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HP Toaster 8508A User's Manual

1. 1 Y followed by eight data bytes in IEEE 754 1985 double precision format E1089 3 39 Operation HP IB Command Set Summary Description Averaging Value Calibration Capability Clear Status Configure Measurement Correction A Value B Value Phase Value Normalize Impedance Termination Perform Normalization Normalization State Direct Analog Output Display State Fetch Results Continuous readings Format Frequency Band Auto Ranging Identification Input Impedance Module Type Measure Timeout Timeout State Output Test Signal Operation Complete Reset Self Test Service Request Enable Standard Event Enable Standard Event Register Status Byte Request Status Control Operation Status Condition Register Positive Transition Filter Negative Transition Filter Event Register Enable Mask System Error Register Key Format Trigger Trigger Setup Source Wait to continue 3 40 Table 3 2 Command and status message summary Query 1 lt lt lt lt lt lt MMC OM XM XMM XA 3 3 lt lt lt E KA AX D X o Xo Xo MMM lt lt lt lt XXX 5 s Command Header 2 AVERage COUNT CAL CAP CLS SENSe CORRection CORRection DATA A CORRection DATA B CORRectio PHASe CORRection IMPedance CORRection TERMination CORRection PERForm CORRection STATe DANalog DISPlay STATe FETCh FETCh CONT inuous FORMat FREQuency FREQuency BAND FREQuency BAND AUTO IDN INPut INPut
2. HLMP 2855 1 LIGHT BAR E6006000 DS 36 HDSP 4850 1 10 ELEMENT BAR GRAPH ARRAY E6006000 DS 37 HDSP 4850 1 10 ELEMENT BAR GRAPH ARRAY E6006000 DS 38 HDSP 4850 1 10 ELEMENT BAR GRAPH ARRAY E6006000 DS 39 47 HLMP 1840 9 SINGLE POINT E6006000 DS 48 61 BLMP 1840 14 SINGLE POINT E6006000 DS 62 HLMP 2300 1 LIGHT BAR LEGEND E6006000 DS 63 HLMP 2300 1 LIGHT BAR LEGEND E6006000 MP 01 5041 4722 1 KEYCAP A E6006000 MP 02 5041 4723 1 KEYCAP B E6006000 MP 03 5041 4719 1 KEYCAP REFL MEAS E6006000 MP 04 5041 4717 1 KEYCAP FORMAT E6006000 MP 05 5041 4721 1 KEYCAP POWER MEAS E6006600 MP 06 5041 4724 1 KEYCAP B A MAG E6006000 MP 07 5041 4725 1 KEYCAP B A PHASE E6006009 MP 08 i 5041 4720 1 KEYCAP REF SEL E6006000 MP 09 5041 4716 1 KEYCAP REF E6006000 MP 10 5041 4718 1 KEYCAP SYS IMP E6006000 MP 11 5041 4712 1 KEYCAP METER SEL E6006000 MP 12 5041 4713 1 KEYCAP LOCK RANGE 6006000 MP 13 5041 4711 1 KEYCAP ARROW E6006000 MP 14 5041 4711 1 KEYCAP ARROW E6006000 MP 15 5041 4714 1 KEYCAP MAG RANGE E6006000 MP 16 5041 4715 1 KEYCAP HOLD VALUE E6006000 MP 17 5041 0982 1 KEYCAP DISPLAY i E6006000 MP 18 5041 0432 1 KEYCAP SHIFT i E6006000 MP 19 5041 4710 1 KEYCAP LCL E6006000 MP 20 i 5041 4709 1 KEYCAP PRESET E6006000 A1SW1 20 3101 2409 20 SW PB SPST NO E6006000 AtW 08508 60010 1 CABLE A1 TO A5 E6006000 08508 60020 1 BUNDLED DISPLAY PACKAGE ES006000 CONSISTS OF THE FOLLOWING DS 2 4 9 12 HDSP 4600 7 COMMON AN
3. SISI SS STERN Y AS ER ANE ROREM Figure 3 1 Front Panel MEASUREMENT KEYS Introduction The following four keys operate similarly One press lights the LED and the measurement result is shown in the appropriate display window A second press turns off the LED and the measurement result Any single measure ment 1s available and any combination can be chosen by selecting the required measurements Note that A B A mag and B B A phase combinations can be selected using shifted functions that is pressing SHIFT and the appropriate key If a new measurement is selected which uses the same display as an existing measurement the existing measurement will be turned off for example selecting Phase when B is displayed will turn B off A Measures the amplitude of A Default is mV on Display 1 changeable to dBuV by toggling the DISPLAY key to dB Power can be displayed by pressing the POWER MEAS key and selecting either 50 or 75 ohms with the SYSTEM IMPD key Units available are uW and dBm B Operates in the same way as A but the value appears on Display 2 units are controlled by the DISPLA Y key B A mag Measures the B A ratio Default is linear units on Display 1 changeable to dB using the DISPLAY key B A phase Measures the phase of B with respect to A in degrees Operation A B A mag Places the A measurement in Display 1 and the B A measurement in Display 2 B B A phase Places the B measurement in Dis
4. VOLTMETER Including Option 001 Operating and Service Manual SERIAL NUMBERS This manual provides complete information for in struments with serial number prefix 2949U With the changes described in Section 7 this man ual also applies to instruments with serial numbers prefixed 2812U For additional important information about serial numbers refer to INSTRUMENTS COVERED BY THIS MANUAL in Section NOTE Use this manual only with instruments that have a U in their serial number prefix First Edition Copyright OHEWLETT PACKARD LIMITED SOUTH QUEENSFERRY WEST LOTHIAN SCOTLAND EH30 9TG Operating and Service Manual HP Part 08508 90000 Microfiche Operating and Service Manual HP Part 08508 90011 Printed in U K May 1988 H EWLETT T Y Pagi CERTIFICATION Hewlett Packard Company certifies that this product met its published specifications at the time of shipment from the factory Hewlett Packard further certifies that its calibration measurements are traceable to the United States National Bureau of Standards to the extent allowed by the Bureau s calibration facility and to the calibration facilities of other International Standards Organization members WARRANTY This Hewlett Packard instrument product is warranted against defects in material and workmanship for a period of one year from date of shipment During the warranty period Hewlett Packard Company will at its option either repair or repl
5. IDN The identification command returns a string which describes the Vector Voltmeter and Input Module The string contains four fields separated by commas as shown below HEWLETT PACKARD 8508A 050 0 REV 2944 emmm m AA A EI NE mi he pie pe i Me Manufacturer Firmware revision Model number Not used Input module option STD or 050 E1089 3 45 Operation Input INPut iMPedance lt nrf gt POD Input impedance sets the impedance of the measurement system used in power and impedance measurements Allowed values are 50 or 75 Ohms The query option returns the current setting POD either 50 75 or HI Measure MEASure meas meas Timeout TIMEout lt nrf gt STATe ON OFF 1 0 This command is used to configure and make a Vector Voltmeter measurement or measurements and return the result s Default is AVOLtage Options for meas are listed below AVOLtage Channel A Voltage using current setting of FORMat LOG LIN BVOLtage Channel B Voltage using current setting of FORMat LOG LIN APOWer Channel A Power using current settings of INPut IMPedance and FORMat LOG LIN BPOWer Channel B Power using current settings of INPut IMPedance and FORMat LOGILIN BA B A Magnitude Ratio using current setting of FORMat LOGILIN PHASE B A Phase TRANsmission 8 A Magnitude Ratio and B Phase computed from the same measurement using current settings of FORMAT L
6. IF Signal FILTER acca l aenal 20kHz CF REGE UMITER PROBE PHASE DETECTOR HM SEARCH 4 amp LOCK 1 ASSEMBLY PULSE i GENERATOR 71 PRECISION Is i PROBE o iaca e E y o eHzs w UMITER Figure 8 1 Simplified Block Diagram of the HP 8508A Vector Voltmeter System Fault finding in the HP8508A is aided by the Self Test routine which is run whenever the instrument power is switched on This routine checks the assemblies in the sequence shown in the following table The current firmware revision will be shown in DISPLAY 2 for a few seconds After this period DISPLAY 1 will indicate tSt while DISPLAY 2 will show a 3 digit series number appropriate to the assembly being tested The whole test routine takes approximately 8 seconds to complete with the AS Processor Assembly occupying about 6 seconds of this time Should an error be detected the routine will halt with an error number in Display 2 E1089 8 3 Service Designation Assembly Test Series Number AS Processor 500 A2 Power Supply 200 A4 Search and Lock 400 A3 IF Board 300 When a faulty assembly is detected an error code in the series will appear in Display 2 However before replacing the suspect assembly a check should be made of the Power Supply Levels cables and connections and any adjust ments relative to the assembly For example an IF Assembly error may be caused by a dam
7. IMPedance INPut IMPedance POD MEASure MEASure TIMEOUut MEASure TIMEout STATe OUTPut OPC RST TST SRE ESE E SR STB STATUS STATus OPERation STATus OPERation CONDition STATus OPERation PTRansition STATus OPERation NTRansition STATus OPERation EVENt STSTus OPERation ENABie SYSTem SYSTem ERRor SYSTem KEY SYSTem FORMat TRG TRIGger TRIGger SOURce WAT Parameter 3 lt nrf gt lt meas gt 4 nrf nrf nrf ON OFF 10 20 SHORT OPEN ON OFF 1 0 ON OFF 1 0 ON Jorr 1 0 LINear LOGarithmic POLar RECTangutar CARTesian lt nrf gt ON OFF 1 0 nrf lt meas gt lt meas gt 4 nrf ON oFF 110 ON orr 110 nrf 5 nrf 6 7 lt nrf gt 7 lt nrf gt 7 lt nrf gt 7 NUMer ic STR ing lt nrf gt ASC i FP64 BUS FREErun E1089 Operation NOTES 1 Commands which allow a query option are indicated by y Commands where the query is mandatory are also shown with the query question mark in the Command Header column 2 Letters in CAPITALS are required The remainder of the command can be added if desired for legibility 3 nrf indicates Numeric Representation Flexible which is a forgiving real format described in IEEE 488 2 4 meas indicates AVOLtage BVOLtage APOWer BPOWer BA PHASe TRANsmission DELay SWR RHO Y ZICORE 5 Status Byte bit usage is as follows bit 4
8. The last five digits comprise the serial number which is unique for each instrument The content of this manual applies to instruments with the serial prefix es listed under SERIAL NUMBERS on the title page of this manual An instrument manufactured after the printing of this manual may have a serial number prefix that is not listed on the title page The unlisted serial number prefix indicates that the instrument is different from those described in this manual The manual for this new instrument is accompanied by a Manual Changes supplement This supple ment contains change information that explains how to adapt the manual to the new instrument In addition to change information the supplement may also contain information for correcting errors in the manual To keep this manual as current and as accurate as possible Hewlett Packard recommends that you periodically request the latest Manual Changes supplement The supplement for this manual is identified by the manual print date and part number both of which appear on the manual title page Complimentary copies of the supplement are available from Hewlett Packard For information concerning a serial number prefix that is not listed on the page or in the Manual Changes supplement contact your nearest Hewlett Packard office 1 1 General Information 1 5 DESCRIPTION The HP 8508A Vector Voltmeter is a dual channel autoranging receiver which measures the voltages of two CW signals and t
9. 08508 80012 5 EPROM ASSEMBLY E6006000 6 10 E1089 VA E da I 6 0 Jo e 12 E1089 Reference Designation HP Part Number 08508 00001 08508 60002 5021 8403 00853 20068 08508 00010 08508 00025 00855 20067 08508 00007 08508 00005 08508 00011 00853 20070 08508 20102 Table 6 3 Replaceable Parts MAIN CHASSIS FRAME ASSEMBLY Refer to Figure 6 2 Description FRONT PANEL DRESS SUB PANEL FRONT FRONT FRAME SIDE FRAME LEFT MAIN DECK LEFT REAR PANEL REAR FRAME BRACKET TRANSFORMER PLATE PSU HEATSINK MAIN DECK RIGHT SIDE FRAME RIGHT WINDOW MACHINED Replaceable Parts Hfr Code E6006000 E6006000 E6006000 E6006000 E6006000 E6006000 E6006000 E6006000 E6006000 E6006000 E6006000 E6006000 Replaceable Parts Table 6 3 Replaceable Parts CABINET PARTS Refer to Figure 6 1 Reference C Qty Description Mfr Designation D Code 5062 3811 4 1 SIDE COVER RIGHT E6006000 5040 7221 2 4 REAR FOOT E6006000 5041 9434 5 1 TOP COVER E6006000 5041 8802 9 1 TOP TRIM E6006000 5062 3836 3 1 SIDE COVER LEFT E6006000 5021 9840 5 1 FRONT HANDLE LEFT E6006000 5041 9446 9 1 BOTTOM COVER E6006000 5021 9840 5 1 FRONT HANDLE RIGHT E6006000 5040 7201 8 4 FOOT E6006000 1460 1345 4 2 TILT STAND E6006000 5040 9805 2 1 STRAP HANDLE E6006000 5041 6019 6 1 SIDE STRAP COVER FRONT E6006000 5041 6820 7 1 SIDE STRAP COVER REAR E60060
10. BH ou iv beat frequency oscillator Bit ihe suede binder head BKDN oo Ga esac breakdown BP ranas bandpass BPP sis bandpass filter BAN RE eu aen Cha brass BWO aa t backwara wave oscillator CAL esie de calibrate OW o vues counter ciockwise GEM i12 ss BEAT CHAN a suu Pus channel EI rain eth centimeter CMO cabinet mount only CORK za ee coaxial Table 6 1 Reference Designations REFERENCE DESIGNATIONS En miscellaneous electrical part A nc acters fuse BL ones ibo ae ga fa fiiter Mia Aas task bed em hardware HY eese ace is circulator Al usd electrica connector stationary portion jack No al ehr reiay dla xA coil inductor COMPERTE Sak ian neds cee ty AIS meter ME ouo veis miscellaneous mechanical part PA A bs siectrica connector movabie portion plug Duron transistor SCR triode thyristor FET N ae es ri resistor AT thermistor SA cr switch Tos nae transformar TE o acer Es terminat board AS trad thermocoupie 2 AA EEE EI test point Table 6 2 Abbreviations 1 of 2 ABBREVIATIONS COEF ames ich coeficient SUP ratos electronic data CUM ear does common Processing COMP o aat composition ELECT ou electrolytic COMPL alaaa comptete ENCAP encapsulated CONN Jog tote connector EXT esse external GP cena i eee cadmium piata EEE NER farad CRT aa cathode ray tube FET fieid affect transistor 2 es complementary A Ua NA LSe ie ah Ca NS as ftip fiop transistor iogic gin M PM ss flat head CS deo sey
11. Condition Register CONDition Positive Transition Filter PTRansition lt nrf gt Megative Transition Filter NTRansition lt nrf gt Event Register EVENt Enable Mask ENABLE lt nrf gt The status command controls the setup and operation of the condition and event registers The registers are set by positive or negative transitions of the appropriate condition enabled by transition filters EVENt and CONDition return the current values of the corresponding registers ENABle selects which events latched using the Positive TRansition and Negative TRansition filters are reported in the Status Byte summary bit 7 The query option of ENABle returns 0 through 255 using encoding as in Table 3 2 The query options of PTRansition and NTRansition return the current transition masks system SYSTem Error Register ERRor NUMeric STRing Key KEY lt nrf gt Format FORMat ASCii FP64 The system command covers miscellaneous housekeeping and global activities in the Vector Voltmeter SYSTem ERRor returns an error code describing any error that occurs Errors are returned as either numeric responses or as a string describing the error By default a string is returned Full details of the error codes appear in the Troubleshooting section of this Manual SYSTem KEY allows direct programming of the front panel key functions to simulate key presses Each key is simulated by sending its keycode given in Table 3 3 3 48 E1089 Operation T
12. ESD protection b Remove the instrument Bottom Cover c Disconnect the cable connections to the assembly d Remove the 2 screws securing the HP IB connector to the rear panel e Remove the 6 screws securing the Processor Assembly to the Instrument deck f The Processor Assembly may now be removed from the instrument Refitting the Processor ssembly Refitting is the reverse of this procedure 8 18 E1089 Service ERROR CODES 600 SERIES Errors in this series indicate a problem in the Input Module Refer to the appropriate Input Module Service Manual for troubleshooting details Service ELE E H oe d Y e n Kr n p t 1 i J i D Le Mop RSS uu E t Dr ver re y OS i a eee eS ety weet AEE Da Sada T C a te AO E IIA y a eite ee tee Lr s pe A srai HH EET E ERA RE nt ry SSMO E slap 0 ema uei iuge at oe oe gen See nee u rn NUS DG TEGERE ELEME SE ea eroe DW f E en net REEL teii cee nee ao HEHE aaa omnis eer RE acea ae ete ee 4 D COLERE EN LNSCR ANS I si ap Ee CAI A AAA A A IR EN s A O AAA en IRE OR ARO ROA E TE TERETA EE TA a x ODES LINEAL SA se ERS IT Fi d aree RIIV et HIIS A RN INN NT A AS a MN DAS E AZ AED ii E intii
13. Message Available bit 5 Standard Event Summary Bit bit 6 Request Service Master Summary Status MSS bit 7 Operation Status Register Summary Bit Other bits are unused 6 Standard Event Status Register bit usage is as follows bit 0 Operation Complete bit 4 Execution Error bit 2 Query Error bit 5 Command Error bit 3 Device Error Other bits are unused 7 Operation Status Register bit usage is as follows bit 0 Calibrating bit 3 Measuring bit 2 Ranging Unlocked bit 4 Awaiting Trigger Other bits are unused Refer to Figure 3 23 for an example of SRQ enabling and handling E1089 3 41 Operation Command Reference Commands which have no parallel in local operation are described fully in this section and are indicated by the lt HP 1B gt logo in the header Commands which operate instrument functions available from the front panel are described only briefly here because full functional descriptions are given in the section describing local operation Averaging Value lt HP18 gt AVERage COUNt nrf When making measurements the Vector Voltmeter accumulates a number of internal readings and averages them to produce a result which is fed to the display and or HP IB The averaging value can be changed only via HP IB The default is 25 measurements per reading Higher values may reduce measurement variation especially with noisy signals at the cost of a lower measurement rate Lower values increase the measurement rate a
14. N Tee i Device Under Test Figure 3 15 50 ohm Inputs Connect the termination calibration standard Press SSAVE REF Replace the termination with the device under test DUT Read result LOCK RANGE Using this function provides a faster lock response in automatic systems and when making repetitive measurements near a specification range boundary This function overrides the automatic selection of frequency lock range MAG RANGE This function has two uses First it overrides the automatic selection of the magnitude display range allowing control of display resolution Second it enables you to control the rear panel output range useful when using auxiliary equipment CAL TEST This function controls the test output and also performs an internal calibration You should use this function regularly to ensure that the instrument maintains its optimum performance This function should be used after instrument warm up allow a 30 minute warm up period In addition if the instrument is used in a constant environment this function should be used at least once per day DIR ANALG OUT This function activates the rear panel outputs and locks the instrument state Using the rear panel outputs for narrowband sweeps gives a faster response SHIFT DELAY This function enables you to make single point delay measurements by converting the measured phase difference to a delay measurement Set for transmission Choose the first
15. NOT HAVE THE REQUIRED EARTH GROUND CONNECTION GROUNDING ONE CONDUCTOR OF A TWO CONDUCTOR OUTLET IS NOT SUFFICIENT PROTECTION CAUTION 1 To prevent damage to the instrument power supply circuits verify that the line voltage selection switch located on the instrument rear panel is set to the correct line voltage 2 The HP 8508A and its Input Modules contain static sensitive devices which may be damaged as a result of static discharge 3 To prevent equipment damage do not disconnect circuit boards when the POWER switch is ON 4 To avoid contamination of circuit board connectors DO NOT HANDLE or TOUCH the connector pins E1089 8 1 Service 8 3 AFTER SERVICE PRODUCT SAFETY CHECKS Visually inspect the interior of the instrument for any signs of abnormal internally generated heat such as dis coloured printed circuit boards or components damaged insulations or evidence of arcing Determine and remedy the cause of any such conditions Using a suitable ohmmeter check the resistance from instrument closure to ground pin on the power cord plug The reading must be less than one ohm Flex the power cord while making this measurement to determine whether intermittent discontinuities exist Check line fuse to verify that a correctly rated fuse is installed 8 4 ANTI STATIC PRECAUTIONS All the printed circuit boards contained in this instrument have components and devices which are susceptible to damage by electro static d
16. and has a gain of approximately 14dB Probing at the input of the amplifier the output of the oscillator gives a reference signal and probing at the output of the amplifier will give the amplifier gain Use the integral source as the stimulus so the amplifier will be tested under normal operating conditions Source Amplifier Figure 3 3 Test Assembly With Measurement Points 3 9 Operation Since the circuit impedance is 50 ohms and the measurements are at relatively low frequencies we can neglect the loading effects of the probe tips on the circuit response For more sensitive applications the HP 11576A 10 1 Divider or HP 10216A Isolator accessories can be used with the probes to minimize loading effects and measure ment errors Measurement details 1 Connect both probes at point 71 the amplifier input in the circuit Press PRESET to return the HP 8508A to a known starting state E 2 Check that the circuit under test is powered up and that the HP 8508A A UNLOCKED indicator is off Press B A MAG and B A PHASE to display vector ratio 3 Select DISPLAY dB to measure the amplifier s gain as a log ratio Press SHIFT then SAVE REF to store the reference and set the ratio displays to magnitude 0 0dB and phase 0 degrees 4 Move the B probe to point 32 the amplifier output and measure the gain and phase change Change the frequency of the oscillator over its operating range and check the frequency respons
17. and service requests All front panel functions except the LINE switch are programmable via HP IB In addition there are HP IB commands offering capabilities under remote control which are not available from the front panel keyboard The HP IB commands used in the Vector Voltmeter conform to the standards set by document IEEE 488 2 1987 Codes Formats Protocols and Common Commands for use with ANSI IEEE Std 488 1 22 January 1987 Consult the standards document for details of the commands and structures recommended For more information about HP IB refer to IEEE Standard 488 1 or the identical ANSI Standard MC1 1 the Hewlett Packard Electronic Systems and Instruments catalog the booklet Improving Measurements in Engineer ing and Manufacturing HP part number 5952 0058 and Tutorial Description of the Hewlett Packard Interface Bus HP part number 5952 0156 Nov 87 Anyone who is unfamiliar with the IEEE 488 Standards should read the Tutorial Description as an introduction HP IB Capability This section gives a general description of HP IB capabilities as they apply to the Vector Voltmeter The instru ment s command set is summarised in Table 3 2 and command details are given in the Command Reference section HP IB system operation normally relies on three types of bus device behaviour as follows A LISTENER is capable of receiving data over the bus when addressed to do so There can be multiple listeners simultaneously a
18. be used to make your measurements easier The measurement examples will use 50 ohm devices refer to the following section for details of configuring the HP 8508A for 50 ohm inputs Measurements in a 50 ohm system 50 ohm measurements can be made directly when the HP 8508A 1s fitted with the type N HP 85082 Input Module or by using adapters with the probes of the HP 85081 Input Module The HP 11536A Feedthru is part of the HP 11570A Accessory Kit The following diagram shows how to connect the probe adapters to make 50 ohm meas urements 50 ohm in line 50 ohm Terminated Probe Probe 50 ohm ans 50 ohm 50 ohm 908A 50 ohm source load source Termination 11536A Probe Tee 115364 Probe Tee Figure 3 8 Probe to 50 ohm Options In this example measure the 3dB point of a low pass filter that cuts off at around 50MHz The circuit includes a source and a power splitter which is used to obtain a reference signal The filter is preceded by a 6dB pad to minimize out of band reflection problems 3 14 E1089 Operation Measurement details 1 Connect the equipment as shown below Press PRESET to get the instrument to a known state then B to measure the filter output To frequency counter optional HP8508A A Input 50 ohms J1 J2 J3 O o v Power Splitter Ay L3 Low Pass Filter URP TE J7 dy HP8508A B Input 50 ohms J4 J6 Figure 3 9 Test Setup 2 Select METER SELECT DISP2 to activate
19. code 2 in Display 2 Press HOLD VALUE and check that the indicator LED is ON 8 Adjust the core of A4L3 slowly until the UNLOCK light extinguishes 9 Press HOLD VALUE to cancel the function 10 Replace the HP 8508A top cover Adjustments A413 32 4MHz OSCILLATOR ADJUST CR6 UNLOCK INDICATOR 1 62MHz OSCILLATOR ADJUST A4 R89 Figure 5 5 Search and Lock Assembly Adjustment Locations 5 13 E1089 Adjustments 5 14 Replaceable Parts Replaceable Parts Section 6 6 1 INTRODUCTION This section contains information for ordering parts Table 6 2 lists the abbreviations used 1n the parts list and throughout the manual Table 6 3 lists all replaceable parts in reference designator order and Table 6 4 lists the names and addresses that correspond to the manufacturer s code number used in the parts list Figures 6 1 to 6 3 illustrate the chassis mounted parts miscellaneous parts and assembly information 6 2 ABBREVIATIONS Table 6 2 lists all the abbreviations used in the parts lists and throughout the manual In some cases two forms of an abbreviation are given one in all capital letters and the other in partial or no capital letters This is because the abbreviations used in the parts list are always all capitals however in other parts of the manual abbreviations are used in partial or no capital letters 6 3 REPLACEABLE PARTS LIST Table 6 3 is organized as follows a Electrical assemblies and
20. continuous wave El AAA filiister head GN ER RER IDR clockwise FM frequency modulation PP sto tints E garde centimeter A front panel DJA ae digital to analog FREIE cis dea frequency GE A FREE TE decibel e ee ER fixed ABM decibel referred gg NES gram to 1 mW Ca N germanium d aus direct current SHE pont gigahertz dog degree temperature El oor 13 dade key aes giass interval or difference GRD S uae RER ground ed i anie are amh degree plane ANTO TATE henry angte TE ES LT hour e or Ei iol degree Celsius HET soe A xsv heterodyne centigrade HEN eee eee hexagonal y ME degree Fahrenheit A Et head gi SI OA E ree ee degree Kelvin HOW e a e ea ae ta hardware DEPO usa deposited carbon SET high frequency DET audi detector PO Kara LIRE mercury OMIM ox is siib ed REX diameter PI nic ees ener LIESS high DIA diameter used in HP vus Es Hewtett Packard parts list HPF high pass filter DIFF AMPL differential Fiss Mans hour used in amplifier parts list UN s duca ata qo division HM cng eee es mend high voltage DPDT oasis doubte pole 7 ACE DNE PEERS Hertz doubte throw a iiit integrated Circuit IDE N qiia nte oi qs drive I aca inside diameter DSB 02i double sideband IE oso iR CS intermediate DTL aedes diode transistor frequency logic IMPG is impregnated DYM xu oss digital voltmeter i Mp incandescent 7 AA emitter coupled INGE toda inctude s logic SAP oo ae Sua is input EMF _ alectro
21. correctly installed LOCAL Returns the instrument to front panel control unless local lockout has been asserted over the HP IB ADDRESS Used to show the current HP IB address of the instrument It is changed by using the STEP keys The display reverts to measurement display when another key is pressed DISPLAY AREA KEYS MAG RANGE When MNL is selected the display resolution is controllable using the STEP keys which move the position of the decimal point When A and B are displayed together both displays show the same resolution DIR ANLG OUT When this mode is engaged the raw phase and magnitude detector outputs are fed directly to the rear panel so that external measurements can be made when a CW or swept source is used Internal gain ranging is forced into manual operation with the display showing XXX mV full scale deflection adjustable by use of the STEP keys The LOCK RANGE is also forced into manual mode The only valid measurement selection is A or B The HP 8508A will lose lock if the sweep rate exceeds approximately 15MHz second or if the frequency reaches a lock range boundary LOCK RANGE When MNL is selected the instrument is prevented from signal searching outside the current frequency range RANGE Display the current lock range the range can then be changed by using the STEP keys The display reverts to measurement display when another key is pressed 3 6 E1089 Operation HOLD VALUE This
22. d Remove the nut and washer securing the power connector Earth lead to the rear panel e Remove the 2 Nuts and Pozidriv screws securing the power connector to the rear panel E1089 8 11 Service f Remove the 3 Cable connections to the Power Supply board g Remove the 3 Pozidriv screws securing the Heatsink to the sideframe h Remove the plastic safety cover after undoing the 4 Pozidrive holding screws i Remove the 2 Pozidrive locating screws on the mains switch j Remove the 7 Posidrive screws securing the Power Supply board to the main deck k The Power Supply board can now be tilted up on the left side and the mains swich unsoldered and removed NOTE Do NOT dismantle the switch assembly and take care not to bend the operating cable The Power Supply board can now be removed from the instrument Refitting the Power Supply Assembly Refitting the Power Supply is the reverse of the above procedure NOTE After installing a new Power Supply assembly the HP 8508A Adjustment procedures and Performance Tests should be performed 8 12 E1089 Service ERROR CODES 300 SERIES Errors in this series indicate a problem in the A3 IF Assembly IF ASSEMBLY A3 Summary Description The two 20 kHz IF signals produced by the RF Input Module are passed to the IF Assembly which operates under Processor control The IF assembly measures the amplitude of these two signals and the phase difference B A between them The res
23. down arrow keys to select band 20 0 02 0 02M Hz Now press SHIFT SAVE REF to store the measure ment as a reference and normalize readings to the saved reference value 4 Insert the device to be tested between the RF source and the detector 3 20 E1089 5 Convert the modulation envelope phase change which is shown on Display 2 to delay using the following formula where In this case the modulation source is 20kHz Substituting this in the formula gives E1089 d phase t d f m x 360deg t d delay in seconds d phase envelope phase shift in degrees f m modulation frequency in Hz d phase t d 4 72E 6 Operation 3 21 Operation 3 10 TYPICAL CONFIGURATIONS Probing measurements with external source HP8508A Source A Probe Tee sh Ach dc ih da Ali W idh S MEM 8 AAN Room Doe mcn d mm oo pijani a Admin att wen ww revere cm viene de HY WL ob AH MY OA Eo ii MM Aka MM HE E RE AL RR RU RAUM A Circuit Under Test Figure 3 17 Probing Measurements Setup Equipment HP 8656B Synthesized Signal Generator HP 8508A Vector Voltmeter HP 11536A Probe Tee Part of HP 11570A Accessory Kit HP 11851B Cable Kit 1 cable required in this setup Or HP 11500B RF Cable Adapter from type N to circuit under test if required Probe Accessories if required HP 11576A 10 1 Divider HP 10216A DC Block HP 5060 0549 Spanner Top Assembly 3 2
24. frequency on the synthesizer Select DELAY Press SAVE VALUES to save the measurement Set the synthesizer to the second frequency 4kHz and read the delay E1089 3 19 Operation d 20kHz Receiver The HP 8508A can be used with the input module extender HP part number 08508 60032 as a 20kHz receiver This feature can be used to allow magnitude and phase measurements on a 20kHz signal For example to make delay measurements by amplitude modulating an RF signal In this case the HP 8508A measures the phase change in the modulation envelope which can be converted to delay Modulation Source RF Source HP 8508A Input Module Extender Calibrate Device under test Detector Figure 3 16 20k Hz Receiver Setup 1 Set the RF source to the frequency of interest Ensure that AM is on and set the amplitude to give approximately 10dBm at the detector input Set the modulation source to 20kHz at a level compatible with the RF modulation input Using an oscilloscope check that the detected signal is an undistorted sinewave Reset the AM percentage and the modulation source level if necessary 2 To calibrate the circuit configure the equipment as shown 1n Figure 3 16 without connecting the device to be tested 3 On the HP 8508A press PRESET to return the HP 8508A to a known state Press B A PHASE to measure amplitude on Display 1 and phase on Display 2 Press LOCK RANGE SHIFT VIEW RANGE and use the up
25. indicates that the instrument is in the setup mode and nnam is the current setup code Use the UP DOWN Arrow keys to set up test code S in Display 2 Press HOLD VALUE and check that the indicator lamp is illuminated 4 Remove the HP 8508A top cover to allow access to the adjustments 5 Configure the equipment as shown in the Figure 5 3 In this test a 100mV signal from the AC Calibrator is applied simultaneously to the Channel A and Channel B Input Amplifiers on the IF board A pair of miniature probe clips should be used to apply this signal between A3C1 and A3R150 for Channel A and between A3C21 and A3R170 for Channel B The location of these points is shown in Figure 5 4 E1089 Adjustments b A3 IF Assembly Sici Dee esta s zici de Tum init Es T uj ac 3 La ul en o EL amp IF Measurement Assembly Test Point Locations 5 Figure E1089 5 10 Adjustments Alternatively install the input module extender HP part number 08508 60032 in the HP 8508A Vector Voltmeter The input module is not required Set switch S1 on the input module extender to CALIBRATION and set switch S2 to EXTENDER CALIBRATION The 100mV signal from the AC Calibrator can be applied to either of the BNC connectors on the input module extender front panel 6 Set up the AC Calibrator for an output frequency of 20 kHz and a level of 100 mV 7 Adjust A3R178 to give a display reading o
26. linked together using appropriate punctua tion as defined in the IEEE 488 2 standard Allowable commands for the Vector Voltmeter are described in Table 3 2 Either upper or lower case characters are accepted Many commands have a query option that returns results or allows the state of the function to be checked remotely Figure 3 22 shows a typical command MEASURE AVOLTAGE cr lf Make a measurement Termination Sequence Return the result Parameter to measure Figure 3 22 A Typical Command Triggered Measurements A feature only available via remote programming is selection of free run or HP IB triggering With triggering set to free run the Vector Voltmeter measures continuously outputting data to the display and if requested the HP IB as each measurement cycle is completed When the trigger source is set to BUS the Vector Voltmeter will make triggered measurements A trigger is initiated by the trigger message a Group Execute Trigger HP IB command or a TRG Instrument command In triggered mode internal settings can be altered but the instrument is inhibited from measuring and sending results to the front panel or the HP IB until a trigger is received When triggered the instrument completes one cycle of the current measurement and then waits for another trigger The results of the completed measurement are held and can be obtained by using the FETCh or MEASure command Returning the Vecto
27. the meter on the B voltage then tune the source frequency for a maximum to set the source in the filter passband Tuning is achieved using the trend indicators LED s An increasing level is highlighted by the top LED being illuminated A decreasing level is highlighted by the bottom LED being illuminated A null is indicated by both LEDs being extinguished BUB tion nnn Figure 3 10 Meter Display 3 Press B A MAG to measure the amplitude ratio and select DISPLAY dB to display a log ratio 4 Press SHIFT then SAVE REF to store the current reading zero the magnitude reading and refer future measurements to the filter passband Operation 5 Now increase the source frequency until the display reads 3dB Note the source frequency This is the filter 3dB cutoff frequency a Transmission One good use of a CW receiver such as the HP 8508A is in the measurement of gain as a function of input level The HP 8508A automatically displays B A as a ratio so effects caused by changing input level can be seen directly To illustrate this we ll measure the 1dB gain compression point of a SOMHz 14dB gain amplifier Since the output at gain compression is specified to be 10dBm we ll use an HP 8491A 10dB attenuator at the output of the amplifier to minimize measurement errors due to high signal levels Source HP8508A 50 ohm 50 ohm A Input B input Power Splitter Cal 10dB Pad Device Under Test Figure 3
28. to peak used SPG Ate ee spring in parts list SA eu oce eate ee split ring PPM iens puise position SPSE ure t esed single pole modulation singie throw PREAMPL preamplifier Dog Service Sheet PAR sten puise repetition SSE neta e aa singie sidaband frequency SST stamless stagi PRR pulse repetition rate SIE tg nee steel Es picosecond cie dauert square PT N de mapa point SWR standing wave ratio PTM eoe Po puise time SING caw eed Da synchronize modulation d esses timed slow blow fuse PWM 0ommeoco pulse width TA Ep HER tantalum modutation Tonada temperature compensating NOTE All abbreviations in the parts list will be in upper ase MULTIPLIERS Abbreviation Prefix Multiple T 1012 G 109 M 108 k 10 da 10 d 107 c 107 m 1073 u micro 1076 n 1079 p 107 12 f famto 19715 a 19718 ID A time delay TERM ocio ees terminal TET A thin film transistor TOL ar toggie PHD onesta ira thread THRU AAA through TE II Fick 3 18 titanium TOR iaa E tolerance TAIM ware ae trimmer TOR Sowas aos erus transistor TTE transistor transistor logic IN aa x x ace le eee television TVi television interference TWT traveling wave tube E micro 1079 used in parts fist E none microfarad used in parts list UHP oux ultrahigh frequency UNDEF undefined UNBEG osa unrequlated MU pa na pa Scb Rad was vot ME LE codi we ase voltampere VAG ica dod d v voits ac VAR 4 aa esq ee ns variabie VCO
29. to talk and then handshaking the bytes It can be cleared by the Reset Command the Device Clear Command IEEE488 1 or by power on The Vector Voltmeter also has an Error Queue which operates as a FIFO and stores error messages until they are read from the Vector Voltmeter The Error Queue is summarised in the error bits bits 2 to 5 inclusive of the Standard Event Status Register It is read by the SYSTem ERRor command and can be cleared by using the Clear Status command CLS When the Error Queue is empty the string 0 NO ERROR is returned Event Registers Event Registers capture changes which occur within a device Each bit in an event register corresponds to some device condition Bits become TRUE when some pre defined device condition transition occurs The event register bits are latched so that once they become TRUE they cannot be cleared except by the user There are two means of clearing an event register Reading a register will clear it and the Clear Status command CLS will clear all event registers The Vector Voltmeter uses two kinds of transition filter for setting these event bits TRUE 1 Positive Transition The event becomes TRUE when its condition makes a FALSE to TRUE transition 2 Negative Transition The event becomes TRUE when its condition makes a TRUE to FALSE transition 3 36 E1089 Operation See Figure 3 26 for a detailed representation of the register model for the status data structure Devic
30. und die Berechtigung zur berpr fung der Serie auf Einhaltung der Bestimmungen einger umt Zusatzinformation f r Me und Testger te Werden Me und Testger te mit ungeschirmten Kabeln und oder in offenen Me aufbauten verwendet so ist vom Betreiber sicherzustellen da die Funk Entst rbestimmungen unter Betriebsbedingungen an seiner Grundst cksgrenze eingehalten werden MANUFACTURER S DECLARATION This is to certify that this product 8508A meets the radio frequency interference requirements of directive 1046 84 The German Bundespost has been notified that this equipment was put into circulation and was granted the right to check the product type for compliance with these requirements Note If test and measurement equipment is operated with unshielded cables and or used for measurement on open set ups the user must ensure that under these operating conditions the radio frequency interference limits are met at the border of his premises er 5 in Contents Contents SECTION 1 GENERAL INFORMATION Introduction 1 1 Specifications 1 1 Safety Considerations 1 1 Instruments Covered by Manual 1 1 Description 1 2 Options 1 3 Mechanical Options 1 3 Instrument Options 1 4 Documentation Options 1 4 Support Option 1 4 Accessories Supplied 1 4 Equipment Available for use with the HP 8508A 1 4 Recommended Test Equipment 1 5 SECTION 2 INSTALLATION Introduction 2 1 Initial Inspection 2
31. uses the value set with the SYSTEM IMPD key the default value being 50 ohms Press POWER MEAS again to return to the voltage measurement mode 6 SINGLE CHANNEL MEASUREMENT B CHANNEL Most measurements with the HP 8508A will be done using the B probe leaving the A probe in place as a reference The B channel is much more sensitive since the A channel already provides the signal to which the instrument is locked Press B to display the B input voltage in Display 2 The A reading remains in Display 1 unless you turn it off by pressing the A key The A probe must still be connected in order to keep the instrument locked Display 2 shows E1089 3 11 Operation the B channel residual noise level of around 100 V when the probe is not connected 7 DUAL CHANNEL MEASUREMENT The HP 8508A can display the ratio of the signals in its two channels making it unnecessary to calculate the results of ratio measurements Connect the two probes to the source output using a tee as shown in the following diagram Source HP8508A A Input B Input Probe and BNC Adaptor Cabie step 9 Figure 3 5 Two Probe Connection Select DISPLAY UNITS to display the levels as voltages The A and B voltages m Displays 1 and 2 respectively should read approximately the same value Press B A MAG to show the voltage ratio of B to A in Display 1 The reading should be approximately 1 0 Display 2 should be off Press B A PHASE t
32. 00 6 12 E1089 Replaceable Parts Table 6 3 Repiaceable Parts MISCELLANEOUS PARTS Reference Description Designation CABLE A3 TO A5 E6006000 DATA CONTROL POWER CABLE A4 TO A5 DATA CONTROL POWER J CABLE A2 TO A5 POWER 5V 12V CABLE A3 TO Ad A CHANNEL IF OUT CABLE A3 TO A4 08508 60011 08508 60011 E6006000 08508 60013 E6006000 8120 2587 E6006000 8120 2585 E6006000 E6006000 E6006000 E6006000 CABLE MAG OUT CABLE PHASE OUT CABLE A1 PROBE POWER 08508 60014 08508 60014 08753 60045 E1089 6 13 Replaceable Parts m Table 6 3 Replaceable Parts OPTION 001 CABINET PARTS 6 14 Reference Designation HP Part Number 00853 00048 00853 00049 00853 60050 00853 20068 5001 0439 00853 40009 0515 0895 0515 1562 2190 0018 00853 40011 00853 40007 5020 8788 5020 8753 1460 0604 2190 0586 0515 0982 2360 0121 5041 2642 Description TOP COVER ASSEMBLY BOTTOM COVER ASSEMBLY FRONT PANEL COVER ASSEMBLY SIDE FRAME TRIM SIDE FRONT REAR FOOT SCREM MACH M3 5x30mm LG PAN HD POZI SCREW MACH M3 5x40mm LG PAN HD POZI LOCK WASHER 141 ID CARRY HANDLE ASSEMBLY COLLAR BEZEL GEAR RING HANDLE GEAR HUB HANDLE SPRING COMP LOCK WASHER SCREW MACH M4x0 7 20mm LG PAN HD SCREW MACH 6 32 5 in LG PAN HD POZI HUB TRIM CAP E6006000 E6006000 E6006000 E6006000 E6006000
33. 1 Preparation for Use 2 2 Power Requirements 2 2 Line Voltage Selection and Fuse 2 2 Power Cable 2 3 Operating Environment 2 3 Mating Connectors 2 4 Rack Mounting 2 4 Hewlett Packard Interface Bus 2 5 HP IB Connector 2 5 HP IB Cables 2 6 HP IB Address Selection 2 6 Storage and Skipment 2 8 Environment 2 8 Packaging 2 8 SECTION 3 OPERATION Getting Started 3 1 Introduction 3 1 Operator s Maintenance 3 1 New User Introduction 3 2 Front Panel Features 3 4 Measurement Keys 3 4 Function Keys 3 5 Instrument State 3 6 Display Area Keys 3 6 Rear Panel Features 3 8 E1089 Contents Making Measurements Basic Measurements Introduction Getting Acquainted with the Vector Voltmeter Measurements with probes What you have achieved Advanced Measurements Measurements in a 50 ohm system Typical Configurations Probing measurements with external source Transmission measurements in 50 ohms Probe Inputs Transmission measurements in 50 ohms Direct Inputs Reflection measurements in 50 ohms Probe Inputs Reflection measurements in 50 ohms Direct Inputs Remote Operation The Hewlett Packard Interface Bus HP IB Capability Local and Remote Operation Addressing Power on Default Conditions Data Messages Instrument Commands Service Requests Status Reporting HP IB Response Formats HP IB Command Set Summary Command Reference SECTION 4 PERFORMANCE TESTS Introduction SECTION 5 ADJUSTMENTS Introduction Warm up Time Safety Consi
34. 11 Transmission Test Setup 1 Connect the A and B inputs to the power splitter Set the source output level in the normal operating range of the amplifier Set the source output frequency to SOMHz Press PRESET to return the HP 8508A to a known state 2 Press B A MAG to measure the magnitude ratio Select DISPLAY dB to measure log gain Press SHIFT then SAVE REF to store the current measurement zero the display and remove splitter and input effects 3 Connect the amplifier between the splitter and the B input and measure and note the gain 4 Press SHIFT then SAVE REF to store and use this nominal gain as a reference and reset the reading to OdB 5 Increase the source output level until the HP 8508A reads 1dB The amplifier is now operating at its gain com pression point 6 Press REF to remove the reference offset Press A MAG to measure the input voltage dBuV and POWER MEAS to convert the reading to dBm Since the splitter is symmetrical the measured power at the A input will be the same as at the amplifier input to within the tracking specifications of the power splitter 3 16 Operation b Reflection The measurement of small reflections in high frequency RF systems requires careful consideration At low levels reflections from the device under test can be masked by leakage signals in the measuring equipment so to make the measurement accurately you will need to use a high directivity reflection brid
35. 2 LE ci E RER SEE A R aaa de dia di 4 4 A o AA E WEAR Oe p o Mc cnm dnd i edle AA dr A amp AA 8 DP E1089 Operation Transmission measurements in 50 ohms Probe inputs HP8508A Source Device Under Test HAI MH M 3 a ree os i T Do Rs rer ni A AE RRA PAI k gt ER TARA 1 sd Termination REN Probe Tee CAL i Probe Tee Figure 3 18 Transmission Measurements Setup Equipment HP 8656B Synthesized Signal Generator HP 8508A Vector Voltmeter HP 11570A Accessory Kit includes 2 HP 11536A Probe Tee and 1 HP 908A Termination HP 11851B Cable Kit 1 cable required in this setup Or HP 11500B RF Cable Adapter from type N to DUT if required E1089 3 23 Operation Transmission measurements in 50 ohms Direct inputs HP8508A AU Lj s j e B Hou Power Splitter CAL Figure 3 19 Transmission Measurements Setup Equipment HP 8656B Synthesized Signal Generator HP 8508A opt 050 Vector Voltmeter with 50 ohm Input Module HP 11851B Cable Kit 3 cables required in this setup HP 11549A Power Splitter dc to 1GHz Or HP 11667A Power Splitter dc to 2GHz Adapter from type N to DUT if required 3 24 E1089 Operation Reflection measurements in 50 ohms Probe inputs dual directional coupler HP8508A Termination Probe Tee EA AAA Source LE Dual Directional Couple
36. 70 PRINT HP8508A UNLOCKED 480 REPEAT 490 OUTPUT Addr STATUS OPER COND 500 ENTER Addr Condition 510 UNTIL BiT Condition 2 0 1 Wait for lockup again 520 PRINT HPB8508A LOCKED 530 OUTPUT Addr CLS t Clear ALL Status Structures 540 END IF 550 560 ENABLE INTR 7 I re enable SRQ 570 SUBEND Figure 3 23 SRQ Enabling and Handling Sending the Service Request Message The Vector Voltmeter sends the Service Request message in either local or remote mode When it is sending the message the front panel S annunciator lights The message is cleared when a serial poll is executed by the controller or when a CLS Clear Status instrument command is received Sending the Status Byte Message The Vector Voltmeter sends the Status Byte message after receiving a Serial Poll Enable SPE bus command and when addressed to talk It complies with IEEE488 2 so bits 4 and 5 are defined as MAV and ESB respectively The Vector Voltmeter also makes use of bit 7 as the Operation Status Register Summary Bit but all other bits are unused The bit pattern of the Status Byte is shown in Figure 3 25 Once the Vector Voltmeter receives the SPE bus command it is no longer able to alter the Status Byte If a bit has been enabled and that condition occurs after bit 6 has been set the bit is stored in a buffer and is read the next time the Vector Voltmeter receives the SPE bus command The Status Byte and any Service Request message pending wi
37. ADJUSTABLE COMPONENTS Perform the following Adjustments None 5 8 5 9 5 10 None Table 5 3 lists all adjustable components in the HP 8508A Vector Voltmeter Reference Designation AZ R 11 A2 R 16 A2 R 19 A3L1 AS LZ A3 R151 A3 R178 A4 R 89 A4 L3 E1089 Table 5 3 Adjustable Components Adjustment Name 50 V 12 0 V 12 0 V Set 20 kHz Ch A Set 20 kHz Ch B Differential Phase 100 mV Ref Set 1 62 MHz Set 32 4 MHz Adjustment Description Paragraph 5 8 Adjusts the 5 0V REG Supply 5 8 Adjusts the 12 0V REG Supply 5 8 Adjusts the 12 0V REG Supply 5 9 Sets centre frequency of bandpass filter 5 9 Sets centre frequency of bandpass filter 5 9 Sets 180 phase range on A3 5 9 Absolute gain adjustment 5 10 RC VCO centre frequency 5 10 LC VCO centre frequency 5 3 Adjustments 5 8 POWER SUPPLY ADJUSTMENTS 12 0V 12 0V and 5 0V DESCRIPTION The 12 0V 12 0V and 5 0V power supplies are adjusted under load for the proper voltage levels with an Input Module installed EQUIPMENT Instrument Recommended Model Input Module HP 85081A or HP 85082A Digital Voltmeter DVM HP 3456A PROCEDURE 1 Install an Input Module in the HP 8508A mainframe 2 Switch on the equipment and allow to warm up for 30 minutes NOTE If an Error Code in the 200 Series is displayed the power supply voltages should be tested with a DVM If the supply voltages are correct the fau
38. B POLar Sets the results from vector measurements to ratio and phase angle RECTangular Sets the results from vector measurements to real and imaginary components CARTesian Identical to RECTangular The default is LINear POLar The query option returns an ASCII string indicating the current state 3 44 E1089 Operation Frequency FREQuency Band BAND lt nrf gt Auto Ranging AUTO ONJOFF 1 0 Sets the frequency band of the Vector Voltmeter lock circuits The band may be set explicitly or the Vector Volt meter can be allowed to auto range It is recommended that explicit band selection is used when possible to minimise lock time FREQuency BAND selects the frequency band explicitly The command forces BAND AUTO to OFF Bands are as follows Band Number Frequency band MHz Band Number Frequency Band MHz 1 0 1 to 0 2 9 25 to 50 2 0 2 to 0 6 10 50 to 80 3 0 6 to 1 11 80 to 150 4 1 to 3 12 150 to 250 5 3 to 5 13 250 to 500 6 5 to 8 14 500 to 1000 7 8 to 15 15 1000 to 2000 8 15 to 25 20 6 02 to 0 02 The default setting is automatic band selection The query option returns the current band FREQuency BAND AUTO selects explicit or automatic frequency band selection Frequency band 20 will not be selected When turned OFF the Vector Voltmeter remains in the current band The default is ON but is forced to OFF when the FREQ BAND command is received The query option returns 1 or 0 Identification HPI8
39. B SRO Enable amp Handling Program 20 i 30 i This program continually sends an illegal command to the 8508A 39 and deals with the returned SRQ It also reports the 8508A 37 going out of lock when the A channel signal is removed 40 i 50 Addr 708 I Vector Voltmeter Address 60 ON INTR 7 CALL Intr Set up SRQ interrupt handler call 79 i 80 CLEAR Addr Clear interface 90 OUTPUT Addr RST CLS Reset Vector Voltmeter 100 i 119 OUTPUT Addr ESE 36 Enable SRQ on Query or Command Error 140 150 OUTPUT Addr STATUS OPER PTR 4 t Enable SR when 8508A becomes 180 OUTPUT Addr STATUS OPER ENAB 4 I Unlocked 200 210 OUTPUT Addr SRE 160 I Generate SRQ on above conditions 230 240 ENABLE INTR 7 2 t Enable SRA interrupts in BASIC 250 REPEAT 260 OUTPUT Addr SYST KET 1 An incorrect Command to generate an SRQ 270 WAIT 5 280 UNTIL 1 0 t Repeat Forever 290 END 300 310 i 329 SUB Intr 330 DIM Err_message 100 340 Addr 708 350 OUTPUT Addr ST18 360 ENTER Addr Stat Read Status Byte 370 IF BIT Stat 5 THEN 380 OUTPUT Addr ESR Read amp Clear Standard Event Register 390 ENTER Addr Std event 400 IF BIT Std event 5 THEN PRINT Command Error 410 IF BIT Std event 2 THEN PRINT Query Error 420 OUTPUT Addr SYST ERR 430 ENTER Addr Err_message 440 PRINT Err message 450 END IF 3 32 E1089 Operation DESIGNED FOR SYSTEMS 460 IF BIT Stat 7 THEN 4
40. E6006000 E6006000 E6006000 E 6006000 E6006000 E6006000 E6006000 E6006000 E6006000 E6006000 ES006000 E6006000 E6006000 E1089 E1089 Replaceable Parts Table 6 3 Replaceable Parts OPTION 001 MAIN CHASSIS FRAME PARTS Reference HP Part Description Designation Number SAME AS THE STANDARD INSTRUMENT EXCEP FOR TH FOLLOWING PARTS 00853 20068 SIDE FRAME LEFT E6006000 6 15 Replaceable Parts Figure 6 1 Cabinet Parts 6 16 E1089 en E1089 Figure 6 2 Mechanical Parts Replaceable Parts 6 17 Replaceable Parts E n a we a ood iod c pe Binn Figure 6 3 Front Panel Keyboard Parts Locations B E1089 Manual Changes Manual Changes Section 7 7 1 INTRODUCTION This section contains a list of current changes to the HP 8508A Vector Voltmeter for instruments with serial number prefix 2949U Instruments with a serial number prefix lower than 29X XU may be upgraded by replacing the EPROM Assembly A5U18 HP part number 08508 80010 with HP part number 08508 80012 Refer to INSTRU MENTS COVERED BY MANUAL in Section 1 for additional important information about serial number coverage 7 2 INSTRUMENT MODIFICATIONS A5U18 EPROM Assembly HP part number 08508 80010 has been replaced by HP part number 08508 80012 Two new commands have been added to the HP IB Command Set This gives the option of adding a timeout facility to the MEAS
41. IB gt RST The reset function sets the Vector Voltmeter to a front panel state the same as using the PRESET key It has no effect on the status registers or results waiting to be read Self Test TST This command initiates an instrument self test and causes a result to be output The result will be zero 0 if the test is completed without errors A one 1 indicates an error has occurred Full details of the error codes appear in the Troubleshooting section of this Manual Service Request Enable lt HPIB gt SRE lt nrf gt Sets the service request conditions Status Byte bit usage is as follows bit 4 Message Available bit 5 Standard Event Status Register summary bit bit 7 Operation Status Register summary bit Other bits are unused The query option returns the currently selected conditions E1089 3 47 Operation Standard Event Status Enable ESE nrf Sets the Standard Event Register mask conditions The query option returns the currently selected conditions Range 0 through 255 using encoding as in Table 3 2 Standard Event Status Register ESR Returns and Clears the current value of the Standard Event Status Register Status Byte Query STB Returns the current value of the Status Byte with Master Summary Status MSS as bit 6 The Byte consists of bits which summarise each Status Reporting Structure Bits are cleared by clearing the related structure Status Control HPIB STATus Operation Status OPERation
42. ODE LH DECIMAL E6006000 DS 1 7 HDSP 4606 2 UNIVERSAL OVERFLOM 4 1 E6006000 DS 36 38 HDSP 4850 3 10 ELEMENT BAR GRAPH ARRAY E6006000 DS 62 63 HLMP 2300 2 LIGHT BAR LEGEND E6006000 DS 24 HLMP 2350 1 LIGHT BAR SINGLE RED E6006000 DS 8 13 14 29 34 HLMP 2500 B LIGHT BAR SINGLE GREEN E6006000 DS 27 HLMP 2800 1 LIGHT BAR DOUBLE E6006000 DS 5 6 25 26 HLMP 2820 PA LIGHT BAR QUAD 6006000 DS 3 8 28 35 HLMP 2855 4 LIGHT BAR E6006000 6 6 E1089 Replaceable Parts p Table 6 3 Repiaceabie Parts POWER SUPPLY ASSEMBLY Reference HP Part Description Designation Number A2 A2 08508 60002 PSU ASSEMBLY E6006000 A281 08508 60017 0 LINE SWITCH ASSEMBLY E6006000 T1 08508 80001 TOROIDAL TRANSFORMER E6006000 E1089 6 7 Replaceable Parts Table 6 3 Replaceable Parts IF MEASUREMENT ASSEMBLY HP Part C Qty Description Mfr Number D Code Reference Designation 08508 60003 1 IF PCB ASSEMBLY E6006000 6 8 E1089 Replaceable Parts Table 6 3 Replaceable Parts SEARCH AND LOCK ASSEMBLY Reference HP Part Description Designation Number 08508 60004 SEARCH AND LOCK ASSEMBLY E6006000 E1089 6 9 Replaceable Parts Table 6 3 Replaceable Parts PROCCESSOR ASSEMBLY Reference HP Part C Description Designation Number D 08508 60005 6 PROCESSOR ASSEMBLY E6006000 08508 60105 PROCESSOR ASSEMBLY WITHOUT EPROM E6006000 A5U18
43. OG LIN and POL RECT DELay Delay SUR Standing Wave Ratio RHO Reflection Coefficient using current settings FORMat LOG LIN and POL RECT Y Admittance 1 2 using current settings of INPut IMPedance and FORMAT POL RECT 2 Impedance using current settings of INPut IMPedance and FORMAT POL RECT CORE All basic measurements AVOLtage BVOLtage and PHASe Equivalent to MEAS AVOL BVOL PHASE MEASure TIMEout allows the measurement to timeout if the instrument has not locked to a signal The range of the timeout is 0 to 30 seconds The default is 30 seconds MEASure TIMEout STATe defines if the timeout function is in use It sets the timeout function to ON 1 or OFF 0 The query option returns 1 or 0 All the above measurements are also dependant on whether CORRection STATe is ON or OFF 3 46 E1089 Operation Output OUTPut ONJOFF 1 0 Controls the front panel Test output signal The default is OFF The query option returns 1 or 0 Operation Complete lt HP1B gt OPC This command causes the Operation Complete bit in the Standard Event Status Register to be set when the Vector Voltmeter has completed all pending operations The Standard Event Status Register can be monitored to find when the bit is set using the ESR command or the Vector Voltmeter can be set to request service when the bit is set true The query option returns 1 when all pending operations have been completed Reset lt HP
44. SE OF AN EXTENSION CORD WITHOUT A PROTECTIVE CONDUCTOR GROUNDING 2 4 POWER REQUIREMENTS The instrument requires a power source of 100 120 220 240V AC 10 48 to 440Hz single phase The maximum power consumption is typically 40VA 2 5 LINE VOLTAGE SELECTION AND FUSE The line voltage is selected by the rear panel switch CAUTION Before connecting the instrument to a power outlet ensure that the line voltage selector is correctly set and that a fuse of the correct rating is fitted Fuse ratings are given in the table below Table 2 1 Fuse Ratings Nominal Fuse O HPPat Line Rating Number 100 120V T1 25A 250V 2110 0305 220 240V T0 75A 250V 2110 0360 2 2 E1089 Installation 2 6 POWER CABLE The instrument is equipped with a three wire power cable When connected to a power outlet this cable grounds the instrument case The type of power cable shipped with each instrument depends on the country of destination Refer to Figure 2 1 for part numbers of the power cable and plug configurations available The number shown below each plug is the Hewlett Packard part number of a power cord equipped with that plug If the appropriate power cord is not included with the instrument notify the nearest Hewlett Packard Sales and Service Office and a replacement will be provided i MAT g AS t vow 120 200 si20 1369 810 1889 8120 1351 8120 1378 us 8120 2936 MU20 42W _ pan km T 5 P A ic Satake ot
45. SPLAY PACKAGE E6006000 Note The LED s marked are available as a set HP Part Number 08508 60020 This set has been selected for intensity matching Should any LED failures occur it is recommended that the set be replaced to maintain intensity integrityj Individual LED s can be replaced However no guarantee can be given that the replacement items will match the intensity level of the existing set 0 1 UNIVERSAL OVERFLOW 1 ES006000 4 1 COM ANODE LH DECIMAL E6006000 4 1 COM ANODE LH DECIMAL E6006000 4 1 COM ANGDE LH DECIMAL 6006000 2 1 LIGHT BAR QUAD E6006000 2 1 LIGHT BAR QUAD E6006006 0 1 UNIVERSAL OVERFLOW 1 E6006000 3 1 LIGHT BAR E6006000 4 1 COM ANODE LH DECIMAL ES006000 4 1 COM ANODE LH DECIMAL E6006000 amp 1 COM ANODE LH DECIMAL 6006090 4 1 COM ANODE LH DECIMAL E6006000 5 1 LIGHT BAR SINGLE GREEN E6006000 5 1 LIGHT BAR SINGLE GREEN E6006000 4 9 SINGLE POINT E6006000 3 1 LIGHT BAR SINGLE RED E6006000 2 1 LIGHT BAR QUAD E6006000 2 1 LIGHT BAR QUAD E6006000 8 1 LIGHT BAR DOUBLE E6006000 3 1 LIGHT BAR E6006000 5 1 LIGHT BAR SINGLE GREEN E6006000 5 1 LIGHT BAR SINGLE GREEN E6006000 5 1 LIGHT BAR SINGLE GREEN E6006000 5 1 LIGHT BAR SINGLE GREEN E6006000 5 1 LIGHT BAR SINGLE GREEN E6006000 6 5 Replaceable Parts Table 6 3 Replaceable Parts Reference HP Part Qty Description Mfr Designation Number Code LIGHT BAR SINGLE GREEN E6006000 DS 34 HLMP 2500 1 DS 35
46. YSTEM IMPD NORM There is no need to recalibrate since the new display is computed from the same measurements as before Other functions HOLD VALUE This function is useful when you are probing in a circuit especially dense circuits where the probe can easily slip onto another track When the signal disappears the display is frozen at the last reading To initiate this function configure the equipment for the measurement you want to make A B A B Now press HOLD VALUE The LED at the side of the key will illuminate Probe on the circuit Use the A probe if A only is active or the B probe if both are active Lift the probe when you are ready to take a reading The display s will freeze and hold the reading The function LED will flash to show that the hold mode is active To make a new measurement probe on the circuit The instrument will automatically re arm the function REF SELECT LOAD This function allows the use of a simple two resistor tee to enable you to make reflection measurements up to 100M Hz In this case a termination is used as the calibration standard Choose LOAD with the following test setup Source HP8508A i t A p IM SO8A mill Termination Power Splitter 908A Termination Eu Calibration Probe Tee Device Under Test Figure 3 14 Probe Inputs 3 18 Operation Source Power Splitter T1 908A Termination Calibration er Type
47. a Figure 2 1 Plug Configurations The colour code used in each over cable is given below Table 2 2 Colour Codes Line Brown Neutral Blue Ground Green Yellow 2 7 OPERATING ENVIRONMENT Temperature The instrument may be operated in temperatures from 0 Centigrade to 55 Centigrade Humidity The instrument may be operated with humidity up to 90 up to 40 Centigrade However the instrument should also be protected from temperature extremes which may cause condensation within the instrument Altitude The instrument may be operated at altitudes up to 4600m 15000ft E1089 23 Installation E 2 8 MATING CONNECTORS Table 2 3 lists the connectors which mate with the instrument ports Table 2 3 Mating Connectors Connector Type Mating Connector Part Number 5060 0466 PROBE POWER i m 1250 1448 1250 0448 1250 0448 see Table 2 4 2 9 RACK MOUNTING Figure 2 2 illustrates the Rack Mount Kits available for use with the HP 8508A CRUS Cad Figure 2 2 Rack Mount Kits 2 4 E1089 Installation 2 10 HEWLETT PACKARD INTERFACE BUS HP IB This section contains information for installing the HP 8508A Vector Voltmeter into a Hewlett Packard Interface Bus HP IB system The HP IB is Hewlett Packard s implementation of IEEE Standard 488 1978 Digital Interface for Programmable Instrumentation This standard defines a physical interface and protocol whic
48. a b No maximum or minimum order value on any mail order there is a minimum order amount for parts ordered through a local HP office when the orders require billing and invoicing c Prepaid transportation there is a small handling charge for each order d No invoices to provide these advantages a cheque or money order must accompany each order Mail order forms and specific ordering information are available through your local HP office Addresses and phone numbers are located at the back of this manual 6 2 Bene assembly NT esas attenuator solator termination Dane ia far motor BT perete rin ge battery U a A OR Cid Shin capacitor GP S O coupler D nsi uranio dioda diode thyristor varactor DG uocis directional coupler E BEINE RER delay tine DES Nina annunciator signaling device audible or visual lamp LED ES pia bert tu d a ampere OG aia alternating current ACCESS oi ketene accessory NE een adjustment BILE ooo ON analog to digital AE Vere audio frequency Cl MP MED automatic trequency control ADU urai automatic gain control Pe ene en aS ea aluminum ALG 22 cee ess automatic lavel control AM amplitude modulation al hee hie aad 4 amplifier APC automatic phase control ASSI MNT assembly AUX du dede bis ale a auxiliary BVO ma nir meas average AWG vetula American wire gauge BAL oig wore raten balance i AAA binary coded decimal BU inns dux adr board BECU beryilium copper
49. a REPL 4 05 0443 reptaceable ES asas Sch sity oic ohm AE lansas radio frequancy A POTENT peak used in parts BEI Versa radio frequency list interference PAM pulse amptitude AM round haad right hand modulation REG Cosi via resistanca PUO Loses ad printed circuit inductance PCM puise coda modula capacitance tion pulse count RMO rack mount only modulation tms root mean square POM riada puise duration AND auan dn KS DH round modulation ROM read only memory DE SI kb X ae td san picofarad RAP era rack and panel PH BRZ phosphor bronze RWV reverse working A enega Goan a Phillips voltage PIN iius positive intrinsic Be scattering parameter negative Be Ense second time PIV peak inverse voltaga v ON SR second plane angie METER TENTI INTE peak FB siow biow fuse ML ee phasa lock used in parts list PLO phase lock oscillator SCR avus silicon controlted PM pak anes phase modulation l rectifier screw PNP positive negative Sake A Mate ee satenium positive SEUT idea sections EID seen part of SEMICON semiconductor POLY we rele RS polystyrene SHF superhigh frequency PORE use porcelain c MEC d im a silicon POS positive position s ci p Silver used in parts list EC ai ee aG slide POS iat ceea s gud position SNR signal to noise ratio POTE I d uus potentiometer SPDT sx RES single pote PD Scare de ap wets peak to peak doubia throw x VP peak
50. ace products which prove to be defective For warranty service or repair this product must be returned to a service facility designated by HP Buyer shall prepay shipping charges to HP and HP shall pay shipping charges to return the product to the Buyer However Buyer shall pay all shipping charges duties and taxes for products returned to HP from another country HP warrants that its software and firmware designated by HP for use with an instrument will execute its programming instructions when properly installed on that instrument HP does not warrant that the operation of the instrument or software or firmware will be uninterrupted or error free LIMITATION OF WARRANTY The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance by Buyer Buyer supplied software or interfacing unauthorized modification or misuse operation outside of the environmental specifications for the product or improper site preparation or maintenance NO OTHER WARRANTY IS EXPRESSED OR IMPLIED HP SPECIFICALLY DISCLAIMS THE IM PLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE EXCLUSIVE REMEDIES THE REMEDIES PROVIDED HEREIN ARE BUYER S SOLE AND EXCLUSIVE REMEDIES HP SHALL NOT BE LIABLE FOR ANY DIRECT INDIRECT SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES WHETHER BASED ON CONTRACT TORT OR ANY OTHER LEGAL THEORY ASSISTANCE Product maintenance agreements and other customer assistance agre
51. ackard for servicing attach a tag indicating the type of service required model number and full serial number Also mark the container FRAGILE to ensure careful handling Other Packaging The following general instructions should be used for re packaging with commercially available materials a Wrap the instrument in heavy paper or plastic If shipping to Hewlett Packard office or service centre attach a tag indicating the type of service required return address model number and full serial number b Use a strong shipping container A double walled carton of 350 pound test material is adequate c Use a layer of shock absorbing material 70mm to 100mm 3 to 4 inch thick around all sides of the instrument to provide firm cushioning and prevent movement inside the container Protect the control panel with cardboard d Securely seal the shipping container e Mark the shipping container FRAGILE to ensure careful handling f In any correspondence refer to the instrument by model number and full serial number Operation Operation Section 3 3 1 GETTING STARTED 3 2 INTRODUCTION This section provides complete operating information for the Vector Voltmeter The items covered include detailed descriptions of each front and rear panel key connector switch and display general and detailed operating instructions information on remote operation 3 3 OPERATOR S MAINTENANCE The only maintenance you as an
52. aged sampler and a Power Supply error may be caused by a faulty Search and Lock Assembly Specific troubleshooting information is given by error code series in the following pages Following any replacement perform any required adjustment procedure then the full performance test to ensure that the instrument meets specifications For the adjustments use tuning tool HP part number 8830 0024 NOTE Under some circumstances it is possible that a 4 digit error code will be displayed although this is not likely to happen during the normal test routine Should this type of Error Code appear the instrument power should be cycled and if the error reappears please contact your local HP Service Office Disassembly and Reassembly Procedure For the Standard Instrument Top Cover Removal To remove the top cover from the Vector Voltmeter follow the procedure listed below a Remove the two rear feet each of which is held in place with a Pozidriv screw b Undoing the Pozidriv screw at the centre of the rear edge of the Top Cover will cause the cover to slide back When it is clear of the front frame it can then be lifted off Refitting the Top Cover Refitting of the top cover is the reverse of this procedure 8 4 E1089 Service Bottom Cover Removai To remove the bottom cover of the Vector Voltmeter follow the procedure listed below a Place the Vector Voltmeter with the bottom cover facing up b Remove the 2 rear feet each of whic
53. arch and Lock Interconnections 8 14 E1089 Service ERROR CODES 400 SERIES Error Codes in this series indicate a problem with the Search and Lock Assembly SEARCH and LOCK ASSEMBLY A4 Summary Description The function of the Search and Lock assembly is to provide an optimally selected frequency to the Sampling Pulse Generator in the Input Module This frequency is generated by a VCO The assembly operates in one of two modes In the SEARCH mode the VCO is swept and the output of the Sampling Gate monitored until a suitable response is found At this point the processor switches the board into the LOCK mode where the VCO is tuned to phase lock the IF to the 20 KHz reference When this has been accom plished the system is able to make measurements Troubleshooting the Search and Lock Assembly A fault in the Search and Lock Assembly will be indicated by an Error Code display in the 400 series If this should occur the assembly and all connections should be checked for integrity The adjustment procedures for the assem bly should be carried out and the system Self Test procedure re run If the assembly still proves faulty it should be replaced with a new one Disassembly and Reassembly Procedures Removing the Search and Lock Assembly To Remove the Search and Lock Assembly from the Vector Voltmeter a Wear a wrist strap for ESD protection b Remove the instrument top cover c Disconnect the cable connections from the Search and Loc
54. ctive A TALKER is capable of transmitting data over the bus when addressed to do so There can be only one active talker at a time A CONTROLLER specifies the talker and listener s for an information transfer including itself There can be only one active controller at a time Local and Remote Operation The Vector Voltmeter can operate under either local or remote control In local mode all front panel controls are operational and control the instrument In remote mode all front panel controls are inoperative except LCL when not in Local Lockout the instrument being controlled by the HP IB controller The front panel display reflects the remote programming commands received unless the display is switched off At power on the instrument assumes the local state Under local control all HP IB instrument commands will be ignored To gain control over HP IB the controller must put the instrument into the remote state This is accom plished by setting the Remote Enable REN bus control line true and sending the Vector Voltmeter s HP IB Listen Address In local mode the Vector Voltmeter s front panel controls are fully operational and it will respond to the Remote message Whether it is addressed or not it will also respond to the Clear Local Lockout and Clear Lockout Local messages When addressed to talk the Vector Voltmeter can issue Data messages and the Status Byte message Whether addressed or not it can issue the Service Request
55. derations Equipment Required Post Repair Adjustments Related Adjustments Adjustable Components Power Supply Adustments 12 0V 12 0V and 5 0V IF Assembly Adjustments Set up the centre frequency of the Channel A and B Bandpass filters To equalize the A and B Channel phase shift Set up the amplitude path gain using an external 20kHz 100mV reference source Search and Lock Assembly Adjustments Set the centre frequency of the 1 62M Hz and 32 4MHz Oscillators 5 1 5 2 E1089 SECTION 6 REPLACEABLE PARTS Introduction Abbreviations Replaceable Parts List Ordering Information Direct Mail Order System SECTION 7 MANUAL CHANGES Introduction SECTION 8 SERVICE Introduction Safety Considerations After Service Product Safety Checks Anti Static Precautions Recommended Test Equipment Troubleshooting General Description Disassembly and Reassembly Procedure for the Standard Instrument Disassembly and Reassembiy Procedure for Option 001 Instruments Front Panel Assembly A1 Error Codes 200 Series Power Supply Assembly A2 Error Codes 300 Series IF Assembly A3 Error Codes 400 Series Search and Lock Assembly A4 Error Codes 500 Series Processor Assembly A5 Error Codes 600 Series E1089 Contents 6 1 6 1 6 1 6 2 8 1 8 1 8 2 8 2 8 2 8 3 8 4 8 5 8 7 8 11 8 11 8 13 8 13 8 15 8 15 8 17 8 17 8 19 General Information 2 I5 25 Ix Figure 1 1 The HP 8508A Vector Voltmeter 1 0 Ge
56. dering components ensure that the soldering iron is grounded Always use a metalized solder remover E1089 Adjustments Anti Static Freezer Spray When attempting to locate a temperature related fault use only an approved anti static freezer spray Anti Static Products Table 5 1 contains details of anti static products which are available from Hewlett Packard Table 5 1 Anti Static Products Product HP Part Number Anti static workstation kit 9300 0792 Metalized Solder Remover 8690 0227 Wrist strap and cord 9300 0970 5 4 EQUIPMENT REQUIRED All adjustment procedures contain a list of required test equipment The test equipment is also identified by callouts in the test setup diagrams where included If substitutions must be made for the specified test equipment refer to the Recommended Test Equipment table in section 1 of this manual for the minimum specifications It is important that the test equipment meet the critical specifications listed in the table if the Vector Voltmeter is to meet its performance requirements Note Use a non metallic tool whenever possible for example HP Part Number 8830 0024 5 5 POST REPAIR ADJUSTMENTS Table 5 2 lists the adjustments related to repairs or replacement of any of the assemblies 5 2 E1089 5 6 RELATED ADJUSTMENTS Adjustments Table 5 2 Related Adjustments Assembly Replaced Al Front Panel A2 Power Supply A3 IF Assembly A4 Search amp Lock AS Processor 5 7
57. dge of the bottom cover will cause the cover to slide back When it is clear of the front frame it can then be lifted off Refitting the Bottom Cover Refitting of the bottom cover is the reverse of this procedure 8 6 E1089 Service FRONT PANEL ASSEMBLY Al There are no error codes associated with this assembly Malfunctions will be visual for example displays not working Summary Description The Front Panel Assembly is the interface between the user and the instrument The digital display shows the results of the system measurements and operating conditions are set up through the front panel keys Troubleshooting the Front Panel Assembly The most likely problems with the front panel assembly are the LED s and switches Tests controlled by the Proces sor Assembly will assist in addressing these problems These Tests are set by setting the test switch on the processor board and monitored by the front panel and the test LED s on the processor board The following diagram shows the location of the switch and LED s Connector Connector Connector HP IR Connector Test Switch Connector Figure 8 2 Processor Assembly Test Switch Location NOTE After selecting a test switch position the HP 8508A power must be cycled When the tests are completed the test switch should be reset to the 0 position and the power cycled to restore normal operation E1089 8 7 Service Test Key Switches Disp
58. e difference No processing is carried out nor are any results available over HP IB The mode is intended for use in applications such as narrowband swept testing of crystal filters The default is OFF The query option returns 1 or 0 E1089 3 43 Operation Display State lt HP18 gt DISPlay STATe ON OFF 1 0 Controls the front panel display The display can be turned off when not needed A speed improvement may be realized by switching the display off The improvement will be greater as AVERAGE COUNT is reduced since updating the display is an overhead at the end of the measurement cycle The default is ON The query option returns 1 or 0 Fetch Results lt HP1B gt FETCh Continuous readings CONT inuous This query returns the result of the measurement most recently started as soon as it is available The result will be generated using the current measurement configuration FETCh CONTinuous causes results to be passed to the HP IB such that when one is read the next is made available for reading as soon as it is calculated Format FORMat LINear LOGarithmic POLar RECTangular CARTesian The format command sets the units in which measurement results will be returned LINear Sets voltage and power units to volts and watts respectively and magnitude ratio to a dimensionless quantity LOGarithmic Sets voltage and power units to dBuV and dBm respectively magnitude ratio to dB and RHO magnitude to Return Loss in d
59. e HP 8508A to a known state The following list shows the preset condition MEASUREMENTS FUNCTIONS MEASUREMENTS A ON REF CREE OFF DISPLAY A uu cuoco UNITS FORMAT uu ox dede ew OFF REFL MEAS 2 2 ew OFF DISPLAYS REF SELECT OFF METER SELECT 4 OFF POWER MEAS 2 2 we OFF LOCK RANGE 2 ee AUTO SYSTEM IMPD 2 OFF MAG RANGE AUTO HOLD VALUE wes OFF DISPLAY mV DISPLAY 2 sun blank 2 UNLOCKED INDICATOR Check that there is no input to the probes With no input signal the A UNLOCKED indicator should be ON and DISPLAY 1 the left display should indicate under range NOTE If there are high level radiated signals present DISPLAY 1 may give a reading This reading is caused by the un terminated probe acting as an antenna It will not affect the instrument s ability to make measurements on your circuit 3 SINGLE CHANNEL MEASUREMENT CHANNEL A The A probe is used as a reference by the HP 8508A and must be connected for the instrument to function The signal level should be in the range 300uV to 1V Connect the A probe to the source and turn on the output The A UNLOCKED indicator should go OFF and DISPLAY 1 should show the source output voltage 4 VOLTAGE UNITS Select DISPLAY dB to have the HP 8508A compute and display the voltage in dBuV 5 POWER MEASUREMENT Press POWER MEAS to display power in dBm in a 50ohm system The conversion of voltage to power
60. e Status Continuously Monitored Condition Registe Transition Filter Seiects which transitions of Condition bits will set corresponding Event bits Event Register Latched Conditions Logical OH eer Event Enable Register SUMMARY n n 1 DEREN FERIEN 2 1 O Selects which events can MESSAGE i set the Summary Message Figure 3 26 Register Model for the Status Data Structure The instrument also provides a Standard Event Status Enable Register and an Operation Status Enable Register and provides further commands to read them These registers work in the same way as the Service Request Enable Register described earlier in Sending the Status Byte Message E1089 3 37 Operation Standard Event Status Register SESR Figure 3 25 shows the operation of the Standard Event Status Register This is a specific application of the event registers discussed previously and its bit definitions are as follows Bit 5 Command Error CME This bit indicates that the device has detected a command error The following events cause a command error 1 An IEEE 488 2 syntax error This means that the device received a message which did not follow the syntax defined by the IEEE488 standard For example it received data which violated the device listening format 2 A semantic error occurred For example the device received an incorrectly spelled command Another example would be that the device received an optional IEEE488 2 command
61. e variation In a circuit with adjustable gain the HP 8508A METER display is an aid to tuning Use of the meter display is covered in the next example Any unmodulated RF signal in the frequency range 100kHz to 1GHz can be used as a source for these measure ments This includes a source that is part of a larger device under test This diagram shows all the keys you will necd to make the measurements o O O JOO 4 7 9 8 S 1 Figure 3 4 Front Panel Keys In the descriptions throughout this section keys on the instrument are described by writing the key name in square brackets for example PRESET Keys that have multiple selections are described by writing select followed by the key name in square brackets then the required function in bold type for example Select REFL MEAS SWR When you press this type of key the next valid state will be selected Press the key the required number of times to light the LED beside the state requested Some selections are only available in combination with other keys so don t worry if all the selections are not available 3 10 Operation Where a function is accessed using the alternative function of a key the function is described by showing SHIFT then the function name which appears in blue on the front panel for example to obtain SHIFT REF this would be described as press SHIFT then SAVE REF 1 PRESET Before beginning a new measurement press PRESET to return th
62. ements are available for Hewlett Packard products For any assistance contact your nearest Hewlett Packard Sales and Service Office Addresses are provided in this manual SAFETY CONSIDERATIONS GENERAL This product and related documentation must be reviewed for familiarization with safety markings and instructions before operation This product is a Safety Class I instrument provided with a protective earth terminal BEFORE APPLYING POWER Verify that the product is set to match the available line voltage and the correct fuse is installed SAFETY EARTH GROUND An uninterruptible safety earth ground must be pro vided from the main power source to the product in put wiring terminals power cord or supplied power cord set SAFETY SYMBOLS Instruction manual symbol the product will be marked with this symbol when it is necessary for the user to refer to the instruction manual refer to Table of Contents Indicates hazardous voltages indicates earth ground terminal WARNING The WARNING sign denotes a hazard It calls attention to a procedure practice or the like which if not correctly performed or adhered to could result in personal injury Do not proceed beyond a WARNING sign until the indicated conditions are fully understood and met CAUTION The CAUTION sign denotes a hazard It calls attention to an operating procedure practice or the like which if not correctly performed or adhered t
63. ess HP IB Address 64 onto the bus in command mode ATN true amp IFC false It remains Addressed to Listen until it receives its Talk Address or a Universal Unlisten command It remains Addressed to Talk until it receives its Listen Address or an Untalk command Power on Default Conditions Several HP IB parameters are reset at power on The parameters and their default conditions are listed below HP IB Local Mode Unaddressed Service Request Enable Register cleared Status Reporting Structure cleared Trigger Source Freerun Display State active Should the Vector Voltmeter fail part of its power on test sequence the Error code will be placed in the Error Queue See also SYSTem ERRor 3 28 E1089 Operation Data Messages The Vector Voltmeter communicates on the interface bus primarily with Data messages Data messages consist of a sequence of bytes sent over the bus data lines when the bus is in the data mode ATN false The Vector Voltme ter receives Data messages when addressed to listen and sends Data messages or the Status Byte message when addressed to talk All instrument operations available in local mode can be performed in remote mode via Data messages except for changing the LINE switch Receiving the Data Message The Vector Voltmeter responds to Data messages when in remote mode REN true and addressed to listen Instrument Commands Instrument commands are sent as data messages Commands may be
64. f 100 0 0 1 on Display 2 8 Press HOLD VALUE to cancel the function 9 Remove the test clips and replace the HP 8508A top cover E1089 5 11 Adjustments 5 10 SEARCH amp LOCK ASSEMBLY ADJUSTMENTS Set up the centre frequency of the 1 62 MHz and 32 4MHz Oscillators DESCRIPTION The centre frequencies are set up using an internal test routine EQUIPMENT No external test equipment is required for this adjustment PROCEDURE 1 Remove the Input Module from the instrument 2 Switch on the equipment and allow to warm up for 30 minutes Note Since the Input Module is not installed in the mainframe the HP 8508A will display the error message Err 601 This reading should be ignored 3 Remove the HP 8508A top cover to allow access to the adjustments 4 Select PRESET SHIFT POWER MEAS to put the instrument into the setup mode The Display will now indicate which setup code is being used It will appear as tSt nnnn tSt indicates that the instrument is in the setup mode and nnnm is the current setup code Use the UP DOWN Arrow keys to set up test code 0 in Display 2 Press HOLD VALUE and check that the indicator LED is ON 5 Adjust A4R89 slowly until the UNLOCK light extinguishes Note The green LED CR6 across the board from A4R89 is functionally the same as the UNLOCK light on the front panel 6 Press HOLD VALUE to cancel the function 7 Use the UP DOWN Arrow keys to set up test
65. ge The Vector Voltmeter has no Parallel Poll capability and makes no response to the status bit message Other Messages Other messages sent by the Vector Voltmeter are responses to the query option of some commands and status information In general the query options return the recommended form of the corresponding command This is either a number where the command sets a range or sends data or sets the function ON or OFF or a string where the command itself is a string Status functions return a number to be decoded to determine conditions which have set status bits Service Requests HP IB devices may request service from the controller by asserting the SRQ bus control line The controller usually responds to this signal by asking each device on the bus in turn for its Status Byte If bit 6 is set it indicates that the device requires service and the controller looks at the remaining bits in the Status Byte for further informa tion The interpretation of these bits depends on whether the device complies only with TEEE488 1 or like the Vector Voltmeter with IEEE488 1 and TEEE488 2 Bit 6 has two distinct functions Within TEEE488 1 it is the Request Service ROS bit and within IEEE488 2 is the Master Summary Status MSS bit IEEEA88 2 also defines bit 5 as the Event Summary Bit ESB and bit 4 as the Message Available Bit MAV When dealing with service requests a key operational difference emerges between instruments which compl
66. ge or directional coupler Use a short circuit as a calibration standard and measure the return loss of a precision termination Source HP8508A 50 ohm 50 ohm A Input B input Short circuit Device Under Test Reflected incident Directional Bridge Figure 3 12 Bridge Test Setup Source HP8508A 500hm 500hm i A input B Input Incident Reflected Short circuit Device Under Directional Coupler Test Figure 3 13 Coupler Test Setup 3 17 Operation 1 Connect the A and B inputs to the bridge or splitter as shown in one of the above diagrams depending on the equipment you have available Set the source power to 0dBm and frequency to the test frequency 2 Connect a short circuit to the test port as the calibration standard Press PRESET to return the HP 8508A to a known state Select REFL MEAS rho angle to measure reflection coefficient 3 Select REF SELECT SHORT to use a short circuit as the calibration standard Select DISPLAY dB to measure the reflection as return loss in dB Press SHIFT then SAVE REF to store the current measurement and display a return loss of OdB and angle 0 degrees 4 Remove the calibration standard and connect the termination to be measured Read the return loss directly The HP 8508A has conversions built in to allow you to read results in normalized impedance for use with Smith charts To make the conversion select REFL MEAS Z and S
67. h are held in place with a Pozidriv screw c Undoing the Pozidriv screw at the centre of the rear edge of the bottom cover will cause the cover to slide back When it is clear of the front frame it can then be lifted off Refitting the Bottom Cover Refitting of the bottom cover is the reverse of this procedure Disassembly and Reassembly Procedure For Option 001 Instruments Top Cover Removal To remove the top cover from the Vector Voltmeter follow the procedure listed below a Remove the 2 rear feet which are each held in place by 5 Pozidriv screws b Separate the Carrying Handle from the top cover by first removing the snap on plastic caps covering the handle hub assembly Access can then be made to remove the single Pozidriv screw holding each hub to the side frame By pulling the handle hubs outwards the handle will then come away from the instrument c Undoing the Pozidriv screw at the centre of the rear edge of the Top Cover will cause the cover to slide back When it is clear of the front frame it can then be lifted off Refitting the Top Cover Refitting of the top cover is the reverse of this procedure E1089 8 5 Service Bottom Cover Removal To remove the bottom cover of the Vector Voltmeter follow the procedure listed below a Remove the 2 rear feet which are each held in place by 5 Pozidriv screws b Place the Vector Voltmeter with the bottom cover facing up c Undoing the Pozidriv screw at the centre of the rear e
68. h enables the remote control of instrumentation systems 2 11 HP IB CONNECTOR Logic Levels The HP IB logic levels are TTL compatible ie the true state is 0 to 0 5V DC and the false 0 SIGNAL COMMON state is 2 5 to 45V DC SIGNAL COMMON TWISTEO WITH PIN 11 SHIELD ATN 12 3 ED SIGNAL COMMON TWISTED WITH pin 10 11122 18 sra Mating Connector SIGNAL COMMON TWISTED WITH PIN 9 IED EIN irc SIGNAL COMMON TWISTED WITH pin 8 11120 LE NDAC HP 1251 0293 SIGNAL COMMON TWISTED WITH PIN 7 18 EN aro Amphenol 57 302040 SIGNAL COMMON TWISTED WITH PIN 6 05 E pav REN 107 EI eo D108 TINI oros 0107 1115 37 li 103 osos KOGA E 0102 53 1 0105 i DIOT TYPE 87 MICRORIBBON CONECTOR Figure 2 3 HP IB rear panel Connector The HP IB connector on the rear panel of the HP 8508A provides the physical interface to connect the HP 8508A into an HP IB system Figure 2 3 illustrates the connector pin configuration Devices in the HP IB system may be interconnected in any suitable arrangement star delta etc using the HP IB cables listed in Table 2 4 However the cable length restrictions should be observed Installation 2 12 HP IB CABLES Table 2 4 lists the HP IB cables available Table 2 4 HP IB Interface Cables HP Part Numbers Cable Lengths HP 10833A im 3 3ft HP 10833B 2m 6 6ft HP 10833C 3m 13 2ft HP 10833D 0 5m 1 6ft To achieve design performance restr
69. he Probe Power connector so that the assembly may be lifted free Refitting the Front Panel assembly is the reverse of the above procedure 8 10 E1089 Service ERROR CODES 200 SERIES Errors in this series indicate a problem with the Power Supply Assembly POWER SUPPLY ASSEMBLY A2 Summary Description The power supply is a conventional linear circuit design that provides the instrument with supplies of 5 Volts and 12 Volts Test Points and adjustments are provided on the Circuit Board Rectifier Regulator L 5 Volt Fuse Toroidal AC Input Transformer Rectifier Pere Regulator Figure 8 4 Simplifed Block Diagram of the Power Supply Troubleshooting A fault in the power supply will be indicated by a display of an Error Code in the 200 series and if this should arise the transformer supply voltages and distribution cables should be checked and any faulty items replaced Because the 12V check is performed using the Search and Lock Assembly A4 a fault on the Search and Lock Assembly A4 can indicate an error on the Power Supply Assembly A2 Should the Error Code persist the defective assem bly should be replaced with a new one Disassembly and Reassembly Procedures Removing the Power Supply Assembly To remove the Power Supply Assembly from the Vector Voltmeter a Wear a wrist strap for ESD protection b Remove the power cord from the instrument c Remove the instrument top cover
70. he phase difference between them The following diagram shows the vector relationship between two signals at the same frequency and the way that one is used as a phase reference in the HP 8508A B A Phase gt A Use A as PR CEIA Ba Phase Ref Figure 1 1 Vector Signals The measurements are either of a single channel or the ratio between the two channels and results displayed as voltage or power in linear or log units normalized magnitude and phase angle or real and imaginary components In addition the HP 8508A has built in procedures for simple network analysis The HP 8508A has two configura tions the first providing two high impedance probe inputs with a frequency range from 100kHz to 1GHz and the second providing two 50 ohm type N connector inputs with a frequency range of 300kHz to 2GHz The configura tion can be changed by replacing the instrument s input module The HP 8508A can be used in applications where vector signal information is required at low cost particularly in the design manufacture or service of RF assemblies The HP 8508A is a simple high sensitivity receiver and can be used with any source including one that is part of the device to be tested Its built in HP IB interface for program ming allows it to be used as an economical tool in automated production environments Typical measurements include voltage power gain or loss impedance and phase matching Measurements can be made either from the
71. he query option returns the code of the last key pressed Table 3 3 Keycodes Keycode Description 1 2 B 3 REFL MEAS 4 FORMAT 5 POWER MEAS 6 B A MAG 7 B A PHASE 8 REF SELECT 9 REF 10 SYSTEM IMPD 11 METER SELECT 12 LOCK RANGE 13 STEP UP 14 STEP DOWN 15 MAG RANGE 16 HOLD VALUE 17 DISPLAY 18 SHIFT 19 LCL 20 PRESET SYSTem FORMat sets the HP IB output format for measurement results Two formats are available ASCh and FP64 and they are described in the earlier section on HP IB Response Formats Trigger HPIB TRG The trigger command performs the same function as the Group Execute Trigger command defined by IEEE 488 1 that is it initiates a new measurement when the TRIGger SOURce is BUS Trigger Setup lt HP1B gt TRIGger Source SOURce BUS FREErun The trigger setup function allows the trigger mode to be selected In freerun the Vector Voltmeter makes measure ments as quickly as possible When the trigger source is set to BUS the Vector Voltmeter waits to receive a trigger before initiating the next measurement Wait to continue lt zHPIB gt WAT This command causes the Vector Voltmeter to complete all current actions before accepting any more commands It can be used to synchronize the instrument s operation with other equipment E1089 3 49 Operation 3 50 Performance Tests Performance Tests Section 4 4 1 INTRODUCTION As the HP Model 8508A mainframe cannot be performance
72. ia metai oxide semiconductor MI riea e millisecond MIG ce dearg e e tati mounting MIR meter indicating device M ran miltivolt MVI voco o E Es millivolt ac IV 2v vex miltivolt dc ui A millivolt peak MYO iss miliivolt peak to peak MYMS mtilivolt rms MW a hi ate SLATE miliiwatt MUX Lived bes multiple x M RARAS mylar HE gota TEEN d 3 a microampere mhear at microfarad BH iouis ELE microhenry SEEN A micromho HS cce SERES microsecond T D microvoit c pr microvoit ac ENGE u eg microvolt de KORK cena microvoit peak ANODD microvolt paak to peak HWIMS microvolt rms M eos scs Sed debida microwatt WAR nanoampera NO sa no connection NIG lt a normally closed NE esse neon NEG terta pias negative n PIN RR nanofarad HL PE uso a tari nicket plate NJO var normally open NON S S an od sawek nominai NORM normal NPN vss negative positive negative NPO neg tive positive zero zero tempera ture coefficient NRFR not recommended for field reptacement NSR REI ET not separately raplaceabie Wir nanosecond i A nanowatt OBD order by description Table 6 2 Abbreviations 2 of 2 OD rss outside diameter PWY onen peak working OM cor SE oval head voltage OP AMPL operationa AG a ek pa resistance amplifier capacitance OPT cdd dedo kya aption REG innen rectifier SC Gen Cite chee we oscilator REP onen reference DR A S oxide HER iva regulated Dira ounc
73. ictions are placed on the length of the HP IB system cable as follows 1 The total length of HP IB cable use to interconnect devices on the HP IB must not exceed 2 meters 6 feet times the number of devices in the system 2 The total length of HP IB cable used to interconnect all devices must not exceed 20 meters 65 feet 2 13 HP IB ADDRESS SELECTION The HP IB address is selected via the front panel Press SHIFT VIEW ADDRESS and use the arrow keys to scroll to the desired number 2 6 Installation Table 2 5 HP IB Address Codes Address Characters cow 09 0 O0 v a No m TOMMUAw gt Eo A ma XL K E M N O P Q R S ae U V W X Y Z Installation 2 14 STORAGE AND SHIPMENT Environment The instrument may be stored or shipped in environments within the following limits Temperature 40 Centigrade to 75 Centigrade Humidity up to 90 at 65 Centigrade Altitude 15300m 50000ft The instrument should also be protected from temperature extremes which may cause condensation inside it Packaging Tagging for Service If the instrument is being returned to Hewlett Packard for service please complete one of the blue repair tags located at the front of this manual and attach it to the instrument Original Packaging Containers and material identical to those used in the factory packing are available through Hewlett Packard offices If the instrument is being returned to Hewlett P
74. ing addressed whether in local or remote its front panel L or T annunciator remains lit Receiving the Local Lockout Message The Local Lockout message is the means by which the controller sends the Local Lockout LLO bus command If in remote mode the Vector Voltmeter responds to the Local Lockout message by disabling the front panel LCL key The local lockout mode prevents loss of system control due to accidentally pressing front panel keys When in local lockout mode the Vector Voltmeter can be returned to local only by the controller using Local or Clear Lockout Local messages or by setting the LINE switch to OFF and ON Receiving the Clear Lockout Set Local Message The Clear Lockout Local message is the means by which the controller sets the Remote Enable REN bus control line false The Vector Voltmeter returns to local mode full front panel control when it receives the Clear Lock out Set Local message When the Vector Voltmeter goes to local mode the front panel R annunciator turns off 3 30 E1089 Operation Receiving the Pass Contro Message The Vector Voltmeter does not respond to the Pass Control message since it cannot act as a controller Receiving the Abort Message The Abort message is the means by which the controller sets the Interface Clear IFC bus control line true When the Abort message is received the Vector Voltmeter becomes unaddressed and stops talking and listening Sending the Status Bit Messa
75. input to the output of the device or by probing within the device Other measurements include transmission and reflection procedures that include test system calibration against known standards 1 2 General Information A typical setup includes a source which may be part of the device to be tested a reference path and a measure ment path Cables adapters and other accessories required depend on the application The following diagram shows an example setup HP8508A A Input B input Module Under Test Reference Path Measurement Path Device Under Test LL Figure 1 2 Typical Probing Set up In order for the source to be suitable for use with the HP 8508A it has to meet certain specifications It must produce a stable CW signal at the frequency of interest with no modulation 1 6 OPTIONS The standard instrument is supplied with front handles HP Part Number 5062 3989 while rack mounting flanges or bail carrying handle and front cover are available as options Mechanical Options Bail Handle Option 001 Adds bail carrying handle rugged feet and front panel storage cover Rack Flange Kit Option 908 HP Part Number 5062 3977 This kit contains all necessary hardware and installation instructions for mounting the Vector Voltmeter not fitted with front panel handles in a rack with 482 5 millimeter standard 19 inch spacing Rack Flange Kit Option 913 HP Part Number 5061 4071 This kit conta
76. ins all necessary hardware and installation instructions for mounting a Vector Voltmeter with front panel handles in a rack with 482 5 millimeter standard 19 inch spacing E1089 13 General Information Instrument Options Option 050 Provides an HP Model 85082 50 ohm Input Module instead of the HP Model 85081 High Impedance Input Module Option 100 Deletes Input Module Documentation Options Extra Manual Set Option 910 Provides an additional copy of the Operating and Service Manual and the User s Guide English version Japanese User s Guide Option 030 Substitutes the Japanese version of the User s Guide for the English version French User s Guide Option 031 Substitutes the French version of the User s Guide for the English version German User s Guide Option 032 Substitutes the German version of the User s Guide for the English version Italian User s Guide Option 033 Substitutes the Italian version of the User s Guide for the English version Spanish User s Guide Option 034 Substitutes the Spanish version of the User s Guide for the English version support Option Extended Hardware Support Option W30 Provides an additional 2 years of return to HP hardware service support 1 7 ACCESSORIES SUPPLIED The accessories supplied with the instrument are Front Handle Kit with standard instrument An appropriate power cable see Section 2 An Operating and Service Manual A User s Guide Accessory kit comp
77. ischarge ESD To minimize the risk of damaging or decreasing the reliabihty of the instrument the following procedures and cautions should be observed when servicing the instrument Static free workstation All servicing should be carried out at a static free workstation De soldering When de soldering components ensure that the soldering iron is earthed Always use a metalized solder remover Anti static freezer spray When attempting to locate a temperature related fault use only an approved anti static freezer spray 8 5 RECOMMENDED TEST EQUIPMENT Equipment required to troubleshoot the HP 8508A is listed in Table 1 2 Other equipment may be substituted if it meets or exceeds the critical specifications listed in the table 8 2 E1089 Service 8 6 TROUBLESHOOTING General Description The HP 8508A mainframe is a dual channel IF processor that receives two 20 kHz IF signals from the Input Module and measures these to determine the Amplitude and Phase characteristics The results of this measurement are presented on the Digital Display and are available at the HP IB programming Interface In addition DC representations and real time outputs of of the Amplitude and Phase values are made available on the instrument rear panel Instrument operation is under the control of a digital processor which also has built in routines to provide the data in a number of different formats INPUT MODULE IF MEASUREMENT ASSEMBLY
78. itivity 1s fixed at 1mV per 0 1 degrees A typical use of this mode might be to make narrowband swept measurements on crystals 3 8 E1089 Operation 3 7 MAKING MEASUREMENTS 3 8 BASIC MEASUREMENTS Introduction There are two types of Input Module that can be used with the HP 8508A Vector Voltmeter mainframe These Input Modules are the HP 85081 High Impedance Input Module and the HP 85082 50 ohm Input Module The HP 85081 High Impedance Input Module has a frequency range from 100kHz to 1GHz This Input Module has high impedance probes which can be used either alone or with accessories to make in circuit measurements The following accessories are available HP 11570A Accessory Kit 50 ohm accessories HP 10216A Isolator probing accessory HP 1157764 10 1 Divider probing accessory The HP 85082 50 ohm Input Module has a frequency range from 300kHz to 2GHz This Input Module has 50 ohm type N connectors Using the HP 85082 gives you a higher frequency range than the HP 85081 for measurements in a 50 ohm environment Getting acquainted with the Vector Voltmeter To introduce you to the main functions of the HP 8508A here are a few simple measurements you can try You will learn to make single channel voltage and power measurements and measure the vector ratio between two voltages a Measurements with probes For this section measurements are made on a printed circuit board buffer amplifier It is part of a 50MHz source assembly
79. k Assembly d Remove the 8 Pozidriv screws that secure the Search and Lock Assembly to the main deck e The Search and Lock Assembly can now be removed from the Instrument Refitting the Search and Lock Assembly Refitting is the reverse of this procedure Note the cable connections detailed in the diagram below E1089 8 15 Service AS IF Assembly A4 Search amp Lock Assembly Front Panel Figure 8 6 IF and Search and Lock Interconnections 8 16 E1089 Service M ERROR CODES 500 SERIES Errors in this series indicate a problem in the A5 Processor Assembly PROCESSOR ASSEMBLY A5 Summary Description The Processor controls the operation of the instrument Mag Phase HP IB OUT QUT VCO Drive FE E A g5081A m Input T Module 2okHz P AS A Chan Ms Processor IF Output Display Test A1W1 Keyboard Out D C D C P b C P c Data Control Power Figure 8 7 HP 8508A Physical Configuration Troubleshooting the AS Processor Assembly The Processor Assembly is checked during the Self Test routine and any failure will result in a 500 series Error Code being displayed If this should occur check that the assembly all cable connections and socketed components are securely located Re run the self test In the event of a Processor Assembly failure it is possible to repair the fault by replacing either the ROM only or by substituting a new processor assembly that utilizes the cur
80. ked mechanically and electrically The Performance Tests check the complete specification of the instrument If the contents of the shipment are incomplete if there is mechanical damage or defect or if the instrument per formance fails to meet specification notify the nearest Hewlett Packard office If the shipping container is damaged or the cushioning material shows signs of stress notify the carrier as well as the Hewlett Packard office Keep the shipping material for the carrier s inspection The Hewlett Packard office will arrange for repair or replacement at Hewlett Packard s option without waiting for a claims settlement providing that Hewlett Packard and or the carrier are notified within 12 days of shipment E1089 Installation 2 3 PREPARATION FOR USE WARNING TO AVOID THE POSSIBILITY OF INJURY OR DEATH THE FOLLOWING PRECAUTIONS MUST BE FOLLOWED BEFORE THE INSTRUMENT IS SWITCHED ON A NOTE THAT THE PROTECTION PROVIDED BY GROUNDING THE INSTRUMENT CABINET MAY BE LOST IF ANY POWER CABLE OTHER THAN THE THREE PRONGED TYPE SUPPLIED IS USED TO COUPLE THE AC LINE VOLTAGE TO THE INSTRUMENT B IF THIS INSTRUMENT IS TO BE ENERGIZED VIA AN AUTO TRANSFORMER TO REDUCE OR INCREASE THE LINE VOLTAGE MAKE SURE THAT THE COMMON TERMINAL IS CONNECTED TO THE NEUTRAL POLE OF THE POWER SOURCE O THE POWER CABLE PLUG SHALL ONLY BE INSERTED INTO A SOCKET OUTLET PROVIDED WITH A PROTECTIVE EARTH CONTACT THE PROTECTIVE ACTION MUST NOT BE NEGATED BY THE U
81. lay LED s Switch Position 4 5 Procedure Press any key on the front panel The display should come on in a cyclic manner Result Green LED on the processor should flash and the number for the key pressed should appear in the display Key numbers are shown in the table below If the green LED does not flash and the display does not show the key number the keyboard is suspect if Green LED flashes but no Key No is displayed then Processor Assembly is suspect If there is no Display check the 5 volt supply to the Front Panel If only part of the Display comes on check the LEDs Otherwise replace the Front Panel Circuit Board NOTE The LEDs forming the main part of the Front Panel Display are available as a set that has been matched for intensity level Although the LEDs are available on an individual basis there can be no certainty that the replace ment will match the installed LEDs in intensity The preferred replacement Front Panel Assembly is HP part number 08508 60101 This assembly is supplied without the Display LED s installed thus permitting re use of the LED s from the defective assembly Keycode 1 2 3 4 5 6 7 8 9 Description A B REFL MEAS FORMAT POWER MEAS B A MAG B A PHASE REF SELECT REF SYSTEM IMPD METER SELECT LOCK RANGE STEP UP STEP DOWN MAG RANGE HOLD VALUE DISPLAY SHIFT LCL PRESET E1089 Service a Disassembly and Replacement Procedures Re
82. ll be cleared if a CLS Clear Status instrument command is received by the Vector Voltmeter E1089 3 33 Operation DESIGNED FOR SYSTEMS Status Reporting The IEEE 488 2 Standard describes a status reporting structure so that controllers know how to ask a device such as the Vector Voltmeter for its status Figure 3 24 shows an overview of the status reporting structure MI a es RAR Summary Status Service Request Enablimg Enabled Summary Status MSS Service Request Generation Service Request Indication rev 488 1 Service Request Function I Figure 3 24 IEEE488 2 Status Reporting Structure Overview 3 34 E1089 Operation DESIGNED FOR AT We m HP IB Y SYSTEMS Status Data Structures IEEE488 2 allows the Status Byte to contain up to seven single bit summary messages from data structures but the Vector Voltmeter only makes use of bits 4 5 and 7 as described earlier in Sending the Status Byte Message The status data structures are queues or event registers and the summary bits are used as follows Bit 4 MAV reports the status of the Output Queue Bit 5 ESB reports the status of the Standard Event Status Register Bit 7 reports the status of the Operation Status Register Figure 3 25 shows the Standard Status Model for IEEE488 2 instruments Two of the Vector Voltmeter s data structures are not shown but are described later The Operation Sta
83. lt may be on the Search and Lock Asssembly A4 3 Remove the HP 8508A top cover to allow access to the adjustments 4 Connect the DVM input to the Test Points shown in the following table and make the appropriate adjustments for the correct voltage levels Test Point Adjustment Voltage Tolerance A2 TP3 A2R16 12 0V 0 1V A2 TP4 A2R19 12 0V 0 1V A2 TP2 A2R11 5 0V 0 05V A2 TPI GND E1089 GND 5V 12V i 12V8 TP3 5V TP2 12V TP4 Figure 5 1 Power Supply Adjustment Locations 5 Replace the HP 8508A top cover E1089 Adjustments 5 5 Adjustments 5 9 IF ASSEMBLY ADJUSTMENTS Set up the centre frequency of the Channel and B Bandpass filters DESCRIPTION The 20 kHz centre frequency for Channel A and B s set up using an internal test routine EQUIPMENT No external test equipment is required for this adjustment PROCEDURE 1 Remove the Input Module from the instrument 2 Switch on the equipment and allow to warm up for 30 minutes Note Since the Input Module is not installed in the mainframe the HP 8508A will display the error message Err 601 This reading should be ignored 3 Remove the HP 8508A top cover to allow access to the adjustments 4 Adjust the cores of A3L1 and A3L2 to the top of the coils 5 Select PRESET SHIFT POWER MEAS to put the instrument into the setup mode The Displays will now indicate which setup code is being used This will appear a
84. message E1089 3 27 Operation Local Lockout Local lockout disables the LCL key and allows return to local only under program control Local Lockout is recommended for purely automatic applications Remote to Local The instrument switches to local whenever it receives the Local message GTL or the Clear Lockout Local message REN false If not in Local Lockout mode the instrument switches to local when the front panel LCL key is pressed NOTE Return to local can also be accomplished by setting the Vector Voltmeter s LINE switch to OFF then to ON However this technique has some disadvantages a It defeats the purpose and advantage of local lockout that is the system controller loses control of a system clement b There are several HP IB conditions which reset to default states at turn on Addressing The Vector Voltmeter s HP IB address 1s stored in permanent memory so that it 1s remembered through power cycling The address can be set from the front panel as follows a Press SHIFT ADDRESS to display the current address b Use the arrow keys to select the required address 0 30 which becomes effective immediately The instrument s normal address setting is 8 c Press SHIFT ADDRESS or any other function to return to normal operation The Vector Voltmeter can be Addressed to Listen Addressed to Talk or Unaddressed It is Addressed by putting either its Listen Address HP IB Address 32 or its Talk Addr
85. motiva force ING near pos aed insulation NOTE Alt abbreviations in the parts list will be in upper case Replaceable Parts t ENT integrated circuit microcircutt MC Cos aces ee electron tube i i PEDE voltage regulator breakdown diode Wis cabie transmission path wire DN eier socket Y ub Ea crystal unit piezo aiectric or quartz Bros tuned cavity tuned circuit IET oe cated a rada internal Eoo cone vss kilogram laa See kilohertz N secta dat N sait at ale A ds xilohm Ma kilovoit UD ote atts Coe hs aa la pound LO een inductance capacitance LED sarsi light emitting diode Hep iow frequency A CE tong EMI sios EEEE dead let hand LINE ous xx utl ta limit LIN ac linear taper used in parts ist LK WASH lock washer EE eis low local oscillator LO ors vues togarithmic taper used in parts list jo EO ee togarithm c LPS Sue een iow pass f ter IS REL aam low voitage IIS sa ome 4 meter distance mA corvi Es miliampere MAN Lern maximum EEE megohm MEG meg 105 used in parts list MET FLM meta fiim MET OX metallic oxide MES 2 244044 medium frequency microfarad used in parts list MFR vo dta manufacturer MO at milligram MINE uuo ss eds megahertz MA sch aac wie muliihenry mh onse audam mho IUD o vci Geb hs minute time ierit bns minute plane angie MINAT criar miniature MR millimeter Replaceable Parts MOD uus uo Ek qued modulator MOM cn x ed momentary MOS ar
86. moval of Front Panel Assembly Al a Wear a wrist strap for ESD protection b Remove the Input Module c Remove the instrument top cover d Remove trim from top and sides of the instrument Front Frame A small flat bladed screwdriver will usually be best for this operation e Remove the 7 Pozidriv screws holding the Front Frame in position see Figure 8 2 Only these screws need to be removed Figure 8 3 Front Panel Removal On the Left Hand side of the frame there is 1 fixing screw On the Top part of the frame there are 3 fixing screws On the underside of the frame there are 3 fixing screws NOTE There are additional screws holding the Module tray and the Left Hand Main Deck These screws do not need to be removed f The Front Panel Assembly can then be withdrawn from the instrument taking care not to damage the ribbon cable connecting the Front Panel assembly to the Processor card Refitting the Front Panel Assembly Refitting the Front Panel Assembly is the reverse of the above procedure E1089 8 9 Service To Gain access to the component side of the Front Panel Assembiy a Remove the Front Panel Assembly from the instrument as mentioned previously b Remove the 9 16 nut and washer securing the TEST OUT connector to the front panel c Remove the 9 Pozidriv fixing screws that hold the circuit board in position on the front panel metalwork d Carefully lift out the front panel circuit board and disconnect t
87. nd and read with the Enable Status ESE query 3 38 E1089 Operation Register Bit Coding The Status Byte SESR Operation Status Register and Transition Filters are set using a value which determines the conditions to be enabled The weights of each of the bits to be enabled are summed to obtain the value required Table 3 1 shows the weighting of each bit for each of the registers Table 3 1 Register Bit Coding Bit 7 6 5 4 3 2 1 0 Weight 128 64 32 16 8 4 2 1 HP IB Response Formats Results returned by the HP 8508A from measurement queries take the ASCII form lt gt lt gt D DDDE lt gt lt gt DD lt term gt CE 33 That is a leading sign a four digit mantissa between 1 000 and 9 999 an exponent designator E or e an exponent sign a two digit exponent between 00 and 99 and a terminator The value is always in fundamental units volts ohms watts dB etc The terminator lt term gt depends on the data requested as follows lt term gt is a comma where another data item follows as part of the same result term is a semicolon where the data item completes a result and another result follows term is linefeed 1f with EOI set true where the data item is the last or only part of a result Using the SYSTem FORMat command results can also be coded as 64 bit Floating Point numbers in IEEE488 2 Definite Length Arbitrary Block Response Data format This will be of the form ASCH characters
88. nd may increase measurement variation Range 0 to 10 Default 5 The number of internal readings made is two raised to the power of AVERage COUNt The query option returns the current setting Calibration CAL Performs an internal device calibration A value of 1 will be returned if the calibration fails A value of 0 indicates successful calibration Capability lt HPIB gt CAPability Returns the instrument s HP IB capability string as follows SH1 AH1 T6 TEO LA LEO SRI RL1 PPO DC1 DT1 CO E2 Clear Status lt HPIB gt CLS Clears the contents of the status register and associated status data structures This command should be used as part of remote instrument preset Configure Measurement SENSE meas This command is used to configure the measurement that the Vector Voltmeter will make and the results it will return in response to a measurement query Default is AVOLtage Options for meas are listed in the Measure section 3 42 E1089 Operation Correction CORRection DATA A Value lt HPIR gt A lt nrf gt B Value lt HPIB gt B lt nrf gt Phase Vaiue zHPIB 2 PHASe nr f Normalize Impedance 1MPedance ON JorF 1 0 Termination TERMination SHORT OPEN ZO Perform Normalization PERForm Normalization State STATe ou JOFF1 0 The correction commands define the normalization values and state Correction values can be sent to the Vector Voltmeter impedance measurements can be n
89. neral Information General Information Section 1 1 1 INTRODUCTION This service manual contains information required to install test adjust and service the Hewlett Packard Model 8508A Vector Voltmeter The HP 8508A is shown in Figure 1 1 On the title page of this manual is a Microfiche Part Number This number can be used to order 4 x 6 inch micro film transparencies of the manual Each microfiche contains up to 96 photo duplicates of the manual pages 1 2 SPECIFICATIONS Instrument specifications are listed in Table 1 2 of the Probe Module Insert These specifications are the perform ance standards or limits against which the instrument is tested The Probe Module Insert document contains the specifications relevant when the Probe Module is inserted into the HP 8508A Vector Voltmeter mainframe 1 3 SAFETY CONSIDERATIONS This instrument is a Safety Class 1 instrument provided with a protective earth terminal The instrument and manual should be reviewed for safety markings and instructions before operation The WARNINGS indicate the possibility of personal danger and CAUTIONS indicate the possibility of instrument damage 1 4 INSTRUMENTS COVERED BY MANUAL Attached to the instrument is a serial number plate The serial number is in the form XXXXUXXXXX The first four digits and the letter comprise the serial prefix which is the same for all identical instruments The serial prefix only changes when a change is made to the instrument
90. o could result in damage to or destruction of part or all of the product Do not proceed beyond a CAUTION sign until the indicated conditions are fully understood and met WARNING Any interruption of the protective grounding conductor inside or outside the instrument or disconnecting the protective earth terminal will cause a potential shock hazard that could re sulting personal injury Grounding one conduc tor of a two conductor outlet is not sufficient protectton Whenever it is likely that the protection has been impaired the instrument must be made inoperative and be secured against any unin tended operation If this instrument is to be energized via an autotransformer for voltage reduction make sure the common terminal is connected to the earth terminal of the power source Servicing instructions are for use by service trained personnel only To avoid dangerous elec tric shock do not perform any servicing unless qualified to do so Adjustments described in the manual are per formed with power supplied to the instrument while protective covers are removed Energy available at may points may if contacted result in personal injury Capacitors inside the instrument may still be charg d even if the instrument has been discon nected from its source os supply For continued protection against fire hazard re place the line fuse s only with 250V fuse s of the same current rating and type for exam
91. o display the input phase difference in Display 2 The reading should be approximately 0 dep 8 SET A REFERENCE Press SHIFT then SAVE REF to store the current measurement as a reference and normalize readings to the saved reference value The displays should now read exactly 1 0 magnitude and 0 0 deg phase NOTE DISPLAY 1 reads 1 0 REL and DISPLAY 2 reads 0 0 DEG REL 3 12 E1089 Operation Figure 3 6 Displays 9 RELATIVE MEASUREMENT Now insert the cable as shown in Figure 3 5 The readings are now of the voltage ratio and phase difference caused by the cable using the reference set in step 8 Select DISPLAY dB to read the cable insertion loss in dB The phase difference can be used to calculate the cable s electrical length 10 REAL AND IMAGINARY Instead of magnitude and phase you can show the measurement results as real and imaginary components Select FORMAT REAL amp IMAG to see results in this form NOTE DISPLAY 1 reads ohm and DISPLAY 2 reads johm Figure 3 7 Displays WHAT YOU HAVE ACHIEVED You have made voltage measurements A and B and a vector ratio measurement B A MAG B A PHASE and normalized the ratio to a reference E1089 Operation 3 9 ADVANCED MEASUREMENTS This section will cover some simple network analysis measurements using the HP 8508A and a companion source Transmission and reflection measurements will be covered to show how some of the features of the HP 8508A can
92. operator should normally perform is replacement of the primary power fuse Fuses may be ordered under HP Part Number 2110 0305 T1 25A 250V for 100 120Vac operation or under HP Part Number 2110 0360 T0 75A 250V for 220 240Vac operation Fault finding in the HP 8508A is aided by the self test routine which is run whenever the instrument power is switched on This routine checks the assemblies in the HP 8508A Vector Voltmeter When the self test routine is initiated the current firmware revision will be shown in Display 2 for a few seconds Display 1 will then show St while Display 2 shows a 3 digit number appropriate to the assembly being tested The entire test routine takes approximately 8 seconds to complete If one or more faults exist the self test routine will halt at the first fault and display the appropriate error number In this situation refer to Section 8 Troubleshooting in this manual You can perform an automatic calibration sequence by pressing SHIFT CAL TEST All other maintenance should be referred to qualified service personnel E1089 3 1 Operation 3 4 NEW USER INTRODUCTION 3 2 WARNING Before the Vector Voltmeter is switched on all protective earth terminals extension cords autotransformers and devices connected to it should be connected to a protective earth grounded socket Any interruption of the protective earth grounding will cause a potential shock hazard that could result _ in personal injury Fo
93. or 0 110dB in 10dB steps HP 8496A G Opt 890 Calibration Certificate required Attenuator Driver Required for HP 84966 HP 11713A RE Power Meter 100kHz to 4 2GHz with Power Sensor HP 436A or HP 438A 1mW Reference Output NBS Traceable 50 ohm 100kHz to 4 2GHz HP 8482A SWR 1 2 luW to 100mW Power Sensor Bandwidth 50MHz HP 542004 Sensitivity 1mV div Sweep Speed 0 2us div Oscilloscope Accessory Kit HP 11570A HP 08508 60032 Input Module Extender P Performance A Adjustment T Troubleshooting O Operation NOTE The HP 8496A G attenuator should be calibrated within 0 03dB for the 10dB through 60dB steps E1089 1 5 General Information 1 6 Installation Installation Section 2 2 1 INTRODUCTION This section provides installation instructions for the Hewlett Packard Model 8508A Vector Voltmeter and its accessories This section also includes information about initial inspection and damage cla ms preparation for use packaging storage and shipment 2 2 INITIAL INSPECTION WARNING IF THERE IS ANY SIGN OF SHIPPINGDAMAGE TO THE INSTRUMENT DO NOT APPLY POWER RETURN THE INSTRUMENT TO THE NEAREST HEWLETT PACKARD OFFICE FOR CHECKING Inspect the shipping container for damage If the shipping container or cushioning material is damaged it should be kept until the contents of the shipment have been checked for completeness and the instrument has been chec
94. ormalized current measurements can be saved as a reference and the normalization function can be switched on and off The default state is all correction off CORRection DATA allows data to be sent to the Vector Voltmeter for use as a reference value A B and PHASe are used to define the destination of the reference value The ability to use specific data as reference values is a function available only from HP IB The query options return the current value COR Rection IMPedance sets the impedance normalization function ON 1 sets the Vector Voltmeter to normal ize impedance measurements OFF 0 implies that inpedance measurements are calculated from the current value of Input Impedance The default is OFF The query option returns 1 or CORRection TERMination sets the termination standard for reflection measurements The default is SHORT The query option returns the current setting as an ASCII string CORRection PERForm sets the A B and PHASe references to be the current measurement values CORRection STATe defines if the CORRECTION function is in use It sets the normalization function to ON 1 or OFF 0 The default is OFF The query option returns 1 or 0 Direct Analog Output DANalog ON OFF 1 0 Sets the Vector Voltmeter to operate as a simple converter The frequency and amplitude ranges are locked and the rear panel outputs represent the A or B voltage depending on which is selected on the front panel and the phas
95. play 1 and the B A phase in Display 2 DISPLAY Defines the scale associated with the display s depending on what measurement is displayed Units selects the linear scale and dB selects the log scale Example 1 Amplitude of A has a units scale in mV and a dB scale in dbuV Example 2 Power in A has a units scale in uW and a dB scale in dBm FUNCTION KEYS REF Works in A amplitude B amplitude B A magnitude and Phase to make measurements relative to a set of reference values SHIFT SAVE REF stores the current A B and Phase values and turns REF on When REF is turned on displayed phase measured phase saved phase and displayed measured amp or mag amplitude or magnitude a saved amp or mag REFL MEAS Uses measurements of B A ratio and B A phase to make simple reflection measurements using an external device The SHORT and OPEN reference impedances are used with a bridge or directional coupler and LOAD is used when making measurements with a Tee Note that LOAD is selected as a shifted function To initialize the measurement connect the external equipment and connect the appropriate reference impedance to the test port Press SHIFT SAVE REF The REF LED is automatically turned on The A B and phase values are then retained and used as a correction for any level and or phase changes occurring between the A channel incident signal and the B channel reflected signal To make a co
96. ple normal blow time delay etc Do not use repaired fuses or short circuited fuseholders Static Sensitive Devices This instrument was constructed in an ESD electro static discharge protected environment This is because most of the semi conductor devices used in this instrument are susceptible to damage by static discharge Depending on the magnitude of the charge device substrates can be punctured or destroyed by contact or mere proximity of a static charge The results can cause degradation of device performance early failure or immediate destruction These charges are generated in numerous ways such as simple contact separation of materials and normal motions of persons working with static sensitive devices When handling or servicing equipment containing static sensitive devices adequate precautions must be taken to prevent device damage or destruction Only those who are thoroughly familiar with industry accepted techniques for handling static sensitive devices should attempt to service circuitry with these devices In all instances measures must be taken to prevent static charge build up on work surfaces and persons handling the devices HEWLETT PACKARD HERSTELLERBESCHEINIGUNG Hiermit wird bescheinigt da das Ger t System 8508A in bereinstimmung mit den Bestimmungen von Postverf gung 1046 84 funkenst rt ist Der Deutschen Bundespost wurde das Inverkehrbringen dieses Ger tes Systems angezeigt
97. pment There are two distinct modes of operation for these outputs Normal Mode This mode provides an analog representation of the digital display values including internal instrument correction factors OUTPUT 1 corresponds to DISPLAY 1 and OUTPUT 2 corresponds to DISPLAY2 The update rate is the same as the display update rate approximately 3 readings per second The sensitivity is 1m V per displayed digit A display value of 123 4mV will produce a d c output of 1234mV A display value of 135 7 degrees will produce a dc output of 1357mV If the MAG RANGE key is used to change the display resolution the rear panel outputs will change with the display values A typical use of this mode might be to drive a chart recorder or similar logging instrument Direct Analog Output Mode This mode provides continuous direct output signals from the internal magnitude and phase detectors through 800Hz low pass filters Only limited internal instrument correction factors are applied to the output signals OUT PUT 1 corresponds to either A or B magnitude in mV whichever is selected on the front panel OUTPUT 2 corresponds to B A phase The full scale deflection FSD chosen on the front panel always produces an output of 1 volt and this defines the OUTPUT 1 sensitivity A display FSD of 1000mV will produce an output of 1000mV for an input of 1000mV A display FSD of 31 6mV will produce an output of 1000mV for an input of 31 6mV The OUTPUT 2 sens
98. quy voltage controlied oscillator MUG Se n PIZ Ra A vOlts dc VDCW voits dc working used in parts Hst Mera da volts filtered VED A variable frequency osciHator VHF very high frequency NDR Loue M URI volts peak VDR volts peak to peak MIIS oss ek ones volts rms VSWR voltage standing wave ratio VTO dh ERR voltage tune oscillator VIVM usa vacuum tude voltmeter imma volts switched a Da an watt WE aaa kh ERBE ARE with WIV aachen working inverse voltage WIN uos sis e de wirawound INI siete E PX add without TIO s usos yttrium iron garnet Er characteristic Replaceable Parts Table 6 3 Replaceable Parts HP Part Number Reference Designation 08508 60001 08508 60101 08508 60020 HDSP 4606 HOSP 4600 HDSP 4600 HDSP 4600 HLMP 2802 HLMP 2820 HDSP 4606 HLMP 2855 HDSP 4600 HDSP 4600 HDSP 4600 HDSP 4600 HLMP 2500 HLMP 2500 HLMP 1840 ko oo X HLMP 2350 HLMP 2820 HLMP 2820 HLMP 2800 HLMP 2855 X HLMP 2500 HLMP 2500 HLMP 2500 HLMP 2500 HLMP 2500 E1089 FRONT PANEL ASSEMBLY C Qty Description 2 1 FRONT PANEL ASSEMBLY E6006000 3 1 FRONT PANEL ASSEMBLY E6006000 supplied without Dispiay LED set 08508 60020 5 1 BUNDLED DI
99. r Figure 3 20 Reflection Measurements Setup Equipment HP 8656B Synthesized Signal Generator HP 8508A Vector Voltmeter HP 11570A Accessory Kit includes 2 HP 11536A Probe Tee and 1 HP 908A Termination HP 908A Termination total of 2 required HP 77xD Dual Directional Coupler See Related Products section for frequency ranges HP 11851B Cable Kit 1 cable required in this setup or HP 115008 RF Cable Adapter from type N to DUT if required Calibration Standard Same as DUT connector E1089 3 25 Operation Reflection measurements in 50 ohms Direct inputs reflection bridge HP8508A Source ree RO Reflected i incident CAL i RF input Transmission Refiection Test Set Figure 3 21 Reflection Measurements Setup Equipment HP 8656B Synthesized Signal Generator HP 8508A opt 050 Vector Voltmeter with 50 ohm Input Module HP 85044A Transmission Reflection Test Set HP 11851B Cable Kit 3 cables required in this setup Adapters from type N to DUT if required Calibration Standard Same as DUT connector 3 26 E1089 Operation DESIQNED FOR SYSTEMS 3 11 REMOTE OPERATION THE HEWLETT PACKARD INTERFACE BUS The Vector Voltmeter is capable of remote operation via the Hewlett Packard Interface Bus HP IB which is Hewlett Packard s implementation of IEEE Standard 488 1 This section gives details of remote operation includ ing capabilities addressing input and output formats status
100. r Voltmeter to local control forces the trigger source to the freerun mode E1089 3 29 Sending the Data Message The Vector Voltmeter sends Data messages when addressed to talk and has data to output The output format for each message is shown in Table 3 2 Receiving the Remote Message The Vector Voltmeter switches to remote operation upon receipt of the Remote message The Remote message has two parts The Remote Enable bus control line REN set true and A Device Listen Address received once while REN is true When the Vector Voltmeter switches to remote the front panel R annunciator turns on Receiving the Local Message The Local message is the means by which the controller sends the Go To Local GTL bus command If addressed to listen the Vector Voltmeter returns to front panel control when it receives the Local message If the instrument is in local lockout when the Local message 1s received front panel control is returned but lockout is not cleared Unless it receives the Clear Lockout Local message the Vector Voltmeter will return to local lockout the next time it goes to remote No front panel instrument settings are changed by the transition from remote to local but the following parameters are set Trigger State is set to freerun Average Count set to 5 Display State on When the Vector Voltmeter goes to local mode the front panel R annunciator turns off However when the Vector Voltmeter is be
101. r continued protection against fire hazard replace the line fuse with only a 250V fuse of the same rating Do not use repaired fuses or short circuited fuse holders CAUTION Before the Vector Voltmeter is switched on it must be set to the same line voltage as the power source or damage to the instrument may resuit E1089 Operation ATTENTION Static Sensitive Devices Don t zap your input probes The probes of the HP 8508A are susceptible to damage from electro static discharge ESD Comply with the following precautions to help avoid damage to your probes Anti static precautions Never touch the tip of the probe Eliminate ESD on the body by wearing a snug fitting ground strap that is connected to earth ground through a 1M ohm resistor Eliminate ESD on the work surface by using a grounded anti static bench mat Optional floor mats provide an extra measure of protection especially in areas with floor carpet Never use this product on a carpeted work surface unless the carpet is of a conductive type specifically designed to eliminate ESD Do not introduce ESD into the Device Under Test DUT while using the probes If an unprotected person touches a part of the DUT a static surge could damage the DUT as well as the probes Always refit the protective cover when the probe is not in use Mechanical abuse The tips of the probes are fragile and can break if the probe is dropped 3 3 Operation 3 5 FRONT PANEL FEATURES
102. rent ROM The following procedure performs addi tional tests that will indicate if the ROM is in fact operating correctly E1089 8 17 Service Error Code 500 indicates a ROM test failure In this case a further ROM test is available as follows 1 Power the HP 8508A off 2 Select Position 1 of the test switch on the Processor assembly 3 Power the HP 8508A on Both the red and green LED s should come on and then both should rapidly extinguish If after approximately 6 seconds the green LED should come on again and stay on the ROM test has been successful If however the red LED should come on the test has failed and the ROM A5U18 should be replaced 4 Switch the instrument off and replace the ROM 5 Repeat the ROM test as in steps 2 and 3 6 If the test should still not be successful replace the AS Assembly Should another Error Code in the 500 series appear the Processor assembly should be replaced with a new one In this case the ROM has passed its self test and can be re used Note that a replacement Processor Assembly can be ordered either with or without a ROM installed The part numbers for both assemblies are given in Section 6 of this manual Reset the test switch to the 0 position and cycle the power to reset the processor to its normal operating mode Disassembly and Reassembly Procedures Removing the Processor Assembly To remove the Processor Assembly from the Vector Voltmeter a Wear a wrist strap for
103. retains the displayed values when the signal voltage crosses a fixed threshold or if the instrument loses lock If both displays are active the function is associated with the B signal level If only the A voltage is displayed Channel B is unused the function is associated with the A channel When the function is engaged the LED beside the key flashes to show that a reading is being held CAL TEST When CAL TEST is selected the instrument performs its power on self checks and an internal calibration cycle If an error number is displayed or if the HP 8508A continues to display a tSt message refer to the Troubleshooting section in Section 8 Service METER SELECT This key is used to associate the METER with either Display 1 or Display 2 or to turn it off If phase is being displayed in Display 2 a HI or LO annunciator lights to show the meter range PROBE POWER This output provides 12V supplies which is sufficient to drive an HP 85024A High Frequency Probe TEST OUT This output provides a signal at approximately 1 6MHz and 150mV to allow the user to check that the HP 8508A Vector Voltmeter is operating The signal is controlled by the SHIFT CAL TEST function The LED beside the connector is on when the test output is enabled E1089 4 7 Operation 3 6 REAR PANEL FEATURES MTL AY AOE d PINE rus he 4 Figure 3 2 Rear Panel The Rear Panel Outputs provide de signals which can be fed to external measuring equi
104. rising Accessory Kit Box 1 1540 0149 Square Plastic Box 1 1540 0034 Probe Tip 6 5020 0457 Probe Tip Nut Driver 1 8710 0084 Pre cut Foam Insert 1 9220 3728 Probe Tip BNC Adaptors 2 HP 10218A 1 8 EQUIPMENT AVAILABLE FOR USE WITH THE HP 8508A A printer and controller can be used with this instrument 1 4 E1089 General Information 1 9 RECOMMENDED TEST EQUIPMENT Table 1 1 lists the test equipment required for testing adjusting and servicing the Vector Voltmeter The Critical Specifications column describes the essential requirements for each piece of test equipment Other equipment can be substituted if it meets or exceeds the critical specifications Table 1 1 Recommended Test Equipment Recommended Use Model Instrument Critical Specification Frequency Range 100kHz to 2000MHz HP 8642B Output Level 60dBm to 20dBm Synthesized Signal Generator de to 18GHz 50ohm Insertion Loss 6dB HP 11636A Power Divider i Tracking lt 0 4dB DVM Sensitivity ImV Range to 1 0V HP 3456A AC Calibrator Frequency Output of 20kHz Datron 4200A Output Level 100mV 20uV 50 ohm Type N m SWR 1 01 50 ohm Termination HP 909A Opt 012 HP 33264 Dual Channel Synthesizer Frequency Range 0 to 13MHz Output Level 10dBm to 192Bm Phase Offset 175 deg Independent adjustment on both channels for both magnitude and phase Attenuat
105. rrected measurement connect the DUT to the test port It is also possible to make an uncorrected measurement by turning REF off When making Z or 1 Z measurements absolute values can be displayed by choosing the appropriate SYSTEM IMPD of 50 or 75 ohms If values normalized to ZO are required choose NORM POWER MEAS Works with A and B amplitude only to convert the measured voltage to an equivalent power using the value selected by the SYSTEM IMPD key E1089 3 5 Operation FORMAT The default display configuration for magnitude and phase related measurements is magnitude in Display 1 and phase in Display 2 An alternative real and imaginary format is available when displaying the following B A and Phase together rho and phase angle Z and 1 Z DELAY Uses the B A phase to make simple delay measurements The delay is calculated assuming a 4kHz change between the two frequencies The delay is shown in Display 1 with Display 2 showing dely for delay The delay can be zeroed by pressing SAVE REF INSTRUMENT STATE PRESET This key forces the instrument into a defined measurement state as follows A is displayed in mV with no other functions engaged and all ranging is automatic Error numbers showing in the display after self test routine indicate possible instrument failure Press PRESET again If the error number remains refer to the Service section information NOTE Err 601 indicates that the Input Module is not
106. s tSt nnnn tSt indicates that the instrument is in the setup mode and nnnn is the current setup code Use the UP DOWN Arrow keys to set up test code 2 in Display 2 Press HOLD VALUE and check that the indicator LED is ON 6 Adjust the A3L1 core to obtain a maximum reading in Display 2 7 Press HOLD VALUE to cancel the function 8 Use the UP DOWN Arrow keys to set up test code 3 in Display 2 Press HOLD VALUE and check that the indicator LED is ON 9 Adjust the core of A3L2 to obtain a maximum reading on Display 2 10 Press HOLD VALUE to cancel the function 11 Replace the HP 8508A top cover 5 6 E1089 Adjustments PHASE SHIFT ADJUSTMENT A3R151 Be Ms rs UNS iba i CENTRE FREOUENCY ADJUSTMENT CENTRE FREOUENCY A3 R178 CHANNEL GAIN ADJUSTMENT CHANNEL B FILTER CHANNEL A FILTER ADJUSTMENT a A3 L2 Figure 5 2 IF Assembly Component Location 5 7 E1089 Adjustments To equalize the A and B Channel phase shift DESCRIPTION An internal test routine is used for this adjustment EQUIPMENT No external test equipment is required for this adjustment PROCEDURE 1 Remove the Input Module from the instrument 2 Switch on the equipment and allow to warm up for 30 minutes Note Since the Input Module is not installed in the mainframe the HP 8508A will display the error message Err 601 This reading should be ignored 3 Remove the HP 8508A
107. tested without a Probe Module installed the full per formance test information is contained in Section 4 of the Input Module insert Performance Tests Adjustments Adjustments Section 5 5 1 INTRODUCTION This section describes the adjustment procedures required to enable the Hewlett Packard 8508A Vector Voltmeter to meet the specifications listed in Table 1 2 ofthe Probe Input Module manual Adjustments should only be made after determining that the instrument is out of calibration or if a repair has been carried out 5 2 WARM UP TIME The HP 8508A must be switched on for a minimum of 30 minutes before carrying out any adjustments This allows the instrument operating temperature to stabilize 5 3 SAFETY CONSIDERATIONS WARNING PROCEDURES DESCRIBED IN THIS SECTION ARE PER FORMED WITH THE PROTECTIVE COVERS REMOVED AND POWER SUPPLIED TO THE INSTRUMENT SERVIC ING SHOULD ONLY BE PERFORMED BY TRAINED PER SONNEL WHO ARE AWARE OF THE HAZARDS INVOLVED Anti Static Precautions The printed circuit boards contained in this instrument have components and devices which are susceptible to damage by electrostatic discharge ESD To minimize the risks of damaging or decreasing the reliability of the instrument the following procedures and cautions should be observed when servicing the instrument Static free Workstation All servicing should be carried out at a static free workstation wherever practical De soldering When de sol
108. their components in alpha numeric order followed by reference designation b Chassis mounted parts in alpha numeric order by reference designation c Miscellaneous parts The information given for each part consists of the following a The Hewlett Packard part number b Part number check digit CD c The total quantity QTY in the instrument d The description of the part e A typical manufacturer of the part in a five digit code f The manufacturer s part number for that part The total quantity for each part is given only once at the first appearance of the part in the list 6 1 Replaceable Parts 6 4 ORDERING INFORMATION To order a part listed in the replaceable parts list table quote the Hewlett Packard part number with the check digit indicate the quantity required and address the order to the nearest Hewlett Packard office The check digit will ensure accurate and timely processing of your order To order a part that is not listed in the Replaceable Parts table include the instrument model number instrument serial number the description and function of the part and the number of parts required Address the order to the nearest Hewlett Packard office 6 5 DIRECT MAIL ORDER SYSTEM Within the USA Hewlett Packard can supply parts through a direct mail order system Advantages of using the system are as follows a Direct ordering and shipment from the HP Parts Centre in Mountain View Californi
109. top cover to allow access to the adjustments 4 Set A3R 151 fully counter clockwise 5 Select PRESET SHIFT POWER MEAS to put the instrument into the setup mode The Display will now indicate which setup code 1s being used It will appear as tSt nnnn tSt indicates that the instrument is in the setup mode and nnnm is the current setup code Use the UP DOWN Arrow keys to set up test code 4 in Display 2 Press HOLD VALUE and check that the indicator lamp is illuminated 6 Adjust A3R151 to obtain a zero reading in Display 2 7 Press HOLD VALUE to cancel the function 8 Replace the HP 8508A top cover 5 8 E1089 Adjustments Set up the amplitude path gain using an external 20kHz 100 mV reference source DESCRIPTION To ensure interchangeability of Input Modules the 100 mV level at the module interface must be accurately set AC Calibrator Figure 5 3 Reference Level Adjustment Equipment Setup EQUIPMENT Instrument Recommended Modei AC Calibrator Datron 4200A PROCEDURE 1 Remove the Input Module from the instrument 2 Switch on the equipment and allow to warm up for 30 minutes Note Since the Input Module is not installed in the mainframe the HP 8508A will display the error message Err 601 This reading should be ignored 3 Select PRESET SHIFT POWER MEAS to put the instrument into the setup mode The Display will now indicate which setup code is being used It will appear as tSt nnnn tSt
110. tus data structure is similar to the Standard Event Status data structure and the Error Queue is summarised in the error bits of the Standard Event Status Register Command Error Execution Error Device Dependent Error Query Error Rey mat Control Standard Event Status Register KESR amp T 0 9 a i Standard Event Status Enabie Register MESE CHRP HESE Not utput Queue read by Serial Pol Service Request Generation Status Bit Register read by XST Logica OR Service Request Enable Register XERE XNRf XSRE Figure 3 25 Standard Status Model E1089 4 35 Operation Queues Queues permit a device to report status or other information in a sequential manner Each queue has a summary message bit which indicates that the queue contains some information This bit will be TRUE when the queue contains any information otherwise it will be FALSE Reading a queue will remove a piece of information from it and a queue is considered empty when it no longer contains any information Queues can be cleared by reading all the information in them The Output Queue There are two queues in the status reporting structure of the Vector Voltmeter The Output Queue is a first in first out FIFO queue It stores output messages until they are read from the instrument The availability of data is summarized in the MAV bit of the Status Byte The Output Queue is read by addressing the instrument
111. ults of this measurement are expressed as DC voltages which are digitised by the on board A D Convertor for further manipulation by the Processor A5 The IF Assembly also provides real time outputs for the Amplitude and Phase values Troubleshooting the A3 IF Assembly A fault in the IF Assembly will be indicated by an Error Code display in the 300 series Check that the assembly and all cable connections are securely in place and also that there are no obvious defects An IF Assembly error report may be caused by a damaged sampler Carry out the appropriate adjustments for the IF Assembly if neces sary replace the sampler assemblies and re run the Self Test procedure Should the Error Code persist the IF Assembly should be replaced with a new one Disassembly and Reassembly Procedures Removing the IF Assembly To remove the IF Assembly from the Vector Voltmeter a Wear a wrist strap for ESD protection b Remove the Input Module from the instrument c Remove the instrument top cover d Disconnect the cable connections from the IF Assembly e Remove the 10 Pozidriv screws that secure the IF circuit board to the main deck f The IF Assembly can now be removed from the instrument E1089 8 13 Service Refitting the IF Assembly Refitting is the reverse of this procedure Note the cable connections detailed in the diagram below A3 IF Assembly A4 Search amp Lock Assembly Front Panel Figure 8 5 IF and Se
112. ure command The new commands are MEASure TIMEout lt nrf gt MEASure TIMEout STATe lt ON OFF 1 0 gt A new frequency band has been added Frequency band 20 adds a 20kHz fixed frequency to the frequency ranges available The current firmware revision is now shown in Display 2 for a few seconds at power up E1089 74 Manual Changes 7 2 Service Service Section 8 8 1 INTRODUCTION The service section contains all the information necessary to enable qualified service personnel to troubieshoot and repair the HP 8508A Vector Voltmeter 8 2 SAFETY CONSIDERATIONS Before applying power to the instrument or removing any of the covers review the following warnings and cautions WARNING THESE SERVICING INSTRUCTIONS ARE FOR USE BY TRAINED SERV ICE PERSONNEL ONLY TO AVOID ELECTRICAL SHOCK DO NOT PERFORM ANY SERVICING OTHER THAN THAT CONTAINED IN THE OPERATING INSTRUCTIONS UNLESS YOU ARE QUALIFIED TO DO SO TO PROTECT OPERATING PERSONNEL THE INSTRUMENT CHASSIS AND CABINET MUST BE GROUNDED THE INSTRUMENT IS EQUIPPED WITH A THREE WIRE POWER CORD WHICH WHEN PLUGGED INTO AN APPROPRIATE RECEPTACLE GROUNDS THE INSTRUMENT THE OFFSET PIN ON THE ON THE POWER PLUG IS THE GROUND CONNEC TION TO PRESERVE THIS PROTECTION FEATURE THE POWER PLUG SHALL ONLY BE INSERTED IN A THREE TERMINAL RECEPTACLE HAVING A PROTECTIVE EARTH GROUND CONTACT THE PROTECTIVE ACTION MUST NOT BE NEGATED BY THE USE OF AN EXTENSION CORD OR ADAPTER THAT DOES
113. which it does not implement 3 The device received a Group Execute Trigger GET inside a program message Bit 4 Execution Error EXE This bit indicates that the device detected an error while trying to execute a command It indicates that 1 A PROGRAM DATA gt element received in a command was outside the legal range for the device or incon sistent with the operation of the device 2 The device could not execute a valid command due to some device condition Bit 3 Device dependent Error DDE A device dependent error is any device operation which did not execute properly due to some internal condition such as overrange It indicates that the error was not a command query or an execution error Bit 2 Query Error OYE This bit indicates 1 An attempt to read data from the Output Queue when no data was present 2 That data in the Output Queue was lost An example of this would be queue overflow Bit 0 Operation Complete OPC This bit indicates that the device has completed any pending operations and is ready to accept new commands This bit is generated only in response to the Operation Complete OPC command SESR Operation The SESR operates in the same manner as the Event Registers described earher It can only be cleared by 1 a Clear Status command CLS 2 reading it ESR 3 a power on transition The associated Standard Event Status Enable Register is written with the Enable Status ESE comma
114. y only with IEEE488 1 and those which meet IEEE488 2 as well If the Status Byte of a TEEE488 1 instrument is read by a Serial Poll Enable bus command the ROS bit is cleared as a consequence of the read operation A Serial Poll of an IEEE488 2 instrument produces the same effect TEEE488 2 provides a further command STB to read the Status Byte If this command is used the state of the MSS bit is returned and the bit is not cleared when read These differences arise because IEEE488 2 defines a status reporting structure which extends the specifications of the original standard In IEEE488 2 the Status Byte summarises the underlying status data structures and the concept of enabling service requests is defined E1089 3 31 Operation Enabling Service Requests The service request enabling operation is shown in Figure 3 24 The user can set bits in the Service Request Enable Register SRER These bits correspond to bits in the Status Byte If a bit is set in the SRER it enables the instrument s ability to generate an SRO when the corresponding event occurs For example setting bit 4 in the SRER will produce a service request when the MAV bit is set If a bit is set in the Status Byte but not enabled in the SRER it cannot cause bit 6 to be set and consequently will not initiate an SRO although it will be read when the Status Byte is read Refer to Figure 3 23 for an example of SRQ enabling and handling 10 t HP8508A Example HP I

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