The Model 172 173 can be powered from line volt age over four ranges from a minimum of 90 V rms to a maximum of 250 V rms Table 3 1 summarizes the line voltages permitted Set the internal line voltage switch to either 117V or 234V 2 Plug the line cord into source of line power 3 Depress LINE pushbutton NOTE Power on will be indicated by a lighted display with one or more digits and mea surement unit showing TABLE 3 1 How to Set Line Voltage Range Switch Transformer Desired 601 Modification 90 105 117 Yes For these ranges the 105 125V 117V No leads must be rewired 195 210V 234V Yes 210 250V 234V No b How to Operate from Battery Power
27. 1 digit g Current Calibration Model 173 only ls OO Vn h Depress DC Depress V A Depress AUTO MAN Set the Model 173 to the 3 ampere range Connect the Current Source G to the Model 173 Adjust the 1 A ADJ R512 for a reading of 1 0000 A Set the Model 173 to the 300 mA range Connect the Current Source to the Model 173 Set the Current Source for A for 100 00 mA Adjust 100 mA ADJ R509 for a reading of 100 00 mA Set the Current Source for 10 00 mA Adjust 10 mA ADJ R506 for a reading of 10 000 mA Current Calibration For Model 172 adjustments can be made Primary component which determines accuracy is resistor R514 10 0 1 10W VM AB INSTRUCTION MANUAL MAINTENANCE Digital Multimeter Models 172 173 6 5 TROUBLESHOOTING AND REPAIR An understanding of basic analog and digital circuit fundamentals is needed to troubleshoot and repair the Model 172 173 It is strongly recommended that the user review the Theory of Operation Section 5 and the Adjustment Calibration procedure paragraph 6 4 before any attempt is made to repair the Model 172 173 a Troubleshooting Hints Table 6 13 describes the Symptoms and Probable Faulty Component for a variety of possible malfunctions lt is beyond the scope of this Instruction Manual to list all possible symptoms Therefore the Keithley represenative in your area should be contacted in the event repair is needed For In
28. 1000V rms 1200V peak 1000V rms 1200V 1000V rms 1200V peak 1000V rms 1200V peak 1000V rms 1200V peak a DC Voltage The Model 172 173 detects dc voltages from 10 microvolts digit to 1200 volts 1200 0 display The maximum display is 29999 When the display exceeds 29999 a 3 remains lighted but all other digits are blanked The display blinks above 1199 9 volts on the highest range l Set to DC Volts 2 Set to AUTO 3 Connect the Signal to be measured between and LO terminals The terminals are designed to accept banana style plugs Such as Keithley part no BG 5 or accessory test leads such as Model 1681 Clip On Test Leads 4 Observe the displayed digits polarity sign decimal point location and measure ment unit mV or V If no polarity sign is indicated a positive polarity is implied b AC Voltage The Model 172 173 detects ac voltages from 10 microvolts rms to 1000 volts 1000 0 display The maximum display is 29999 When the display exceeds 29999 a 3 remains lighted but all other digits are blanked The display blinks above 999 9 volts on the highest range 1 Set to AC Volts The AC indicator should be lighted 2 Set to AUTO 3 Connect the signals to be measured between HI and LO terminals The terminals are designed to accept banana style plugs such as Keithley part no BG 5 or accessory test leads such as Model 1681 Clip On Test Leads h Observe the displayed digits dec
29. 2 1065 40 199 3HY 53821385 11 NOI123NNO2 5310930 47 3 AS 24 OY 255015 0832 0414 OL NOMISOd 180 MOLINS HShd 3H 5 Y Y 3 227 Tuv 12v1803 HILS MOLING HSNd 71 5 OT TNS 5310830 A 320642 5 320622 2113995 v 1 39v4831M 2241 335 zz ON 1235 u31H3ANO2 A V a poe S21v NOU335 3094 COIN 5310430 9 o MO 21 TVMOIS 19 5 0 5310830 535 U3ANGO Q Y A 031234N02 anay Ton anos WOmmQ2 514405 d3mOd S310N3Q lt gt 5 sia S310N9 14 NOIL235 9MINOLLIONCOO 3MOZ Z 3994 39v801 Ou3Z Qinv Qi WOiiviOw 31433012 5310930 AV 134 S310N30 A v E S 2 i M NOS 7 916 or 02 J 7081802 vwazin 5310030 A 2N3Misnr aw YN431N 5310 50 8 307 4 34 3SIMH3RLO 5537 wor SOVEVJORIM Wi 3uv SINAIA BOLIDVeY Tv 2 v t 207 t NO 031v201 S310430 o SmHOTGN Q3xuvm e 7 3 89 3 83780 8 S3NOZ Z Fwa 1081M02 T3Mvd 15084 310430 6 553 n SMHO SINA UOLSIS38 Tw 7 83A HQ MOLIMS OL Ase 8X INOZ 2 39 801 1612 0109 SILON
30. 24h 25 1 C 6 months 20 30 C 1 year 20 309 T of rdg 9 081 7 RESISTANCE ALLOWABLE INPUT 300mv 295 95 0 009 19 0013 1 0 015 1d 0007 018 1000M 1200 pear 3 v 2 9999 0 006 td 0 013 1d 003594 10 0 001 018 gt 1000 1200v 30 v 29 999 0 009 10 0013 18 0 015 10 0 0015 O 1c 1200 pear 300 V 299 95 C 009 1 0 01390 1d 0 015 1d 00015 0 ta t 1200 peas 3000 V 1200 0 0 009 10 0 013 Id 0 018 1d 0 0035 4010 1290V Overload on manua range to exceed 600 volis continuous or 1200 for 3 seconds NORMAL MODE REJECTION RATIO Greater than 8048 over 1 digit at 50 COMMON MODE REJECTION RATIO tk unbalence Greater thar 12048 amp 60Hz 7088 50Hz to 0 2 and 50 Hz to 10 2 ANALOG SETTLING TIME on range less than 0 3 second to within 0 01 ot reading AS AN AUTO MANUAL RANGING AC VOLTMETER TEMPERATURE ACCURACY COEFFICIENT READING 1 year 20 30 C FREQUENCY 07 20 and 30 55 RANGE MAXIMUM 2 rdg digits RANGE 2 9 of rdg digits CC 300mv 299 99 0 20 6477 50Hz to 20nHz 015 05 5 20998 0504 a Ed SOHz Yo 20kHz 018 050 MAXIMUM ALLOWABLE INPUT 1000V rms sine de 10 V Hz maximum 30 v 29 999 020 69 0Hz to 20kHz 015 050 ANALOG SETTLING TIME on range iess than 0 5 second to within 0 05 300 299 99 0 20 50 2 10 20kHz 01
31. 8 105 104 81009 3 9 10 1 4W Comp A B 392 104 41010 3 9 10 1 4W Comp A B 392 10 R101 154 0 1 1 8W IRC CEA TO 154 R1012 3 9 10 1 4W Comp 5 A B 392 10 81013 155 0 1 1 8W Mtf IRC 154 81014 158 Q 1 1 8W MtF IRC 0 154 81015 154 Q 14 1 8 IRC 154 81016 10 Q 10 1 4W Comp CB 100 102 INSTRUCTION MANUAL Digital Multimeter Models 172 173 Keithley Part No RP 97 500 R 88 1M RP 97 200K 1 1 t 0 9 0 ad Co MJ CO CO 1 W ml w x BA INSTRUCTION MANUAL REPLACEABLE PARTS Digital Multimeter Models 172 173 RESISTORS R Circuit Mfr Mfr Keithley Desig Description Code Desig Part No 11100 SERIES Schematic 28019E R1101 ll kR 1 250V A BW cx eoe IRC 11 R 88 11K 1102 Resistor Newwork Thick Film Rel TF 54 R1103 Resistor Network Thick Film K i TF 54 R1104 Resistor Network Thick Film Kel 54 81105 Resistor Network Thick Film TF 54 R1106 kB ES Wow ue ye Ge TRE 0 6 5 R 88 6 5K amp 1107 10 KQ es tae ARE 10 R 88 10K SWITCHES S Circuit Mfr Mfr Kei thley Desig Description Code Desig Part No 600 SE
32. ETT 6 1 O 47uF Sov Cer Film ERI 100 SERIES Schematic 28656E 0 1 uF 16V CerD CLB 0 1 pF 16V CerD BE 0 1 uF 16V CerD exo CLB 0 1 yF 16V CerD CLB 0 1 yF 16 CLB 0 022 uF 50V MPC 0022 200V 10 setae ag ESC 0 01 uF 100V 10 33 pF 1000V A E 0 1 uF 16V CerD ed Bice x a DEB 0 1 uF 16V CerD CLB 0 22 pF 50V MPC ECI 0 22 uF 50V MPC ECI 0 22 uF 50V MPC ECI 8 2 pF 50V Cer CLB INSTRUCTION MANUAL Digital Multimeter Models 172 173 Keithley Part No 31 31 30 Keithley Part No C 238 1M C 238 IM C 238 1M C 238 1M 238 1 C 64 33P 238 01 C 238 OJM C 179 2 2M C 237 0 47M 238 1 C 238 IM C 238 1M C 238 1M C 238 1M C 201 022M C 221 0022M C 38 01M C 64 33P C 238 1M 238 1 C 201 22M C 201 22M 201 22 282 8 2 INSTRUCTION MANUAL REPLACEABLE PARTS Digital Multimeter Models 172 173 CAPACITORS C Circuit Mfr Mfr Keithley Desig Description Code Desig Part No 200 SERIES Schematic 28656E 6201 15 pF 10007 CerD CLB 00 150 C 64 15P C202 2 2 uF 20V ETT 6 1 TD1 20 225 20 C 179 2 2M C203 8 11 pF 1000 HI K Glass SPG GHCt 1000 C 202 8 11P C204 3 3pF 50V Cer CLB ChOC3R3D C 282 3 3P C205 8 11 pF 1000V HI K Glass SPG GHC
33. For DC voltage measurements rejection is much greater than specified when the Model 172 173 LO terminal is driven rather than the HI terminal Where there is a need for even greater isolation from LO to power line ground or where there is a need to float at potentials greater than 1800 volts above power line ground the Model 1728 Battery Pack should be used dox Meg dU Po 103 SOURCE RESISTANCE DIGITAL MULTIMETER EXTERNAL SOURCE 1000V TYPICAL DC 10110 ISOLATION RESISTANCE GROUND FIGURE 14 Use of Multimeter Off Ground AA 3 11 OPERATING INSTRUCTIONS INSTRUCTION MANUAL Digital Multimeter Models 172 173 3 11 HOW TO USE OPTIONAL PPOBFS AND SHUNTS a Model 1600 High Voltage Probe Set the Model 172 173 to DC volts and 30 volt range The input resistance on the 30 volt range is 10 megohms so that no shunt resistor is needed The Model 1682 has a 1000 1 division ratio For maximum safety review the instructions furnished with the Model 1600 probe above 30kV switch to the 300V range CAUTION The alligator clip ground must be connected to the source low so that high volt age is not applied between low and ground Severe damage to the instrument will occur if the alligator clip is not connected b Model 1682 RF Probe Set the Model 172 173 to DC volts and 30 volt range The Model 1682 has a lVdc output corresponding to V rms input over the range 100 kHz to 100 M
34. Install the Model 1728 Rechargeable Battery Pack See Section 2 2 3 2 Depress BAT pushbutton 3 If LO BAT indicator is lighted the battery pack must be charged a minimum of 16 hours to provide fully charged operation of the Model 172 173 NOTE To charge the Model 1728 release both LINE and BAT pushbuttons and connect the line cord to line power If it 15 desired to use the Model 172 173 immediately depress LINE The Model 172 173 will be useable for measurements although the battery charging rate is decreased considerably h If the LO BAT indicator is not lighted in BAT mode the model 172 173 may be used for measurements CB gt 3 1 JPERATING INSTRUCTIONS INSTRUCTION MANUAL Digital Multimeter Models 172 173 NOTE The Model 1728 is shipped from the factory in uncharged condition Therefore the Model 1728 should be installed and charged prior to use After the Model 1728 has been charged for at least 16 hours the Model 172 173 can be powered continuously for at least 6 hours TABLE 3 2 Summary of Operation in LINE and BAT Modes Condition of Instrument Line Power Connected Line Power Connected Line Power Not Connected 1728 not installed 1728 installed 1728 installed ON ON OFF Battery trickle charged ON Batteryslowly discharqed F ON OFF OFF OFF Battery charged at max imum rate 3 3 HOW TO SELECT FUNCTION Function is selected by means of four pushbuttons DC V A and Q a D
35. MODEL 172 ONLY 7 8 9 1 1 1 1 OA Es 1 HON TO MEASURE CURRENT MODEL 173 ONLY HOW TO MEASURE RESISTANCE E FURTHER MEASUREMENT CONSIDERATIONS 52 Ge ow de x 0 HOW TO USE MODEL 172 173 OFF GROUND 1 HOW TO USE OPTIONAL PROBES AND SHUNTS 2 HOW TO USE THE MODEL 1722 DIGITAL INTERFACE EDESSURIES i uoo ob Ele Ed XS xe d 4 1 GENERAL LL 4 2 POWER OPTIONS Rr xL eU 4 3 ISOLATED DIGITAL OUTPUT 4 4 RACK MOUNTING s 4 5 PROBE AND SHUNTS 4 6 CABLES AND CONNECTORS 4 324 4 7 5 THEORY OF 5 1 GENERAL EDGE UE SE deck E 2624 4244 5 2 INPUT SIGNAL CONDITIONING E 25 254 E 5 3 POWER SUPPLY SCHEMATIC NO 280675 EE 5 4 DISPLAY BOARD PC 403 SCHEMATIC NO 274780 5 5 CURRENT BOARD SCHEMATIC 274780 8224 08 34 5 6 MODEL 1728 RECHARGEABLE BATTERY 5 7 ANALOG TO DIGITAL CONVERTER 5 8 MODEL 1722 DIGITAL INTERFACE 5 9 DETAILED 4 WIRE OHMS OPERATION 4 s INSTRUCTION MANUAL Digital Multimeter Models 172 173 AA INSTRUCTION MANUAL Digital Multimeter Models 172 173 CONTENTS continued AINTENANCE GENERAL REQUIRED TEST EQUIPMENT PERFO
36. Red Print Motor Off Remote Standby Continuous Print inhibit Compatible Logic TTL OTL or open collector inputs are 2 TTL loads External Print and Continuous Print 3 TTL loads Inputs are low true except External Print requires low to high transition CONTROL OUTPUT Printer in Cycle PIC End ot Print Data Hold Manual Print Print Twice 4 6 The Model 750 is an 18 column printer which is plug to plug compatible Output Logic TTL can drive 8 TTL loads PIC 4 TTL loads Outputs are high true except End of Print s 3ms pulse Printer in Cycle and Data Hold are low true INPUT OUTPUT I O CONNECTIONS Two 50 pin recessed card edge connectors I O for data input columns 1 through 10 I O for accessories and or additional data columns 11 through 18 see Drum Diagram ISOLATION Input Lo to chassis ground greater than 10 ohms Lo may be fioated up to 350 volts peak with respect to chassis ground PAPER 2 4 in fan fold or roll RIBBON Black red 1 2 in wide ENVIRONMENT OC to 50 C 0 to 80 relative humidity at up to 35 POWER 90 110 105 125 200 240 volts switch selected 50 60 Hz 30 watts 40 watts with accessories DIMENSIONS WEIGHT Style 0 7 in half rack overall bench size 7 in high x 872 in wide x 1514 in deep 190 x 220 x 390 mm Net Weight 16 pounds 7 kg ACCESSORIES FURNISHED One ribbon installed one pack fanfold paper AA INS TRU UO THEORY OF OPERATION D
37. Rin where Rin shunt resistance of the Model 172 173 Rs source resistance d Resistance Measurements l Maximum Allowable Voltage Input The maximum input should not exceed 250V rms sine wave 250 dc 2 Polarity of Ohms The Model 172 173 provides positive voltage at the terminal 3 Maximum Open Circuit Voltage When the HI and LO terminals are open in either or LO ohms the maximum voltage developed between and LO is 5 volts This illustration is typical of a 4 terminal measuring technique using a separate Voltmeter and Current Source The Model 172 173 combines these features LEADS 2 SOURCE HIGH H eS 4 EM CONSTANT ANA SH LOW LEADS SOURCE LOW SOURCE m 1 VOLTMETER CURRENT D When using the 4 WIRE method connect one pair of Ccurrent leads to 0 SOURCE input Connect a second pair of voltage leads to and LO Then set to 4 WIRE Care should be taken to connect current leads and voltage leads properiy The LO terminal and 0 Source low must always connect to the same side of the unknown resistance FIGURE 12 Typical 4 WIRE Resistance Measurement CB 3 9 OPERATING INSTRUCTIONS INSTRUCTION MANUAL Digital Multimeter Models 172 173 lh Four terminal Measurements 4 WIRE mode connects the lower set of SOURCE terminals to the DMM ohmmeter source 5 shown in Figure 12 th
38. Set 0 bias R707 for 10 000 MQ R707 Release 1 10 Set 10 MQ ADJ R705 for 10 000 MQ Depress HI LO Set Q bias R707 for 10 000 MQ Connect the Oscilloscope to the test points shown in Figure 38 The wire should be connected between power supply low and Oscilloscope low The black wire should be connected between pre filter output and Oscilloscope vertical input The wire should be connected between FON and the Oscilloscope trigger AB 6 17 AINTENANCE INSTRUCTION MANUAL 15 16 17 18 19 20 Digital Multimeter Models 172 173 Set the Oscilloscope to 4 sensitivity and a time base of 20 ms cm Set the instrument to 3K range Depress HI LO Ohms and release 2 WIRE 4 WIRE Connect a short across INPUT HI and LO Adjust O 3V REF 8208 for 1V x0 1V during Auto Cal Verify that level is 1 0 3V during Auto Zero Repeat steps e 2 through 20 unti all conditions are satisfied 2l 22 23 24 25 26 27 28 29 Set the instrument to 300 0 range HIQ Connect the Decade Resistor D to the upper set of terminals Set the Decade Resistor to 290 000 Adjust the 290 0 ADJ R704 for a reading of 290 00 1 digit Set the instrument to range Depress 2 WIRE 4 WIRE Connect the 4 WIRE test cable between the input terminals and Decade Resistor Set the Decade Resistor to 2 9000 Adjust the 2 9 0 ADJ R709 for a reading of 2 9000K2
39. Set the Current Source to 200mA Verify a reading of 199 48 to 200 52mA e Set the Current Source to the lA Verify a reading of 0 9973 to 1 0027A NOTE Readings do not account for source inaccuracy Add 0 02 uncertainty if Current Source E is used cc 6 7 MAINTENANCE INSTRUCTION MANUAL Digital Multimeter Models 172 173 TABLE 6 8 Summary of Adjustment Controls Schematic Shown C203 INPUT Current ADJ 27904F 205 OHMS Zero 27904F 817 100V 20kHz ADJ 27903 6819 IV 20 kHz ADJ 27903 C820 20 kHz ADJ 27903E 0821 IKV 20 kHz ADJ 27903E R103 Auto Cal 27904F R201 Auto Zero 27904F R208 0 3V Ref 27904F R209 X10 Gain 27904F R213 2 9V Cal 27904F R217 Buffer Zero 27904F R704 290 0 ADJ 27903E 8705 JOMA ADJ 27903E R707 Q Bias 27903E R709 2 9 0 ADJ 27903 R803 v IkHz ADJ 27903E R809 lRHz ADJ 27903E R816 100V 1 2 ADJ 27903 R817 MV 6 IkHz ADJ 27903E R901 DC ADJ 27903E R904 300mV Zero 27903E R9 1 290V DC ADJ 27903E R913 30V Zero 27903E R506 173 only 10 DC ADJ 274780 R509 173 only 100 DC ADJ 274780 R512 173 only 1A DC ADJ 274780 INSTRUCTION MANUAL Digital Multimeter Models 172 173 COVER 27979 METALCAL pu S MC 236 F ES FRONT PANEL SPACER ar 8945 27958A 173 257628 777221 oo 28029A 172 METALCAL MC
40. an overall A D converter timing diagram showing one complete conversion 2 The first major division of the conversion period is into an error correction segment 120 ms long and a signal measurement segment 200 ms long During the former the input multiplexer supplies known reference voltages to the V F block and as described in Section the correction currents and CAL are established During the latter the now error corrected V F converter has the unk signal voltage applied to its input and its output pulses are counted by the digital chip As the next conversion period begins the chip processes the resulting pulse count and dis plays the result 3 The error correction segment of the conversion cycle is further divided into three 40 msec phases During the first two of these phases the buffer amplifier gain is held constant at either IX or 10X depending on DMM range and function During the AZ phase the input multiplexer supplies the buffer with a zero reference voltage and the Auto Zero feedback loop is closed The value of 1 required to correct any system zero errors is established and the closure of the 2 1 switch see Figure 31 causes the source follower gate voltage which produces this current to be stored on the corresponding Auto Zero storage capacitor 4 During the ACAL phase the multiplexer connects the buffer input to a full scale reference voltage either 3 38 0 334 V depending on
41. at the bottom of the schematic consists of a 2 ampere fuse and one ohm resistor it is switched in front of the ac voltmeter or dc voltmeter for ac or dc amps It allows 200 milliamperes on the 300 millivolt range and up to 2 amperes on the 3 volt range limit of 2 amperes limits the power in the ohm resistor The input impedance is approximately 1 3 ohms on both the 300 milliampere and the 2 ampere range Above ampere the self heating effect and TC of the resistor causes the reading error to crease ror Model 173 the voltmeter is held on the 300 millivolt range and resistors are switched by means of relays K501 502 503 504 505 K501i connects the input on the 300 range K502 on the 3 milliamp range K503 30 milliamps K504 on 300 milli ips and R505 on the 3 ampere ranqe The current resistors are connected in series R502 is connected to the high of the voltmeter high sense R510 goes to signal low low inse The measurement is thus done four terminal 3 ampere range is adjusted with stentiometer 512 the 300 milliampere range 509 and the 30 milliampere range with R506 Input protection is provided by diode bridge CR501 which limits the voltage to 2 diode drops in either positive or negative polarity Unity gain amplifier 0501 guards center connection of these diodes This assures good performance on the 300 micro ampere range which nas 10 nanoampere sensitivity A 3
42. logic 0 no output change occuring Logic Levels HIGH open collector to output LO LOW closure to output LO Output device 2N5134 greater than 20V breakdown 0 5V at 5mA sink 3TTL loads Internal pull up resistors may be installed on these open collector outputs 4 7K minimum value is recommended when using internal 5 volt power supply OUTPUT TIMING Data is updated typically every 320 msec non trigger mode Update time ts typically 1 2 msec Data will appear at an output only if its respective strobe is active The FLAG will low Logic 0 typically 2 msec before update and go high typically 100 usec after update Data can be expected to be unchanging so long as the flag is high If FLAG RESET is activated the FLAG mill reset go to Logic 10 until the end of the next data update REMOTE CONTROLS Strobe Strobe lines permit word serializing in 4 bit increments or multiples thereof HIGH inhibits controlled output lines from conduction LOW enables conduction Range In 4 bit exponential code Load enables remote ranging as set by Range Hold LOW inhibits display update output update and autorange A D continues conversions Printer Hold Same as hold but grouped with outputs for convenience in interfacing printer Trigger Mode LOW enables TRIGGER control Trigger Mode Disable LOW disables TRIGGER Trigger LOW to HIGH transition initiates a new A D conversion Flag Reset LOW
43. 1000 202 8 11 C206 0 0022pF 200V MPC ECC 625B1C222 221 0022 C207 100 pF 1000V CerD CLB 00 101 C 64 100P C208 100 pF 1000V CerD CLB DD 101 C 65 100P C209 100 pF 10007 CLB 00 101 C 64 100P C210 1500 pF 1000V CerD CLB DD 152 C 64 1500P 300 SERIES Schematic 27404D C301 180uF 20 6V DIC 0180 6 C 270 180M C302 O OluF 16V CLB UK16 103 C 238 01M 500 SERIES Schematic 27478D C501 47 pF 1000V CerD CLB DD 470 C 64 47P 500 SERIES Schematic 280670 C601 270 uF ETT 6 1 5 506277 20 C 194 270M C602 10 pF 20V ETT C 1 TD2 20 106 20 C 179 10M C603 10 pF 20V ETT 6 1 TD2 20 106 20 179 10 C604 10 iF 20V C 1 TD2 20 106 20 C 179 10M C605 2000 pF 25V RIC JC P 2000 25 8P C 255 2000M c606 0 47 uF 20V ETT 6 1 TD1 20 474 20 C 179 47M C607 470 uF SOV TPL 511 470 C 246 470M C608 10 pF 20V ETT uou 3 oe 2 1 2 20 106 20 C 179 10M C609 t0 pF 20V C TD2 20 106 20 C 179 10M C610 O tuF 50V CerF EDI 812105061 104M 67237 0 1M C611 470 uF 50V EAL TPL 511 570yF C 246 470M C612 O luF 50V Cerf EDI 812105061 104 237 0 1 700 SERIES Schematic 28656E 701 100 pF 1000V CerD CLB 00 101 C 64 100P C702 1500 pF 500V Poly CLB CPR 1500J 138 1500 479 REPLACEABLE PARTS INSTRUCTION MANUAL Digital Mullimeter Models 172 173
44. 10M C 78 220M 180 120 C 160 120M C 179 10M C 64 33P C 179 10M C 179 10M C 278 2200P 238 01 278 185 C 284 1 9 15 7P C 278 440P C 184 25 1 5P C 184 25 1 5P C 184 25 1 5P C 201 01M C 269 1M C 64 33P C 269 15M C 269 15M 138 1000 286 0 01 C 285 1M C 238 1M 238 INSTRUCTION MANUAL Digital Multimeter Models 172 173 Circuit Desig C100 C1002 C1003 C1004 C1005 C1006 C1007 C1008 C1009 C1010 1011 1012 C1013 1018 1015 1016 C1017 C1018 C1101 1102 1103 C1104 1105 C1106 1107 Description CAPACITORS C Mfr Code REPLACEABLE PARTS Mfr Desig 1000 SERIES Schematic 27902 PC 415 0 01 uF 500V CerD 0 01 uF 16V CerD 0 01 uF 16V 0 01 uF 16V CerD 1550 uF 25V EAL 0 01 pF 500V CerD 0 01 uF 16V CerD 1000 pF 10007 CerD 0 01 uF 16V CerD 39 uF 15V ETT 0 01 uF 16 CerD 0 01 pF 16V 0 01 uF 16V CerD 0 01 uF 16V 10 uF 20V 0 01 uF 16V CerD 0 01 uF 16V CerD 100 uF 15 ETT ERI CLB RIC ERI CLB ERI a CLB sov 6 1 CLB CLB CLB TT CLB CLB C 871 2500 103 UK16 103 UK16 103 UK16 103 16 1550258 871 25 0 103 UK16 103 808 000 2580 102 UK16 103 TD401539610 URI6 103 UK16 103 UK16 103 UK16 103 TAP FO10F200 UK16 1
45. 133 high and 9 in 483 mm wide The hardware mm x 19 in 483 mm rack mounting with 11 included in this kit includes 19 inch wide 280 mm depth behind the front panel panel and other miscellaneous hardware Parts List ltem No Description Front Panel Qty Keithley Req d d Part No No 28092D Illustration Support Plate Shelf 28094C 28096B Left Side Bracket 280978 Bracket Right Side gt Slotted Screw 26 32 x 2 1 4 in Flat Wasner 76 1 48 32 1 2 in Phillips Screw Blank Cover Plate Hole Plug Kep Nut 8 Assembly Instructions See Figure 21 page 4 4 1 Using four Phillips screws Item 7 attach left and right hand Side Plates Items 3 and 4 to the Support Plate Item 2 2 Using three Kep Nuts Item 9 attach the Support Plate Item 2 to Front Pane Item 1 3 Fasten the Side Plates to the Front Panel using two additional Kep Nuts Item 9 h Assembly of rack hardware is complete except for mounting of the Instrument s 5 The plastic tilt bail handle on each instrument must be removed before mounting The top and bottom covers of the instrument must be disassembled in order to remove the handle Loosen four screws on the bottom cover of the instrument lift off the top cover and remove handle Replace the top cover and tighten the four screws on t
46. 3 ISOLATED DIGITAL OUTPUT The Model 1722 Digital Output Interface is available factory installed or field installable Complete specifications are given in Section 3 paragraph 3 12 IMPORTANT The Model 1722 and 1728 cannot be installed and used at the same time since both options occupy the same location on the Model 172 173 chassis 4 4 RACK MOUNTING THE Model 172 173 can be rack mounted in a full rack 19 inch width in either a single or dual mounting configuration rr NR TI YI EE LE _____ ____ __ ___ _ ____ __ _ _ _ BET MODEL 1010 SINGLE RACK MOUNTING KIT Description Application The Model 1010 is a single rack mounting The Model 1010 adapts one Keithley Style kit with overall dimensions 5 1 4 in 133 instrument for Standard 5 1 4 in 133 mm mm high and 19 in 483 mm wide The x 19 in 483 mm rack mounting with 11 in hardware included in this kit includes a 280 mm depth behind the front panel For 19 inch wide panel and other miscellaneous dual rack mounting of Style instruments hardware the Model 1017 Dual Rack Mounting Kit must be used Parts List Item Qty Keithley No Description Req d Part No lllustration 1 Front Panel 265950 2 Support Plate Shelf 1 26599C 3 Bracket Left Side 1 266008 4 Bracket Right Side 1 266018 5 Slotted Screw 46 32 2 1 4 in 2 ex 6 Flat 6 2 7 Phillips Screw 98 32 x 1 2 in 10 e AB ACCESSORIES INSTRUCTION
47. DD 13 DD 13 DD 13 DD 13 PL 63 AB INSTRUCTION MANUAL Digital Multimeter Models 172 173 Circuit Desig 2501 F402 F403 F501 Model 173 3A 250V 3AG Quick FUSES F Mfr Mfr Description Code Desig 400 SERIES Schematic 26758C IA 250V Slo Blo FUS MDL 1 250V Slo Blo FUS MDL IA 3AG 250V Slo Blo FUS MDL TAMP 500 SERIES Schematic 27478D 312003 22 Model 172 2 250V Quick L F 312002 F601 Circuit Desig 4201 4801 4802 4501 4502 4503 600 SERIES Schematic 28656 Slo Blo I 4A 1179 L F 313 250 Slo Blo 1 8A 220V BUS MDL 1 8 CONNECTORS J Mfr Mfr Description Code Desig 200 SERIES Schematic 28656 Socket lh pin DIP T I C931402 400 SERIES Schematic 267580 5 pins 8 8 s MOL 2139 5 5 2139 5 500 SERIES Schematic 274780 5 pin Housing 20370 8 pin Housing BRG 65039C 2 pin Housing Model 173 only MOL 03 06 1023 Female Contacts 2 req d for J503 MOL 02 06 5103 Keithley Part No FU 10 FU 10 FU 10 FU 2 FU 13 FU 17 FU 20 Reithley Part No s0 70 5 287 5 5 287 5 5 251 5 310 5 326 2 CS 328 REPLACEABLE PARTS 7 11 REPLACEABLE PARTS CONNECTORS J INSTRUCTI
48. INSTRUMENT TOGETHER TURN QVER TOP COVER BACK AND UP DISCONNECT 2 CONNECTORS CURRENT FUSE LINE ANO SELF CHECK Models 172 173 AB INSTRUCTION MANUAL INITIAL PREPARATION Digital Multimeter Models 172 173 SECTION 2 INITIAL PREPARATION 2 1 GENERAL This section provides information needed for incoming inspection and preparation for use 2 2 INSPECTION The Model 172 173 was carefully inspected both mechanically and elec trically before shipment Upon receiving the instrument check for any obvious damages which may have occurred during transit Report any damages to the shipping agent To verify the electrical specifications follow the procedures given in Section 6 2 3 PREPARATION FOR USE The Model 172 173 is shipped ready to use The instrument can be powered from line voltage or from rechargeable nickel cadmium batteries when the optional Model 1728 echargeable Battery Pack is installed a Line Power The Model 172 173 has an attached three wire line cord which mates with third wire grounded receptacles NEMA 5 15P The permanently installed line cord is stored by wrapping the cord around the base of the instrument as shown in Figure 4 CAUTION This instrument has an internal line power selector switch that must be set to A 234V position for operation above 125 volts rms 50 60 Hz l How to Set the Internal Line Voltage Switch 5601 The Model 172 173 has a two position slide switch loca
49. MANUAL Digital Multimeter Models 172 173 Assembly Instructions 1 Using two Phillips Screws Item 7 attach Support Plate Item 2 to Front Panel Item 1 2 Using four Phillips Screws Item 7 attach left and right side Brackets Items 3 and 4 to Front Panel Item 1 3 Using four Phillips Screws ltem 7 secure left and right side Brackets to Sup port Plate Item 2 4 Assembly of rack hardware is complete except for mounting of Instrument 5 Rotate handle of Instrument so that handle is toward rear of Instrument dle be removed completely if desired by separating top and bottom covers 6 Remove two Slotted Screws 1 1 4 in long used to hold top and bottom covers to gether near front feet 7 Position Instrument so that holes in bottom of Instrument alian with two front holes on Support Plate 8 Using two Slotted Screws Item 5 and two Flat Washers Item 6 secure Instru ment to Support Plate SUPPORT PLATE BRACKET BRACKET RIGHT INSERT INSTRUMENT THROUGH OPENING FROM BACK OF PANEL S OTTED SCREW FIGURE 20 Model 1010 Single Rack Mounting Kit 4 2 AA INSTRUCTION MANUAL ACCESSORIES Digital Multimeter Models 172 173 MODEL 1017 DUAL RACK MOUNTING KIT Description Application The Model 1017 is a sinqle dual mounting kit The Model 1017 adapts two Keithley Style with overall dimensions 5 1 8 in 133 mm instruments for Standard 5 1 4 in
50. P101 P301 P501 P502 P503 P601 P602 P603 P604 P605 P606 P607 P608 P609 P610 AB REPLACEABLE PARTS RELAYS K Mfr Mfr Keithley Description Code Desig Part No 500 SERIES Schematic 27478D Relay Reed 0 5A Form A 1170 3 1 RL 44 Relay Reed 0 5A Form A 1170 3 1 81 34 Relay Reed 0 53 Form 1170 3 1 RL 44 Relay Reed 1 5A Form A QTN H5A1M S20 RL 50 Relay Reed 1170 2 1 81 49 8800 5 900 SERIES Schematic 27903E Relay reed form 1 A 20V 1170 5 2 81 53 Relay gt e gt b P amp B 10 3738 1 RL 51 CONNECTORS P Mfr Mfr Keithley Description Code Desig Part No 100 SERIES Schematic 28656E 3 pin Housing BRG 65507 136 CS 339 3 300 SERIES Schematic 278085 Cable Assembly 1 2796 500 SERIES Schematic 28656 Not Used ds B 55 Not Used gt 7 Connector Model 172 only 600 SERIES Schematic 28656 Receptacle 5 pin MOL A 2391 5A CS 288 5 Receptacle 2 pin MOL 2391 2 5 288 2 Receptacle 4 BRG 65507 136 CS 339 4 Receptacle 3 pin BRG 65507 136 5 339 3 Receptacle 2 pin BRG 65507 136 CS 339 2 Receptacle 5 MOL A 2391 5A Cs 288 5 Not Used T 25 2 Not Used T Not Used 22 se Line Cord BLD 17237 0 9 INSTRUCTION MANUAL Digital Multimeter Models 172 173 F PLACEABLE PARTS CONN
51. PNP Case 110 PNP Case 8 110 PNP Case 8 110 PNP Case 8 110 nn nn nan n nn nn 1 PN4392 1752538 PN4393 1TE4392 PN4392 2N3565 2N3905 1753538 PN4392 PN4392 PN4 392 2N3565 2N3565 2N3565 2N3565 2N3905 274040 2N4355 2N4355 2N4355 2N4355 2N4355 2N4355 517638 517638 517638 517638 517638 517638 517638 517638 REPLACEABLE PARTS Keithley Part No TG 129 16 88 TG 130 TG 77 TG 130 TG 39 T6 53 16 53 16 128 TG 128 16 128 TG 39 28234A 28234A 28234A TG 53 TG 90 TG 90 TG 90 TG 90 TG 90 TG 90 76 33 TG 33 TG 33 TG 33 TG 33 TG 33 TG 33 TG 33 7 15 t PARTS circuit Desig 0501 0502 0103 0404 0405 0501 9701 3702 Q703 0704 1705 3706 Q707 3708 3709 Q710 0801 0802 Q803 0804 0805 0901 0903 7 16 Description PNP Case TO 5 NPN Case T0 39 PNP Case TO 5 NPN Case T0 106 PNP Case T0 92 TRANSISTORS Q Mfr Code Mfr Desig 400 SERIES Schematic 26758C RCA MOT RCA s Ez MOT Transistor Array l4 pin DIP RCA 700 SERIES Schematic NPN Case TO 106 Fel N Chan J FET 4 o 4 o ENT N Chan J FET Case T0 18 INT PNP Silicon Case T0 92 MOT NPN Case TO 106 dec Silicon PNP T0 92Case MOT N Chan J FET Case 0 18 INT Case TO 106 Selected TG 39 F I NPN Case 106 Selected
52. QUT OUT X IN OUT 0v OV 4 8 102 OUT IN IN 0v 8V 8 V DON T CARE Function selection is accomplished by connecting function lines AC DC 6 VI according to Table 5 5 The function lines are level sensitive 5 3 POWER SUPPLY SCHEMATIC 28656E This schematic contains the voltage regulators line transformer line voltage switching and power switching for the Models 172 173 There are three separate regulators used in the Model 172 173 One is 15 volt regula tor VR603 which has three percent accuracy typically 0 1 regulation and delivers 15 volts at approximately a 65 milliampere level to most of the circuitry on the 172 173 There is also an 8 volt regulator VR601 which is used as the positive supply to the LSI chip U103 on A D converter schematic 27904F There is also a 5 volt regula tor VR602 This regulator is used to drive the display the digital logic circuitry in the A D converter and all the relays VR603 is a 15 volt dual tracking regulator It is an integrated circuit with complete regulated circuitry and reference elements built into the unit It is either driven by T60 transformer or from 219 2 volt batteries in the Model 1728 Battery pack Connected to the transformer is a full wave rectifier CR602 then two filter capacitors C607 and 611 supply and 30 volts unregulated to VR603 These voltages are higher than VR603 needs because they are used to recharge the battery pack If the i
53. Set to 2 WIRE d Set to AUTO e Connect the Decade Resistor D to the instrument input terminals f Set the Decade Resistor to the resistance specified in Table 6 5 Verify the readings given TABLE 6 5 Resistance Performance Check HI OHMS Resistance Allowable Reading at 25 C Setting Relative Accuracy Absolute Accuracy 2 0000 1 9993 to 2 0007 1 9991 to 2 0009 30KQ 20 000 19 993 to 20 007 19 991 to 20 009 0 30040 200 00KQ 199 93 to 200 07R 199 91 to 200 09KQ 2 0000MQ 1 9991 to 20 009K 1 9989 to 2 0011 0 30M 20 000M9 19 969 to 2 0031 19 967 to 20 03 3M2 300M9 200 00M9 197 99 to 202 01 197 79 to 202 21M2 Does not include the uncertainty of the Does include the uncertainty of the Resistance Source Resistance Source CC 6 5 MAINTENANCE INSTRUCTION MANUAL Digital Multimeter Models 172 173 IMPORTANT Measure the resistance of the leads and subtract from the resistance reading on the Model 172 173 2 Low Ohms a Set to Q OHMS b Set to LO c Set to 2 WIRE d Set to AUT0 e Connect the Decade Resistor D to the instrument and source terminals f Set the Decade Resistor to the resistance specified in Table 6 6 Verify the readings given TABLE 6 6 Resistance Performance Check LO OHMS Resistance Allowable Reading at 25 C Setting 199 93 200 072 199 91 200 09 2 0000Kt 1 9992 to 2 0007K9 1 999 to 2 0
54. Use DMM H to accurately monitor the voltage drop 6 4 ADJUSTMENT CALIBRATION PROCEDURE The following adjustments should be performed when a specification has been determined to be out of tolerance For checking the in strument to its maximum published specifications the Performance Verification procedure should be used The tolerance on reading is adjusted to allow for time drift of crit ical components Ambient temperature should be maintained at 25 C 1 C a How to Open the Instrument Turn the instrument over so that the bottom cover is facing up Loosen the four slotted screws in the bottom panel the screws are captive and will only unscrew until the screw head is flush with the top of the holes Turn over the instrument Carefully lift off the top cover and disconnect the wires going to the rear panel CAUTION Disconnect the line cord from the line voltage before opening the instrument Care should be taken to avoid contact with line voltages at various points on the pc board when the line voltage cord is connected To discharge voltage on capacitors disconnect the line cord and depress LINE CC 6 11 MAUN ICNANCE INSTRUCTION MANUAL Digital Multimeter Models 172 173 b Power Supply Check The following measurements can be made using the instrument in LINE BAT modes if the Model 1728 is installed Set the internal Line Switch 5601 appropriately for the line voltage beinq used 2 Using DMM H measu
55. Warranty repairs within the continental U S A contact the factory for shipping instructions TABLE 6 13 Troubleshooting Hints SYMPTOM PROBABLE CAUSE CORRECTIVE ACTION a No display 1 Line switch set Check connection to line power LINE mode incorrectly Check LINE switch setting to conform to line voltage available See Figure 36 2 Fuse F101 is missing Check fuse Replace with pro or Open per rating 3 Line voltage connector Check connection to pc board 4601 improperly connec shown in Figure 39 ted to pc board at P601 b No display 4 Batteries need recharg Connect instrument to line BAT mode ing Check for LO BAT power Release LINE indication 2 Battery fuses blown Check F401 F402 and F403 3 Batteries improperly Check battery pack for proper installed on battery polarity on all batteries pack See Figure 7 4 Battery cables improp Check battery connections at erly installed P602 and R606 as in Figure 7 c No display 1 Display cable P301 not Check plug P301 and mating All modes properly connected connector 201 Make certain all pins are making proper contact pins should not be bent Check for proper orien tation of the connector 2 LSI module improperly Check 0103 for proper install installed ation Make certain all pins are making contact pins should not be bent 3 Power supply malfunction Check power supply voltages as described in Section 6 4b d Display is bla
56. a relatively high frequency triangle wave form the combination of comparator and comparator filter functions as switching mode class D amplifier for the ramp voltage with gain equal to the ratio of the Ve switch to the triangle amplitude The comparator filter s function is to smooth the switching output of the comparator so that only the low frequency amplified ramp signal is passed on to the remainder of the Auto Zero or Acal feedback loop d The Auto Zero feedback and storage block completes the control loop used to generate the Auto Zero correction current Ignore for the moment the two storage capacitors and consider only the direct signal path via the Auto Zero loop switch and the JFET source follower Consider the following circuit elements Transcond uctance amplifier integrating capacitor switching mode amplifier comparator and comparator filter auto zero loop switch source follower and the resistor between FET source and 0101 summing junction Examination shows that these circuit elements constitute a simple low frequency and dc feedback loop which will strive to adjust the voltage across the integrating capacitor to a value near zero Once this condi tion has been achieved then the Auto Zero correction current must have taken on the desired value since the total current being fed to the integrating capacitor must now be exactly balanced by the switched reference current The remainder of the auto zero system operatio
57. amp medium acting fuse limits the maximum current The fuse is rear panel accessible The relay drive tran istors are driven by U502 Spike suppression diodes across the relay coils prevent amage to the transistor drivers Range lines from the LSI chip lines A B and C autorange the ohms function and the Model 173 current function They are decoded in 770 to decimal decoder U502 See Table 5 7 There is a possibility of a small period of me during ranging where all relays may be open This will not present an open circuit to the source because the diode bridge will conduct DiodesCR507 508 509 block the ignal lines B and C from reverse biasing the inputs of 0502 when at 12V Resistors 315 516 517 513G 513H and 513F are input dividers to drop 8 volts to 5 volts to protect 0502 Resistors R513D C A B and E limit base current to the transistor drivers Resistors for the top three current ranges are adjusted in shunt rather than in series Ithough adjustment ranges are equal plus and minus from the nominal value the adjust ments are nonlinear Resistors R511 R508 and R505 limit the range of the adjustment in one direction The pots plus these resistors limit the adjustment range in the posite direction 0501 has amaximum input current of 7 nanoamperes less than digit the 300LA current range TABLE 5 7 173 Current Ranging RANGE LINE RANGE RANGE RELAY LEVELS ACA amp DCA RESISTANCE OPERATED 81 120
58. buffer gain and a similar process results in a scale factor correction voltage being stored in the Auto Cal storage capacitor 5 Buffer gain during the AZ2 phase is always the same as it is during the signal measurement phase it may differ from its value during AZ and ACAL Because of the possibly changed buffer gain the effective system offsets may have changed so the second Auto Zero operation is required to prepare the V F converter for an error corrected signal measurement This new value of the Auto Zero correction voltage is stored on the capacitor controlled by the AZC2 switch Figure 31 5 8 MODEL 1722 DIGITAL INTERFACE a Overall Block Diagram As shown in Figure 33 Serial data from the DMM and its associated clock lines are first isolated Bidirectional data line SERDAT is then split Output data DOWNDAT goes to the output register block where it is converted to parallel form and then to the output buffers The clock lines go to the control block which decides where the data is going out or in and also generates the flag 22 INSTRUCTION MANUAL THEORY OF OPERATION Digital Multimeter Models 172 173 Control input data and strobes are first buffered by the input buffer bloch The strobes go to the output buffer to gate the outputs The control data inputs go to the input register and control block where they are converted from parallel to serial form and sent to the isolation block The input register
59. clock periods The resulting reference current pulse rate is equivalent to an output frequency from the charge balance system of 1 2 the clock frequency In the Auto Calibrate mode QR is forced to a one constantly with the result that the reference current is on at every opportunity reference current pulse frequency thus equals the clock frequency Two chip out puts FON and COFF are used to control these two operating modes FON is one during both Auto Zero and Auto Calibrate and COFF is zero during Auto Zero and one other wise 4 2 DES r 2 222 zs os ca O gt m THEORY OF OPERATION X 3007 Ce Le 3998045 3 XOV80333 2 gt 9NID8O 2 324383318 da SS el 4 zuo 381 30 1 i 314419 2 2 EE 39vuOis 3 7980333 iv u3x3 gli TW 794915 1983803430 ADEE Simplified Schematic of Complete A D Converter FIGURE 31 AB 5 20 INSTRUCTION MANUAL THEORY OF OPERATION Digital Multimeter Models 172 173 c The block labeled Comparator Filter not previously mentioned serves an important function in the Auto Zero and Auto Calibrate feedback loops As discussed above the component of the integrator voltage which is of interest for Auto Zero and Auto Cal purposes is the slow ramp arising from the effective error currents Because this ramp has superimposed on it
60. continued Component Designations For 07 Q803 0804 0805 0901 0902 0903 ROOI R002 R003 ROOK ROOS ROO6 ROO7 8008 R009 8010 RO R012 RO13 Circuit Desig Location Code INSTRUCTION MANUAL Digital Multimeter Models 172 173 Circuit Desig R209 R210 2211 8212 8213 R214 R215 R216 R217 R218 R219 R220 R221 R222 R223 R224 R225 R226 R227 NS R228 R229 R230 8231 R601 R602 R603 R604 R605 R606 R607 R608 R609 R610 NS R611 R612 R613 R70 R702 R703 R704 R705 R706 R707 R708 R709 R710 Location Code 8 19 0 18 U 24 U 21 U 23 U 18 W 24 V 2 V 20 W 18 21 18 2 23 2 18 b 24 b 22 b 18 d 18 d 20 17 9 24 9 22 e 28 8 30 8 31 C 30 D 31 x x r r 1 AD NN N 1 d CN UJ UT CN Lu Un 1 lt lt C C lt C gt Q Z l AB INSTRUCTION MANUAL Digital Multimeter Models 172 173 Circuit Desig AB U 12 R902 11 R903 0 1 R904 T 9 R905 U 10 R906 U 9 R907 NOT USED R908 NOT USED R909 X 12 R910 W 11 R911 Y 12 R912 2 12 8913 12 R91 NOT USED R915 b 8 R916 7 R917 d 12 R918 e 12 R919 11 8920 10 R921 12 R922 R923 9 5 R924 e 18 R925 f 19 R926 f 18 Location Code va o 1 va FS Un GCN Q fo r ON xD
61. from line power Battery I pack if inst lled is charged at maximum rate if line cord is connected to power IN DMM is powered by internal Battery Pack BAT Push Push BAT Push Push Out DMM is disconnected from Battery Pack interlock prevents both pushbuttons IN at the same time Both pushbuttons must be set to OUT before either can be set to IN Push Push means that a single depression will place the pushbutton to IN a second depress oon will release the pushbutton to OUT S CR AUTO MAN Push Push in DMM is set to MAN Manual mode To change range depress either RANGE or UP RANGE See also REMOTE PROGRAMMING OPTION AUTO MAN Push Push Out DMM is set to AUTO Automatic Ranging Mode DMM range is set automatically DN Range Momentary in Momentary depression causes the to down range decade to lesser sensitivity Operable only when AUTO MAN is IN Momentary depression causes the DMM to up range One decade to greater sensitivity Operable only when AUTO MAN is IN DMM is set to DC mode Overrides AC and Q functions due to interlocked pushbuttons DMM is set to AC mode Overrides DC and Q functions due to interlocked pushbuttons DMM is set to Q mode Overrides AC and DC functions due to interlocked pushbuttons also overrides V A switch Momentary Interlock
62. i i L r dece simi Sa 944947 OM 2 ST anpa WE mo hd eg bs ee M et mor M RUE S om coa 11 a a k e j FORES Dur EE a CIE l i TU ENIM u El LLA LI EA UJ LLA LL LLA LLA LA AA 12111111 LA AA LLL ua men 2 CA s a aga zog FU ven ie iD eee LS LA LLULL Lia da da Et id 11511112 m i ee m 4 f a i FM NUR 22 r gt ee UM 2 hnc 70 ine 3 as to 026 1 P NONSu3ANO 110 4 4 N vn 1 014318 P LES FS 1 5 EE T r 1 T 4 T 73 b Y A 8 c l 389282 _ ds 320 DATA FLAG rout pera pegar FIGURE Cc 3 k Ta Tre OUTPUT WT PRO _ c ce et je S 1 r 9e epe 2 gt 8 EE 2 16
63. mons 9 i s DS L T na DEM 3 mm 2 92 sea tlli 01 BINS c r 1 gt at 2 Agom Aron om 5 1 1 6 ponn van 5 2 ul 11525 4474 Term tie sont Store 2961 gt 1 amp 30 3792 211093925 3313701100 YLA 50 3NOz 2904 ONY a 7 3802 H3143 NO02 01 473 S3NQI 1 men H 5 20 3 Ov 01 33 48 3NOZ i 39vd 0 9 18 wj ZOQtf SILVA 274475 83002 GJLSiML Q36713INS 0 2 Nid 21193926 A dsid 09 24 335 1054 S3IYM ASS CO 58011235 3 2382 4135 718905 WH 1NOD 80 9 539 I ae Age A lt 3 14 6223 29 gt CE 72535 TX 170825 2 4 v xOBdav pn SN 2 39vd noua soe 2 3948 31422 90055 82000 2094 AlddNS H3MOd AlddNS A21 TN 1
64. of 21017 timer buffered version of UPCLK is also run via diode gate 1002 to the threshhold input of 01017 11017 is such that its output will go high when a falling edge goes into trigger A filter made up of 1007 and 1008 will try to charge however since this threshhold is clamped low through diode 81002 It will not be able to time out in the time period of the clock pulses on INCLK until the last rising edge of INCLK at which time it will clock out at 30 microseconds therefore UPTIME the output of 01017 will be length of the INCLK pulse stream plus approximately 30 microseconds which is the time in which data will be flowing from the 172 to the DMM The beginning conversion See Schematic 27902E This is done by clocking DOWNCLK with UPTIME n flip flop 01015 The beginning of downtime also defines the time when the flag is set high that is when data has finished being updated Setting the flag low during data change time or resetting the flag is accomplished in two ways FR or UPDATE Downtime also gates DOWNCLK thru UIOIAC 6 010180 where it is called GATECLK and goes to the output register e Output Register The output register is made up of shift registers amp B 1009 amp 1010 6 B 1011 amp B it is 32 bit shift register of which only 30 are used Serial data enters 110088 and is clocked through all of the shift registers by the parallel clock GATECLK At the end of the clocking time a
65. saturating switches 0301 thru 0306 The segment driver transistors are emitter followers 0307 thru 0314 R302A thru R302H are current limiting resistors Segment current is approximately 30 milliamperes peak R303 6 C301 decouple current spikes from the 5 volt power supply 302 decouples 0301 from power supply CR301 and R304 prevent parasitic oscillation of segment driver transistors 5 10 AB INSTRUCTION MANUAL THEORY OF OPERATION Digitat Multimeter Models 172 173 TABLE 5 6 Display Data MUX Lines 8 LINES a for last 5 of th Off other half b for last 4 of t Off other half mV mA V indicator 173 indicator 172 mV indicator 173 indicator 172 indicator 173 not used 172 d Same as above mA indicator 173 not used 172 e Same as above A indicator 173 not used 172 f f f f f indicator indicator all of t 9 g g for last h of ty indicator Same as above Off other half indicator indicator All of ty NOT USED_ gt POLARITY NOT USED FIGURE 26 Digital Display Multiplex Scheme CB dEORY INSTRUCTION MANUAL Digital Multimeter Models 172 173 5 5 CURRENT BOARD Schematic 278780 contains all of the current circuitry which is intained the Model 173 and also in the 172 The current circuitry for the Model 172
66. sets FLAG FLAG to LOW HIGH Control Logic Levels 6 Source Requirements HIGH either an open circuit or a voltage between 2 4V and referred to output LO LOW closure to output LO _ within 0 8V while sinking 1 6 milliamperes 1771 load When TRIGGER MODE HOLD and LOAD RANGE code bits are all HIGH inactive the 172 173 is under front panel control These REMOTE CONTROL inputs have priority and mill override any front panel setting once activated ISOLATION Al digital outputs and remote controls are isolated from 172 173 analog input by 107 0 and 500pF 1200 VDC 1000V rms AC maximum All digital outputs and IH H remote controls are isolated from chassis ground by 106 0 and O 0luF 250V rms maximum LE ET ee 20 AA INSTRUCTION MANUAL Digital Mullimeter Models 172 173 OPERATING INSTRUCTIONS e Detailed Explanation of Model 1722 TRIGGER MODE AND TRIGGER See schematic 28248E HOLD LOAD RANGE REMOTE CONTROLS TRIGGER MODE DISABLE See Schematic 28249D AB When TRIGGER MODE is active Low output data and dis play will not be updated TRIGGER MODE enables TRIGGER Conversion starts within 1 6 milliseconds after TRIGGER Integration starts 120 milliseconds after start of conversion If either HOLD or PRINTER HOLD is low the output data and the display will not be updated and the FLAG wil stay at HIGH unless reset by FLAG RESET When LOAD RANGE
67. silicone elastoplastic resin 2 Parts coated with QR4 3117 coating can be repaired by either of two methods a Apply a small amount of solvent see below and allow the coating to dissolve After cleaning make the repair unsolder component etc Recoat with Conformal Coating b For minor repairs a soldering iron can be used to melt through the coating to unsolder or resolder a component lead After cleaning the soldered area recoat with Conformal Coating 3 Cleaning may be accomplished using a small brush or cotton swab and solvent such as FREON TE TOLUENE XYLENE OR CHLOROTHENE CAUTION Use solvent on circuit tape side only Solvent may adversely affect components 4 Recoat with undiluted Conformal Coating using a small brush or other applicator 5 Shelf life of the coating material is approximately 12 months Always use fresh coating material in order to maintain the properties of the material WARNING The Conformal Coating is combustible Keep away from heat and open flame Use with adequate ventilation Avoid prolonged breathing of vapor Avoid prolonged or repeat ed skin contact Take necessary precautions when using cleaning solvents See appli cable manufacturers data sheets 22 AA INSTRUCTION MANUAL REPLACEABLE PARTS Digital Multimeter Models 172 173 SECTION 7 REPLACEABLE PARTS 7 1 GENERAL This section contains information for ordering replacement parts The parts list is arranged in alphabeti
68. 004 Vdc 300V 200 00 199 97 to 2200 03 Vdc 199 96 to 200 04 Vdc 1000V 1000 0 999 8 to 1000 2 999 7 to 1000 3 Does not include the uncertainty of Does include the uncertainty of the the DC Catibrator OC Calibrator 2 AC Voltage a Set to AC Volts b Set to AUTO c Connect the AC Calibrator B to the instrument input terminals d Set the AC Calibrator to the output specified in Table 6 4 Set frequency to 50 Hz then repeat at 20 KHz e Connect the High Voltage Amplifier C to the instrument input terminals f Set the High Voltage Amplifier as shown in Table 6 4 g Verify a displayed reading as shown in Table 6 4 6 4 INSTRUCTION MANUAL MAINTENANCE Digital Multimeter Models 172 173 Voltage Applied 0 20000 Vrms TABLE 6 4 AC Voltage Performance Chech Allowable Reading at 25 Relative Accuracy 0 19964 to 0 20036 Vrms 0 19959 to 0 20041 Vrms gt 2 0000 Vrms 1 9964 to 2 0036 Vrms 1 9960 to 2 0040 Vrms 30V 20 000 Vrms 19 964 to 20 036 Vrms 19 960 to 20 040 Vrms 300V 200 00 Vrms 199 64 to 200 36 Vrms 199 56 to 200 44 dine 1600V 1000 00 Vrms 997 4 to 1002 6 Vrms 997 0 to 1003 0 Vrms Does not include the uncertainty of the Does include the uncertainty of the DC DC Calibrator Calibrator e Resistance Accuracy Check High Ohms a Set to C OHMS b Set to HI c
69. 009K2 20 000 19 993 to 20 007K2 19 991 to 20 009 0 200 00RR 199 91 to 200 090 199 89 to 200 1 K9 2 0000M2 1 9979 2 0021M amp 1 9977 to 2 0023 5 20 000 19 899 20 101 19 897 to 20 103 0 Does not include the uncertainty of the Does include the uncertainty of the Resistance Source Resistance Source IMPORTANT Measure the resistance of the leads and subtract from the resistance reading on the Model 172 173 gt INSTRUCTION MANUAL MAINTENANCE Digital Multimeter Models 172 173 f Current Accuracy Model 173 only 1 DC Current a Set to DC Amperes b Set to AUTO c Connect Current Source E to the instrument input terminals d Set the Current Source to the current specified in Table 6 7 Verify the readings given TABLE 6 7 DC Current Performance Check Model 173 only Current Allowable Reading at 25 C Applied Relative Accuracy Absolute Accuracy 1200 00yA 199 78 to 200 22 199 77 to 200 23 2 0000mA 1 9978 to 2 0022mA 1 9977 to 2 0023mA 20 000 19 978 to 20 022 19 977 to 20 023mA 200 OOmA 0 19978 to 0 20022 0 19858 to 0 20142A 2 0000 1 9958 to 2 0042A 1 9838 to 2 0162A Does not include the uncertainty of the Does include the uncertainty of the Current Source Current Source g Current Accuracy Check Model 172 only l DC Current a Set to DC Amperes b Set to AUTO c Connect Current Source E to the instrument input terminals d
70. 03 UK16 103 TD501510710 81100 SERIES Schematic 28019 PC 416 0 01 uF 16V CerD 0 01 uF 16V CerD 1 2 UF 20 20V 0 01 uF 16V CerD 0 01 uF 16V 220 pF 1000V CerD 1000 pF 1000 CerD CLB 55 CLB C 1 CLB CLB P s CLB 5 ER UK16 103 UK16 103 T01 20 125 20 UK16 103 UK16 103 221 808 000 2580 102 Keithley Part No C 22 01M C 238 01M C 238 01M C 238 QIM C 272 1550M C 22 01M 238 01 C 64 1000P C 238 01M C 228 39M C 238 OJM C 238 014 C 238 01M C 238 01M C 179 10M C 238 01M C 238 01M C 228 100M C 238 0 01M C 238 0 01M C 179 1 2M C 238 0 01M C 238 0 01M C 64 220P C 64 1000P 7 7 REPLACEABLE PARTS DIODES CR rcuit Mfr Mfr esig Description Code Desig 000 SERIES Schematic 28656 Rectifier 75 mA 75V T I 1N91 CR002 Rectifier 75 mA 75V T I 11914 1003 Resonator Ceramic 669 kHz VER TF 01 669 8100 SERIES Schematic 28656E CR101 Rectifier 75 mA 75V sos 1 9 18 8102 Rectifier 75 mA 75V Tal IN915 200 SERIES Schematic 28656 rR201 Rectifier 75 mA 75V TI 189814 3202 Rectifier 75 mA 75V IN914 4203 Rectifier 75 mA 75 Tel 1 9 14 CR204 Rectifier 75 mA 75V T I IN914 3205 Rectifier 75 mA 75V 1 1 914 3206 Diode Dual Low Leakage INT 10101 CR207 Rectifie
71. 04 mV Measurements from relatively high source resistances could cause an additional reading error The amount of error due to loading can be determined by the following relationship error 100 x Rs Rs Ri where Rs source resistance in ohms input resistance of 172 173 in ohms h Self Check Feature The Model 172 173 has a rear panel Voltage test point for functional check of the Model 172 173 in DC Volts To use this feature connect the input Hi terminal to the rear panel white terminal Verify a display of approximately 5 volts dc To check dc current depress V A andverify a display of mA b AC Voltage Measurements Overloads When the display exceeds 1000 0 V rms all digits blink to in dicate an overload condition 2 Input Impedance The input impedance is 2 megohms shunted by less than 50 picofarads The effects of circuit loading should be considered when evaluating the total accuracy of measurement See Accuracy 3 AC to DC Conversion The Model 172 173 operates as an average reading voltmeter calibrated in terms of the root mean square rms of a sine wave The calibration is exact for sinusoidal waveforms in the specified frequency range h Frequency Response The frequency range given in the specifications is the mini mum and maximum frequencies which accuracy is valid 5 Accuracy The Model 172 173 accuracy is specified in terms of a of reading and a of range Measurement
72. 07 and the output resistance is R802 in series with R803 adjustment pot FET 0801 is located in the feedback loop of the converter amplifier and the gate of this FET is driven from the output of the amplifier for one polarity 3 For the other polarity the feedback path for U801 and input FETs 0803 a b is through diode CR801 and transistor 0802 When the ignal is positive at the input side of R812 current flows into the summing junction of the amplifier which is the gate Pin 3 of 0803 and this current causes the output of 0801 to go negative This turns on the base emitter junction of 0802 and pulls current through diode 8801 so that the connection path is through R812 R807 CR801 and 0802 emitter to collector to 15 volt supply The reason that 0802 is a transistor and not a diode is to equalize the output load on amplifier U801 in each of its two polarities and avoid any parasitic oscilla tion which might occur in U801 because of unequal output current loading AA 5 5 Tt ORY OF OPERATION INSTRUCTION MANUAL Digital Multimeter Models 172 173 Ac 908 INPUT CONVERTER luF FIGURE 28 Simplified AC Attenuator Circuit c8o8 Ein C809 OIN Rin R812 R807 FIGURE 25 AC Converter Circuit 5 6 AA INSTRUCTION MANUAL THEORY OF OPERATION Digital Multimeter Models 172 173 h When the input voltage is negative to the input side of R812 the current will flow out R807 and R812 and thus the outpu
73. 1006 Quad 2 Input AND 18 DIP RCA 08081 10 138 U1007 Quad 2 Input AND 18 DIP v utu RGA CD408 1BE IC 138 U1008 COS MOS Dual 4 Stage Static Shift Register s gt RCA 5 16 136 91009 COS MOS Dual h Stage Static Shift Register cher UL x doter abro pent CD4015AE 1C 136 01010 COS MOS Dual 4 Stage Static Shift Register RCA 08015 1 136 01011 COS MOS Dual 4 Stage Static Shift Register es gp ie 08081 1C 136 01012 Quad 2 Input AND 14 DIP CD4081BE IC 138 91013 Quad 2 Input AND J4 pin DIP RCA CD4O81BE 12 138 01014 Quad 2 Input NOR 18 DIP RCA CD4001AE 16 108 01015 Dual D Type Flip Flop 14 DIP RCA CDA013AE 1C 103 41016 COS MOS Hex Inverter lh pin DIP RCA CD4069BE 1C 139 01017 Timing Logic 8 DIP SIG NE555V IC 71 1018 Optically coupled Isolator 8 H P HP5082 435 IC 142 U1019 Optically coupled Isolator 8 DIP H P 5082 8351 16 142 01020 Optically coupled Isolator 8 pin DIP H P HP5082 5351 16 182 01021 Optically coupled Isolator 8 pin DIP H P 5082 4351 1 182 REPLACEABLE PARTS INSTRUCTION MANUAL Digital Multimeter Models 172 173 INTEGRATED CIRCUITS U Circuit Mfr Mfr Keithley Desig Description Code Desig Part No 1100 SERIES Schematic 2
74. 153 84411 Pomona Electric Vishay Resistor Products Pomona CA 91766 Malvern PA 19355 18612 Q Tron Vernitron Santa Ana CA 92705 Laconia NH 03246 13150 Raytheon Company Wabash Magnetics Quincy MA Wabash IN 46992 01101 RCA Corporation Moorestown NJ 08050 AB 7 3 IEPLACEABLE PARTS Circuit esig 8 401 71402 T403 ircuit esig C001 002 003 C004 005 006 C007 008 009 6010 101 102 103 C104 105 106 C107 108 109 4110 2111 112 4113 C114 115 7 4 Description Multicell Multicell Set of Seven cells C cell volts used for 03 Nichel Cadmium required Description 19 2V Nickel Cadmium 19 2V Nickel Cadmium BATTERIES 400 SERIES Schematic 267586 Mfr Code GLD GLD 8 4 Volts 1 2 seven GLD Mfr Desig 403041 403041 2 0SCB CAPACITORS C Mfr Code Mfr Desig 000 SERIES Schematic 28656 UK16 104 0 16 108 UK16 104 9 16 108 UK16 104 DD 330 UK16 103 UK16 103 TD1 20 225 20 8131050651474M URI6 104 UK16 104 UK16 105 UK16 104 0 16 108 625814223 625B1C222 PT420 DD 330 UK16 104 UK16 104 625B1A224J 625B1A225J 625814224 ChOCBR2K 0 1 uF 16V CerD CLB 0 1 pF 16V 0 1 pF 16V CerD CLB 0 1 uF 16V CerD CLB O l uF 16 CLB 33pF 1000V CerD CLB 0 01 16 CerD CLB 0 01 uF 16 CLB 2 2 yF 20V
75. 1722 for its regulated 5 volt supply Thus when the 172 or 173 are turned off the 1722 turns off Transformer T601 has two internal shields one secondary shield tied to pin 10 and one shield tied to power ground This shielding provides line isolation When the jual primary of 7601 are tied in parallel by switch S601 the Model 172 173 is connected for 117 volt operation Switch 5601 also puts these primaries in series for 230 volt operation as indicated on the schematic Provision for 100 volt line is interchanging zonnections 5 and 6 and connections 2 and 3 on the primaries This is a physical wire change that must be made on the printed circuit board and is a factory option fhere are two connectors for the Model 1728 battery pack P602 and P606 The self check terminals are on the rear panel There is an self check dc self check and an ohms self check Connect from the appropriate self check terminal to the input high terminal to exercise the instrument The self check is not accurate the voltages and zurrents are only approximate A battery test point on the bottom of the instrument allows checking of the 19 2 volt battery in the Model 1728 Normally the low battery light mill indicate when the batteries have become low and need recharging However it could be Jsed to troubleshoot for a defective cell 5 8 DISPLAY BOARD SCHEMATIC 27404D a This schematic shows the display digits the LED function indicato
76. 235 US COVER me 25727 INSERT 26090A HANDLE FIGURE 35 Top and Bottom Cover Assembly MAINTENANCE 6 9 MAINTENANCE INSTRUCTION MANUAL Digital Multimeter Models 172 173 A 4 503 NOTE CONNECTS TO DRESS WIRES P604 BETWEEN SHELL AND POSTS BEFORE TOP COVER IS PLACED IN POSITION LINE F601 votrace Mg OR eseni BBR SHOWN SWITCH icr dl GIGAS CURRENT 5601 BOARD INSTALLED m FIGURE 36 Location of Line Fuse and Line Switch INSTRUCTION MANUAL MAINTENANCE Digital Multimeter Models 172 173 TABLE 6 9 List of Test Equipment Required For Adjustment Calibration ITEM DESCRIPTION MINIMUM SPECIFICATION NEEDED MFR MFR MODEL A DC Calibrator 0 290005V 2 90005V 429 0005V 343A 290 005V 1000 05 to within 20 ppm B AC Calibrator 100V 1000 0 lkHz 745 IV 1007 1000V 20kHz C High Voltage Amplifier See B above 746A D Decade Resistor 2R through 20MQ 0 01 RS725 F Oscilloscope 465 G Current Source 00mA lOmA 0 02 382A H DMM 1 0000V 0 0017 5900 Test Circuit Resistor 2 0 R 253 2M Capacitor luk Paralleled C 215 1lLF NOTE An alternate Current Source may be assembled using a precision 17 resistor Stabilized at constant temperature and a Keithley Model 227 wiich has been adjusted to obtain a 1 0000 V reading across the 10 resistor
77. 28656 VR6OI Voltage Regulator 8V Case 10 92 NAT LM340LA2 8 0 12 164 VR602 Regulator 5v Case 70 220 10 93 F 1 UGH7805393 28515A VR603 Regulator 15 70 66 Case RAY RCA4195TK 1 128 800 SERIES Schematic 28656 VR801 Zener 12V 8008 DIC 1N9638 02 54 INSTRUCTION MANUAL Digital Multimeter Models 172 173 JUMPERS W Circuit Mfr Mfr Desig Description Code Desig 200 SERIES Schematic 28656 W201 K 1 500 SERIES Schematic 28656 W501 600 SERIES SCHEMATIC 28656 W601 R I 800 SERIES SCHEMATIC 28656 W801 1 27 900 SERIES Schematic 28656 901 Used only Model 173 K 1 REPLACEABLE PARTS Reithley Part No J 3 J 3 J 3 4 3 WIRE REPLACEABLE PARTS INSTRUCTION MANUAL Digital Multimeter Models 172 173 MISCELLANEOUS RE I THLEY DESCRIPTION PART NO Cover less metalcal 27979 Metalcal for top cover MC 236 Bottom Cover less metalcals 25727 Metalcal operating instructions 239 Metalcal rear panel 235 Handle less insert 25729D Insert 2 req d 26090A Spacer 4 req d 257628 Rubber foot 4 req d FE 10 Front Panel Model 172 28029A Front Panel Model 173 27958A UN Ring Used to hold display board GA 18 INSTRUCTION MANUAL REPLACEABLE PARTS Digital Multimeter Models 172 173
78. 395982 TO INPUT Pace 2 AS v REF Qv 20 byt 1 915 7405 500 10 i VOLTAGE LIMITER 2803 i do 5 55 PAGE 2 ZONE b i b CLAMP MATES 250 SEE CURRENT BOARD SCHEMATIC 274780 aO 67 OtGITAL SECTION PONE PAGE 3 ZONE US TO INPUT 4 i PAGE 2 ZONE i ak LO P NS iSv ACTIVE RTT ATTENUATOR RECTIFIEF i Ce N PEL sss AC OC CONVERTER i INPUT W1 4 6 rol D 5 8929 39 s WAN ya EE _____ _______ ISOK icc C uo i FROM MATES WITH 2502 D csoe 2 1 23 is REL DIGITAL SECTICN SEE CURRENT BOARD i qe ion 5 EX 3 ZONE iey SCHEMATIC P N 274780 m O Ki 16 TO INPUT IMBl Q 20 Put 90 TAL 2 ZONE i 6 renes P 915 49 9 i 2 I 5 PAGE 2 e eV f i ZONE AS Lo Sv cee 3 3444V be SENSE SENSE COMMON 12 5 m S dM FROM REFERENCE Su i PAGE 2 ZONES 2 amp I 3922 3 19 cso 133x ISOOpF FROM
79. 4 TG 65 01006 NPN Case 70 106 F 1 2N5134 TG 65 01007 NPN Case 0 106 m 2N5134 16 65 01008 70 106 2N5134 TG 65 01009 NPN Case 0 106 F 1 2N5 134 16 65 01010 NPN Case 70 106 Fel 2N5134 TG 65 01011 NPN Case T0 106 Fed 2N5134 TG 65 01012 NPN Case 0 106 Fel 2N5131 TG 65 01013 NPN Case 0 106 Fes 2N5134 16 65 01018 NPN Case 70 106 Fei 2N5134 6 65 01015 NPN Case 70 106 2N5134 TG 65 01016 NPN Case T0 106 F 1 245134 16 65 01017 NPN Case 0 106 245134 10 65 01018 NPN Case 70 106 Fel 2N5134 TG 65 01019 NPN Case T0 106 pud 2N5134 TG 65 01020 Case T0 106 F 1 2N5134 76 65 01021 NPN Case 0 106 Fe 245134 16 65 01022 NPN 0 106 F 1 245134 76 65 01023 NPN Case 10 106 2N5134 TG 65 01024 NPN Case T0 106 F I 2N5134 TG 65 01025 NPN Case 0 106 F I 2N5134 TG 65 01026 NPN Case T0 106 F 1 2N5134 TG 65 01027 NPN Case T0 106 F 1 2N5134 TG 65 01028 NPN Case T0 106 Fed 2N5134 TG 65 Q1029 NPN Case TO 106 2N5134 TG 65 Q1030 NPN Case T0 106 Fel 2N5134 TG 65 01031 NPN Case 70 106 pel 2N5134 TG 65 Q1032 NPN Case 0 106 215134 TG 65 01033 NPN Case T0 106 ET 2N5134 T6 65 01038 PNP Case 8 110 F I 17638 TG 33 Q1035 PNP Case 8 110 17638 TG 33 Q1036 PNP Case R 110 F I 517638 16 33 01037 PNP Case R 110 F I 517638 TG 33 1100
80. 4 V 18 P902 p C609 L 10 CR205 wW 21 C610 CR206 Y 17 REPLACEABLE PARTS INSTRUCTION MANUAL Digital Multimeter Models 172 173 TABLE 7 2 continued Component Designations For PC 407 Circuit Location Circuit Location Circuit Location Desig Code Desig Code Desig Code P 9 R209 R 19 0802 N 6 R210 Q 18 0803 P 4 R211 U 24 Q804 0 9 R212 U 21 0805 b 3 R213 U 23 R214 U 18 0901 V 10 R215 W 24 i 0104 i J 21 0902 9 R216 21 0105 24 0903 f 10 R217 20 0106 23 R218 W 18 Q107 1 21 H 27 R219 Y 21 Q108 i M 22 ROO2 J 27 R220 18 0109 21 R003 Q 27 8221 2 23 0110 5 23 ROO R 2 R222 2 18 0111 5 22 8005 5 26 8223 b 24 0112 5 21 8006 5 30 R224 b 22 0113 5 20 ROO7 T 30 R225 b 18 R008 S 29 R226 d 18 R009 U 30 R227 d 20 29 R228 17 RO 30 R229 9 2 amp 012 29 R230 9 22 8013 T 27 R23 e 28 8101 27 R601 B 30 R602 8 31 R603 C 30 R604 0 31 R605 E 30 R606 0 27 R607 L 4 R608 L 4 R609 M 4 R610 NS k 28 R611 p 26 R612 M 10 R613 M 9 8701 N 15 R702 P 13 R703 R 13 R704 U 16 R705 16 R706 U 15 R707 U 13 R708 V 15 R709 W 14 R710 Y 16 7 30 AB INSTRUCTION MANUAL REPLACEABLE PARTS Digital Multimeter Models 172 173 TABLE 7 2 continued Component Designations For PC 407 Circuit Location Circuit Location Circuit
81. 63017 71400 St Louis MO 63107 71400 C l Components Inc General Electric Company Biddeford ME 04005 06751 Syracuse 13201 03508 C W Continental Wirt Elec Corp General Instrument Corp Warminster PA 18974 79727 Newark NJ 07104 72699 CAD Caddock Gould Inc Riverside CA 92507 19647 St Paul MN 55165 52431 ITT Electric Santa Ana CA 92702 Hewlett Packard Palo Alto CA 94304 50434 CLB Centralab Division Dale Electronics Inc Milwaukee 53201 71590 Columbys NE 6860 91637 INSTRUCTION MANUAL REPLACEABLE PARTS Digital Multimeter Models 172 173 TABLE 7 1 Cont d FEDERAL FEDERAL SUPPLY SUPPLY NAME AND ADDRESS CODE NAME AND ADDRESS CODE Intersil Inc RCL Electronics Inc Cupertino CA 95014 Manchester NH 03102 01686 IRC Division Siemens Corporation Burlington IA 52601 Iselin NJ 08830 25088 Reithley Instruments Inc Signetics Corp Cleveland Ohio 44139 Sunnyvate CA 94086 18324 Littlefuse Inc Siliconix Inc Des Plaines IL 60016 Santa Clara CA 95054 17856 Molex Sprague Electric Co Downers Grove IL 60515 Visalia 93278 14659 Motorola Semi Prod Inc Texas Instruments Inc Phoenix AZ 85008 Dallas TX 75231 01295 National Semi Corp Tepro Electric Corp Santa Clara CA 95051 Rochester NY 14606 02985 Potter amp Brumfield Temple Princeton IN 47670 Tecate CA 92080 29505 Paktron TRW Capacitor Div Vienna VA 22180 Ogallala NB 69
82. 7 10K R 238 91 R 88 40 2 97 1 R 239 102 R 76 2 7 RP 97 10 TF 44 R 221 1 R 102 120 R 102 120 R 257 15 R 1 686 R 2 100 R 1 270 R 88 6 65R R 88 4 99k R 88 10K R 1 680 R 76 10K R 76 10 AB INSTRUCTION MANUAL Digital Multimeter Models 172 173 REPLACEABLE PARTS RESISTORS R Circuit Mfr Mfr Keithley Desig Description Code Desig Part No 700 SERIES Schematic 28656 R701 Thick Film Resistor Network KI 61 8702 Thick Film Resistor Network TF 62 R703 620 10 1 2W Comp A B 620 10 R 1 62 R704 5 0 5W 2 2 s 7 2PMR 5K RP 97 5K R705 500 Potentiometer 0 54 72 500 97 500 R706 335 3 RR 0 1 1 TRW MAR 6 T10 0 12 R 241 335 3K R707 Potentiometer 0 5W 72 IR RP 97 IR R708 3 280 0 1 1 8W IRC MARG R 240 3 280K R709 50 Potentiometer 0 5W 72PMR 50 RP 97 50 R710 33 2 0 25 20 CAD MG721 R 2h2 33 2M 800 SERIES Schematic 28656 R801 150 1 1 84 MtF IRC 150 R 88 150K R802 2 196 kn 0 1 1 84 MF IRC MAR 6 R 241 2 196K R803 50 0 Potentiometer 0 5W BEC 72PMR 50 RP 97 50 amp 805 10 ko 10 1 4W Comp A B CB 103 10 R 76 10K 8805 68 1 kQ 1 MET uos IRC CEA TO 68 IK R 88 68 1K R806 68 1 1 1 8W
83. 73 2 Line Fuse Requirement The Model 172 173 use a single line fuse to protect the line operated power supply The fuse is a 3 AB or 3 AG slow blow type Replace with 1 4 ampere for 117 volts operation or 1 8 ampere for 234 volts IMPORTANT A Replace fuse with correct rating otherwise damage to the instrument could result 3 How to Replace the Line Fuse The fuse is installed on the main circuit board as shown in Figure 36 page 6 10 The top cover must be removed to gain access to the circuit board as described in Section 6 Use Keithley FU 17 for 117 FU 20 for 234V WARNING Disconnect the line cord before removing the top cover of the instrument Line voltage is present at various points on the circuit board and represent a SHOCK HAZARD CAUTION N The fuse installed on the rear panel of the Model 172 173 is used only for current range protection This fuse is not a line voltage protection fuse b Battery Power To operate the Model 172 173 from batteries the Model 1728 Rechargeable Battery Pack must be installed The Model 1728 can be either field or factory installed at the time the Model 172 173 is purchased NOTE The Model 1728 Rechargeable Battery Pack can be installed by the user within the Model 172 173 at any time However if the Model 1722 Digital Output is already installed the Model 1728 cannot be used simultaneously 1 How to Install the Mode 1728 Rechargeable Battery Pack The batteries furnishe
84. 8 0 56 of final reading 1000 v Meri wi Mp NUS 10 YOkHz 02 0 59 INPUT IMPEDANCE 2 megohms shunted by less than 50 picotarads verage responding an rms sine wav COMMON MODE REJECTION RATIO tx unbaiance Lo driven Greater EE EM e Delta than 10038 at cc and 50 to BOHz decreasing 10 70 dB ot 1001 AS AN AUTO MANUAL RANGING OHMMETER TEMPERATURE MAXIMUM VOLTAGE COEFFICIENT ACCURACY 1 year 202 302 ACROSS UNKNOWN ALLOWABLE 07 20 C and 30 55 C1 READING 21 ol rdg digits ON RANGE 4 T LEAD 01109 digis C RANGE MAXIMUM HI mode Lo HI mode 10 ___ RESISTANCE 8 __ mode to 329 9 0 035 03v _ Cre 3k t 00359 19 0035 1 3v C3v 00035 COL 2 304 6 0 035 10 00365 td 3v 0003 012 0063 jc 0 035 1d 0046 10 3v 63v O0G3 012 COOA 36 3M t 005 9 18 015 5510 3v 023v 00049 Ord 002 s C le 018 9 414 08 1 03v 0 02 Gig 015 C 1c 300M 15 14 015 032 Maximum open circull voltage 5 votts CONFIGURATION 4 termina or 2 terminal switch selected ANALOG SETTLING TIME on range Hi ohms 10M less than 0 4 MAXIMUM ALLOWABLE INPUT 360V 250V rms or dc second to within 0 01 of final reading to 100M and Lo ohms less than 1 7 seconds to within 0 01 of final reading AS AN AUTO MANUAL RANGING AC AND DC AMMETER MODEL 172 ONLY MODEL 173 ONLY AC A
85. 8019 01101 Hex Inverters Open Collector Output TEXAS SN74LSOSN IC 11 01102 Hex Inverters Open Collector Output TEXAS SN74LSOSN 16 1481 01103 Hex Inverters Open Collector Output TEXAS SN74LSOSN 01108 Positive NAND Gates and Inverters Totem pole Outputs TEXAS SN7ALSIAN 1 137 01105 Hex Inverters Open Collector Output TEXAS SN74LSOSN 16 147 01106 Dual D Type Flip Flop lh pin RCA CD4013AE IC 103 01107 Quad 2 Input J4 pin DIP RCA 8001 1 108 01108 COS MOS 8 Stage Static Shift Register 4 2 s ow ow W se 2 08021 16 130 41109 Quad 2 Input AND 14 DIP RCA CO4081BE IC 138 11110 05 05 Dual 4 Input NAND Gates RCA CD40 2AE 1 180 01111 Six COS MOS Hex Inverter RCA CD4O69BE 1C 139 VOLTAGE REGULATORS VR Circuit Mfr MFR Keithley Desig Description Code Desig Part No 11100 SERIES Schematic 28656 VRIOI Zener 9 1V S0OMW a s DIC 1N960B 02 55 VR102 Zener 6 2V Wis 5 o Le obse 1 827 02 48 8200 SERIES Schematic 28656E VR201 Zener 6 2V 1 4W Part of matched set 280408 VR202 Zener 9V Part of matched set 280406 VR203 Zener 12V 00 DIC 1N963B 02 58 600 SERIES Schematic 28656 VR601 Voltage Regulator 8V Case 92 NAT LM350LAZ 8 0 1C 164 VR602 Regulator 5v Case 70 220 1C 93
86. 8V 12V 8V 5 12 CC gt INSTRUCTION MANUAL THEORY OF OPERATION Digital Multimeter Models 172 173 5 6 MODEL 1728 RECHARGEABLE BATTERY PACK The Model 1728 provides 19 2 voits and 48 4 volts from nickel cadimum batteries 87401 and BT402 19 2 volt 45 AH nickel cadmimum packs which are fused by 1 Slo Blo fuses BT403 is an 8 4V pack composed of seven 1 2 volt cells and is also fused by 3AG Slo Blo fuse The Model 1728 has a built in recharging circuit which operated from 29 5V unregulated supplied by the DMM line power supply a 87801 Charging BT401l is charged via a constant current from 0401 Diodes and CR402 and resistor R402 place a diode drop across The resulting current is the maximum charging current Diode CR403 prevents the battery from supplying current through 0401 maximum charging current occurs only when the DMM is set to OFF A trickle charge is maintained when the DMM is line operated The reduced current is obtained by inserting a limiting resistor in series with the charging circuit not shown on Schematic 26758C full charge the batteries are charged at a 10 rate 45 mA for 6 BT4O2 6 200mA for BT403 When trickle charged the charge rate varies according to line voltage amp battery condition from a minimum of C 100 rate to a maximum of C 20 rate Thus trickle charge may never fully charge the batteries but is intended to
87. ACCESSORIES Digital Multimeter Models 172 173 MODEL 1651 CURRENT SHUNT Description The Model 1651 15 a 0 001 ohm shunt for use with an AC or DC voltmeter having at least 100 microvolts resolution The shunt is rated at up to 50 amperes 4 6 CABLES AND CONNECTORS The following cables and connection Kits enable effective use of the Model 172 173 MODEL 1683 UNIVERSAL TEST LEAD KIT Description The Model 1683 is a set of flexible test leads 40 in Im in length with interchangeable screw on adapters MODEL 1681 CLIP ON TEST LEAD KIT Description The Model 1681 is a set of test leads 48 in 1 2m in length terminated by a banana plug and spring action clip on probe MODEL 1727 DIGITAL OUTPUT CABLE SET Description The Model 1727 is a cable set consisting of 26 and 40 conductor ribbon cable terminated by mating card edge connectors to the model 1722 The Model 1727 3 is 3 feet long 1 m and the Model 1727 10 is ten feet long 3 1 m MODEL 7004 SHIELDED CABLE Description The Model 7004 cable is a shielded cable 42 inches 1 1 m long and is terminated by 2 tinned leads plus shield Two banana plug adapters are furnished for use with Models 172 173 Application The Model 7004 cable is useful when making low level voltage connections to the Model 702 7029 Low Voltage Scanner both analog INPUT and OUTPUT The shield may be connected to the GUARD terminal 4 7 MISCELLANEOUS MODEL 1725 MAINTENANCE KIT Descri
88. Basic Functional Blocks of A D Converter 5 14 28 Basic Charge Balance Converter Q Q 15 15 29 Operating Waveforms of A D Converter 4 15 15 30 Simplified Schematic of A D Converter 15 18 31 Detailed Schematic of A D Converter 5 20 32 A D Converter System Timing 15 21 33 Model 1722 Bloch Diagram 5 24 34a Simplified Ohms Diagram Shown i in 2 WIRE Configuration 5725 34b Four Wire Ohms Measuring Technique INSTRUCTION MANUAL Digital Multimeter Models 172 173 12 75 324 10 75 273 8 5 3 25 216 83 DIMENSIONS IN INCHES MM 19 0 483 TMLRY AUTOR Mee Dein FIGURE 1 Dimensional Data INSTRUCTION MANUAL Digital Multimeter Models 172 173 AA RANGING Automatic or manual Upranges at 30000 downranges at 02599 OVERLOAD INDICATION Blinks above 1200V de 1000 ac Blanks last tour digits above 29999 counts on all other ranges Model 1727 Mating Output Connector Set Model 1723 IEEE Standard Bus Interface NOTE Models 1722 1723 and 1728 can only be installed and used Model 1682 RF Probe one at a time Model 1683 Universal Test Lead Kit SPECIFICATIONS Calibrated at 25 C 21 C AS AN AUTO MANUAL RANGING DC VOLTMETER TEMPERATURE COEFFICIENT MAXIMUM ACCURACY i 5 of rdg digits 0 20 C 30 55 C INPUT MAXIMUM RANGE READING
89. C This pushbutton must be used with V A to select either DC voltaqe or DC cur rent functions l DC Voltage Depress DC Release V A 2 DC Current Depress DC bepress V A AC This pushbutton must be used with to select either AC voltage or AC cur rent fuactions Button Depressed BAT NEITHER LINE NOR BAT 1 AC Voltage Depress Release V A 2 AC Current Depress AC Depress V A c V A This pushbutton selects either voltage V or current A When V A is depressed along with DC or AC a shunt resistor is connected across the and LO terminals to pro vide current sensing d 0 Depress to measure resistance NOTE DC AC and pushbuttons are interlocked so that only one pushbutton is depressed at a time However it is possible to have all pushbuttons out which disconnects the input and LO terminals and no measurement can be made The Q indicator will be lighted in this instance INSTRUCTION MANUAL OPERATING INSTRUCTIONS Digital Multimeter Models 172 173 st 2 P es E p AUTORANGING DMM FIGURE 8 Front Panel Pushbutton Selection 3 4 HOW TO SELECT RANGE The Model 172 173 provides automatic or manual ranging The AUTO MAN pushbutton determines the ranging mode where AUTO fully automatic ranging a AUTO When released the Model 172 173 automatically selects the appropriate range in accord with the following rules l
90. CCURACY AC ACCURACY DC ACCURACY 1 year 207 30 C INPUT FUSE DC ACCURACY 1 year 20 30 C INPUT FUSE MAXIMUM 1 year 20 30 C 50Hz SkHz RESIST PROTEC MAXIMUM 1 year 20 30 50 5 RESIST PROTEC RANGE READING ofrdg digiis of r g digits ANCE TION RANGE READING ol rdg digits 2 of r g digits ANCE TION 300mA 29999 0 25 24 0 5 1Bd 130 2A 3004 29999 01 22 03 185 2 2 0006 025 2d 0 5 18 130 2 2 9995 0 1 28 03 182 10 t 29995 01 2d 03 155 300mA 299 99 01 2 03 182 12 3 2 9999 01 25 0356 185 04 t Self healing effects of currents greater tnan 1 ampere can 0 016 ot reading TEMPERATURE COEFFICIENT 0 20 C and 30 55 DC 2 0 005 reading 0 2 digits C 0 03 of reading 1 digit C ANALOG SETTLING TIME on range DC less than 03 second to within 0 01 of tinal reading jess than 0 5 second 10 within 0 05 tina reading GENERAL ZERO STABILITY Autozeroed to within accuracy specifications 0 C 55 C SELF CHECK Rear panet tip jacks give of functional operation DISPLAY 4 2 digits appropriate decimal position function and polarity on 30 volt ac and dc ranges 30k ranges and 3mA ac and dc ranges indication Three readings per second WARMUP 1 hour to rated accuracy CONVERSION PERIOD 320 milliseconds ENVIRONMENT witho
91. ECTORS P Circuit Mfr Mfr Keithley esig Description Code Desig Part No 900 SERIES Schematic 28656 901 Connector 8 pin BRG 65507 136 CS 339 8 P902 Connector b pin a 65507 136 CS 339 1 1000 SERIES Schematic 27902 PC 415 1001 Not Used 1002 Not Used P1003 Not Used Pap gt ey pd cum Es Connector 10 pins MOL 09 67 1104 CS 331 10 21005 Connector 12 pins MOL 09 67 1124 CS 331 12 1006 dae 80 pins part of Model 1727 MMM 3464 0000 CS 294 3 81100 SERIES Schematic 28019 1101 Card edge 26 pin part of Model 1727 MMM 3462 0000 CS 294 TRANSISTORS Q Circuit Mfr Mfr Keithley Des ig Description Code Desig Part No 000 SERIES Schematic 28656 3001 Transistor Dual Monolithic PNP A D AD820 TG 121 3002 NPN Case T0 106 Fel 2N5134 T6 65 Q003 NPN Case 0 106 F I 245138 16 65 8100 SERIES Schematic 28656 101 PNP Silicon T0 92 Case MOT 2N3905 TG 53 0102 Differential Amp INT 17122 TG 73 Q103 NPN Case 0 106 Selected 1 TG 39 F 1 2N3565 28234A 2104 P Chan MOS FET M INT 3N163 TG 126 3105 Differential AMP INT 17122 TG 73 0106 Dual FET TG 118 3107 N Chan J FET Case To 18 dios rds INT 1753538 TG 88 3108 N Chan J FET INT 1TE4392 TG 77 0109 N Cha
92. F I UGH7805393 28515 VR603 Regulator 15V 0 66 Case RAY RCAI95TK IC 128 800 SERIES Schematic 28656E VR801 Zener 12V hO0mW 0 1N963B DZ 54 2 24 INSTRUCTION MANUAL Digital Multimeter Models 172 173 JUMPERS W Circuit Mfr Desig Description Code Desig 200 SERIES Schematic 28656 W201 K 1 2 2 500 SERIES Schematic 28656 W501 600 SERIES SCHEMATIC 28656 W601 800 SERIES SCHEMATIC 28656 801 K 1 900 SERIES Schematic 28656 w901 Used oniy on Model 173 K 1 AB REPLACEABLE PARTS Keithley Part No J 3 J 3 4 3 4 3 WIRE REPLACEABLE PARTS INSTRUCTION MANUAL Digitat Multimeter Models 172 173 MISCELLANEOUS RE ETHLEY DESCRIPTION PART NO n F Y B Top Cover less metalcal 27979 Metalcal for top cover MC 236 Bottom Cover less metalcals 25727 Metalcal operating instructions 239 Metalcal rear panel MC 235 Handle less insert 257290 Insert 2 req d 26090A Spacer 4 req d 257628 Rubber foot 4 req d FE 10 Front Panel Model 172 28029A Front Panel Model 173 27958A QC Ring Used to hold display board GA 18 INSTRUCTION MANUAL REPLACEABLE PARTS Digital Multimeter Models 172 173 TABLE 7 2 COMPONENT DESIGNATIONS FOR 407 MODEL 173 See Figure 43 1 i 1 Location Circuit Location Circuit Location
93. GED 100 STROBE CB INSTRUCTION MANUAL Digital Multimeter Modeis 172 173 OPERATING INSTRUCTIONS 2 h 6 6 101215 1618 20 222426 1 3 5 7 9111315 1719212325 L 6 10 121516 182022252628 3032 38 38 hC 3 5 7 9 111315 17192123252729 3133 35 3739 FIGURE 17 Connector Pin Identification for 1006 and P1101 epe fe Mates with P1101 soles sels sz oloslas Mates with Mates with _________ 9 5 de bilo FIGURE 18 Card Edge Connectors Model 1727 Cable Set How to Select Vext Using Internal Jumper The Model 1722 may wired for use with internal or external voltage references and internal pull up resistors See Figure 16 1 Jumper A When this jumper is installed the pull up resistors are connected to the external reference Vext 8 P1006 2 Jumper B When this jumper is installed the pull up resistors are connected to the internal reference 454 3 Jumper C When this jumper is installed Vext is connected to internal 45V reference The pull up resistors are not connected in this instance The 5 volt reference is rated at 40 mA maximum CB 3 17 OPERATING INSTRUCTIONS INSTRUCTION MANUAL Digital Multimeter Models 172 173 LOCATION OF OPTIONAL PULL UPS JOPTLONAL JUMPER INSTALLS ERA 157253 5 42 2 1559 15500 373 FIGURE 19 Location of Ju
94. Hz IMPORTANT For use On the 3 volt range the banana plug adapter with 10 megohm resistor should be used since the Model 172 173 input resistance is 21000 megohms on the 3 volt and 0 3 volt ranges Model 1685 Clamp On AC Current Probe Set the Model 172 173 to AC volts and 0 3 volt range The Model 1685 provides a 0 1 volt rms output corresponding to a ampere rms input Review the instructions furnished with the Model 1685 to achieve best pos sible accuracy d Model 1651 Current Shunt Set the Model 172 173 to AC or DC volts as appropriate and 0 3 volt range Connect the voltage leads to the Model 172 173 input terminals Connect separate leads not furnished between the source and the Mode 1651 hex head bolts The Model 1651 shunt resistance is 0 001 ohm which produces a sensitivity of 1 millivolt per ampere INSTRUCTION MANUAL OPERATING INSTRUCTIONS Digital Multimeter Models 172 173 3 12 HOW TO USE THE MODEL 1722 DIGITAL INTERFACE a General THE Model 1722 provides binary coded decimal outputs 8421 and range control lines Outputs are open collector positive true unless otherwise specified This accessory is available either factory installed or field installable The Model 1722 consists of a two layer circuit with card edge and mating output connectors b Installation 1 Disconnect the Model 172 173 line cord from line voltage 2 Turn the instrument over so that the bottom cover faces up 3 L
95. LO ENSE gt ni SENSE t gt 2 2 N s m 102098 6 DC ADJ CRSOS NOTES ALL RESISTOR VALUES ARE IN OHMS UNLESS MARKED OTHERWISE R XILORMS M MEGOHMS ALL CAPACITOR VALUES ARE IN Mi CROFA RADS UNLESS MAAKEC OTHERWISE pF PICOFARADS CENOTES INTERNAL DENOTES CLOCKWISE ROTATION OENOTES REAA CONTROL HIGHEST SCHEMATIC DESIGNATIONS USED F EE LL LS 15293 ads ca r Ram re 1 4401 4 3 4 8 4V OUT J402 5 3 R405 0403 409 UNREG 3 3 4 RE 419 2V OUT le29 5v CR403 NREG 2 9 2 2 29 5V UNREG NOTES I ALL RESISTOR VALUES ARE IN OHMS 9 2 OUT UNLESS MARKED OTHERWISE K KILOHMS 76 2 DENOTES POWER SUPPLY COMMON s TO LO BAT LED HIGHEST SCHEMATIC USED M MEM MEM scaue nee BCALE Bip ES poate 4 219 scar m 1778 SCHEMATIC PC 404 COT Om Sel E7272 BATTERY PACK 4 inervaduanre Dg 267586
96. Location Desig Code Desig Code Desig Code N 10 R927 NS P 9 R928 NS 5 11 R929 NS 6 8930 20 N 4 R931 p 20 i Q 4 4 5601 B 20 R 3 R 2 T601 D 7 W901 f 19 T 6 101 M 23 T 6 TP102 M 24 T 5 9 0001 J 28 y 8 U002 N 27 W 5 U003 0 29 V 4 U004 U 28 W 2 U005 26 b 4 i 2 2 U101 H 20 2 0102 P 21 0103 26 i i U 12 T 1 U201 W 23 9 11 0202 X 20 T 9 U 10 0701 S 15 0 9 0702 13 NOT USED NOT USED 0901 4 1 12 VROO X 29 W 11 VRIO F 26 12 VRIO2 G 21 2 12 12 VR201 gt 4 19 NOT USED VR202 N 18 i b 8 VR203 2 23 c 7 4 12 VR601 8 25 e 12 VR602 F 16 11 VR603 L 13 10 12 VR801 Y 9 f 11 g 5 20 P 18 e 18 f 19 W601 D 29 f 18 W602 0 29 AB RANA AA ora Se TER te pcm jaso 5 ac 9301 05302 INPUTS O oo SEE NOTES SHIFT REGISTER ALL RESISTOR VALUES ARE IN OHMS ALI CAPACITOR VALUF S ARE IN MICROFAPADS FOR MODEL 172 055 6 05307 AND 05299 ADE USED AND DS3OP AND BECOME DUAL FUNCTION AND v e A Sr SPECTINELY BO JA ms T ET a a tS UE MATIC DESIGNATIONS 1532 72 NT USED eil d UT E co Ica sos i o 4 4 4 4 voe 2501 502 FOR MODEL 173
97. Mfr Desig 500 SERIES Schematic 28067D 900 2 0 052 1 2W 90 2 0 052 9 1 0 0 5 499 Q 12 y 1 8 1 2M 1 8W MtF 10 0 50 Var 0 91 9 0 5 Sw 40 2 Q 1 1 0 5W 1 8W MtF 0 102 2 0 5 104 2 7 Q 102 10 2 0 5 Thick Film Resistor Netw WW used on Model 15 0 12 l hW Comp Var ork IRC IRC TEP RC BEC TEP IRC BEC TEP A B BEC Rel 173 only 8514 used Model 172 only 30 1K2 1 30 1KQ 1 30 1KQ 18 120 0 5 120 2 5 159 680 Q 102 100 Q 103 2702 10 6 65 12 4 9 1 10 RR 1 680 2 10 10 10 100 10 1 8 MtF 1 84 1 84 600 SERIES Schematic IW Comp IW Comp 4 5 WM e 1 24 Comp Comp 1 2W Comp 1 8wW MtF 1 8W MtF 1 8W MtF 1 2W Comp 1 4W Comp 1 4W Comp IRC IRC IRC we a MC MAR6 9002 MAR6 902 TS 5S 9 15 899 72PMR 10K 155 0 91 0 40 2 72 510 0 1022 CB 2R7 10 72PMR 10 5 10 14 30 1 12 30 1 13 CEA 30 1K 1 28656E GB 121 5 68 121 5 4565 681 10 GB 101 10 271 10 CEA TO 6 65 CEA TO 4 99K 0 10 681 10 103 10 8 100 10 INSTRUCTION MANUAL Digital Multimeter Models 172 173 Reithley Part No R 236 900 R 236 90 R 237 9 1 R 88 499 RP 9
98. ON MANUAL Digital Multimeter Models 172 173 Circuit Mfr Keithley Desig Description Code Desig Part No 600 SERIES Schematic 280670 4601 2 pins MOL 2139 2 CS 275 4602 Not Used 4 0 603 Not Used 4604 3 Housing 204 PEE BRG 65039 034 CS 270 Ssss Female pin 3 req ig for J604 BRG 75691 005 CS 236 J605 Not Used 3606 Not Used En 4607 Tip Jach Recessed Red EFJ 105 0602 001 BJ 10 2 J608 Tip Jack Recessed White EFJ 105 0610 001 BJ 10 9 J609 Tip Jack Recessed Blue EFJ 105 0601 001 BJ 10 6 4900 SERIES Schematic 28656E 4901 Not Used 3902 Not Used 4903 Banana Jack Red POM 2854 BJ 9 2 J904 Banana Jach Blach POM 2854 BJ 9 J905 Banana Jach Red 2854 BJ 9 2 J906 Banana Jack Black POM 2854 BJ 9 0 1000 SERIES Schematic 27902 41001 Housing S pins mates with CS 236 20370 ESS261 31002 Housing 6 pins s s x 0 a4 BERG 65043 093 55335 41003 Housing 2 pins BERG 65039 035 CS 266 11007 SERIES Schematic 28019 41101 Not Used 41102 Not Used 41103 Not Used Tu J1104 Card edge Connector MOL 09 52 3102 CS 332 10 41105 Card edge connector MOL 09 52 3122 5 332 12 INSTRUCTION MANUAL Digital Multimeter Models 172 173 Circuit Desig K501 K502 K503 K504 K505 K801 K901 Circuit Desig
99. ORANGE AUTORANGE 24 AA INSTRUCTION MANUAL OPERATING INSTRUCTIONS Digital Multimeter Models 172 173 3 13 COMMENTS RELATIVE TO THE MODEL 172 173 SPECIFICATIONS Above ampere there is decrease in accuracy This decrease in accuracy is due toself heating and the temperature coefficient of the resistors that are used in these currents This degradation in accur acy will not exceed those values that are listed in the specification sheet However prolonged operation at the high currents for instance 2 amperes on the Model 172 or 3 amperes on the Model 173 may give temporary zero shifts because of the thermals which are generated due to the self heating of the devices AC voltage specifications are listed down to 1 of range Below 1 of range additional 10 digits is added to the accuracy This does not occur immediately at the 1 level but gradually as the level is decreased because the zero of the ac dc converter is not very well defined It has to overcome the threshhold level of various semiconductor devices a MOS FET and diode As a result there will typically be a 10 digit offset at zero even with the input shorted on the 300 millivolt range and on the 30 volt range The 30 volt range offset wil be somewhat smaller because the noise mill be somewhat less For best accuracy use the Model 172 173 on whatever range gives the largest reading Autoranging will accomplish this automatically 3 14 MODEL 1728 OPERATING TIP
100. Observe the displayed digits decimal point location and measurement unit AC ma or AC FIGURE 9 Typical Model 172 Current Display DCmA CB 3 5 OPERATING INSTRUCTIONS INSTRUCTION MANUAL Digital Multimeter Models 172 173 3 7 HOW TO MEASURE CURRENT MODEL 173 ONLY The Model 173 measures ac and de current in five ranges 0 3mA 3mA 30mA 0 3A and CAUTION The Model 173 DMM is protected by a 3 ampere fuse on all ranges If the fuse is blown a replacement Keithley Part No FU 2 should be installed in the rear panel fuse holder See Figure 5 DC Current The Model 173 DMM detects dc currents from 10 nanoamperes to 23 amperes The maximum display is 29999 When the display exceeds 29999 a 3 remains lighted but all other digits are blanked l Set to DC Amperes 2 Set to AUTO 3 Connect the signal to be measured at the HI terminal h Observe the displayed digits polarity sign decimal point location and measure ment unit mA or A If no polarity sign is indicated a positive polarity is implied b AC Current The Model 173 DMM detects ac currents from 10 nanoamperes rms digit 0 3 amperes rms The maximum display is 29999 When the display exceeds 29999 a 3 remains lighted but all other digits are blanked Set to AC Amperes The AC indicator should be lighted 2 Set to AUTO 3 Connect the signal to be measured at the Hi terminal 4 Observe the displayed digit
101. R103 AUTO CAL ACAL for a level of 1V 0 2 during AUTO CAL time period INSTRUCTION MANUAL MAINTENANCE Digital Multimeter Models 172 173 IMPORTANT When adjusting trimmer capacitors C203 C205 C817 C819 820 and C821 use an insulated screwdriver to avoid shorting to the metal shield In addition the screwdriver should be rigid so that adjustments can be made with minimum backlash R103 R90 R201 R707 WARNING DISCONNECT LINI CORD BU ORC SERVICING LE 2 Lae mii 7 ACD RE r EB fi Model 173 is shown above with Current Board Installed Model 172 has a 12 Low Resistor R514 mounted on the metal shield Not shown FIGURE 37 Location of Calibration Adjustments MAINTENANCE INSTRUCTION MANUAL Digital Multimeter Models 172 173 Regulator VR603 requires the use of heat sink assembly Reithley part no 28203A If the regulator must be removed bend the tabs the h eat sink to provide clearance After a new regulator is installed bend the heat sink t bs to their original condition to avoid a short circuit to the meta shield or other conduct ing surfaces adjacent to the regulator L VR603 4 BARNIAG DISCOMMECT pint COR Buh SOS ON FIGURE 38 Locations of Connectors and Test Points AA INSTRUCTION MANUAL 4 MAINTENANCE Digital Multimeter Models 172 173 SIGNAL INTEGRATION PREFILTER OUTPUT
102. RATION period the output at 102 Prefilter has no more than 10 transitions from positive slope to negative slope and vice versa d DC Voltage Calibration Depress DC release V A depress AUTO MAN 1 Zero Adjustments a Connect the DC Calibrator to the input terminals b Set the instrument on the 300 mV range by using DOWN RANGE NOTE It may be necessary to compensate for dc offset of the DC Calibrator For example if the dc offset is 2 uV dc then the DC Calibrator should be adjusted 2 uV to compensate for the offset Use a Keithley Model 155 c Set the DC Calibrator for an output of 5 uV see note above d Adjust the 300 mV ZERO 8908 for a display which flashes between 0 and e Set the instrument on the 30 V range f Set the DC Calibrator for an output of 5 mV g Adjust the 30 V ZERO R913 for a display which flashes between 0 and I 2 Full Range Calibration a Connect the DC Calibrator to the input terminals b Set the instrument to the range given in Table 6 11 c Set the DC Calibrator to the output given in Table 6 11 d Adjust the control given in Table 6 llto achieve the display specified NOTE Perform the calibration in the exact order given TABLE 6 11 Full Range DC Calibration 2 9 V ADJ R213 2 9000 to 42 9001 V 290 V ADJ 8911 290 00 to 290 01 V Applied Input 2 90005 290 005 29 0005 1000 05 ange Setting lt
103. RGE BALANCE c SYSTEM AUTO Z2ERO SIGNAL ANC INPUT AUTO CALIBRATE SYSTEM CORRECTION SIGNALS O PULSE TRAIN OUTPUT CONTROL SIGNALS DIGITAL CONTROL SIGNALS 151 DESPLAY INFORMATION gt DIGITAL INTERFACE INFORMATION FRONT PANEL CONTROLS FIGURE 27 Basic Functional Blocks of A D Converter 5 14 AB INSTRUCTION MANUAL THEORY OF OPERATION Diglta Multimeter Models 172 173 b AB Voltage to Frequency Converter 1 The greatly simplified circuit shown in Figure 28 illustrates the basic principles of the charge balance V F converter Its operating waveforms are shown in Figure 29 Assume the integrating capacitor voltage Vi to be initally negative As the input signal current l is integrated by the capacitor V rises and even tually becomes more positive than the threshhold of the comparator time t in Figure 29 The comparator output voltage Ve which is a logical variable then rises to logic At the next positive going edge Of the clock CID time t2 in Figure 29 this is latched by the flip flop and appears as the latched output QR A quarter of a clock period after that event at 537 the out of phase clock Cl goes high and enables the output of the AND gate thereby turning on the current switch For the next half clock period from t to t the reference current is forced to flow out of the integrating capacitor dischargins it and bringing V t
104. RIES Schematic 28656 S601 Switch Slide DPDT ao do C W GF326 0006 SW 397 900 SERIES Schematic 27903E 5901 Modified W 393 Kel 280048 TRANSFORMERS T Circuit Mfr Mfr Reithley Desig Description Code Desig Part 600 SERIES Schematic 28656 T601 Power Transformer TR 163 11000 SERIES Schematic 27902E T1001 Transformer 4 a TR 164 REPLACEABLE PARTS Circuit Desig 400 1 0002 003 J004 005 3101 9102 0103 0201 0202 INTEGRATED CIRCUITS U Description Code 000 SERIES Schematic Transistor array l pin DIP RCA Flip Flop l4 pin DIP 4 Fri Flip Flop l4 pin DIP Fl Hex Inverter l6 pin DIP RCA Timing Logic 8 pin DIP SIG 100 SERIES Schematic Linear Op Amp 8 pin DIP INT Large Scale Integrated Circuit K I Large Scale Integrated Circuit 200 SERIES Schematic Transistor array 14 DIP RCA Operational Amplifier 8 pin TO 5 Case ee er ae Selected 10 53 U301 0801 0501 0502 0701 0702 7 24 300 SERIES Schematic 8 Bit Parallel Out Serial Shift Register 1 DIP T I 400 SERIES Schematic Operational Amplifier 8 pin 500 SERIES Schematic Operational Amplifier 8 pin DIP INT COS MOS BCD TO DECIMAL decoder l6 pin DIP
105. RMANCE VERIFICATION 1 2 3 E 5 h ADJUSTMENT CALIBRATION PROCEDURE 5 TROUBLESHOOTING AND REPAIR PLACEABLE PARTS 1 GENERAL 2 ORDERING INFORMATION 3 SCHEMATICS M 6 6 6 6 6 RE J 7 7 ILLUSTRATIONS igure No Title Dimensional Data div 2 Tilt Bail Positions Livi 3 Front Panel 411 2 m Bottom View Showing Line Cord 1 3 5 Rear Panel Showing Current Fuse and Check Points 12 2 6 Model 1728 Rechargeable Battery Pack 2 amp 7 Installation of Battery Pack 2 5 8 Front Panel Pushbutton Selection 3 3 9 Typical Model 172 Current Display 3 5 10 Typical Model 173 Current Display u Typical 2 WIRE Resistance Measurement 3 7 12 Typical 4 WIRE Resistance Measurement 13 Semiconductor Diode and Transistor Testing 14 Illustration of Floating Operation 13 11 15 Model 1722 Digital Output Interface 13 14 16 installation of Model 1722 17 Connector Pin Identification 17 18 Card Edge Connectors a 17 19 Location of Jumpers and Pull Migs on Model 1722 5 20 Model 1010 Single Rack Mounting Kit 21 Model 1017 Dual Rack Mounting Kit 202 2 22 Overall Block Diagram of Model de Morus a Ue 23 DC Volts Input Circuit 5 4 2h Simplified AC Attenuator Circuit E 5 6 25 AC Converter Circuit 2 6 26 Digital Display Multiplex Scheme 27
106. ROBE i nme ds P lt T NN 104 STROBE 5 i lt i 193 STROBE 5 s Q STROBE j i 5 51 pr 30 STROBE wo d 42 109 STROBE T gre i i vey DR s D MES d Pe ift eR LE f T s ak Quo tt WELK SERDAT c SDAT SEE SCHEMATIC VERT BANTER gt AC 5 PILARIT 6 amp lt OVERFLO A E TION 94 SERCLE T PON L YW SU SCHEMATIC NOT DO NOT SC 7 4 nt KEITMLET AMD we DIGITAL NTESPACE BOTTOM 5 27902E N N x H 9 3 3 9 8 Y o ryt LLLE L w DOS 8 79041 0915 wisi yoonoinv WORD ASe xTom Jirgen 18140 3miidn n n q 6 vz 4 Va else DE Els DS Vu Y 222 ee RUM aD tee eee s Oun 3149 035090 i A i 042 2012 i i 5 3 4 380815 i Onn 4 30Os1S i 1 sonn h
107. S Although the manufacturers of the nickel cadmium batt eries used in the 1728 claim that their cells can be charged at a 10 rate indefinitely once a cell is fully charged the energy fed to the cell is converted to heat which increases the temperature of the cell If cells are overcharged at 10 rate for extend ed periods of time weeks this may cause cel degradation Keithley recommends that the 1728 not be overcharged for extended periods to maximize useful battery life Trickle charging should have no effect on useful battery life Nickel Cadmium batteries also ex hibit a memory effect If the 1728 is only used to operate the instrument for relatively short periods of time 1 or 2 hours the 1728 may not be able to provide the full operat ing time of 6 hours Do not operate the Multimeter in BAT mode after the LO BAT indicator is lighted The discharge characteristic of Nickel Cadmium batteries is such that it maintains a fairly constant 1 2V through most of its discharge cycle At the end of the discharge curve the cell voltage drops fairly rapidly to zero volts After a given cell in the battery pack drops to zero it is reverse charged by the rest of the cells in series with it Although the cells used in the 1728 are guaranteed by the manufacturer to withstand re verse charge for 10 of their discharge time it is not a good practice to continually reverse charge cells as more rapid cell degradation may occur The cells used in t
108. SERIES Schematic 28019E 01101 NPN Case 0 10 6 Fl 2N5134 TG 65 AB REPLACEABLE PARTS ircuit Desig ROO 1002 4003 6005 005 3006 ROO 1008 3009 3011 3012 013 8018 8101 8102 R103 RIO R105 RI06 R107 R108 R109 R110 RIII R112 R113 R20 R202 R203 R204 R205 R206 R207 R208 R209 R210 R21 R212 Description RESISTORS R Mfr Code INSTRUCTION MANUAL Des ig O00 SERIES Schematic 28656E 6 08 kn 15 1 8W MtF Thick Film Resistor Network 10 kc 102 1 4W Comp 18 kc 10 1 4 Comp 6 8 2 105 1 4W Comp 5 89 2 14 1 8W MtF 7 68 2 1 1 8 IOM2 10 I AW Comp 1002 1 1 8M 1 5 0 1 1 8W MtF 4 22 2 1 1 8W MtF 1 15 0 1 1 8W 9 9 1 1 8W 150 10 1 4W Comp 100 SERIES Schematic 280 1 15 1 8W MtF 280 0 1 1 8W MtF Potentiometer 0 54 6 336 0 1 1 8W MtF 150 1 1 8W 470 105 1 4W Comp 870 2 103 1 4W Comp 200 12 1 8W MtF Thick Film Resistor Network Thick File Resistor Network 2252 101 1 4W Comp 13 52 1 4W Comp 22K2 10 1 4W Comp 22K 10 1 4W Comp ARC Rel A B IRC gt IRC IRC IRC IRC ERC IRC IRC IRC BEC DLE IRC A B A B IRC Rel A B MEP
109. TABLE 7 2 COMPONENT DESIGNATIONS FOR PC 407 MODEL 173 See Figure 43 1 Location Circuit Location Circuit Location Code Code Desig Code 4 2 1229 C612 1 14 CR208 6 23 c 701 TM CR209 E CR210 CR211 d 23 CR212 d 23 802 N B CR213 H 33 c803 Q 9 8214 W 18 C804 R 9 CR601 J 8 C805 N 7 CR602 J 5 C806 N 5 6807 R 8 701 18 C808 R 5 CR702 P 13 C809 5 CR703 5 13 c810 P 2 CR704 13 C811 U 7 CR705 812 V 8 CR801 Q 5 C813 Wed CRBO2 5 814 153 2 C815 X 10 CRBO b 2 C816 5 817 5 9 818 X 3 CR902 9 9 6819 2 6 CR903 h 19 C820 f lt 5 CRIOU m 23 C821 f 4 CR905 NS m 24 05601 30 2901 11 C902 D 19 F601 C 16 C903 f 14 C904 9 14 1 1201 5 30 c905 9 12 C906 g 7 U 6 C907 h 6 C908 9 3 K901 K 9 C909 NS k 26 P101 e 25 C910 NS h 24 P601 31 P602 B 16 001 3 26 P603 K 7 002 1 26 P604 K 4 CROO3 W 30 P605 9 31 CR201 U 19 P606 31 CR202 v 17 CR203 V 19 P901 1 CR204 v 18 P902 1 CR205 W 21 CR206 Y 17 AB 7 29 EPLACEABLE PARTS Circuit Desig 0108 0105 0106 0107 0108 0109 0110 0111 0112 0113 7 30 Location Code 4 21 K 24 L 23 L 2 M 22 M 21 5 23 5 22 S 21 S 20 TABLE 7 2
110. TE i lt ANOD le tay NCO ANAJ icr Za 4 V 9 380914 8 510 300N 539941 ANY 039 010 30 357 M a 45 88 88 02 12 ee E 03 1508 119 0 18902 11219 031683224 ON 118 JOMINDO t 031439224 118 1O81NO2 310818 d 31034 2411921041 513538 v 14 ME MEE daca 2905 TREES mens l 7 Le E dal orang DIST 5533 t OINO Ceo uit 1 m em li prima ioa So i H 1 H u es s il b Z s a OS 4 118 vieQ Cv ui dii 33790 3 i 0 10819 ONY viv aivoon viva 194300 8314 31v040 INANI LSH 39093 R PARTS Circuit l sig 901 C802 C805 06 C808 809 10 toll 812 13 C815 16 117 c818 rq19 20 L321 301 C902 903 304 305 c906 307 308 C909 310 CAPACITORS C Mfr Mfr Description Code Desig 800 SERIES Schematic 28656E 0 1 uF 200V v7 75 625B1C104 10 uF 20V ETT Cel TD2 20 106 20 4 7 20V ETT TAP4X7E200 150 pF 1000V CerD CLB 00 151 20V 3o T02 20 106 20 TO UF 20 ETT
111. TG 39 FET Case 70 18 Selected TG 88 INT 800 SERIES Schematic FET Case TO 72 6 PNP Silicon TO 92 Case MOT Dual FET SIL FET Case 18 Selected TG 88 INT Transistor Array l4 pin RCA Selected 10 53 900 SERIES Schematic N Chan J FET Case 18 INT NPN Case 110 Fei PNP Silicon T0 92 Case MOT 2N4032 2833005 284032 283565 2N5087 500 SERIES Schematic 27478D CA3086 28656E 2N3565 1TE4392 1753538 2N3565 2N5087 1753538 2N3565 283565 11535385 28656 20210 2N3905 E41 11535385 086 28656 1753538 2853643 283905 INSTRUCTION MANUAL Digital Multimeter Models 172 173 Keithley Part No TG 92 TG 117 TG 92 TG 39 TG 61 16 53 TG 39 TG 77 16 88 T6 99 TG 39 TG 61 TG 88 28234A 28234A 28250A TG 119 TG 53 TG 118 28229A 28228A TG 88 TG 123 TG 53 BA INSTRUCTION MANUAL REPLACEABLE PARTS Digital Multimeter Models 172 173 TRANSISTORS Q Circuit Mfr Keithley Desig Description Code Desig Part No 1000 SERIES Schematic 27902 PC 415 01001 NPN Case 70 106 F 2N5134 16 65 01002 NPN Case T0 106 Fel 2N5134 TG 65 01003 NPN Case 0 106 4 F 2N5134 76 65 01004 NPN Case TO 106 F I 2N5134 TG 65 Q1005 NPN Case 0 106 v fel 2N513
112. Thick Film Resistor Network BEC 898 3 R62 TF 43 R303 174255 EE Ds 422287 TR de DCC 1c 8 12 1 R304 2 284 52 1 4W ouo vox DE SBB 2 2 R 218 2 2 400 SERIES Schematic 26758C RAO 13 70 1 1 84 i RC 0 13 72 R 88 13 7 R402 12 10 1 2W Comp A B EB 123 104 amp 1 12 R403 12 10 1 2W Comp A B 123 10 R 1 12K R404 13 79 1 1 8W MtF 4 0 0 70 13 70 R 88 13 7 R405 3 3 8 10 1 2W Comp A B EB 3R3 102 R 1 3 3 R406 1 5 10 1 2 Comp 152 10 R 1 1 5K R407 71 5 kR 1 1 8W 2 IRC CEA TO 71 5K R 88 71 5K R408 100 10 1 4 Comp CB 104 104 R 76 100 R409 2 2 10 1 4 Comp A B CB 222 10 R 76 2 2K R410 76 8 1 1 8W IRC CEA T0 76 8K R 88 76 8K R41 499 1 1 8W IRC CEA TO 499K R 88 499K R412 100 kR 1 1 8W MtF 2 x IRC 100 R 88 100K R413 110 1 1 8W a IRC 110 R 88 110K 199 1 1 8W 8 o 4 o ERC CEA T0 499R 88 499 zPLACEABLE PARTS Circuit Desig R501 R502 R503 R504 R505 R506 R507 R508 R509 R510 8511 8512 8513 8514 515 R516 R517 R601 R602 R603 R604 R605 R606 R607 R608 R609 R610 R611 R612 7 20 Description Not Used RESISTORS R Mfr Code
113. When the display exceeds 29999 the Model 172 173 upranges that 15 it changes to less sensitivity and the decimal point moves appropriately 2 When the display reaches 02599 the Model 172 173 downranges that is it changes to greater sensitivity and the decimal point moves appropriately b MAN When depressed the range is placed in hold The user can cause the Mode 172 173 to uprange or downrange by using the UP RANGE and DN RANGE pushbuttons 1 When DN RANGE is momentarily depressed the Model 172 173 will downrange one decade of sensitivity Each time the pushbutton is depressed and released one downrange will occur until most sensitive range is obtained 2 When UP RANGE is momentarily depressed the Model 172 173 will uprange one decade of sensitivity Each time the pushbutton is depressed and released one uprange will occur until least sensitive range is obtained AA 3 3 OPERATING INSTRUCTIONS INSTRUCTION MANUAL Digital Multimeter Models 172 173 3 5 HOW TO MEASURE VOLTAGE The Model 172 173 measures ac and dc voltage in five ranges 0 3V 30V 300V and 1200V DC 1000VAC CAUTION Maximum input voltage depends on the range selected Table 3 3 gives the maximum A allomable continous input for each range on AC and DC Do not exceed these volt ages Or damage to the instrument mill occur TABLE 3 3 Maximum Allowable Continuous Input DC Voltage DCV _ Range AC Voltage ACV _
114. Y o5 R SW 1 NCTE lt Pi de 2 O Z TABLE 7 2 continued Component Designations For PC 507 Location Code Circuit Desig R927 NS R928 NS g 15 R929 NS 16 R930 p 20 560 B 20 i T601 D 7 TP101 M 23 TP102 M 24 U001 1 28 0002 N 27 9003 9 29 0004 u 28 0005 U 26 U101 H 20 5102 p 24 U 03 26 i 0201 W 23 U202 X 20 0701 5 15 0702 b 13 0901 4 14 VROO x 29 VRIOI F 26 VR102 G 21 VR201 L 19 VR202 N 18 VR203 2 23 VR601 B 25 VR602 F 16 VR603 L 13 VR801 Y 9 w601 D 29 W602 D 29 Circui Desig W801 901 REPLACEABLE PARTS Location t i Code i 7 31 2 pT lt tan LIE el 0503 d INPUTS SHIFT REGISTER 1 ALL RESISTOR VALUES OHMS ti CAPACITOR VALUES ARE IN MICROFARADS FOR MODEL 172 D 306 0 307 AND ARE NOT USED AND 05306 AND 05 70 BECOME DUAL FUNCTION V A AND m V A DFNPECTIVELY GEGT SCHEMATIC DESIGNATION 1352 pm 847 eo los kaso n lt va mus ec ANAN Duet TUE MATIC DESIGNATIONS MOT st b 1 I le Fae DIN EES ISPLAY
115. a function of only the stability of the Q resistor The lead drop in the high terminal of the ohms source amplifier is compensated for by connecting it to auto zero 2 when in the ohms mode Auto zero 2 is the zero for the input signal In 2 wire ohms the leads connect at the front panel binding post Therefore a 4 terminal ohms system exists up to the front panel terminals See Section 5 9 AB 5 7 OF OPERATION INSTRUCTION MANUAL Digital Multimeter Models 172 173 5 The ohms switching FETs 0703 0702 are driven by transistor 0701 and the C line Q710 is driven from the A line and Q707 is driven from the B line These lines are also used and decodes to operate the Model 173 autoranging current Amplifier 0702 is FET input amplifier This amplifier is overload protected by Q709 base emitter junction connected to the signal ground and Q708 base emitter junction connected through Q706 clamp transistor Thus the input swing is clamped Very large voltage excursions on the output side of 0702 are allowed This 15 done by 0708 0705 and CR703 Under normal operating conditions Q704 is operated in the saturated mode However under overload conditions 0708 becomes a current source with its collector to emitter break down handling large voltage excursions when signals are positive with respect to the ohms source high However if signals are negative with respect to the ohms source high CR703 reverse biases cutting off that po
116. able of measuring ac dc voltage ac dc current and resistance 1 2 FEATURES a Automatic Ranging and Polarity b Manual Range Selection and Range Hold c HI and LO Ohms Capability d Line Operation e Optional Battery Operation Model 1728 f Floating Capability to 1400V peak g Optional Isolated Digital Interface Model 1722 1 3 WARRANTY INFORMATION The warranty is stated on the inside front cover of the manual If there is a need for service contact your Keithley representative or author ized repair facility as given in our catalog 1 4 CHANGE NOTICE Improvements or changes to the instrument not incorporated into the manual will be explained on a change notice sheet attached to the inside back cover of the manual 1 5 OPTIONAL MODEL 1728 RECHARGEABLE BATTERY PACK The Model 1728 is accessory battery pack which enables either line or battery operation The Model 1728 has built in recharging circuitry The Model 1728 is field installed on the Model 172 173 chasis 1 6 OPTIONAL MODEL 1722 DIGITAL INTERFACE The model 1722 is a field installable digital output option It provides isolated open collector BCD outputs and control lines IMPORTANT theZ can be found in various places in this Instruction Manual Carefully read the associated CAUTION statements with regard to proper use and handling of the instrument Damage to the instrument may occur if these precautions are ignored The X symbol can be found
117. and control block also decides based on control data input whether there is to be an output update Power isolation for the 1722 is provided by transformer T1001 which is powered by a secondary winding of the DMM power transformer b Signal Isolation The bidirectional data line SERDAT and the two clock lines SERCLK and INCLK each drive an emitter follower made up of transistors Q1036 Q1035 and 01037 whose loads are LED s in the opto isolators are pulled up by resistors 1010 81009 and 1018 which is driven by Q1034 similar to the three just mentioned The out put pullup on U1018 is on the DMM mainframe Power for the DMM side of the isolation is taken directly from the DMM 5 volts through 1016 and C1018 and C1017 which provide the coupling c Power Supply Low voltage ac from the secondary of the DMM transformer is sup plied via pins and on Switching for the power for T1001 provided at J1003 Pins A and B and comes via the DMM mainframe through its Power On switch The secondary of T1001 is rectified filtered and run through an integrated circuit Wreguiator TRIOO where it is again filtered by 1015 C1002 C1003 C1004 CIOI The core of 1001 is connected to chassis ground by a green wire to a screw on the DMM mainframe or transformer Also common mode filtering is performed 1008 and C1006 between output low and chassis ground d Control Block UPCLK the isolated form of INCLK is run to the trigger input
118. ange is 300 millivolts The Model 172 173 measures to 30 megohms in LO mode For the 2 wire method the lower set of termina s is not used 1 Set to LO Onms 2 Set to 2 WIRE 3 Set to AUTO h Connect the resistance under test between the upper set of Hl and LO terminals 5 Observe the displayed digits decimal point location and measurement unit i KG or MQ This illustration 15 typical of a 2 terminal ohmmeter design CURRENT SOURCE OHMMETER When measuring resistance less than 1000 ohms it may be necessary to use the 4 wire mode to eliminate the measuring error of the test leads For example a pair of lOft leads made from 18 AWG copper wire has 0 14 ohms resistance FIGURE ll Typical 2 WIRE Resistance Measurement OPERATING INSTRUCTIONS INSTRUCTION MANUAL Digital Multimeter Models 172 173 3 9 FURTHER MEASUREMENT CONSIDERATIONS a DC Voltage Measurements Overloads When the display exceeds 1200 0V DC all digits blink to indicate an overload condition 2 Input Resistance The input resistance is 1 000 on the 0 3V and ranges 10 the 30V 300V and 3000V ranges The effects of circuit loading should be considered when evaluating total accuracy of measurement See Accuracy 3 Accuracy The Model 172 173 accuracy is specified in terms of of reading and a 2 range For a full range reading of 299 99 mV DC the accuracy of measurement would be 0 03 mV 0 01 mV or 20
119. at Multimeter 172 173 REPLACEABLE PARTS RESISTORS R Circuit Mfr Mfr Keithley Desig Description Code Desig Part No 5200 SERIES Cont d R213 100 RG 52 0 5W eo BRN 32999 11 104 532 RP 114 100K R214 Thick Film Resistor Network Kel TF 51 R215 Thick Film Resistor Network K i TF 45 R216 909 1 1 8W IRC 0 909 R 88 909 R217 10 Potentiometer 0 5W BEC 72PMR RP 97 10K R218 Thick Film Resistor Network K TF 50 R219 128 Ep 1 1 8W MtF voy IRC 1 8 R 88 1 8K R220 10 k2 13 1 8W MEP xoxo IRC CEA TO 10K R 88 10K R221 200 12 1 8W MtF 3o v IRC 10 200 R 88 200 R222 200 1 178W MtF 5 IRC CEA T0 200R R 88 200K R223 39 10 1 4 Comp A B CB 393 10 R 76 39K R224 Thick Film Resistor Network Rel TF 48 R225 10 ko 1 1 84 ERC 0 10 R 88 10K R226 210 0 1 1 8W MtF IRC CEA TO 210K R 88 210K R227 22 Q 10 1 4W Comp CB 100 10 R 76 22K R228 22 Q 10 1 4W Comp 5 A B 100 10 R 76 22K R229 15 10 1 4W Comp A B CB 100 102 R 76 15R R230 Thick Film Resistor Network 251 60 R23 8 2 10 1 4 Comp A B 822 10 76 8 2 300 SERIES Schematic 274040 R30 Thick Film Resistor Network K i TF 42 R302
120. ate guard voltage MAXIMUM LEVELS 200 volts between signa ine pairs trom signal lines to guard Mainframe Common 100 volts peak between guard and Mainframe digital Com mon DIMENSIONS WEIGHT Style M 3 1 2 in overall bench size 4 in high x 8 3 4 in wide 15 1 4 in deep 100 x 220 385 mm Net weight 8 pounds 3 5 ACCESSORIES SUPPLIED 7021 2 System Interconnect Cable ACCESSORIES AVAILABLE Mode 7021 2 System Interconnect Cable 2 foot 0 6m cable interconnects scanners for scanner operation n 1 used for interconnecting n canners 40 toot 12m maximum recommended tota system cable length extra MODEL 750 PRINTER WITH MODEL 7501 1722 PRINTER INTERFACE Description with the Model 172 173 COLUMNS 18 see Drum Diagram DECIMAL POINT 13 decimal points 9 are floating and print to right of number columns 6 through 10 12 through 15 FRONT PANEL CONTROLS Power Run Manual Print Paper Feed Print Interval PRINT RATE Print interval contro provides intervals from 1 sec line to 10 sec line continuously adjustable In the Ex terna position up to 2Y2 print commands sec are accepted DATA INPUT Parallel BCD 8421 high true low true with removal of jumper Floating decimal points are low true only Compatible Logic TTL DTL or open collector inputs are 2 TTL loads floating decimal points 1 TTL load CONTROL INPUTS External Print
121. ble 3 5 TABLE 3 5 Summary of Mating Connectors cringed Ribbon cable Style 3 13 OPERATING INSTRUCTIONS INSTRUCTION MANUAL Digital Multimeter Models 172 173 CJ i ors i 4 b 3 T us enced T grate e 5 SANTA is 2 s 24 wa 22 25 ssop FIGURE 15 Model 1722 Digital Output Interface INSTRUCTION MANUAL OPERATING INSTRUCTIONS Digital Multimeter Models 172 173 FIGURE 16 Installation of Model 1722 CB 3 15 OPERATING INSTRUCTIONS INSTRUCTION MANUAL Digital Multimeter Models 172 173 TABLE 3 6 Summary of Digital Output at P1006 CASE GND COMMON COMMON COMMON PRINTER HOLD AUTOMODE rin wo signet 21 104 2 22 103 1 23 10 1 25 103 1 02 8 26 101 8 27 102 4 28 101 4 29 102 1 0 101 2 31 102 1 32 101 1 33 109 8 34 FLAG 109 1 36 FLAG 37 100 2 38 OVERFLOW 39 109 1 40 POLARITY TABLE 3 7 Summary of Remote Commands at P1101 CASE GNDY I GND COMMON COMMON AUTORANGED STROBE TRIGGER MODE AUTOMODE STROBE HOLD OVERFLOW STROBE LOAD RANGE FLAG FLAG STROBE RI FUNCTION STROBE R2 RANGE STROBE R4 POLARITY STROBE 104 STROBE TRIGGER 103 STROBE FLAG RESET 102 STROBE TRIGGER MODE DISABLE 10 STROBE AUTORAN
122. cal order of their Circuit Designations 7 2 ORDERING INFORMATION To place an order to obtain information concerning replacement parts contact your Keithley representative or the factory See the inside front cover of the catalog for addresses When ordering include the following infor mation a Instrument Model Number b Instrument Serial Number Part Description d Circuit Designation if applicable e Keithley Part Number 7 3 SCHEMATICS a Input Signal Conditioning 28656E Sheet l of 3 This schematic describes the input switching ac dc conversion filtering attenuating and ohms source Circuit designation series is 700 800 and 900 b A D Converter 28656 Sheet 2 of 3 This schematic describes the analog to digital converter and the range selection circuitry Circuit designation series is 000 100 and 200 Display 278010 This schematic describes the display driver circuitry Circuit designation series is 300 d Power Supply 28656E Sheet 3 of 3 This schematic describes the line power supply Circuit designation series is 600 See schematic 26758C for the Model 1728 Rechargeable Battery Pack e Current Board 274780 This schematic describes the current circuitry for both the Models 172 and 173 Circuit designation series is 500 f Model 1728 Rechargeable Battery Pack 26758C Circuit designation series is 400 g Digital Interface Bottom 27902E This schematic describes
123. d 8911 500 2 Potentiometer 0 5W BEC 7 2PMR 500 R912 1 MQ 1 1 8W MtF e amp IRC 1 R913 200 Potentiometer 0 5W 72PMR 200K R914 NOT USED R915 9 75M2 Part of matched set R 8916 19 1 1 2 IRC DCC 1 1 R917 133 1 1 8 MtF e e n e IRC 133 R918 89 9 19 1 8W IRC CEA TO 49 9K R919 49 9 13 1 80 IRC 49 9k R920 470 0 10 1 4W Comp A B CB 121 10 R921 1 T 8w IRC 0 10 R922 133k2 1 1 89 IRC 0 133 R923 27k2 10 1 2W Comp A B 273 10 8924 3 3 0 10 1 4W Comp CB 332 10 R925 3 32 102 1 4W Comp A B CB 332 10 R926 3 3 0 10 1 4W Comp A B CB 332 1032 R927 10 J 4W Comp A B CB 102 10Z R928 150 2 1 84 MtF IRC CEA TO 150K R929 150k2 12 8W wv CAD 5 281 150K R930 3 3kQ 10 1 4 Comp A B 332 10 8931 3 310 10 1 4W Comp 332 10 11000 SERIES Schematic 27902 001 Resistor Network Thick Film R1002 Resistor Network Thick Film K I 81003 Resistor Network Thick Film Rel R1004 Resistor Network Thick Film K I R1005 Resistor Network Thick Film K t R1006 10 1 4W Comp E A B 102 10 81007 32 4 1 1 8W MtF IRC 0 32 4 R1008 10 1 4 Comp A B
124. d with the Model 1728 are already installed in the battery pack The battery pack in cludes 7 rechargeable cells 1 2V 2 AMP Hr and two 19 2 volt packs sixteen 1 2V cells per pack See Figure 6 a Check the fuses on the Battery Pack Three fuses are used All are l ampere 3 AG Slo Blo types Keithley Part No 0 10 b Check for proper installation of batteries in the Battery Pack If replacement battery cells are to be installed be certain to observe the proper polarity of the individual cells as shown in Figure 6 c To install the Battery Pack turn the instrument over so that the bottom cover faces up Loosen four slotted screws on the bottom cover as shown in Figure 4 The screws are captive that is they cannot be removed completely Turn over the instru ment with the top cover facing up taking care to hold the top and bottom covers to gether Carefully remove the top cover to gain access to the printed circuit board There are 2 connections between the top cover and the main circuit board which must be temporarily removed in order to free the top cover Check to see that the four insulating spacers are in position on the circuit board as shown in Figure 7 Plug the two 5 wire connectors J401 J402 into the mating receptacles P602 P606 tak ing care to orient the connectors as shown Place the Model 1728 in position on the spacers with the pack oriented as shown in Figure 7 Replace the connectors from the t
125. d BAT N Recharge for at least 16 hours to fully charge c Input Resistance Check DC VOLTS Depress MAN Depress BAT Select the 3 volt DC range using UP RANGE or DN RANGE pushbutton Measure the input resistance between HI and LO using DMM F 2 3 8 5 Input resistance should be gt x 109 ohms Make sure that 173 does not read off scale 6 Select the 30 volt DC range using UP RANGE pushbutton 7 Measure the input resistance between and LO using DMM F 8 Input resistance should be 10 megohms 22138 NOTE Battery pack may be discharged to the point where the LO BAT indicator circuit will not operate If in doubt recharge the battery pack at least 16 hours AB 6 3 MAINTENANCE INSTRUCTION MANUAL Digital Multimeter Models 172 173 d Voltage Accuracy Chech l DC Voltage a Set to DC Volts and AUTO b Connect the DC Calibrator A to the instrument c Set the DC Calibrator to the output specified in Table 6 3 d Verify that the instrument reading is within the limits specified e Repeat steps c and d with negative voltages TABLE 6 3 DC Voltage Performance Check Range Voltage Allowable Reading at 25 Applied Relative Absolute Accuracy 300mV 20 20000Vdc 0 19997 to 0 20003 0 19995 0 20005 2 0000 1 9997 to 2 0003 Vdc 1 9996 to 2 000 Vdc 30V 20 000 19 997 to 20 003 19 996 to 420
126. dE U CS TD2 20 106 20 220uF 10V ETT A SIE D220EDIOMI 120 UE 104 o 2 4 6 1 T05 010127 20 120 uF 10 ETT Cel TD5 010127 20 10 uF 20V ETT C 1 TD2 20 106 20 33 pF 1000 CerD CLB DD 330 10 uF 20V ETT TD2 20 106 20 10 uF 20V ETT C I TD2 20 106 20 2200pF 500V Gel ROMISFD 0 01 uF 16V CerD CLB UK16 103 185 500V Mica 4 w G I 145 1 1 9 15 7 pF 250V Trimmer gt 59 187 0109 005 1440pF 500V Mica 6 1 1 25 1 5 Variable EFJ 273 1 25 1 5 pF Variable EFJ 273 1 1 25 1 5 pF Variable EFJ 273 1 1 900 SERIES Schematic 28656E 0 01 uF 50V sos uev a ECI 625B1A103 J 0 1 uF 10 200VDC TRW 1 200 10 X363UW 33 pF 1000V CerD DD 330 0 15 uF 10 200VDC TRW 15 200 10 X363UW 0 15 uF 102 200VDC TRW 15 200 10 X363UN 1000 pF 500V Poly CLB CPR 1000 001 12700 STD PYW R 01 luF 100V 20 STD M2WF 0 lyF i eF 16DC NER PEE CLB 0 16 108 luF 164 0 2 2 4 2 CLB UK16 104 INSTRUCTION MANUAL Digital Multimeter Models 172 173 Keithley Part No C 22 M C 179 10M C 179 4 7M C 64 150P C 179 10M C 179
127. e bottom panel usually needed only for troubleshooting purposes See Figure 4 b The LO BAT indicator mill be lighted mhen the Battery Pack goes below normal operating voltaqe When the indicator turns on the Model 172 173 should switched to LINE or OFF to permit recharging of the Pack c The test point may be checked at any time using the Model 172 173 or other mea suring instrument The voltages are summarized in Table 2 3 iMPORTANT The instrument must be operated in BAT mode in order to obtain a valid battery con dition at test point This will ensure that the batteries are supplying power to the instrument If the voltage is measured when the Model 172 173 is operated in the LINE mode a different reading may be observed since the batteries are being charged TABLE 2 3 Summary of Battery Voltage Levels BAT mode Acceptable Battery Levels Test Recharge Battery Point Range Normal if Below Tested 19V gt 420 5V 81402 3 Hom to Charge the Batteries The Model 1728 provides built in recharging cir cuitry The Model 172 173 must be connected to line voltage Recharging occurs at the most rapid rate when the Model 172 173 is set to OFF Typically the recharge time is 2 5 hours per hour of discharge CAUTI ON Overcharging the batteries will raise the internal temperature of the battery pach and may shorten the life of the batteries 2 6 CB INSTRUCTION MANUAL Digital Multimeter Models 172 173
128. e lower terminals are the current carrying terminals while the upper terminals are the voltage sensing terminals This arrangement eliminates the error due to voltage drop across the cur rent carrying leads 5 Semiconductor Diode and Transistor Testing The Model 172 173 can be used to test diodes and transistors to determine the relative condition of the device For semiconductor diodes the voltage applied must be sufficient to cause conduction in the forward direction The OHMS mode provides a voltage up to 3 volts at a current upto milliampere Since the HI terminal is positive with respect to LO terminal con nections should be made as shown in Figure 13 to cause forward conduction of diodes Since the maximum current is available on the 3 K range depress AUTO MAN Set to MAN and manually range to the 3 range down ranae 6 Self Check Feature The Model 172 173 has a rear panel ohms test point for functional check of the Model 172 173 in OHMS To use this feature place the DMM in OHMS and 2 WIRE mode Connect the HI terminal to the blue terminal Verify a display of approximately 10 kilohms EMITTER TO BASE CONDUCTION CONDUCTION CATHODE TYPICAL DIODE TYPICAL PNP TRANSISTOR FIGURE 13 Semiconductor Diode and Transistor Testing 3 10 INSTRUCTION MANUAL OPERATING INSTRUCTIONS Digital Multimeter Models 172 173 3 10 HOW TO USE MODEL 172 173 OFF GROUND LO terminal can be operated of
129. f ground at potentials of up to 1400V Isolation from the LO terminal to power line ground is specified at 1000 or 1090 shunted by 300pF 152 09 the isolation resistance from LO to GND is two decades greater than 1090 101 0 Because of this excellent isolation operating the Model 172 173 off ground results in very little loading from LO to GND of a floating source At 1000V above ground the Model 172 173 will require typically only lOnA from the source The excellent isolation also accounts for the high common mode rejection ratio of the Model 172 173 Even with the HI terminal driven and a source resistance of 1k2 1000 VDC from HI to GND will produce typically onty lOuV DC error This error voltage is determined directly from the ratio of the source resistance to the isolation resistance See Figure 14 1000V 10 84 10 10 The l isolation capacitance from LO to GND is important when AC common mode signals present In the Model 172 173 this capacitance is specified at 300 pF At a frequency of 60Hz 300 picofarads has a reactance of approximately 10 0 With the HI terminal driven and a source impedance of lkQ a 1000 60 Hz common mode signal mill produce a voltage of only l00mV across the input terminals This 100 signal will be further rejected by the input filter and A D converter so that the total rejection at the digital display is at least 20 dB driven Ik5 source impedance
130. f the operation of this digital subsystem will not be given in the following discussion How ever various of its outputs which are necessary for the operation of the remaind er of the A D converter will be referred to when necessary AB 2713 THEORY OF OPERATION INSTRUCTION MANUAL Digital Multimeter Models 172 173 3 The first step of the A D conversion process the Voltage to Frequency conver sion is performed using a principal known as charge balancing The resulting output pulse train has the property that its average frequency over a given time period is proportional to the average of the input voltage over the same time period Thus the charge balance technique has the property that the digital output is a representation of the trueintegral of the analog input over any specified sampling time The circuitry which performs the V F function is explained in detail in Section b 4 The charge balance circuitry described in Section b although highly linear has certain intrinsic scale factor and zero offset errors In the complete A D converter these errors are corrected for by the use of additional circuitry This so called Auto Zero and Auto Calibrate circuitry is described in Section c Section d contains a description of overall A D converter system operation combin ing the circuit functions described in sections b and c into a complete A D conver sion cycle REFERENCE VOLTAGES V F CONVERTER MULTIPLEXER CHA
131. ferred to as Auto Zero and Auto Calibrate these intrinsic errors can be cancelled resulting in a system whose scale factor is essentially as stable as the voltage of a reference zener diode and whose zero stability is limited principally by thermo electric offsets The techniques used to achieve this performance are described in this section 2 t can be shown that all zero error sources in the charge balance system such as offset voltage drift of amplifiers U202 and UlOl input current drift of amp lifier 0101 etc can be represented as a total effective error current at the summing junction of amplifier 010 In a similar wav all gain errors are equiva lent to an error current at the emitter of the reference current output transistor Q102B lt is thus possible to correct for all such errors by introducing an appropriate correction current at each of these two locations in the circuit The function of the Auto Cal and Auto Zero circuitry then is to discover the proper values of these two currents and to supply them during the measurement of the input signal 3 The method used to discover the proper value of the correction signals is as follows Consider first the Auto Zero operation In an error free system a zero volt input would cause the charge balance loop to deliver reference current pulses to the integrator at exactly 1 2 the clock frequency In the Auto Zero mode the buffer input is supplied with zero volts and the current s
132. fier 75 Rectifier 75 Rectifier 75 Rectifier 75 Rectifier 75 Rectifier 75 Bridge Rectifier Bridge Rectifier Rectifier 75 mA 75V Rectifier 75 mA 75V Rectifier lA 800V mA 75V mA 75V Rectifier 75 Rectifier 75 Rectifier 75 Rectifier 75 Rectifier 75 Rectifier 75 Rectifier 75 Rectifier 75 Rectifier 75 Rectifier 75 Rectifier 75 mA mA mA mA mA mA mA mA mA mA mA DIODES CR Mfr Code Mfr Desig 500 SERIES Schematic 274780 52 2m 301 75V 75V 75V 75V 75V 75V 75V 75V 600 SERIES Schematic 100V 2 A 100V 2 A 700 SERIES Schematic 800 SERIES Schematic 75V 75V 75V 75V 900 SERIES Schematic 75V 75V 75V 45V TaN ao ure S 1 T I 2 Te 1 T I T I T I T I EDI EDI 71 1 05 IN911 11914 14914 1 918 11914 11915 11918 14914 28656 PDIO PDIO 28656 189 14 18915 1N4006 11918 11914 28656 1N914 1 914 14914 11914 28656E 1 918 1 9 14 18914 1 918 11918 REPLACEABLE PARTS Reithley Part No 48 28 RF 28 RF 28 RF 28 RF 28 RF 28 RF 28 RF 28 RF 36 RF 36 RF 28 28 38 RF 28 RF 28 RF 28 RF 28 RF 28 RF 28 RF 28 RF 28 RF 28 RF 28 RF 28 288 EPLACEABLE PARTS Circuit Desig 1001 CR1002 CR110 Circui
133. he 1728 should give a minimum of 250 discharge charge cycles and typically 500 discharge charge cycles Thus based on daily useage 5 day week one per day the battery pack should give a minimum of one year operation and typically two years Longer life should be expected for less frequent useage AB 3 25 UPERATING INSTRUCTIONS ITEM Fuse 3 AB 3 AG 1 4 A Slo Blo Fuse 3 AG 1 8 A Slo Blo ruse 3 AB 3 1 Slo Blo 3 AB 3 AG 2 A Quick use 3 AB 3 AG 3 A Quick op Cover less metalcal Cover less metalcal tandle less insert Insert tubber Foot 26 TABLE 3 12 WHERE USED 117V Line Volts 234V Line Volts Model 1728 Model 172 Amperes Mode 173 Amperes INSTRUCTION MANUAL Digital Multimeter Models 172 173 Summary of Fuses and Miscellaneous Replaceable Parts KEITHLEY PART NO FU 17 FU 20 FU 10 FU 13 FU 2 27979C 25727 257290 26090 10 INSTRUCTION MANUAL ACCESSORIES Digital Multimeter Models 172 173 SECTION h ACCESSORIES 4 1 GENERAL This section describes the various accessories and options available for use with the Model 172 173 Digital Multimeter 4 2 POWER OPTIONS The Model 172 173 can be powered by line voltage 105 125V standard Or rechargeable Battery Pack Model 1728 Other line voltage ranges are available as described in Section 2 The Model 1728 is available factory installed or field installable 4
134. he bottom cover 6 Remove two Slotted Screws 1 1 in long used to hold top and bottom covers to gether near the front feet on each instrument These screws are captive and needle nose pliers should be used to pull the screw out after it is loosened with a screwdriver 7 Position the Instrument so that holes in the bottom of the Instrument align with the two front holes in the Support Plate 8 Using two Slotted screws Item 5 and two Flat Washers Item 6 secure the Instru ment to the Support Plate AB 4 3 ACCESSORIES INSTRUCTION MANUAL Digital Multimeter Models 172 173 FIGURE 21 Model 1017 Dual Rack Mounting Kit 4 5 PROBE AND SHUNTS The following probes and shunts extend the capabilities of the Model 172 173 MODEL 1600 HIGH VOLTAGE PROBE Description The Model 1600 is a divider probe for measurement of high voltage up to hO kilovolts dc probe is optimized for use with a dc voltmeter having 10 megohms input resistance MODEL 1682 RF PROBE Description The Model 1682 15 an RF probe for measurement up to 100 MHz The Model 1682 is optimized for use with a dc voltmeter having 10 Megohms input resistance MODEL 1685 CLAMP ON AC CURRENT PROBE Description The Model 1685 is a clamp on current probe for measurement of ac current up to 200 amperes The Model 1685 is used with an AC voltmeter and provides an out put of 0 1 volt rms per ampere 4 4 AA INSTRUCTION MANUAL
135. iated MOS FET 0104 and resistors converts the voltage which appears at the output of buffer amplifier U202 into a proportional current which is used to charge the integrating capacitor The reference diode and the resistor connected from it to the summing junction of 0101 provide a fixed current component of in addition to the variable component which is proportional to the input voltage This fixed offset current labeled allows the overall A D converter to handle both positive and negative input voltages With this arrangement the output pulse frequency is one half of its maximum possible value when the input voltage to the entire converter is zero This transposition is accounted for in the digital subsystem LSI chip by subtracting a fixed number from the accumulated count before displaying it d The remaining circuitry in Figure 30 is functionally equivalent with some added details to the basic charge balance loop shown in Figure 28 The digital output signals QR and CLK are used by the digital subsystem in effect to reconstitute the pulse train discussed in connection with Figure 28 Auto Zero and Auto Calibrate Circuitry l The charge balance system shown in Figure 30 is inherently highly linear but both its zero and full scale calibration scale factor are susceptible to drift with time and temperature due to a variety of effects Through the use of a pair of related circuit functions re
136. igital Multimeter Models 172 173 SECTION 5 THEORY OF OPERATION 5 1 GENERAL This section contains circuit description information for the Model 172 173 The description is broken down into the following major categories a Input Signal Conditioning b Power Supply c Display Board d Durrent Board e Battery Pach Model 1728 f A D Converter g Digital Interface Model 1722 OPTION POWER MODEL 1728 SUPPLY BATTERY SCHEMATIC 286566 PACK SCHEMATIC 27903 SHEET 3 OF 3 SIGNAL A D DIGITAL CONDITIONING CONVERTER DISPLAY SCHEMATIC 28656C SCHEMATIC 286566 SCHEMATIC 27404D SHEET OF 3 SHEET 2 OF 3 MODEL 173 MODEL 1722 CURRENT DIGITAL BOARD INTERFACE SCHEMATIC 27902 SCHEMATIC 274785 OPTION 28019E FIGURE 22 Overall Block Diagram of Model 172 173 AB THEORY OF OPERATION INSTRUCTION MANUAL Digital Multimeter Models 172 173 5 2 INPUT SIGNAL CONDITIONING Schematic 27903E This circuit consists of input switching overload protection ohms converter ac dc converter and filter a Switching The interlocked pushbutton switches set the DMM to the appropriate function Table 5 1 summarizes the switching scheme TABLE 5 1 Summary of Pushbutton Switching Style ISetting Remarks Line Push Push i is powered by ac line power Battery pack if installed has a trickle charge Line eo Push Push i Qut i DMM is disconnected
137. imal point location and measurement unit mV or V 3 8 CB INSTRUCTION MANUAL OPERATING INSTRUCTIONS Digital Multimeter Models 172 173 3 6 HOW TO MEASURE CURRENT MODEL 172 ONLY The Model 172 measures ac and de current in two ranges 0 3A and 2A The current is limited by the current fuse even though the DMM is capable of displaying 2 9999A CAUTION The Model 172 is protected by a 2 ampere fuse on all ranges If the fuse is blown a replacement Keithley Part No FU 13 should be installed in the rear panel fuse holder See Figure 5 a DC Current The Model 172 detects de currents from 10 microamperes digit to 2 amperes When the input exceeds 2 amperes the current fuse will blow When using the MAN mode it is possible to select 30A 300A amp 3000A Ranges but 2A Max is still the limit 1 Set to DC 5 2 Set to AUTO 3 Connect the signal to be measured at the HI terminal 4 Observe the displayed digits polarity sign decimal point location and measure ment unit uA mA or A If no polarity sign is indicated a positive polarity is implied b AC Current The Model 173 DMM detects ac currents from 10 nanoamperes rms digit to 3 amperes rms The maximum display is 29999 When the display exceeds 29999 a 3 remains lighted but all other digits are blanked l Set to AC Amperes The AC indicator should be lighted 2 Set to Auto 3 Connect the signal to be measured at the Hl terminal 4
138. in various places in this Instruction Manual This symbol indicates those areas on the instrument which are potential shock hazards Carefully read the associated WARNING statements with regard to proper use and handling of the instrument Serious personal injury may result if these precautions are ignored 1 1 GENERAL INFORMATION INSTRUCTION MANUAL Digital Multimeter Models 172 173 FUNCTION AND UNITS DISPLAY my INPUT HI AND LO UPPER PAIR OHMS SOURCE LOMER PAIR R ANGING VOLTAGE FUNCTION OUT AMPERES FUNCTION IN DC FUNCTION AUTORANGING OUT MANUAL RANGING IN LINE POWER LINE AND BAT MUST BE OUT FOR BATTERY CHARGE FIGURE 3 Model 173 Front Panel 1 2 cc AB INSTRUCTION MANUAL Digital Multimeter 172 173 DF CAC UT VOLTAGE 45 S VATIC MANUAL 108 GIMER REGIONS 172 112 CONDENSED 024 RATIOS gt TARE BHIMA my ALLURATY I tay 4 i MSI GG OVI AR S i6 AND WII 4 191 CONSICTLO OW 11 30081 810 Uh ib USE 172 ALLOWS FULL AU Ai DNS 04113413 UT AND DA gt vr Y IKSIAUMIART 18233 Ads Tan
139. ing connector J201 Make certain all pins are making contact bar Check R302 pin 14 for signal When voltage should be approx 1 8V b bar Check R302 pin 16 bar Check R302 15 bar Check R302 pin 9 bar Check R302 pin 12 bar Check R302 pin 10 bar Check R302 13 decimal point Check R302 pin 11 Check plug P301 connector 201 If units digit missing check collector of Q305 for signal When voltage should be approx 4 8y If tens digit missing check collector of Q304 If hundreds digit missing check collector Q303 f thousands digit minus sign and function indicator missing check collector Q302 On 10 000 digit check collec tor 0301 f no signals are present problem could be tran sistor or integrated circuit U301 and mating Set to 2 WIRE Connect HI input to the same side of unknown as the Q SOURCE lead Replace fuse on rear panel 6 21 AINTENANCE INSTRUCTION MANUAL Digital Multimeter Models 172 173 b How to Repair Circuits and or Components Which Have a Conformal Coat The Model 172 173 circuit board has a conformal coat which protects the circuit from moisture and yables the 172 173 to function over a range of environmental conditions 1 The circuits and or components are covered by a Conformal Coating manufactured by Dow Corning Corporation Dow Corning QR4 3117 Conformal Coating is a transparent one part
140. is is accomplished by putting Rx in the feedback of summing amplifier 2 AMP the input to this amplifier being a reference 0 Vref voltage t rough an input resistor RQ 2 1 ACAL 2 2 6 A D Signal are the 4 A D inputs This A D operation compensates for time 6 temperature variation of 2 VRef and Q Amp as wel as compensating for lead r sistance The A D looks at each of these inputs in time sequence in the following aner 1 2 1 looks at 0 AMP input for HO ms and stores this zero level 2 ACAL looks at VREF for 40 ms and calibrates itself to the difference between 2 1 and ACAL Thus it is calibrated to the voltage across Since is a fixed stable resistor the value of is now known Since 1 flows through Rx the calibration is fixed 3 AZ 2 looks at the voltage at the top of Rx for HO ms This is defined as the zero level for signal measurement and is stored in A D 4 A D Signal looks at the bottom of Rx for 200 m seconds The A D thus measures the difference between A D signal and AZ 2 without polarity sign The voltage across Rx is displayed C The measurement is essentially a ratio measurement between the voltage across Rx and the voltage across d Note that the voltage at the top of Rx is essentially at signal LO of the instru ment QAMP offset and lead resistance drop and the voltage at the bottom of Rx is negative Thus the high impedance terminal is guarded and relative fast respo
141. is low the 172 173 will go to the range as set by the RANGE IN code Table 3 10 at the beginn ing of the next conversion As long as LOAD RANGE is held low each instrument will remain on its programmed range overriding front panel UPRANGE DOWNRANGE and AUTORANGE RANGE JN codes programmed outside the limits of table 3 10 will result in the nearest valid range to that programmed LOAD RANGE will always cause a DMM range change However the display and output data wil be held not updated during TRIGGER MODE or HOLD Referring to timing schematic 28249D it is possible to just miss a REMOTE CONTROL update prior to data output This can be misleading especially in the case of HOLD just missed unknown to the user just before data begins to change could result in erroneous data To check if this occurred it is suggested that the FLAG be examined no sooner than 10 usec after activation of the HOLD bit If flag is low wait until it goes to HIGH before expecting the HOLD bit to have been accepted Other REMOTE CONTROL bits such as TRIGGER MODE and TRIGGER LOAD RANGE and the RANGE IN code can be kept active for longer than an output data update time i e 3 2 msec to insure proper REMOTE CONTROL acceptance When in TRIGGER MODE and triggering into an autoranging condition normal operation will give an output for each range encountered during the autorange However if this is undesirable the AUTORANGED output bit can be tied
142. lifier configuration is used The current is generated by applying a reference voltage to the input resistor of the summing amplifier and connecting the unknown resistor in the feedback loop of U702 to force the current through the unknown resistor Refer to Figure 34a Either the 3 3444 V or the 33444 V reference is connected to buffer amplifier U Ol thru switching FETs 0702 0703 The output of the buffer drives one of three resistors 3 3888 33 444MR to give six decade values of current from 10 nanoamperes to 1 milli ampere and thus six ohms ranges Each resistor consists of an adjustment potentiometer a fixed resistor and the on resistance of a FET no FET for 33 888 0 2 H gh ohms puts the A D converter on the 3 Volt range allowing 6 resistance ranges which can turn on semiconductor junctions for on scale readings 3 Low ohms puts the A D converter on the 300 m V range allowing 6 resistance ranges which do not turn on semiconductor junctions for on scale readings See Table 5 3 4 There are time and temperature drifts associated with amplifiers 070 and U702 These effects are compensated for by the A D converter The reference used to calibrate the A D converter in 0 function is the output of 0701 Therefore any drift in 0701 is compensated for every conversion cycle The negative input of 0702 is what auto zero one is calibrated to every conversion cycle Therefore the stability of the ohms current is
143. ll 30 bits have been shifted in and are presented in parallel to the output buffer f Output Drive and Buffer Parallel data on the output registers goes to output gates U1001 thru 1007 and 01012 and 1013 Here they are gated with the output strobes and drive transistors 01001 thru 1030 to output connector 1006 g Input Buffers Strobelines are buffered by 01101 and 01102 and go out to the output drive and buffer block Remote control inputs buffered 01108 01111 01105 01108 is a Schmitt trigger and is put on certain control lines to prevent false triggering AA 5 23 Digital Multimeter Models 172 173 INSTRUCTION MANUAL t ORY OF OPERATION 3592 430 lt 09014340 aa DM HOLIAS I 2v 1140104 83154938 54313109 404100 3704 279110 3723169 i 104100 916 AVINA Num QIINVUQLAY 3081402 3 1102942 anani 83151338 1981905 3011051 101005 981003 39444 AA 1722 Block Diagram Mode FIGURE 33 1 IEORY OF OPERATION INSTRUCTION MANUAL Digital Multimeter Models 172 173 5 9 DETAILED h WIRE OHMS OPERATION a The circuit measures a resistor by putting a constant current through Rx and meas u ing the voltage drop across Rx Th
144. ls 172 173 6 3 PERFORMANCE VERIFICATION Use the following procedures to verify basic operation of the instrument All measurements should be made at ambient temperature of 25 C and relative humidity less than 80 If the instrument is out of specification at any point perform a complete calibration as given in paragraph 6 4 For each function that is checked an additional uncertainty due to temperature coefficient should be considered if the ambient temperature is different from 25 C Example If calibrated at 30 add 5 C of temperature coefficient specification NOTE This procedure is intended to verify only the basic accuracy of the Model 172 173 in voltage current and resistance modes Test equipment accuracy should be X10 better than measurement accuracy n many cases the equipment listed is not XIO better than instrument accuracy because such equipment is not commercially available a Battery Check With the Model 1728 Rechargeable Battery Pack installed l Check for proper installation of individual celts in the battery pack as shown in Figure 7 2 Depress BAT pushbutton 3 Verify that the LO indicator is not lighted If lighted recharge batteries b How to Charge the Batteries Perform this procedure only if the batteries are not sufficiently charged 1 Set the internal line switch S601 to the appropriate line voltage range Connect the line cord to the appropriate line voltage Release LINE an
145. mpers and Pull Ups Model 1722 INSTRUCTION MANUAL OPERATING INSTRUCTIONS Digital Multimeter Models 172 173 TABLE 3 8 Digital Output Lines Grouped By Function P1006 P1101 Name Pin Pin No No 109 STROBE 26 FUNCTION STROBE 12 109 1 VOLTS 10 109 2 AMPS 12 109 1 AC 14 109 8 Labs ce UMSO ed SORT ee ae m OVERFLOW STROBE 8 or 222222 OVERFLOW 38 its AUTOMODE STROBE 6 101 4 ____ 101 8 AUTORANGED STROBE AUTORANGED 102 STROBE 22 PRINTER HOLD 102 1 102 2 TRIGGER MODE 102 4 HOLD 102 8 LOAD RANGE 103 STROBE 20 103 1 25 R 107 2 22 RB l TRIGGER LS alee FLAG RESET 10 STROBE 18 TRIGGER MODE DISABLE 10 1 23 ia 108 2 21 COMMON 10 4 19 CASE 107 8 17 POLARITY STROBE 16 FLAG FLAG STROBE 10 RANGE STROBE 14 FLAG 36 RI 15 FLAG _ Dl R2 13 VEXT 8 84 n 88 9 3 19 OPERATING INSTRUCTIONS INSTRUCTION MANUAL Digital Multimeter Models 172 173 TABLE 3 9 General Characteristics of Model 1722 Digital Interface DIGITAL OUTPUTS Logic BCD 8421 Open collector positive true unless otherwise specified Data 4 full digits l partial digit 0 1 2 3 and exponential range code Function 4 bit code 0 AC VOLTS AMPS Polarity HIGH Overflow LOW gt 29999 Autorange LOW range change Automode HIGH autorange mode FLAG FLAG HIGH
146. mv HI LO IN TO 29 999 1 301652 IN RANGE QIN 2 99994 0 03 10 HI L0 0UT to 298 99M2 TO 30040 IN RANGE OVERRANGE FIRST DIGIT 3 REMAINING DIGITS BLANK IN OVERRIDES V A OC OR AC IN OVERRIDES HI LO AND 2 WIRE 4 WIRE MAXIMUM OPEN CIRCUIT VOLTAGE 1 5 VOLTS SEE INSTRUCTION MANUAL FOR OTHER REGIONS IN 4 WIRE OHMS INPUT MUST BE CONNECTED ON Q SOURCE HIGH SIDE amp LO ON LO RANGE SELECTION USE OF 1722 DIGITAL INTERFACE ALLOWS REMOTE RANGING FULL AUTORANGING ALL FUNCTIONS DEFEATS UP AND DN IN _ MANUAL P MAR NG B SING UP amp ON PUSHBUTTON DN UNE D WNRAN 3 LATS AL n UP MOMENTARY EACH PUSH CAUSES ONE UPRANGE SEE INSTRUCTION MANUAL FOR 1728 PACK INSTALLATION IN OPERATES INSTRUMENT FROM AC LINE TRICKLE CHARGES 1728 OUT CHARGES DISCHARGED 1728 IN 16 HOURS IN OPERATES INSTRUMENT FOR 6 HOURS FROM 1728 BAT BAT IF INSTALLED FRONT PANEL LO BAT LIGHT COMES ON IF BATTERY 18 DIGITS OPERATION WOULD CAUSE FAULTY READINGS EST II ll READ APPROX 5V IN DC VOLTS AND 1mA IN DC AMPS ee TO READ APPROX 6V IN AC VOLTS AND 1 2mA AC AMPS TO READ APPROX 10k IN 2 TERMINAL OHMS TO OPEN INSTRUMENT CAUTION DISCONNECT LINE CORD LOOSEN 4 SCREWS THIS SIDE HOLO
147. n Case To 18 1753538 76 88 2110 N Chan J FET Case 0 18 INT ITS3538 TG 88 3 N Chan J FET Case TO 18 INT 1153538 TG 88 0112 N Chan J FET Case 70 18 INT 1753538 88 0113 N Chan J FET Case T0 18 INT 1753538 16 88 ESL AB INSTRUCTION MANUAL Digital Multimeter Models 172 173 Circuit Desig 0201 0202 0203 0204 0205 0206 0207 0208 0209 0210 0211 0212 0213 9214 0215 0216 Selected 0301 0302 0303 0308 0305 0306 9307 0308 0309 0310 0311 0312 0313 031 TRANSISTORS Q Description Mfr Code Mfr Desig 200 SERIES Schematic 28656E N Chan J FET Case To 92 N Chan J FET Case 10 18 N Chan J FET Case 0 92 N Chan J FET 4 N Chan J FET Case T0 92 Transistor NPN Case 70 106 PNP T0 92 Case PNP Case to 70 92 J FET Case 10 92 N Chan J FET Case TO 92 N Chan J FET Case TO 92 Transistor NPN Case T0 106 Transistor NPN Case TO 106 Transistor NPN Case TO 106 Transistor NPN Case T0 106 PNP T0 92 Case 70 106 16 39 INT NAT INT F 1 MOT MOT NAT NAT NAT F INT INT INT MOT 300 SERIES Schematic PNP Case TO 106 PNP Case TO 106 PNP Case T0 106 PNP Case TO 106 PNP Case TO 106 PNP Case T0 106 PNP Case 110 PNP Case R 110 PNP Case R 110 PNP Case 110
148. n is quite simple Once the stable closed loop condition has been achieved one of the two capacitor switches is then closed and the gate voltage on the source follower which has the value necessary to produce the correct value of 7 is stored on that capacitor When the loop switch finally opens at the end of the Auto Zero phase the value of which was established during the Auto Zero phase thus remains in effect until the next Auto Zero operation ONE A D CONVERSION SIGNAL INTEGRATE OPERE LESER ERROR SIGNAL CORRECTION MEASUREMENT FIGURE 32 A D Converter System Timing AB 5 21 gt OPERATION INSTRUCTION MANUAL Digital Multimeter Models 172 173 e The Auto Cal feedback and storage block works in manner identical to that of the Auto Zero feedback and storage block with the exception that its output current is fed to the emitter 01028 instead of the summing junction of 0101 Although the Auto Zero and Auto Cal correction operations interact to some degree a few sequential iterations of these operations suffice to establish the correct values of the two correction currents d Overall A D System Operation l In the preceeding two sections the structure and function of each major analog circuit block has been explained This section contains a description of the manner in which these elements are combined in a complete A D conversion The description is based on Figure 32
149. nce of 200K 89 9 of which is 918 The other 150 0 comes from various sources the following manner in DC Volts 300 m V and 3 V range R929 30 V and 300 V range R919 R908 R911 R910 In AC Volts all ranges 801 In Q all ranges R928 R929 K901 91 915 8919 O VI rm z 0 O HI 150K 9 75M R907 11 2 R909 C907 901 R908 Pn R911 100K FIGURE 23 DC Volts Input Circuit INSTRUCTION MANUAL THEORY OF OPERATION Digital Multimeter Models 172 173 This 200K2 is also maintained so that the etfect of A D input current is autozeroed out See A D discussion section 5 7 The DC filter contributes no DC offsets to the signal path They are blocked by C905 5 904 8922 R917 C902 5 1901 complete the filter circuit R92lisacurrent limiting resistor and C903 frequency compensates 0901 d AC Attenuator 1 voltages are first attenuated if necessary converted from AC to DC then filt ered and passed on to the A D converter 2 The AC attenuator Figure 24 is really a frequency compensated summing amplifier with maximum gain of unity Its other gains are 100 and 1000 which are switched by relay and FET 0804 respectively RL line controls and H line controls 0804 see table 5 2 3 908 blocks DC signals up to 1000V so that AC signals may be looked at in the pressure of DC voltages The attenuator is refe
150. nk 1 Clock waveform is miss Check pin of LSI 0103 for or Some segment on ing a clock waveform of approx 334 kHz swinging between 4V and V If waveform is present 151 U103 is probably faulty If waveform is not present integrated circuits 0003 transistor 0003 ceramic resonator CROO3 may be faulty AA 6 19 INSTRUCTION MANUAL Digital Multimeter Models 172 173 SPACER 4 REQUIRED Mer X N P603 P60 usn i 1 y FIGURE 40 Plug In Connections on PC 407 6 20 CB INSTRUCTION MANUAL Digital Multimeter Models 172 173 SYMPTOM e f j AA One display bar missing on all digits Qne digit missing 10 000 digit missing except if reading is less than 10 000 counts Function indicator off Faulty reading on Q function Faulty reading on Current function TABLE 6 13 Con t Hints Troubleshooting MAINTENANCE PROBABLE CAUSE CORRECTIVE ACTION l 2 1 2 Faulty connection between P301 and 201 Cathode driver cir cuitry faulty See schematic 274040 Faulty connection between R301 and 201 Anode driver circuitry faulty See schematic 278080 0301 Transistor 0306 DMM set for H ohms and SOURCE terminals are not connected DMM set for 4 WIRE ohms but leads are reversed Current fuse F501 is blown Check plug P301 and mat
151. nse is hieved at high resistance values 5 26 AA INSTRUCTION MANUAL MAINTENANCE Digia Multimeter Models 172 173 SECTION 6 MAINTENANCE 6 1 GENERAL This section contains information necessary to maintain the instrument Included are procedures for Electrical Performance Verification Calibration Trouble shooting and Battery Replacement and Charging 6 2 REQUIRED TEST EQUIPMENT Recommended test equipment for checking and maintaining the instrument is given in Table 6 1 Alternate test equipment may be substituted if specifications equal or exceed the stated characteristics TABLE 6 1 List of Test Equipment For Performance Verification SPECIFICATION MFR MODEL DC Calibrator 0 2 V through 1000 0 002 or 20 B AC Calibrator 0 2 through 20 v rms HP 7454 0 022 10 i C High Voltage Amplifier 200V through 1000 0 v rms HP 746A 0 04 i D Decade Resistor 2 through 10 0 ESI 0862 0 01 i 200M 30 14 CADDOCK MG75C Current Source 200uA through 20 mA FLUKE 33308 0 0065 200mA and 2A 40 024 FLUKE 382A Ohmmeter 1072 19 1090 5 RI 616 NOTE The equipment listed here in many cases mill introduce an additional uncertainty in the Performance Verification The Absolute Accuracy should be used when evaluating the displayed reading on the DMM 6 1 INSTRUCTION MANUAL MAINTENANCE Digital Multimeter Mode
152. nstrument is off but the line cord is powered unregulated voltages are generated If a Model 1728 battery pack is installed in the Model 172 173 the batteries of the Model 1728 will be charged through the unregulated voltages When instrument is line powered resistors R604 R610 and R605 feed the charge inputs on the battery pack These resistors drop the charging current down to the trickle charge level When the instrument is in the line operated mode the 30 volts unregulated is connected to R601 which goes to the input of VR603 The 30 volts unregulated passes through R602 and goes to the input on VR603 These resistors are used to absorb some of the excess power which is not necessary to be dissipated in the regulator AB 5 9 OF OPERATION INSTRUCTION MANUAL Digital Multimeter Models 172 173 fhe 8 volt regulator VR601 gets its unregulated input from the unregulated V input on VR603 This input goes through a dropping resistor R606 to further reduce the voltage lown to an acceptable level for VR601 The input for VR602 SV regulator is derived irom transformer secondary 7 and 8 full wave rectifier CR601 and R603 This voltage also changes the 8 4V batteries In BAT mode the 19 2 volt batteries and the 8 4 volt vatteries connect to the input terminals of VR603 and VR602 VR601 the 8 volt regulator fed through the 270 ohm resistor The line switch applies ac voltage from the transformer to the Model
153. o 80 relative humidity up to 35 C POWER 90 125 or 200 250 volts switch selected 50 60H2 15 watts CONNECTORS Digital input Digital Output rear 26 pin 3M Part No 3429 1002 Common Ground Binding posts Scanner Plug in Card rear Internal connector mates with plug in card edge Analog Inputs Output and Guard rear Clamp type barrier strips for use with 5 14 to 22 AWG wire Scanner Maintrame Card edge mates with Scanner frame internal connector SIGNAL INPUYS 10 channels per card SWITCHING CONFIGURATION Guarded 2 pole break before make RELAY CLOSURE TIME Less than 5 mitliseconds EXPECTED LIFE 105 closures per channel SIGNAL LEVEL 10 volts 10 mililamperes with a re sistive load for expected life Absolute maximum peak in Stantaneous ratings 200 volts 100 miliiamperes 2 vol amperes with resistive load THEAMAL OFFSET LABORATORY ENVIRONMENT Less than 3 microvolts trom input to output when copper wires are used SIGNAL PATH RESISTANCE Initially less than 0 5 per pole less than 2 onms end of life ISOLATION Guarded interchannel reststance is nominally 10 2 ohms at room temperature and guaranteed greater than 1070 ohms at environmental extremes Unguarded capacitance is less than 10 picotarads between any two Signal terminals GUARDING Guard surrounds all analog signal paths Each 10 channel scanner plug in card in mult scanne systems may have a separ
154. o a negative value Sometime t during this reference current pulse V crosses the comparator threshhold in a negative direction and V_ goes to a logical tzerol At the next positive going edge of clock CID t th comparator voltage V is still a zero and therefore the flip flop output 15 becomes a zero The r ference current consequently is not turned on during that clock period and in fact stays off until the next time the integrator voltage once again rises above the comparator threshhold COMPARATOR C10 CLOCX CURRENT SWITCH OUTPUT PULSES TO LOGIC FIGURE 28 Basic Charge Balance Converter THEORY OF OPERATION INSTRUCTION MANUAL Digital Multimeter Models 172 173 2 For relatively large values of the input the time required for the integrating capacitor to be recharged above the comparator threshhold is relatively small and the charging discharging cycle described will occur at a high frequency For lower values of input current the recharging time of the integrator will be correspond ingly longer and the events described will occur at a lower rate Thus the repeti tion rate of reference current pulses and digital output pulses is a function of the input current 3 Notice that the amount of charge removed from the integrating capacitor during each discharge cycle is equal to the product of the reference current and one half the clock period Through appropriate circuit design these t
155. oosen four slotted screws on the bottom cover as shown in Figure 4 screws are captive that is they cannot be removed completely 4 Turn over the instrument with the top cover facing up taking care to hold the top and bottom covers together 5 Carefully remove the top cover to gain access to the printed circuit board There are 2 connections between the top cover and the main circuit board which must be temporarily removed in order to free the top cover see Figure 40 6 Remove the Model 1728 Rechargeable Battery Pack if installed Carefully disconnect connectors from the mother board NOTE The Models 1722 and 1728 cannot be installed on the Model 172 173 chassis at the same time 7 Check to see that the four insulating spacersare in position on the circuit board as shown in Figure 16 8 Place the Model 1722 on the spacers as shown in Figure 16 9 Lift up the Mode 1722 slightly to gain access to the Model 172 173 mother board and plug in connectors J1003 J1002 and J1001 in order given 10 Connect ground return wire from the Model 1722 to the extra lug on transformer T101 11 Replace the connections to the top cover 12 Reinstall the top cover 13 Turn the instrument over and tighten the four screws Connector Terminations The Model 1722 uses two card edge connectors P1006 40 pin and P1101 26 pin Ribbon cable style of mating connectors may be used with these cardedge connectors as shown in Ta
156. op cover to the circuit board Replace the top cover Turn over the instrument with the bottom cover facing up and tighten down the four slotted head screws INITIAL PREPARATION INSTRUCTION MANUAL Digital Multimeter Models 172 173 4801 4802 2650 wont t 191082 INJR3 1831348 WIVd AH311Vv8 IDE POr azi 1872 d FIGURE 6 Model 1728 Rechargeable Battery INSTRUCTION MANUAL INITIAL PREPARATION Digital Multimeter Models 172 173 WARNING Disconnect the line cord on the instrument before the Battery Pack is installed Line voltage is present at various places on the circuit board and is a SHOCK HAZARD FIGURE 7 Installation of Battery Pack CB 2 5 INITIAL PREPARATION INSTRUCTION MANUAL Digital Multimeter Models 172 173 TABLE 2 2 Summary of Batteries Used in the Model 1728 Vo tage Keithley Part No 1 24 cell Saba 7 8 Ay BA 30 19 2V pack 16 1 2V cells 19 2V 31 19 2V _ 5 CAUTION The Model 1728 is shipped from the factory in an uncharged condition Therefore A the pack should be installed in the Model 172 173 and charged prior to use 2 How to Check Batteries a The Model 172 173 has a built in LO BAT indicator to permit easy determination of battery condition The Model 172 173 also has an individual test point on th
157. ption The Model 1725 contains a specially punched calibration cover for access ability to adjustment controls on the Model 172 173 chassis AA 8 5 ACCESSORIES INSTRUCTION MANUAL Digital Multimeter Models 172 173 MODEL 702 7029 LON VOLTAGE SCANNER Description The Model 702 7029 15 ten channel low voltage scanner 702 7029 can be used for manual scan or remote scanning operation CHANNELS 10 channels per scanner maintrame multiple scanner maintrames be connected for up to 100 chan nels CONTROL MODES FRONT PANEL SELECTABLE All Ott No Channel selected Manual Channel selected by front pane switch Scan Channels sequentially selected at a rate determined by front panel control Initia channel may be preset Remote Channel randomly selected using 4 line BCD code sequentially selected at remote ciock rate SCAN RATE Variable from nominally 0 1 to 10 seconds per channel by front panel control Scan rate using remote clock is limited only by relay closure time DISPLAY Single digit front pane LED display identifies chan nel selected DIGITAL INPUT AND DIGITAL OUTPUT TTL interface lines provide tor remote channel selection clock and control of mode Output data includes present channel address maintrame identification clock and relay ready The digital Common may be floated up to 30 volts peak with respect to chassis Ground ENVIRONMENT 0 50 0 t
158. put sufficient charge into them for short intermittent use b 02 amp BT403 Charging BT402 6 BT403 are charged via a constant current from 0502 0401 respectively These circuits operate similarly to the above circuit except that they powered by unregulated 29 5V 5 7 ANALOG TO DIGITAL CONVERTER Schematic 28656 a Introduction l The A D converter as its name implies performs the function of generating a digital representation of an analog voltage applied to its input The basic func tional blocks involved in this process are shown in Figure 27 This A D converter has several distinct modes of operation broadly grouped as signal measurement mode and error correction mode The signal flow in the signal measurement mode is shown in heavy lines in Figure 27 It can be seen that the transformation from voltage input to display output occurs in two major blocks The first block V F Converter generates a digital pulse train whose frequency is proportional to the input voltage The second block digital chip contains circuitry which counts the incoming pulses for a fixed time period producing a total count which is proport ional to the average of the input voltage over that time period 2 The digital chip a custom MOS LSI circuit which performs the pulse counting function also performs a number of other functions necessary for the analog to digital converter and for other portions of the DMM Details o
159. r 75 75V T I 15914 74208 Rectifier 75 75V T I 3209 Rectifier 75 mA 75V scr 210 Rectifier 75 mA 75V T I 14915 8211 Rectifier 75 mA 75V se 11918 3212 Rectifier 75 mA 75V 1 918 CR213 Rectifier 75 mA 75V T I IN914 21 4 Rectifier 75 mA 75V T IN914 9100 SERIES Schematic 26758C 8401 Rectifier 75 mA 75V T 18914 8502 Rectifier 75 mA 75V T I 1N915 CR403 Rectifier 1 A 800V MOT 148006 8404 Rectifier 75 mA 75V 1 91 R405 Rectifier 75 mA 75V 1914 CR406 Rectifier 1 A 800V MOT IN4006 CR4O7 Rectifier 75 mA 75V Ti 11914 R408 Rectifier 75 mA 75 174 11914 R409 Rectifier 1 A 800v MOT 1N4006 CRA IO Rectifier 75 mA 75V 171 1N914 INSTRUCTION MANUAL Digital Multimeter Models 172 173 Keithley Part No RF 28 RF 28 CR 7 RF 28 RF 28 RF 28 RF 28 RF 28 RF 28 RF 28 DN 3 RF 28 RF 28 RF 28 RF 28 RF 28 RF 28 RF 28 RF 28 RF 28 RF 28 RF 38 RF 28 RF 28 RF 38 RF 28 RF 28 RF 38 RF 28 AB INSTRUCTION MANUAL Digital Multimeter Models 172 173 Circuit Desig CR501 CR502 CR503 CR504 CR505 CR506 CR507 CR508 CR509 CR601 CR602 CR701 CR702 CR703 CR704 CR705 CR801 CR802 CR803 CR801 CR901 CR902 CR903 9 CR905 AB Description Bridge Rectifier Rectifier 75 Rectifier 75 Recti
160. ranges and all other functions is not affected by the Model 1722 when operating in TRIGGER MODE 3 22 INSTRUCTION MANUAL OPERATING INSTRUCTIONS Digital Multimeter Models 172 173 TABLE 3 10 MODEL 1722 6 FUNCTION CODING FOR MODEL 172 FUNCTION OUTPUT OUTPUT INPUT FUNCTION RANGE RANGE CODE 1 CODE 1 3 V AAC Q Re Ry R DC VOLTS AUTORANGE 5 6 7 8 9 AC VOLTS AUTORANGE 5 7 300 8 1000 9 DC AMPS l 1 1 1 AUTORANGE _ 300 mA 1 5 0 1 O 6 0 0 AC AMPS AUTORANGE 300 0101 5 0 1 1 0 6 LOW Q 000 I 1 1 4 AUTORANGE 2 l 1 O 1 3 l 0 O h 0 1 5 l 0 1 O 6 i 7 1000 HI R l 1 1 1 AUTORANGE 3 l 1 O O 4 l 0 1 l 5 l 0 1 O 6 l 0 01 7 1 8 0 1 1 1 1 Coding in this table is defined to be HIGH POSITIVE TRUE HIGH and 0 LOW Refer to output and remote control logic levels for definitions of HIGH amp LOW 2 Function code for Model 172 current is volts 3 Note that except for AUTORANGE CODE INPUT amp RANGE CODE is the compliment of the OUT PUT RANGE CODE i e the INPUT RANGE CODE is the LOW TRUE BCD code of EXP AA 9723 OPERATING INSTRUCTIONS INSTRUCTION MANUAL Digital Muitimeter Models 172 173 TABLE 3 11 MODEL 1722 RANGE 6 FUNCTION CODING FOR MODEL 173 Same as Table 3 10 except as follows FUNCTI ON OUTPUT OUTPUT INPUT FUNCTION RANGE RANGE CODE 1 CODE 1 CODE 1 3 AUT
161. re the voltages listed in Table 6 10 TABLE 6 10 Power Supply Voltage Check Test Point Allowable Voltage Range 4 75V to 5 25 14 5 to 415 5 14 5 to 15 5 NOTE To achieve calibration to published specifications the instrument should be cali brated using the Model 1725 Calibration Cover The instrument should be allowed to stabilize for approximately 1 hour after the Calibration Cover is put in place It is important that the calibration sequence be followed exactly because the ad justments are interrelated and dependent on prior calibration steps c A D Calibration This must precede the regular analog section calibration to that the instrument mill meet all rated specifications 1 Capture Range Adjustments a Set the DMM to MAN b Set to 300mV DC c Place a short between input and LO d Connect a Berg type 2 pin housing Keithley CS 266 with approx 30 inch leads at 101 and 102 on 07 See Fiqure 38 e Connect Oscilloscope G between the following points 1 Oscilloscope Ext TRIGGER to 101 FON 2 Oscilloscope VERTICAL INPUT to TP102 Prefilter 3 Oscilloscope GND to signal ground test point JIOOIA low f Set the Oscilloscope controls as follows 1 Trigger DC coupled 2 Vertical DC 0 5 V division 3 Time Base 20 ms division g For the following adjustments refer to trace shown in Figure 39 h Adjust potentiometer
162. renced to 6 Volts to keep the DC bias voltage on C808 and C809 figure 25 near zero Zf Rf 1 4 The gain of the attenuator is ZIN I jeRfCf By making the RC time constant of Zf equal to the RC time constant of Z IN the gain of the attenuator is constant with frequency and equal to Rie This is true in the midband region Low frequency is limited by RC time constant of C908 and RIN 8818 and high frequency U803 Nominal values of resistance and capacitance are shown in Figure 24 5 Amplifier 0803 is powered from 3 V and 15 V When overloaded the average volt at the output is 6 Volts which keeps DC voltage off of C808 and C809 This minimizes settling time when autoranging e AC Converter l The AC converter is a transconductance amplifier The simplified circuit shows the basic operation The AC input voltage Ein is converted to a current lin because of the summing amplifier configuration This current flows through the FET when negative and through the diode when positive Thus Eout is a half wave rectified signal if the polarity is negative Eout is the input current flowing through Rout The terminal of the converter amplifier is referenced to a negative voltage to allow voltage swing across the FET 0801 2 The ac converter consists of dual FET 0803 operational amplifier 0801 and MOSFET 0801 diode CR801 and transistor 0802 semiconductor elements The input resistance is R812 and R8
163. rs all display drivers and timing mux generator The entire display including minus sign and function indicators are fully multiplexed This is accomplished with six time slots timing mux The mux times are generated by shift register 0301 whose inputs come from the LSI chip 0103 Schematic 27904F These time slots are referred to as tos tp 12 tz ty t5 The common anodes of each digit and the common anodes of the function indicators are driven from the appropriate mux line See fiqure 26 These mux times are also used in operating digital interfaces See Section 5 8 1722 mux times occur in the sequence tg thru ts tg and t are 383 microseconds each and t2 thru 5 19 micro seconds each One complete cycle is 1 53 milliseconds b The data mux lines a b c d e f g and dp drive the cathodes of the display segments and the function indicators See Table 5 6 The data mux lines are generated in the LSI chip U103 Schematic 27904F The 10 000 digit only indicates 2 3 in overrange If the 10 000 digit 15 zero it is blanked by the data mux lines It is necessary to operate the function indicator and minus sign twice as long as the digits Since and are activated juring tl the 10 000 digit time tl is as long as tO To keep the 10 000 digit the same brightness as the other digits a b c d e and f data mux lines for this digit are on for half of tl time d The anode driver transistors are
164. rtion of the circuit All of these high voltages will cause current to flow through R703 120K which is connected to the 15 volt supply The maximum limitation of 250 volts rms is a function Of the power rating of R703 a half watt resistor and Q704 s 400 volt breakdown TABLE 5 3 OHMS RANGES RANGE R OHMS RANGE LINES Vi CURRENT A B 33 444M 334 44V 3K 3002 3 3444 30K 3K 3 3444K 33444Y 300K 30K 334 44K 3 3444Y 3M 300K 334 44K 33484V 30M 3M 33 444M 3 3444 g Range Selection Ranging is accomplished by RSA 5 RSB lines going to LSI circuit 0103 They are controlled by the front panel switches AUTO MAN DN UP according to Table 5 4 RSA amp RSB edge sensitive causing range changes when their levels are changed This causes one uprange or one downrange per button push TABLE 5 4 Range Selection Range Switches Range Lines AUTO MAN DN UP RSA RSB HOLDRANGE DOWNRANGE UPRANGE DON T CARE 5 8 AA INSTRUCTION MANUAL THEORY OF OPERATION Digital Multimeter Models 172 173 h Function Switching TABLE 5 5 Function Selection FUNCTION SWITCHES FUNCTION LINES FUNCTION DC AC V A Q HI LO AC DC VI IN OUT 8 8 8 8 172 DCI IN IN OUT X 8V 48V n 173 ACV OUT IN OUT OUT 8 8V 8 172 AC T OU IN IN X 8V OV 173 HIQ
165. s decimal point location and measurement unit AC A AC ma or AC A c Omy Ov 1 ORA FIGURE 10 Typical Model 173 Current Display ACmA 3 6 CB INSTRUCTION MANUAL Digital Multimeter Models 172 173 OPERATING INSTRUCTIONS 3 8 HOW TO MEASURE RESISTANCE The Model 172 173 measures resistance 10 milli ohms diait to 300 megohms The maximum display is 29999 When the display exceeds 29999 a 3 remains lighted but all other digits are blanked a Ohms Measurement When the HI LO pushbutton is released set to age developed across the resistance under test at full range is 3 volts 173 measures to 300 megohms in HI mode is not used the volt The Model 172 For the 2 wire method the lower set of terminals l Set to HI Ohms 2 Set to 2 WIRE NOTE When the 172 173 is set to 2 WIRE the lower set of and LO input terminals are not connected When set to 4 WIRE the higher set of HI and LO input terminals are used as voltage sensina terminals See Section 3 9 for more detailed infor mation 3 Set to AUTO lh Connect the resistance under test between the upper set of HI and LO terminals 5 Observe the displayed digits decimal point location and measurement unit 5 or b LO Ohms Measurement When the HI LO pushbutton is released set to LO the volt age developed across the resistance under test at full r
166. s from relatively high source impedance could cause an additional reading error The amount of error due to loading can be determined by the following relationship Zs Soci om error where Zs source impedance Zin effective input impedance of Model 172 173 6 Self Check Feature The Model 72 172 has a rear panel Voltage test point for functional check of the Model 172 173 in AC Volts To use this feature connect the HI terminal to the rear panel red terminal Connect the line cord to line voltage Verify a display of approximately 6 volts ac To check ac current depress V A and verify a display of approximately 1 2 mA 3 8 AA INSTRUCTION MANUAL OPERATING INSTRUCTIONS Digital Multimeter Models 172 173 c Current Measurements l Overloads Fuses are as follows Model 172 2 Model 173 2 Shunt Resistance The Model 173 develops approximately 300 millivolts across the input terminals at full range The 172 has 1 3 Q on all ranges For example on the 300 milli ampere range the shunt resistor is 1 3 ohm which results in a voltage drop of 0 3 x 1 3 390 millivolts at full range 3 Accuracy The Model 172 173 accuracy is specified in terms of a of reading and a of range An additional reading error should be considered if the source re sistance is not greater than 1000 times the shunt resistor The amount of error can be determined by the following relationship 100 x Rin 4 error r Rs
167. t Desig 05301 05302 05303 05301 05305 05306 05307 05308 05309 05310 05311 05312 05313 05314 05315 05601 Description 1000 SERIES Schematic 27902 815 Rectifier 75 mA 75V Bridge Rectifier 100V 2 Rectifier 75 mA 75V Description Pilot Pilot Pilot Pilot Pilot Pilot Pilot Pilot Pilot Pilot Pilot Light Light Emitting Diode H P Light Light Light Light Light Light Light Light DISPLAYS DS Mfr Desig IN914 010 11100 SERIES Schematic 28019 IN911 Mfr Desig 300 SERIES Schematic 27404D Light Red LED Light Emitting Light Emitting Light Emitting Light Emitting Light Emitting Light Emitting Light Emitting Light Emitting Light Light Emitting Digital Digital Digital Digital Digital Display 7 segment Display segment Display 7 segment Display 7 segment Display 7 segment t 1 1 II BG D D 9 D O 9 D U VU 8 031075 2501 1 HP5082 4494 HP5082 4494 HP5082 4494 HP5082 4494 HP5082 4494 HP5082 4494 HP5082 4494 HP5082 4494 HP5082 4494 5082 7650 5082 7650 5082 7650 5082 7650 5082 7650 600 SERIES Schematic 28656 HP5082 4494 INSTRUCTION MANUAL Digital Multimeter Models 172 173 Keithley Part No RF 28 RF 36 RF 28 Keithley Part No PL 64 PL 63 PL 63 PL 63 PL 63 PL 63 PL 63 PL 63 PL 63 PL 63 DD 13
168. t of Q8Ol will go positive thus forward biasing the gate of 0801 This turns 0801 pulling current through resistors R802 and R803 from signal ground Thus Q801 only conducts for negative input signals and the output current is a half cycle sine wave of negative polarity This output current flows thru C803 and R802 which filters the DC voltage This filtering action allows the necessary 3 V DC with only 6 volts available from 0801 Without C803 more than 9 V swing would be needed The transfer gain of the AC converter is unity One volt AC RMS sine in causes Volt DC out 5 0803 is a dual FET used as source followers with source resistors R805 and R806 The 10 m V adjustment feeds a small correction current to the summing junction to adjust for leakage current errors The Volt 1 2 adjust calibrates the system gain on the 300 m V and 3 V ranges Additional output filtering is provided by the DC filter Section 5 C whose input is R80 6 C801 in this case 6 The only blocking capacitors needed are C808 and C809 on the input of the AC converter They keep voltage offsets of 0803 AC attenuator and 0803 and 080 from reaching the output 7 The AC System common is the 6 Volt reference It is composed of voltage follower 0802 and input divider R811 and R810 0807 is used to provide a low impedance AC path between 6V and signal lo to minimize AC noise pickup f Ohms Circuit 1 The ohms circuit is a current generator A summing amp
169. ted on the main circuit board To set the switch for operation above 125 volts the switch setting must be changed The top cover must be removed to gain access to the circuit board as described in MAINTENANCE section WARNING Disconnect the line cord before removing the top cover of the instrument Line voltage is present at various points on the circuit board and represents a SHOCK HAZARD NOTE Other line voltage ranges are available when miring modifications are made to transformer T601 as shown on schematic 280670 TABLE 2 1 Summary of Standard and Optiona Line Voltages Standard 105 to 125 V rms 90 105 V rms b Transformer wiring 210 to 250 V rms 195 210 V rms must be modified INITIAL PREPARATION SELF CHECR W gt emt CAUTION SEE INSTRUCTION MANUAL S 3607 608 N CAUTION CONNECT ONLY TO INDICATED VOLTAGE RANGE VOLTAGE RANGE 90 nov 105 125 2 0 250v FIGURE 5 1 INTERNAL LINE SETTING INSTRUCTION MANUAL Digital Multimeter Models 172 173 FUSE F501 REITHI EV AUTORANGING DMM DIGITAL INTERFACE Made in USA LINE RATING 50 60 Hz AC ONLY 25 vA MAX S N 11010 Cleveland FUSE 3AB SLO BLOW VBA Rear Panel Showing Current Fuse and Check Points AA STRUCTION MANUAL INITIAL PREPARATION Multimeter Models 172 1
170. the Model 1722 cir cuitry Circuit designation series is 1000 h Digital Interface Upper 28019 This schematic describes the Model 1722 cuitry Circuit designation series is 1100 i Timing Diagrams for Model 1722 28247 28248 282490 AB REPLACEABLE PARTS INSTRUCTION MANUAL Digitat Multimeter Models 172 173 TABLE 7 1 Cross Reference of Manufacturers FEDERAL FEDERAL MFR SUPPLY MFR SUPPLY CODE NAME AND ADDRESS CODE CODE NAME AND ADDRESS CODE O F IoI iJi TY A B Allen Bradley Corp Clarostat Mfg Co Inc Milwaukee WI 53204 01121 03820 12697 0 Analog Devices Inc CTS Corporation Cambridge 02142 24355 Elkhart 486514 71550 Amp Inc Dichson Electronics Harrisburg PA 17105 00779 Scottsdale AZ 85252 12954 APH Amphenol Dielettron Consolidated Broadview IL 60153 02660 New York City NY 10013 APX Amperex Electro Cube Inc Elkgrove Vlg IL 60007 73845 San Gabriel 91776 14752 BEC Beckman Inst Inc Electronic Devices Inc Fullerton CA 92634 73138 Yonkers NY 10710 BLD Belden Mfg Co E F Johnson Co Chicago IL 60644 70903 Waseca MN 56093 74970 BRG Berg Electronics Inc Erie Technological Prod New Cumberland PA 17070 22526 Erie PA 16512 72982 BRN Bourns Inc Fairchild Inst Corp Riverside CA 92507 80294 Mountain View CA 94043 07263 BUS Bussman Mfg Div Bussman Mfg Fusetron St Louis MO
171. the exact amount voltage which the charge balance system can measure b The current switch is forced to a frequency equal to the clock frequency rather than one half of it c The feedback correction current is delivered to the emitter of the reference current output transistor 01028 5 The circuitry which performs the operations described above is shown in Figure 31 together with most of the charge balance system redrawn from Figure 30 The added c rcuitry is grouped in five major blocks a Input Multiplexer b Reference current forcing circuitry c Comparator filter d Auto Zero feedback and storage circuitry e Auto Cal feedback and storage circuitry 6 This circuitry will be described block by block with reference to the above description of its basic mode of operation a The input multiplexer supplies the necessary voltages to the input of the buffer amplifier at appropriate times and connects the buffer amplifier to the signal source when that signal is to be measured The multiplexer consists of JFET switches controlled by signals from the LSI chip the two adjustable capacitors shown in Figure 31 are used primarily to neutralize the JFET switching charge in order to minimize the A D input current b The reference current forcing circuitry controls the input of the comparator latch flip flop n the Auto Zero mode it forces the output of this flip flop to alternate between one and zero on successive
172. to TRIGGER MODE DISABLE and FLAG RESET This will prevent the FLAG from being set and ignore further triggering until the final range 15 reached OPERATING INSTRUCTIONS ext LINE GROUND GROUNDS CONNECTORS ENV I RONMENT Installed in a 172 173 INSTRUCTION MANUAL Digital Multimeter Models 172 173 Internal jumpers user installed select internal or external voltage reference for user installed pullup resistors for all open collector outputs or applies internal 5V to Ve maximum external current load on internal 5V is 06 Minimum pull up resistor recom mended is 4 7K One pin on each output connector 4 pins for digital outputs 2 pins for remote control One 40 pin card edge and one 26 pin card edge Operating 0 C to 55 C humidity 80 35 C Storage 25 to 65 C f Modifications to 172 173 Specifications When operating 172 173 with a 1722 in TRIGGER MODE only the accuracy specifications for the top two ohms ranges change as follows HI 8 300M2 Range R 30M amp Range LO 30M Range LO Q 3M Range From 1 of reading to 1 5 of reading From 0 15 of reading to 0 2 of reading From 0 5 of reading to 1 of reading From 0 1 of reading to 0 15 of reading Also when operating in TRIGGER MODE repeatability of readings may be up to 0 5 300M2 and 30M9 Lo ranges and 0 05 on 30 Hi Q 3 0 Lo R ranges Accuracy of all other ohms
173. ut batteries instalied ISOLATION Input LO to power line ground greater than 1000 megohms Operating 0 C to 55 C shunted by approximately 300 picotarads Maximum sale input between 0 to 80 relative humidity up to 35 C LO and power line ground 1400 volts peak Storage 25 C to 65 C POLARITY Automatic POWER 105 125 or 210 250 volts switch selected 50 60Hz 20V A 90 110 volts available Optional rechargeable 6 hour battery pack CONNECTORS Input Banana jacks Self check Tip sacks DIMENSIONS WEIGHT 85 mm high x 235 mm wide x 275 mm deep 312 in x 9 x 1034 Net weight exclusive of batteries 2 3 kg 5 155 ACCESSORIES AVAILABLE ACCESSORIES AVAILABLE Continued Model 1726 Rechargeable Battery Pack Model 1010 Single Rack Mounting Kit Model 1722 Digita Interface Model 1017 Dual Rack Mounting Kit Model 1600 High Voltage Probe Model 1725 Maintenance Kit Model 1681 Clip on Test Lead Se INSTRUCTION MANUAL Digital Multimeter Models 172 173 NORMAL BENCH POSITION LEVEL POSITION TILTBAIL AT FRONT 25 AR 45 POSITION HANGING POSITION SHELF POSITION LEVEL POSITION TILTBAIL AT REAR FIGURE 2 Tilt Bail Positions 4 INSTRUCTION MANUAL GENERAL INFORMATION Digital Multimeter Models 172 173 SECTION 1 GENERAL INFORMATION 1 1 INTRODUCTION The Models 172 and 173 Digital Multimeters are wide range general purpose measuring instruments cap
174. witch is digitally forced to deliver reference current pulses at precisely 1 2 the clock frequency In a real system with finite offset errors the current being delivered to the integrat 5 17 THEORY OF OPERATION INSTRUCTION MANUAL Digital Multimeter Models 172 173 Qi04 p QU 1 COMPARATOR PAAT OF 1502 V vooze INTEGRATING CAPACITOR DIGITAL CURRENT PN SWTCH 17 SIN ES lt C uc LEVEL SHIF TING STAGE Tr REFERENCE CURRENT OUTPUT TRANSISTOR OSCILLATOR FIGURE 30 Simplified Schematic of V F Converter INSTRUCTION MANUAL THEORY OF OPERATION Digital Multimeter Models 172 173 AB or through the transconductance amplifier does not exactly match this forced reference current the difference exactly equals the correction current required to cancel the offset errors Thus the integrator voltage V exhibits a charge balance sawtooth waveform like that shown in Figure 29 Super imposed on a much slower ramp whose slope is proportional to this difference current The auto zero feedback system adjusts a correction current which flows into the summing junction of amplifier 0101 so that the slope of the ramp is equal to zero In this way all zero errors are preciselv cancelled 4 Auto Calibrate system works an analogous manner with three differences of detail a The voltage supplied to the input of buffer amplifier U202 is
175. wo parameters can be made very stable with the result that whether the frequency of the discharge cycle is high or low each increment of charqe removed i e each reference current pulse is precisely the same size Since the total charge removed from the capacitor in any given time period is equa to the total charge that flowed in during the same time period within a resolution of one discharge increment the uniformity of size of the reference current pulse guarantees that the total number of such pulses is precisely proportional to the time integral of the input current TIME NOT TO SCALE Ve ___ j gt BASE LINE LOGIC 0 ra ab PULSE FIGURE 29 Operating Waveforms of A D Converter 5 16 AB INSTRUCTION MANUAL THEORY OF OPERATION Digital Multimeter Models 172 173 AB 4 Figure 30 is a simplified schematic diagram of the circuitry actually employed to perform the V F conversion In addition to some added details of the circuitry already discussed Figure 30 shows three major circuit elements not previously mentioned a The input buffer amplifier U202 serves two functions First it provides a high impedance input to the A D converter Second it provides a selectable voltage gain of 10 giving the A D converter in effect two voltage ranges selected by the line labeled 610 an output from the LSI chip b The transconductance amplifier consisting of op amp 0101 and its assoc

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