1977 - HP Archive
Contents
1. HEWLETT iy PACKARD Signature Analysis A NEW CONCEPT IN DIGITAL TROUBLESHOOTING by Jim Bechtold Editor Troubleshooting an analog circuit is a lot like playing horseshoes being close counts but the digital world is unforgiv ing One bad bit out of a thousand can cause a malfunction The technique of signature analysis finds those bad bits The HP 5004A Signature Analyzer is a technician s tool for field troubleshooting microprocessor based instruments down to the component level when the instru ment has been designed with the neces sary features required for signature analysis It has been learned that although the microprocessor has simplified instru ment design it has complicated trouble shooting to no end However when signature requirements are designed into an instrument the 5004A can process lengthy bit streams from the instrument into short four digit signatures see Figure 1 for examples The technician compares these with the correct signatures noted on the instrument s schematic If a bit stream is faulty the technician can trace it back through gates and memory elements until he isolates an element with correct inputs but faulty outputs This method has a 99 998 certainty of spotting a faulty bit stream regardless of its length or how subtle its faults Signature analysis uses the advantages of analog equipment troubleshooting where the service man uses an annotated schematic see Figu2. 3595A 3490A 59405A Manuals Inter 1 Block Diagram of Amplitude Section face Bus User s Guide and Condensed 2 Block Diagram of Digital Section Description of the Hewlett Packard C Calibration and Adjustments Interface Bus Special Emphasis on Crystal Filter Adjustment WWW HPARCHIVE COM CUSTOMER SERVICE SEMINARS D Troubleshooting 1 Troubleshooting the Measurement Channels 2 Troubleshooting the Digital Channels E Service Literature and Service Kits IV Hewlett Packard Interface Bus A Description B Interfacing V 3042A System System Troubleshooting System Service Kits and Service Literature A Basic System Concepts B System Operation C System Performance D Controllers E Programming F Interfacing G H PREREQUISITES should have read the Interface Bus User s Guide for the appro priate calculator and the Con densed Description of the Hewlett Packard Interface Bus Must also be able to operate and program the appropriate calculator PRESTUDY Interface Bus User s Guide and Condensed Description of Hewlett Packard Interface Bus Also 3330B and 3570A Manuals 8640 AM FM SIGNAL GENERATOR 8660 SYNTHESIZED SIGNAL GENERATOR 435 436 POWER METERS 8480 SENSOR AND 11683A CALIBRATOR AUG 29 SEPT 2 PALO ALTO CA A Ks EW N COURSE CONTENT LECTURE L Introduction II Features and Model Options Ill Front Panel Features A Video Tape B Demonstrati
3. Analog vs digital e ic Technology DCTL RTL DTL CTL TTL ECL EECL HTL MOS f L Specialized tools and techniques to troubleshoot these technologies Workshop four hours of hands on experiments with gates and troubleshooting tools SECOND DAY Logic Symbology Positive Negative logic notation Understanding the implication of logic schematics Implementation of logic gates AND OR NOR NAND XOR Wired OR Decoders and their uses Comparators and their uses Flip flops R S D J K standard and master slave Workshop four hours of hands on experiments with decoders comparators and flip flops Students will also have an opportunity to use modern tools to troubleshoot faults in a printed circuit assembly PACIFICA HOTEL 6161 Centinela Bivd Culver City Los Angeles Area CA 90230 213 649 1776 THIRD DAY Often encountered circuits containing flip flops Counters BCD and binary synchronous and ripple dividers shift registers ring counters Numbering systems including binary BCD octal and hexidecimal Introduction to binary math including half and full adders Workshop four hours of hands on time building and debugging counter circuits FOURTH DAY ROM S PROM masked E and UV RAM S bipolar and MOS static and dynamic Typical failures and the troubleshooting difficulties en countered with ROM S PROM S and RAM S Typical memory addr
4. Palo Alto California 94303 Name S eee Company Name Address City 463A 3AS 618C 12 620B 14 740B 9 S 1220A 25 1222A 5 1310A 17 1311A 18 1402A 10 1740A 5A 1740A 6A 1740A 11A 1741A 1 3400A 9 3459A 12 Safety 3460A4 16B8 34G60B11A Safety 3476A 3 3476A 4 3476B 2 3476B 3 3490A 1C 3490A 9A 3490A 12A 3495A 1 Sate Zip 3556A U 1003 3570A 2A og 3570A 3A 3570A 4A 3570A 7A 37012 6 3702B 34A oo0ag 37022 8 3745A B 2 3745A B 4 3745A B8 6 3745A B 7 ooaago 3761A 6 3770A 30 3770A 31 3770A 32 3770B 1 ooooo 3770B 2 37708 3 37708 4 3770B 5 3770B 6 WWW HPARCHIVE COM ooo00o oo ood ooo o ooo ooo0o0 O000 37708 7 3780A 12 3964A 6 8864A 6 3968A 7 8868A 7 5341A 2 7200A 16 7200A 17 7201A 7 7202A 17 9125A B 5 7202A 16 7203A 17 7210A 17 9862A 20 7402A 6 7402A 7 7404A 1 8412A5 8505A 2 8505A 3 8552B 10 85528 11 8690A 16 86908 13 54420A 1 54440A 1 626XXJ 3A 86242C 1A O R ENEA A U S SEMINAR REGISTRATION FORM COORDINATOR COURSE DATE COST LOCATION 141 Pete Johnson 8552 W 120 Century Road O 8553 May 9 12 300 Student Paramus NJ 07652 8554 201 265 5000 8555 O Digital June 7 10 300 Student Jim Whitley Trouble 6305 Arizona Place shooting Los Angeles CA 90045 O 3050 July 11 14 300 Student Tom Ely P O Box 301 815 Fourteenth St o 3040 July 18 20 275 Student
5. power switch 3968A INSTRUMENTATION TAPE RECORDER 3964A 6 8864A 6 3968A 7 8868A 7 Serials 1702A and below Improved power switch WWW HPARCHIVE COM 5341A FREQUENCY COUNTER 5341A 2 All serials Revision of adjustment procedures for AS IF board and A4 prescaler board Supersedes 5341A 1 7200A 7201A 7202A GRAPHIC PLOTTER 7200A 16 All serials Conversion kit for standard 7200A to EIA RS232C interface Supersedes 7200A 7 7200A 17 7201A 7 7202A 17 9125A B 5 Serials 1620A and below New chart hold Autogrip module 7202A 16 All serials Conversion kit for standard 7202A to EIA RS232C interface Supersedes 7202A 6 7203A 17 7210A 17 9862A 20 Serials 1620A and below New chart hold Autogrip supply board 7203A 17 7210A 17 9862A 20 Serials 1620A and below New chart hold Autogrip supply board 7402A OSCILLOGRAPHIC RECORDERS 7402A 6 All serials Preferred replacements for ink valves cartridges 7402A 7 All serials Motor transmission pulley part number history 7404A OSCILLOGRAPHIC RECORDER 7404A 1 Serials 1610 and 1630 Ink cartridge replacement procedure 8412A PHASE MAGNITUDE DISPLAY 8412A 5 Serials 1625A02890 and below Recommended replacement for bandwidth switch 1 8505A NETWORK ANALYZER 8505A 2 Serials 1602A00111 thru 1610A00140 Modification to reduce 50 Hz line related variations on CRT trace 8505A 3 Serials 1622A00185 and below Recommended replacement for OP amp 140T 141T DISPLAY SECTI
6. Loveland CO 80537 03042 July1822 350 Student ea ear eee Bill Whitney py 8840 _ Aug 29 350 Student 1501 Page Mill Road 8660 Sept 2 Palo Alto CA 94304 Name Company Address City State Zip To enroll in any of the seminars fill out the registration form and mail it with your check to the address shown for the coordinator location Please use separate registration forms for each student Make J REGISTRATION INSTRUCTIONS your check payable to Hewlett Packard Company in U S currency Upon receipt of your registration and check we will confirm your enrollment by returning all necessary prestudy material along with a list of nearby motel accommodations and reservation forms Attendees are responsible for their own transportation accommodations and meals HEWLETT PACKARD COMPANY 1820 Embarcadero Road Palo Alto California 94303 BENCH BRIEFS MAR APRIL 1977 Volume 17 Number 2 Service information from Hewlett Packard Company To obtain a qualification form for a free subscription send your request to the above address Reader comments or technical article contributions are welcomed Please send them to the above address attention Bench Briefs Editor Jim Bechtold HP Palo Alto California 124847ROUTAAALEWIAAA Bulk Rate U S Postage PAID Sunnyvale CA Permit No 317 172 MR PAUL R LEWIS ROUTE 2 BOX STON E RIDGE Address Correction Requested sos NY 12484 Printe
7. ON SYSTEMS 85528 10 All serials Spectrum analyzer assembly instructions 8552B 11 All serials Simplified crystal band width filter adjustment 8690A SWEEP OSCILLATOR 8690A 16 All serials A10 sweep generator improvement 8690B SWEEP OSCILLATOR 8690B 13 Serials 1646A and below A10 sweep generator improvement 8864A INSTRUMENTATION TAPE RECORDER 3964A 6 8864A 6 3968A 7 8868A 7 Serials 1702A and below Preferred replacement for the power switch 8868A INSTRUMENTATION TAPE RECORDER 3964A 6 8864A 6 3968A 7 8868A 7 Serials 1702A and below Preferred replacement for the power switch 9125A B GRAPHIC PLOTTERS 7200A 17 7201A 7 7202A 17 9125A B 5 Serials 1620A and below New chart hold Autogrip module 9862A GRAPHIC PLOTTERS 7203A 17 7210A 17 9862A 20 Serials 1620A and below New chart hold Autogrip supply board 626XXJ SWITCHING MODULAR SUPPLY 626XXJ 3A All serials Troubleshooting switch failures 86242C RF PLUG IN 86242C 1A All serials YTO replacement kit Supersedes 8624C 1 C ooo oo000 OORO QO ooo oopoo SERVICE NOTE ORDER FORM INSTRUCTIONS 1 If you want service notes please check the appropriate boxes below and re turn this form separately to one of the following addresses For European customers ONLY Hewlett Packard Central Mailing Dept P O Box 529 Van Hueven Goedhartlaan 121 AMSTELVEEN 1134 Netherlands All other customers Hewlett Packard 1820 Embarcadero Road
8. RE I Block diagram related to front panel controls Op tional viewing of video tape 141T 8552B 8553B Spectrum Analyzer Operation 90030__607 26 minutes Il Video tape 141T 8552B 8554B Spectrum Analyzer Operation 90030__646 20 minutes III Overall block diagram and system description IV Detailed block diagram V Circuit descriptions Input circuits First second and third mixers and IF stages YIG drive circuits 50 MHz amplifier Marker generator Phase lock circuits Tm OQ VI Troubleshooting techniques bugged instruments with typical failures Vil Repair cautions and mechanical tuning adjustments WWW HPARCHIVE COM States in an effort to bring our training facilities closer to your area For registra tion please use the form on page 15 of Bench Briefs or contact your Hewlett Packard Sales and Service Office I Front panel familiarization II Change first mixer II Set up YIG frequency IV Normal calibration PREREQUISITES None Read Application text 150 Spectrum Analysis Spectrum Analyzer Basics View video tape 141T 8552B 8554B Spectrum Analyzer Operation 90030__646 20 minutes Optional Read Application text 136 Under standing and Operating the 8555A Spectrum Analyzer and 8445B Auto matic Preselector View video tapes 141T 8552B 8555A Spectrum Analyzer Operation Part I 90030__ 647 28 minutes and Part I1 90030__ 697 18 minu
9. TES Since the function of a high gain ac amplifier requires the amplification of low level ac signals to a high voltage level the prevention of the conditions described above would severely degrade the performance of any high gain ac amplifier We therefore recommend that extreme caution be exercised when using a high gain ac amplifier such as the 463A 740B DC Voltmeter 740B DC _ Voltmeters with serials 61000375 and below may have a defec tive range switch S1 that would put up to 1500 volts on the input terminals Examine the G wafer of the range switch The absence of a blue wire attached to pin 17 on the front of the G wafer and the absence of a 10 ohm resistor between pins 7 and 15 on the front of the G wafer indicates that the range switch should be replaced The replacement switch is HP part num ber 00740 61907 Please refer to Service Note 740B 9 S for more information 3459A Digital Voltmeter ae COREE gt on Some 3459A Voitmeters have a potential shock hazard in that if the instrument is floated above ground the RATE con trol shaft and control knob set screw is above ground potential Use the following procedure to test your instrument for this potential shock hazard 1 Turn the power switch off disconnect all power cords and signal cables Connect the ground strap between INPUT LOW and INPUT GUARD terminals this tests both terminals at the same time 2 Set an ohm
10. a design time a few more ROM locations and the extra jumper wire were the price paid for this kind of serviceability The cost evaluation proved to be interesting the production cost actually fell and the extra design time amounted to approximately 1 of the overall development time Toward the goal of serviceability Hewlett Packard now has about 40 projects underway with some products already being introduced IN THIS ISSUE SIGNATURE ANALYSIS SERVICE TRAINING SEMINARS 3476A 8 PRODUCT IMPROVEMENT SAFETY SERVICE NOTES NEW SERVICE NOTES SIGNATURE ANALYSIS THE OPERATING AND SERVICE MANUAL Besides the design engineer the writer of the service manual made an important contribution to the successful application of the signature analysis to the 3455A Voltmeter The service manual is written in such a way that a technician un familiar with the signature analyzer can walk up to a defective voltmeter read the instructions and within a short time locate the fault One element in the manual is a troubleshooting flow chart see Figure 3 that systematically guides the technician through the fault finding process The initial tests may or may not rely on signature analysis They allow isolation of the fault down to a specific area Diag nostic programs cannot carry on from here since they do not have access to individual nodes but it is from here on down to the components that signature analysis excels At this
11. d in U S A All rig ts are reserved No part of Bench Briefs may be reproduced without the express consent of the Editor The Editar may be telephoned at 415 493 1501 ext 4253 WWW HPARCHIVE COM m oo
12. d to date Microprocessors are relatively low in cost and easy to design around But they are just as complex and difficult to repair as computers because of time related faults Industry predicts that ten million IC s will fail in the field this year many of them in microprocessor products which will cost one to two billion dollars in repairs Thus the signature analyzer promises to have a significant impact on present service costs WWW HPARCHIVE COM all BRlife SERVICE INFORMATION FROM HEWLETT PACKARD MARCH APRIL 1977 THE TECHNIQUE IN USE As an example consider the first HP instrument to use signature analysis the 3455A Digital Voltmeter from the HP Loveland Instrument Division in Colorado The digital portion is quite extensive it is microprocessor controlled and contains a self test program stored in ROM If the self test fails a jumper inside the enclosure is removed breaking feed back loops and also enabling the signature analysis routine which is used now to diagnose the instrument The decision to go with signature analysis influenced the product design in several ways all of which make it easier to troubleshoot down to the component level The whole digital portion is on one board The elimination of connectors and a multitude of smaller PC assemblies reduce the production cost and also make all the parts easily accessible for testing without the use of special extender boards Naturally some extr
13. er part number error 1402A DUAL TRACE AMPLIFIER 1402A 10 All serials Loss of alternate operation in some 14X series mainframes 1740A OSCILLOSCOPE 1740A 5A Serials 1533A and below Modifica tion to improve vertical amplifier balance and gain 1740A 6A Serials 1541A and above Modifica tion to improve vertical amplifier balance 1740A 11A Serials 16164 01725 and below Modification to eliminate short sweep problem 1741A OSCILLOSCOPE 1741A 1 Serials 1624A00550 and below Preferred replacement for A15R15 and A15R16 focus resistors 3400A RMS VOLTMETER 3400A 9 All serials Preferred range switch replacement 3459A DIGITAL VOLTMETER 3459A 12 All serials Revision to minimize shock potential 3460A B DIGITAL VOLTMETER 3460A 16B 3460B 11A All serials Elimination of a potential safety hazard Supersedes 3460A 16A 3460B 11 Dated 10 75 09 3460A 16 3460B 6 Dated 7 75 09 Does not supersede 3460B 6 dated Sept 1967 9 3476A B DIGITAL MULTIMETER 3476A 3 Serials 1619A05840 and below Modification to improve ohms protection 3476A 4 Serials 1619A05840 and below Modification to improve performance 3476B 2 Serials 1617A05610 and below Modification to improve ohms protection 3476B 3 Serials 1617A05610 and below Modification to improve performance 3490A MULTIMETER 3490A 1C All serials Replacement of optical isolation assemblies 3490A 9A All serials Preferred LED display replacement 3490A 12A All s
14. erials Intermittent failures 3495A SCANNER 3495A 1 All serials Installation of low thermal relay assemblies connector guide 3556A PSOPHOMETER 3556A U 1003 Serials 1547U and below New battery modification 3570A NETWORK ANALYZER 3570A 2A All serials Recommended replace ments for 03570 66555 log amplifier 03570 66556 output buffer boards and adjustment procedures 3570A 3A All serials changes 3570A 4A All serials Recommended replace ments for 03570 66551 50 ohms 66558 75 ohms input amplifier and adjustment procedures Replacement parts 3570A NETWORK ANALYZER 3570A 7A Serials 1331A00386 to 1331A00670 Procedure to replace air capacitor 3701A TRANSMITTER 3701Z 6 Serials 1119U 01176 and below Preferred replacement for rectifier assy A22 3702B8 IF BB RECEIVER 3702B 34A Serials 1642U 01746 and below Modification to prevent possibility of D C offset on I F display 3702Z DEMODULATOR DISPLAY 37022 8 Serials 1119U 01176 and below Preferred replacement for rectifier assy A24 3745A B SELECTIVE LEVEL MEASURING SET 3745A B 2 Serials 1645U and below Modifica tions to prevent incorrect phase jitter readings in presence of noise 3745A B 4 Serials 1607U and below Modifica tion to improve performance 3745A B 6 Serials 1647U and below Recommended modification to improve oper ation of 5 2V power supply 3745A4 B 7 All serials Troubleshooting and adjustment procedures for XY dr
15. essing techniques Modern display technologies their application and common failure modes Introduction to the ROM controlled device with emphasis on methods used to fault isolate Workshop four hours of experiments leading to the building of a functioning strobed display device WWW HPARCHIVE COM 3 SAFETY RELATED SERVICE NOTES Service Notes from HP relating to per sonal safety and possible equipment damage are of vital importance To make you more aware of these important notes HP has recently modified the Safety Service Note format The note is now printed on paper with a red border and a S suffix has been added to the note s number In order to make you immedi ately aware of any potential safety prob lems we are highlighting safety related Service Notes here with a brief descrip tion of each problem Also in order to draw your attention to safety related Service Notes on the Service Note order form at the rear of Bench Briefs each appropriate number is highlighted by being printed in color 463A AC Amplifier Up to 210 volts ac may exist on the output terminals of the 463A with no input applied Such a voltage on the 463A output terminals can be caused by The amplification of noise in the environment A signal coupling between input and output through attached leads and the subsequent amplification of this feedback signal A failure in the 463A SAFETY SERVICE NO
16. iver assembly A601 03745 66001 3761A ERROR DETECTOR 3761A 6 Serials 1707U 00306 and below Modification to improve performance 150MB S NRZ data input 3770A AMPLITUDE DELAY DISTORTION ANALYSER 3770A 30 All serials Preferred replacement of A23R5 3770A 31 All serials Preferred replacement of A23C1 amp C2 3770A 32 Serials U 00430 and below Modifi cation to ensure sender measurement frequency S L A at switch on 3770B TELEPHONE LINE ANALYSER 3770B 1 All serials Preferred replacement of A23RT1 3770B 2 Serials U 00116 and below Improve ment of 3dB check facility at low output levels 3770B 3 Serials U 00126 and below Preferred replacement of A21R36 3770B 4 Serials U 00131 and below Modifica tion to improve noisy group delay perform ance at high temperature 3770B 5 Serials U 00131 and below Modifica tions to correct averaging time of RMS detector WTD amp tone modes 37708 6 Serials between U 00131 and U 00151 Modification to prevent erratic display in noise tone mode with input frequency 1kHz 3770B 7 Serials U 00156 and below Modifica tion to prevent erroneous impulse noise count 3780A PATTERN GENERATOR ERROR DETECTOR 3780A 12 Serials 1638U 00301 and below Modification to improve the failure protec tion for the inverter driver circuits on the A30 power supply assembly 3964A INSTRUMENTATION TAPE RECORDER 3964A 6 8864A 6 3968A 7 8868A 7 Serials 1702A and below Improved
17. l buttons in front and rear of the voltmeter are correctly set This means the confidence level of the user is very high at the start of a test WHAT S A SIGNATURE Everything depends on the signature A kind of compressed fingerprint of the data present on a node it is compared with the correct signature printed on the schematic of the product so that any discrepancy may be noted and traced to the source The signature is derived through linear fedback shift registers which generate pseudo random binary sequences For signature analysis bit sequences being measured are summed in modulo 2 with the register feedback The register is clocked by the same clock as the bit stream under measurement Input sequences may be any length but at the end of the measurement only the residue remaining in the register is looked at These 16 bits when displayed in a 4 digit format comprise the signature of the measured bit stream Figure 4 shows a simplified block diagram of this concept WWW HPARCHIVE COM DESIGNING IN SIGNATURE ANALYSIS A portion of the circuits read only memory perhaps 5 must contain a special program for stimulating the various nodes in the circuits The stimula tion serves more to excite or force a state change on the nodes than to generate meaningful data Frequently this stimulus program may be merged with the products performance verification pro gram The correct signatures are developed by
18. level the repair man uses the annotated schematics and graphs of board layouts together with the flow chart to find the bad node A node is defined as a terminal of any branch of a network or a terminal common to two or more branches Also called junction point vertex or nodal point In some cases the manual includes instructions as to which IC to replace In other cases the use of a logic probe which is an integral part of the logic tracer may be required A current sensor such as the HP 547A helps to find short circuits between traces or to ground and is particularly helpful when bus problems are encountered The 3455A Service Manual shows pictures of the board and defines the set up for each test see Figure 3 Each picture shows only the signatures related to the particular test directing the technician s effort toward the important areas on the board The ROM program even simulates interrupt signals ensuring however that they occur predictably at the same spot within a window so that stable signatures result The signature analyzer has its own self check Each test set up is tested by touching the power supply voltage with the instrument s probe to input a sequence of all one s If this characteristic signature is correct the setup conditions and framing of the measurement window are verified Specifically this tells the user that the switches on the signature analyzer as well as all the jumpers switches and contro
19. meter to the 1 kilohm range and connect one lead to the INPUT LOW or GUARD terminal 3 Connect the other ohmmeter lead to the set screw on the front panel RATE control 4 The ohmmeter should indicate infinity If not order the following parts and Service Note to modify the 3459A to conform to current safety standards Service Note 3459A 12 lea 14 5 mm round knob 0370 2551 0370 2553 7120 4082 lea 14 5 mm knob cap lea Warning label wn U INDIN NEED ANY SERVICE NOTES Here s the latest listing of Service Notes available for Hewlett Packard products To obtain information for instruments you own remove the order form and mail it to the nearest HP distribution center WWW HPARCHIVE COM 463A PRECISION AC AMPLIFIER 463A 3A S All serials Elimination of potential safety hazard Supersedes 463A 3 618C SHF SIGNAL GENERATOR 618C 12 Serial prefixes 1546A and below Preferred replacement for Q1 620B SHF SIGNAL GENERATOR 620B 14 Serial prefixes 1546A and below Preferred replacement for Q1 740B DC STANDARD DIFFERENTIAL VOLTMETER 740B 9 S Serial Number 61000375 and below Elimination of potential safety hazard SERVICE NOTES 1220A OSCILLOSCOPE 1220A 25 All serials Improved knobs 1222A OSCILLOSCOPE 1222A 5 All serials Improved knobs 1310A DISPLAY 1310A 17 1311A 18 All serials Power transformer part number error 1311A DISPLAYS 1310A 17 1311A 18 All serials Power transform
20. on IV Theory A Block Diagram B Assembly Locations C Schematic LAB IL Adjustments Il Performance Tests Ill Troubleshooting PREREQUISITES Basic knowledge of digital logic cir cuits and general knowledge of elec tronics including operational ampli fiers and phase lock circuits PRESTUDY Review digital logic and block dia gram information in 8640 8660 and 435 436 manuals Read pages 1 48 in Signal Generator Seminar textbook View video tape 90030__566 Optional WWW HPARCHIVE COM CUSTOMER SERVICE SEMINARS 5340A MICROWAVE FREQUENCY COUNTER SEPT 1 2 PARAMUS NJ 6 a a COURSE CONTENT LECTURE Overall Block Diagram Numerical Examples of Frequency Measurements Input Phase Lock Loop Circuit Description IV Transfer Phase Lock Loop Circuit Description V Instrument Flow Diagram and Algorithmic State Machine VI Options LAB The lecture is given in a lab environment Attendees make voltage and waveshape measurements at different times during the lecture A familiarization with adjustment pro cedures is also included PREREQUISITES Basic knowledge of microwave measur ing techniques April 1973 HP Journal describing 5340A The Fundamentals of Electronic Frequency Counters Application Note 172 PRESTUDY DIGITAL TROUBLESHOOTING TECHNIQUES INTRODUCING MODERN DIGITAL TECHNOLOGY AND TROUBLESHOOTING TO THE ANALOG REPAIRMAN JUNE 7 10 FIRST DAY
21. re 2 for an example that clearly shows voltages and wave forms and allows him to make repairs without a detailed understanding of the circuits By comparing actual voltmeter readings and oscilloscope traces to those displayed on the schematic he deter mines the point at which circuit opera tion becomes faulty and from there traces the problem back to a failed component in the unit But in the programmed digital world ser vice schematics are devoid of waveform voltage and other service information for the not very comforting reason that all bit streams look pretty much alike on an oscilloscope The problem is compounded with microprocessors state machines and controllers for a more subtle reason with them there is no longer a one to one association between product features and particular sections of hardware For example if a keyboard debouncing function fails in an older random logic product a service manual might advise checking the integrated circuits that con trol that function With microprocessors on the other hand key debouncing is more likely a timeshared function tying up the whole processor for a brief moment When it fails any one of a large number of IC s could be faulty The signature analyzer is a troubleshoot ing tool designed specifically for micro processor based products More instru ments that are microprocessor based will be introduced this year than the sum of all computer systems installe
22. rtesy SAMS WWW HPARCHIVE COM SIGNATURE ANALYSIS Check The Signatures At The Following Ports Locanon Signature Alu Pun 2 8cPU Pin 5 UPUH 2031 ALU A1U 8 Outout Butter AIU21 The Signatures At Check The Following Ports Location Signature AlU29 Pin 2 UCHE Pin 5 8702 Pin H074 Pin 10 HHES Atu23 OF Input Latch ALU AlU28 CLOCK Ar Check The Signatures The Following Points ron FIGURE 3 Example of Troubleshooting Flow Chart from 3455 DVM manual INPUT NOTE The output of s multiple input exctuswe OR gate must be such that the bits at aff terminatu inputs and output surm to rero modulo 2 FIGURE 4 Simplified Block Diagram of the Signature Service Notes 3476A 3 and 3476B 2 describe a modification that may be desired for all 3476A s serials prior to 1619A05840 and 3476B s serials prior to 1617A05610 This modification increases the input voltage protection of the ohmmeter circuits from 30 volts rms where the 32 milliamperes fuse F2 now blows to 150 volts rms This modifica tion should help in the Case of accidental application of voltage between the volt ohm input terminals and COM terminal when in the ohms function ATTENTION 3476A B MULTIMETER OWNERS hee Rey Pii Aes 1 To determine if your 3476 has already been modified examine A1R2 If A1R2 is a 5 kilohm resistor the modification has been made Other
23. simply exercising the various parts of a circuit that is known to be good and noting the results on the circuit diagram A second requirement is to break feed back paths within the circuit either by using hardware switches jumpers or connectors or by disabling gates with software This requirement is necessary to prevent a fault from being fed back around and disturbing all data nodes When these two requirements are met back tracing a fault to its source is a straight forward process of tracing faulty signatures In using signature analysis the procedure varies slightly depending on whether the fault lies in the kernel the minimum con figuration of microprocessor and ROM necessary to run the simplest test pro gram or in the outlying circuitry If the fault is in the outlying circuitry a keyboard or display scanner input output latch etc the technician simply switches the circuit to the diagnostic mode Then guided by the manual he uses the test instrument to trace faults back to their source But what if the problem lies in the kernel and even the ROM stimulus program will not run Here the microprocessor itself can pro vide a stimulus if its address counter is allowed to sequence through the address field To do this it is only necessary to open the data instruction bus and force the no operation instruction onto it This stimulus program checks out all the address lines and the individually enabled ROMs as
24. tes Optional 3050B DATA ACQUISITION SYSTEM 3040A NETWORK ANALYZER JULY 11 14 3 1 2 DAYS LOVELAND CO JULY 18 20 LOVELAND CO AND 3042A NETWORK ANALYZER JULY 18 22 LOVELAND CO NOTE 3042A instruction same as 3040A plus two addi tional days July 21 22 COURSE CONTENT COURSE CONTENT LECTURE LECTURE AND LAB k 3495A Scanner A Operation I Introduction To Low Frequency Network Analysis B Theory of Operation Il 3330B Synthesizer C Troubleshooting A Operation and Specifications I 3490A Multimeter B Theory of Operation A Operation 1 Block Diagram of Amplitude Section B Guarding 2 Block Diagram of Frequency Section C Theory of Operation 3 Reference Frequency Section D Troubleshooting Cc Unique Circuitry Ill Hewlett Packard Interface Bus 1 N Loops IV Calculator Control of HP IB 2 Logarithmic Amplitude Control by Refer ence Frequency LAB D Introduction to Algorithmic State Machines ert q 1 Basic ASM Concepts The lecture is given in a lab environment 2 Functional Discussion of Controller PREREQUISITES Must be familiar with Sections I through Section V of the 3490A 3495A and 59405A E Repair and Calibration Manuals Must have read Interface Bus F Service Literature and Service Kits User s Guide for the appropriate calcu II 3570A Network Analyzer lator and Condensed Description of A Operation and Specifications the Hewlett Packard Interface Bus B Theory of Operation PRESTUDY
25. well All of these nodes are readily characterized with signatures O Since signature analysis relies on the ability of an instrument to control itself in a synchronous manner asynchronous circuits like monostables direct memory access dynamic memory or interrupts need to be carefully controlled Generally simple provisions in the hard ware can be made to force them into a ROM RAM 2PH2 7516 9042 112uU 253P Z 3F6A 2 SFPU B14F o io lt gt VALID MEMORY ADDRESS ee cu a MG le ty 5s SYNC SEP HORIZ AFC ss HORIZ OSC SIGNATURE ANALYSIS synchronous or disabled condition when that is required for a particular test In summary HP expects the Signature Analyzer to have a significant impact on our own in house service costs True there are some design costs to be OUTPUTS lt eja nj aja j oj wj uj oj a F291 ics 288F 5P68 S72F oo o gt oy gt w a FIGURE 1 Example of Block Diagram with Signatures accounted for in the new products utiliz ing signature analysis However in the long run these costs will be more than offset by the serviceability of the instru ment And as of today Signature Analysis is the first new and workable concept for servicing microprocessor based instruments GPAP ATPO 8226 3POH 3813 258F P256 CUBH OUTPUTS 17 65ViG FIGURE 2 Example of Annotated Analog Schematic Cou
26. wise make the changes as described in Table 1 Service Notes 3476A 4 and 3476B 3 describe a modification to improve per formance on 3476A s serials prior to WWW HPARCHIVE COM Two new Service Notes have been issued for your multimeter that show modifica tions to improve OHMS protection and operating performance TABLE 4 1 COMPONENT JAR A Rs or BOARD NUMBERS DESIGNATOR LD Pte NEW Pn 03476 0650 AIR 00076 66511 1 KE SS dw SKIL 1 Sw 034750850 s 0757 0449 wee 3152 3476 6987 ORL th Ow 148 1619A05840 and 3476B s serials prior to 1617A05610 The 3476 sometimes exhibits the overload condition five horizontal bars with the instantaneous application of about 1000 volts de or 700 volts rms A gradual increase in voltage to these values will not cause an overload indication In the event a 3476A fails to respond to a step input R51 which is in series with pin 6 of U1 should be changed from hp part number 0683 1035 10 kilohm 5 to part number 0683 1025 1 kilohm 5 General location of R51 is shown in Figure 1 CUSTOMER SERVICE SEMINARS C CUSTOMER SERVICE Hewlett Packard continually offers train ing to customers on a worldwide basis to SEMINARS help keep service skills current with HP s extensive product line Seminars are pro vided throughout Europe and the United 141T 8552A B 8553B 8554B 8555A SPECTRUM ANALYZERS MAY 9 12 PARAMUS NJ PRESTUDY COURSE CONTENT LECTU
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