Keithley 3930A User manual

Model3930A
Multifunction Synthesizer
Service Manual
Contains Operating and Servicing Information

WARRANTY
Keithley Instruments,Inc. warrantsthis productto befreefrom defectsin materialandworkmanshipfor aperiod of 1yearfrom dateof
shipment.
Keithley Instruments,Inc. warrantsthe following itemsfor 90 daysfrom the dateof shipment:probes,cables,rechargeablebatteries,
diskettes,anddocumentation.
During the warrantyperiod,we will, atour option, eitherrepairor replaceanyproductthatprovesto bedefective.
Toexercisethis warranty,write or call your local Keithley representative,or contactKeithley headquartersin Cleveland,Ohio. You will
be given prompt assistanceandreturn instructions. Sendthe product, transportationprepaid,to the indicated servicefacility. Repairs
will bemadeandtheproductreturned,transportationprepaid.Repairedor replacedproductsarewarrantedfor thebalanceof theorigi-
nal warrantyperiod,or atleast90 days.
LIMITATION OF WARRANTY
This warranty doesnot apply to defectsresulting from product modification without Keithley’s expresswritten consent,or misuseof
any product or part.This warranty alsodoesnot apply to fuses,software,non-rechargeablebatteries,damagefrom batteryleakage,or
problemsarising from normal wearor failure to follow instructions.
THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSEDOR IMPLIED, INCLUDING ANY IMPLIED
WARRANTY OF MERCHANTABILITY OR FITNESS FORA PARTICULAR USE.THE REMEDIES PROVIDED HEREIN ARE
BUYER’S SOLEAND EXCLUSIVE REMEDIES.
NEITHER KEITHLEY INSTRUMENTS, INC. NOR ANY OF ITS EMPLOYEES SHALL BE LIABLE FOR ANY DIRECT, INDI-
RECT,SPECIAL, INCIDENTAL ORCONSEQUENTIAL DAMAGES ARISING OUT OFTHE USEOFITS INSTRUMENTS AND
SOFTWAREEVEN IF KEITHLEY INSTRUMENTS, INC., HAS BEEN ADVISED IN ADVANCE OF THE POSSIBILITY OF
SUCHDAMAGES. SUCH EXCLUDED DAMAGES SHALL INCLUDE, BUT ARE NOT LIMITED TO: COSTSOF REMOVAL
AND INSTALLATION, LOSSESSUSTAINEDAS THE RESULTOFINJURY TO ANY PERSON,ORDAMAGE TO PROPERTY
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Model 3930A Multifunction Synthesizer
Service Manual
Q 1991, Keithley Instruments, Inc.
Test Instrumentation Group
All rights reserved.
Cleveland, Ohio, U.S.A.
August 1991, First Printing
Document Number: 3930A-902-01 Rev. A

All Keithley product names are trademarks or registered trademarks of Keithley Instruments, Inc.
Other brand and product names are trademarks or registered trader&k of their respective holders.

Safety Precautions
The following safety precautions should beobserved before using the Model 3930AMuhifunction Synthesizer and any
associated instruments.
This instzument is intended for useby qualified personnel who recognize shock hazards and arefamiliar with the safety
precautions required to avoid possible injury. Read over this manual carefully before using the instrument.
Exercise extreme caution when ashock hazard is present at the test circuit. The American National Standards Institute
(ANSI) states that a shock hazard exists when voltage levels greater than 30V rms or 424V peak are present. A good
safety practice is to expect that hazardous voltage is present in any unknown cikuit before measuring.
Inspect the connecting cablesand test leads for possible wear, cracks, or breaks before each use.
For maximum safety, do not touch the test cables or any instruments while power is applied to the circuit under test.
Turn off the power and discharge any capacitors before connecting or disconnecting cablesfrom the instrument.
Do not touch any object which could provide a current path to the common side of the circuit under test or power line
(earth) ground. Always make measurements with dry hands while standing on adry, insulated surface capable of with-
standing the voltage being measured.
Instrumentation and accessoriesshould not be connected to humans.

HOW TO USE THIS MANUAL
Details procedures to verify that the instrument meets
SECTION 1
stated specifications.
Performance Verification
Describes basic operating principles for the various cirtits in
SECTION 2
the Model 3930A.
Principles of Operation
.
Covers fuse replacement, calibration and repair of the instru-
ment, and lists replacement parts.
SECTION 3
Service Information
WARNJNG
The information in this manual is intended for qualified serv-
ice personnel who can recognize possible shock hazards. Do
not attempt these procedures unless you arequalified to do so.

Table of Contents
SECTION 1 - Performance Verification
1.1 INTRODUCTION .............................................................. 1-l
1.2 ENVIRONMENTALCONDITIONS.. ............................................... l-l
1.3 INTTIALCONDlTIONS ......................................................... l-l
1.4 LINEPOWER ................................................................. l-l
1.5 RECOMMENDED TESTEQUIPMENT .............................................. l-l
1.6 VERIEICATIONPROCEDTJEES ................................................... 1-2
1.6.1 Frequency and Duty Cycle Accuracy .............................................. l-2
1.6.2 Amplitude Accuracy .......................................................... l-4
1.6.3 Frequency Response (Sine) ..................................................... l-5
1.6.4 Frequency Response (Triangle, Sawtooth, Square) ..................................... l-7
1.6.5 TotalHmonicDistortion ..................................................... l-8
1.6.6. DC Voltage Accuracy ......................................................... l-9
1.6.7 DCLevel(Square)andDCOffsetError(Sine) ........ . .............................. l-9
1 1.6.8 RiseandFaLlTimes ........................................................... l-9
SECTION 2 - Principles of Operation
2.1 INTRODUCTION .............................................................. 2-l
2.2 BLOCK DIAGRAM ............................................................ 2-l
2.2.1 ControlSection .............................................................. 2-l
2.2.2 Display and Keyboard Section ................................................... 2-l
2.2.3 TriggerSection.. ............................................................ 2-l
2.2.4 Synthesizer Section ........................................................... 2-l
2.2.5 AnalogSection .............................................................. 2-l
2.2.6 Power Supply Section ......................................................... 2-3
2.3 ANALOGCIRCUITDESCRD?TION
................................................ 2-3
2.3.1 Analog Section Block Diagram .................................................. 2-3
2.3.2 D/A Converter .............................................................. 2-3
2.3.3 SquareWaveGenerator ....................................................... 2:3
2.3.4 AmplitudeModulation ........................................................ 2-3
2.3.5 Amplitude and DC Offset Control ................................................ 2-3
2.4 SYN’IHESIZEROl’ERATINGPRINCII’LES .......................................... 2-5
SECTION 3 - Service Information
3.1 INTRODUCTION .............................................................. 3-l
3.2 LINEFLJSEREPLACEMENT ..................................................... 3-l
3.3 CALIBRATION ............................................................... 3-l
3.3.1 EnvironmentalConditions ..................................................... 3-2
3.3.2 InitialConditions ............................................................ 3-2
3.3.3 LinePower ................................................................. 3-2

3.3.4 Recommended Calibration Equipment ................. ............................ 3-2
3.3.5 Cover Removal .............................................................. 3-3
3.3.6 Calibration Adjustments ....................................................... 3-3
3.3.7 CalibrationProcedures ........................................................ 3-6
3.3.8 Cover Replacement ........................................................... 3-9
3.4 FAN FILTER CLEANING ........................................................ 3-9
3.5 FCTN OTJTJUMPER ........................................................... 3-9
3.6 RECHARGEABLE BATTERY REPLACEMENT ........................................ 3-10
3.7 REPAIR ..................................................................... 3-10
3.7.1 Factory Service .............................................................. 3-10
3.7.2
PowerSupplyTestPoints ...................................................... 3-10
.3.7.3 Board-Level Repair ........................................................... 3-12
3.8 REPLACEABLE PARTS ......................................................... 3-12
3.8.1 Parts List .................................................................. 3-12
3.8.2 Ordering Parts .............................................................. 3-12
APPENDICES
A TypicalData............................................................,..... A-l
B Model3930ASpecifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-l

List of Illustrations
SECTION 1 - Performance Verification
Figure l-l Connections to Timer/Counter ............................................... l-3
Figure l-2 Connections to Model 197A DMM ............................................ l-4
Figure l-3 Connections to Wideband AC DVM ........................................... l-5
Figure l-4
Co~ections to Audio Analyzer .............................................. l-8
SECTION 2 - Principles of Operation
Figure 2-l Overall Block Diagram ..................................................... 2-2
Figure 2-2 Analog Selection Block Diagram .............................................. 24
Figure 2-3 Frequency Synthesizer Address Generator Diagram ............................... 2-5
Figure 2-4 Address Generator Waveform ............................................... 2-6
Figure 2-5 Waveform Memory and D/A Converter ........................................ 2-6
SECTION 3 - Service Information
Figure 3-l CoverRemoval ........................................................... 3-3
Figure 3-2 Analog Board (NP-21022) Calibration Adjustments ................................ 3-4
Figure 3-3 Control Board (NJ?-10408)Calibration Adjustments ................................ 3-5
Figure 3-4 Co~eciions to Model 197A DMh4 ............................................ 3-6
Figure 3-5 Second Model 3930A Corux!ctions ............................................. 3-7
Figure 3-6 Co~eciions to PM 6654CCounter ............................................ 3-8
Figure 3-7 connections to Dv’M ...................................................... 3-9
Figure 3-8 Power Supply Test Point Locations ............................................. 3-11
Figure 3-9 ExplodedView ........................................................... 3-13
-. -

List of Tables
SECTION 1 - Performance Verification
Table l-l VerificationEquipment ..................................................... l-2
Table l-2 Limits for Frequency and Duty Cycle Accuracy ................................... 13
Table l-3 Limits for Amplitude Accuracy ............................................... l-4
Table l-4 Limits for Frequency Response (Sine) .......................................... l-6
Table l-5 Limits for Frequency Response (Triangle, Sawtooth, Square) ......................... l-7
Table l-6 Limits for Total Harmonic Distortion .......................................... l-8
Table l-7 Limits for DC Voltage Accuracy .............................................. l-9
Table l-8 Limits for DC Level (Square) and DC Offset Error (Sine) ............................ l-9
Table l-9 Limits for Rise/Fall Times ................................................... l-10
SECTION 3 - Service Information
Table 3-l Recommended Line Fuses ................................................... 3-l
Table 3-2 Recommended Test Equipment for Calibration ................................... 3-2
Table 3-3 Power Supply Test Point Summary ............................................ 3-10
Table 3-4 Board Level Repair Summary ................................................ 3-12
Table 3-5 Replaceable Parts ......................................................... 3-12