HP 3455A Service manual

OPERATING AND SERVICE MANUAL
DIGITAL
VOLTMETER
3455A
HEWLETT
PACKARD
-hp-
3455A

HEWLETT
PACKARD
OPERATING AND SERVICE MANUAL
MODEL 3455A
DIGITAL VOLTMETER
Serial Numbers: 1622A00I01 and Greater
IMPORTANT NOTICE
This loose leaf manual does not normally require achange sheet. All
major charrge information has been integrated into the manual by
page revision. In cases where only minor changes are required, 8
change sheet rnay be suttplied.
If the Serial Number of your instrument Is lower than the one on
this title page, the manual contains revisions that do not apply to
your Instrument. Backdatirtg information given in the manual adapts
it to earlier instruments,
Where practical, backdating Information Is Integrated into the text,
parts list and schematic diagrams. Backdating changes are denoted
by adelta sign. An open delta (A) or lettered delta (A^) on agiven
page, refers to the corresponding backdating note on that page.
Backdating changes not integrated into the manual are denoted by
anumbered delta <At Iwhich refers to the corresponding change in
the Backdatirtg section (Section VIO.
To help minimize the possibility of electrics! fire or shock
hazards, do not expose this instrument to rain or excessive
moisture.
Mtnual Part No. 03455-90003
Microfiche Part No. 03455-90053
(DCopyright Hewlett-Packard Company 1976
P.O. Box 301, Loveland, Colorado, 80537 U.S.A.
Printed: July 1979

Who\ HEWLETT
%LfiM PACKARD
CERTIFICATION
Hewlett-Packard Company certifies that this product met its published specifications at the time ofshipment from the
factory. Hewlett-Packard further certifies that its calibration measurements are traceable to the United Slates Ha-
lional Bureau ofStandards, 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 product is warranted against defects in material and workmanship for aperiod of one year
from date of shipment (.except that in the case of certain components listed in Section Iof this manual, the warranty
shall be for the specified period] .During the warranty period, Hewlett-Packard Company will, at its option, either
repair or replace products which prove to be defective.
For warranty service or repair, this product must be returned to aservice facility designated by -hp-. Buyer shall
prepay shipping charges to -hp- and -hp- shall pay shipping charges to return the product to Buyer. However, Buyer
shall pay all shipping charges, duties, and taxes for products returned to -hp- from another country.
Hewlett-Packard 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. Hewlett-Packard 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. HEWLETT-PACKARD SPECIFICALLY
DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR APARTICULAR
PURPOSE.
EXCLUSIVE REMEDIES
THE REMEDIES PROVIDED HEREIN ARE BUYER'S SOLE AND EXCLUSIVE REMEDIES. HEWLETT-
PACKARD SHALL NOT BE LIABLE FOR ANY DIRECT, INDIRECT. SPECIAL. INCIDENTAL. OR CONSE-
QUENTIAL DAMAGES. WHETHER BASED ON CONTRACT. TORT. OR ANY OTHER LEGAL THEORY.
ASSISTANCE
Product maintenance agreements and other customer assistance agreements are available
for Hewlett-Packard products.
For any assistance, contact your nearest Hewlett-Packard Sales and Service Office.
Addresses are provided at the back of this manual.
10/1/7*

Model 3455A Table of Contents
TABLE OF CONTENTS
Section Page
I. GENERAL INFORMATION 1-1
1-1. Introduction 1-1
1-5. Specifications 1-1
1-7. Instrument and Manual Identification ...I-l
1-11. Description 1-1
1-13. Options 1-1
1-15. Accessories Supplied 1-1
1-17. Accessories Available 1-1
1-19. Recommended Test Equipment 1-1
Section Page
II. INSTALLATION 2-1
2-1. Introduction 2-1
2-3. Initial Inspection 2-1
2-5. Preparation for Use 2-1
2-6. Power Requirements 2-1
2-8. Line Voltage Selection 2-1
2-10. Power Cable 2-1
2-12. Grounding Requirements 2-1
2-14. Bench Use 2-1
2-16. Rack Mounting 2-2
2-18. Interface Connections 2-2
2-22. Environmental Requirements 2-2
2-23. Operating and Storage Temperature. ..2-2
2-26. Humidity 2-3
2-28. Altitude 2-3
2-
30. Repackaging for Shipment 2-3
Section Page
111 OPERATING INSTRUCTIONS 3-1
3-
1. Introduction 3-1
3-3. Operating Characteristics 3-1
3-4. Turn-On and Warm-Up 3-1
3-6. Self-Test Operation 3-1
3-10. DC Voltage Measurement 3-1
3-12. Resistance Measurement 3-2
3-14. AC Voltage Measurement 3-2
3-19. Math Feature 3-3
3-23. Enter and Store 3-4
3-27. High Resolution Mode 3-4
3-29. Auto-Cal 3-5
3-33. Trigger 3-5
3-36. Sample Rate 3-5
3-38. Auto Range 3-6
3-41. Guarding 3-6
3-42. Common-Mode Voltages 3-6
3-44. Guard Connection 3-6
3-46. Guarding Information 3-6
3-48. Remote Operation 3-7
3-49. General 3-7
3-53. Address Selection 3-7
3-56. Program Codes 3-8
3-61. Data Messages 3-9
3-69. Device Control Messages 3-12
3-78. Interrupt and Device Status
Messages 3-12
3-82. Data Output Characteristic 3-13
3-84. Bail Out Message 3-13
3-86. Instrument Measurement Times
(Remote Control) 3-13
3-88. Remote Programming Examples 3-14
3-90. Operators Checks 3-14
3-92. Bench Use 3-14
3-
94. HP-IB Operation 3-14
Section Page
IV. PERFORMANCE TESTS 4-1
4-
1. Introduction 4-1
4-3. Equipment Required 4-1
4-5. Performance Test Card 4-1
4-7. Calibration Cycle 4-1
4-9. Input Terminals/Control Settings 4-1
4-11. Performance Test Failure 4-1
4-13. Specification Breakdown 4-1
4-17. I>C Accuracy Test Considerations 4-2
4-26. Operational Verification Tests 4-3
4-27. DC Operational Accuracy Test 4-3
4-30. Test Procedure 4-3
4-31. AC Operational Accuracy Test 4-5
4-34. Test Procedure 4-5
4-35. Ohmmeter Accuracy Test 4-8
4-37. Test Procedure 4-8
4-38. DC Voltmeter Input Resistance Test. ...4-9
4-39. Performance Test 4-9
4-40. DC Voltmeter Accuracy Test 4-9
4-43. Test Procedure 4-10
4-44. CVoltmeter Accuracy Test 4-12
4-47. Test Procedure 4-12
4-48. Ohmmeter Accuracy Test 4-16
4-50. Test Procedure 4-16
4-51. Common-Mode and Normal-Mode
Rejection Test 4-17
4-54. Test Procedure 4-17
4-55. DC Voltmeter Input Resistance
Test 4-18
4-
56. AC Voltmeter Input Impedance
Test 4-19/4-20
Section Page
V. ADJUSTMENTS 5-1
5-
1. Introduction 5-1
5-3. Equipment Required 5-1
5-5. Adjustment Interval 5-1
5-7. Adjustment Sequence .5-1
5-9. Test Point and Adjustment Locations. ..5-1
5-11. DC Zero Adjustments 5-1
5-12. DC and Ohms Reference Adjustments. ..5-2
5-14. Adjustment Procedure 5-2
5-15. RMS Convertor Adjustments
(Standard Model 3455A Only) 5-3
5-16. Average Convertor Adjustments
(345SA Option 001 Only) 5-4
5-18. Adjustment Procedure 5-4
iii

Table of Contents Model 3455A
TABLE OF CONTENTS (Cont'd)
Section Page
VI. REPLACEABLE PARTS 6-1
6-1. Introduction 6-1
6-4. Ordering Information 6-1
6-6. Non-Listed Parts 6-1
6-8. Parts Changes 6-1
6-10. Proprietary Parts 6-1
6-12. Exchange Assemblies 6-2
6-
15. Service Kit 6-2
Section Page
VII. MANUAL CHANGES 7-1
7-
1. Introduction 7-1
Section Page
VIII. SERVICE 8-1
8-
1Introduction 8-1
8-3. Safety Considerations
8-8. Recommended Test Equipment 8-1
8-10. Introduction 8-2
8-12. Input Switching and DC Attenuator. ..8-2
8-13. General 8-2
8-15. Detailed Description 8-2
8-17. Operational Attenuator 8-2
8-19. Auto Calibration-DC Voltage 8-2
8-20. General 8-2
8-22. Circuit Description 8-4
8-34. Auto-Calibration-Ohms 8-9
8-35. General 8-9
8-37. Circuit Description 8-9
8-42. Auto Calibration-A/D Convertor. ...8-10
8-44. Circuit Description 8-11
8-47. True RMS AC Convertor 8-11
8-48. General 8-11
8-50. Circuit Description 8-11
8-56. Average Responding AC Convertor
(Option 001) 8-12
8-57. General 8-12
8-59. Circuit Description 8-12
8-65. Ohms Convertor 8-13
8-66. General 8-13
8-68. General Description 8-13
8-73. DC Preamplifier 8-14
8-74. General 8-14
8-76. Circuit Description 8-14
8-82. Reference Assembly 8-16
8-83. General 8-16
8-85. Circuit Description 8-16
8-87. Analog-to-Digital Convertor (A/D).. 8-16
8-88. General 8-16
8-92. Circuit Description 8-17
8-103. Inguard Controller 8-19
8-104. General 8-19
8-107. Circuit Description 8-19
8-M5. Main Controller 8-22
8-116. General 8-22
8-118. Circuit Description 8-23
8-141. HP-IB Circuit 8-29
8-142. General 8-29
8-144. Circuit Description 8-29
8-168. Front Panel Operation 8-32
8-169. Circuit Description 8-32
TROUBLESHOOTING
8-174. Introduction 8-35
8-176. General Block Diagram Theory
of Operation 8-35
8-179. Outguard Section 8-35
8-185. Inguard Section 8-36
8-194. Preliminary Troubleshooting Check.. 8-36
8-195. Instrument Half-Splitting
Techniques 8-36
8-198. Service Group Summary 8-37
SERVICE GROUP A
8-A-l Turn-On Circuitry (Inguard and
Outguard) 8-40
8-A-3. Inguard/Outguard Isolation 8-40
8-A-5. Outguard Troubleshooting
(Schematic 8) 8-40
8-A-6. Inguard Troubleshooting
(Schematic 5, 6, 7) 8-40
8-A-8. AlO Motherboard Troubleshooting
(Schematic 5, 6, 7) 8-40
8-A-lO. A/D Board Troubleshooting
(Schematic 5, 6) 8-41
8-A-12. Inguard/Outguard Transfer Circuit
Troubleshooting (Schematic 7,8) 8-41
SERVICE GROUP 6
8-B-l. Auto-Cal and DC Troubleshooting
(Inguard) 8-43
8-B-3. Auto-Cal Constants 8-43
8-B-9. Auto-Cal Switch Closures
(Schematic 1, 5, 6, 7) 8-50
8-B-l I.Cal Constants Service Procedure 8-50
8-B-14. Switch Closure Table 8-52
8-B-16. Auto-Cal Troubleshooting
(Schematic I, 7) 8-52
8-B-18. DC Inoperative (Schematic 1) 8-54
8-B-20. Leakage and Other Various
Malfunctions 8-54
8-B-23. 10 VRange or Constant 10 and 11 Fail. ..8-55
8-B-24. 1VRange or Constant 0, I,and 2Fails ..8-55
8-B-25. 100 mV Range or Constant 3Fails 8-55
8-B-26. 100 VRange or Constants 5, 4, and 7
Fail 8-55
8-B-27. 10(X) VRange or Constant 6 Fails 8-56
8-B-28. Various Other Malfunctions 8-56
8-B-30. Other Troubleshooting Hints 8-57
8-B-3I. General Noise 8-57
8-B-33. IX: Noise (Schematic 1, 5. and 6) 8-57
iv

Model 3455A Table of Contents
TABLE OF CONTENTS (Cont'd)
SERVICE GROUP C
8-C-l. AC Convertor Troubleshooting 8-59
8-C-2. True RMS Convertor Servicing
(Schematic 3) 8-59
8-C-4. Preamplifier and Input Alternator
Circuitry 8-60
8-C-6. Absolute Amplifier Circuitry 8-61
8-C-8. Squaring Amplifier, Intergrator, and
Antilog Circuitry 8-61
8-C-IO. AC/DC Operation 8-62
8-C-12. AC Noise (Schematic 3) 8-62
8-C-16. Miscellaneous Troubleshooting
(Schematic 3) 8-63
8-C-17. Average Responding AC Convertor
(Schematic 2) 8-64
SERVICE GROUP D
8-D-l. Ohm Troubleshooting (Schematic 1,4).. .8-65
8-D-2. Ohms Circuit Isolation 8-65
8-D-4. Ohms Servicing 8-65
8-D-6. Ohms Convertor Troubleshooting
(Schematic 1, 4) 8-65
8-D-8. Miscellaneous Ohms Troubleshooting
Hints 8-66
8-D-9. Ohms Offsets 8-66
8-D-ll. Ohms Noise (Schematic 1,4) 8-67
SERVICE GROUP E
8-E-l. A/D Convertor and Inguard Logic
Troubleshooting 8-68
8-E-2. A/D Convertor Servicing
(Schematic 6, 7) 8-68
8-E-4. No A/D Waveform 8-69
8-E-6. Incorrect A/D Waveform 8-69
8-E-7. Correct A/D Waveform 8-69
8-E-8. A/D Noise (Schematic 6) 8-70
8-E-lO. Inguard Logic Troubleshooting
(Schematic 7) 8-70
8-E-12. Inguard Logic Troubleshooting with
no A/D Waveform 8-70
8-E-I3. Inguard Logic Troubleshooting with
an A/D Waveform 8-72
SERVICE GROUP F
8-F-l. Outguard Logic Troubleshooting
(Schematic 8, 9, 10) 8-73
8-F-3. Main Controller Troubleshooting
(Schematic 8) 8-73
8-F-4. Front Panel Troubleshooting 8-73
8-F-5. Front Panel Operation Check 8-73
8-F-6. Front Panel Servicing (Schematic 10). ...8-74
8-F-7. Front Panel LED’s Switch, and Key
Cap Replacement Procedure 8-74
8-F-8. HP-IB Troubleshooting (Schematic 9). ..8-75
SERVICE GROUP 6
8-G-l. Miscellaneous Troubleshooting 8-76
8-G-2. Power Supplies (Schematic 11) 8-76
8-G-3. Reference Assembly (Schematic 5) 8-76
8-G-4. Turn-Over Errors (Schematic 1, 5,
and 6) 8-77
8-G-6. Other Troubleshooting (Schematic 8
and 11) 8-77
SERVICE GROUP H
8-H-l .Troubleshooting Diagrams 8-78
8-H-3. General Troubleshooting Diagram 8-78
8-H-4. Inguard Troubleshooting Diagram. 8-8 1/8-82
8-H-6. Outguard Troubleshooting 8-117/8-118
APPENDIX
Page
A-1. Introduction A-1
A-4. Program Example #1 A-1
A-5. Program Example #2 A-2
LIST OF TABLES
Table Page
1-1. Specifications 1-2
1-2. Typical Operating Charaaeristics 1-4
1-3. Recommended Test Equipment 1-6
3-1. Maximum Front Panel Reading Rates 3-6
3-2. HP-IB Interface Capability 3-7
3-3. Bus Messages 3-8
3-4. HP-IB Program Codes 3-9
3-5. Binary Program Codes 3-11
3-
6. Typical HP-IB Controlled Meassurement
Times 3-14
4-
1. DC Accuracy Test (1 V, 10 VFull Scale;
High Resolution On) 4-3
Table Page
4-2. DC Accuracy Test (High Resolution Off). ..4-5
4-3. DC Accuracy Test (High Resolution On). ..4-5
4-4. AC Accuracy Test 30 Hz to 100 kHz
(Standard Model 3455Aonly) 4-7
4-5. AC Accuracy Tests 100 kHz to 1MHz
(Standard Model 3455Aonly) 4-7
4-6. AC Accuracy Test 30 Hz to 100 kHz
(3455AOption 001 only) 4-8
4-7. Two-Wire Ohm Accuracy Test 4-8
4-8. Four-Wire Ohms Accuracy Test 4-9
4-9. DC Accuracy Test (1 V, 10 VFull-Scale;
High Resolution OfO 4-10
V

Table of Conienis Model 3455A
LIST OF TABLES (Cont'd)
Table Page
4-10. DC Accuracy Test (1 V, 10 VFull Scale;
High Resolution On) 4-10
4-11. DC Accuracy Test (High Resolution OfO. -^11
4-12. DC Accuracy Test (High Resolution On). .4-11
4-13. AC Accuracy Test 30 Hz to 100 kHz
(Standard Model 34SSA only) 4-14
4-14. AC Accuracy Test 100 kHz to 1MHz
(Standard Model 34SSA only) 4-IS
4-15. AC Accuracy Test 30 Hz to 100 kHz
(Model 345SA Option 001 only) .4-15
4-16. Two-Wire Ohm Accuracy Test 4-16
4-
17. Four-Wire Ohms Accuracy Test 4-17
5-
1. DC Zero Adjustment Padding List
(AlORllO) 5-2
5-2. Jumper Removal (A15 Board) 5-4
5-3 .Jumper Removal (A 13Board) 5-4
6-1. Standard Abbreviations 6-1
6-2. Code List of Manufacturers 6-2
6-3. Replaceable Parts 6-3
8-1. AC Convertor Ranging 8-11
8-2. A/D Convertor Switch Control Signal
Descriptions 8-21
8-3. Service Group Listing 8-38
8-B-l. Auto-Cal Constants 8-43
8-B-2. Auto-Cal Switch Closures 8-50
8-B-3. Gate Function in Auto-Cal 8-51
8-B-4. Switch Driver Voltage Levels 8-51
8-B-5. Cal Constant Monitoring Points.
8-B-6. 3455ADVM Switch Closures 8-53
8-B-7. Possible Auto-Cal Failure Causes 8-54
8-D-l. Ohms Gain and Switch Configuration. ...8-66
8-E-l. Mneumonic Definitions 8-71
8-G-l. Power Supplies Locations 8-76
LIST OF ILLUSTRATIONS
Figure Page
2-1. Line Voltage Selection 2-1
2-2. Power Cord Configuration 2-1
2-
3. Typical HP-IB System Interconnections. .,.2-2
3-
1. Front and Rear Panel Features 3-0
3-2. Ohmmeter Measurement Connections 3-2
3-3. Connecting the Guard 3-7
3-4. Address Selection 3-8
3-
5. Operational Verification Flowchart. .3-15/3-16
4-
1. Ambiguous Regions 4-3
4-2. DC Accuracy Test 4-4
4-3. AC/E>C Thermal Transfer Measurement
(Alternate Frequency Response Test). . . .4-6
4-4. DC Accuracy Test 4-11
4-5. AC/DC Thermal Transfer Measurement
(Alternate Frequency Response Test). ..4-13
4-6. DC Common-Mc^e Rejection Test 4-18
4-
7. AC Common-Mode Rejection Test 4-18
5-
1. 100 Volt Zero Adjustment 5-1
5-2. 1Volt Zero Adjustment 5-2
8-1. Function Block Diagram 8-1
8-2. Simplified Input Switching Diagram 8-2
8-3. Operational Attenuator Diagram 8-3
8-4. Basic Voltmeter Diagram 8-3
8-5. Simplified Auto-Cal Switching Schematic. .8-3
8-6. 10 Vdc Input Offset Error measurement. ..8-4
8-7. 1Vdc Input Offset Error Measurement. . . .8-4
8-8. .1 Vdc Input Offset Error Measurement. ..8-5
8-9. 100 Vdc and 100 Vdc Input Offset
Error Measurement 8-6
8-10. 10 Vdc Gain Error Measurement 8-6
8-11. .1 Vdc and 1Vdc Gain Error
Measurement 8-7
8-12. 1Vdc Reference Offset Error
Measurement 8-7
8-13. 100 Vdc and 1000 Vdc Gain Error
Measurement 8-8
8-14. 100 Vdc Reference Offset Error
Measurement 8-8
8-15. Basic Ohms Measurement Diagram 8-9
8-16. 10 kO. 100 kft, 10 MO Offset Error
Measurement 8-9
8-17. Ohms Reference Measurement 8-10 8-10
8-18. Simplified A/D Convertor Diagram 8-10
8-19. Simplified True RMS Convertor 8-11
8-20. Simplified Average Responding AC
Convertor 8-12
8-21. Ohms Convertor Current Source 8-13
8-22. Ohms Convertor Voltage Limit 8-14
8-23. Equivalent DC Preamplifier Output
Circuit 8-15
8-24. DC Preamp, Simplifier Feedback
Circuitry 8-15
8-25. Simplified Voltage Reference Diagram. . . .8-16
8-26. Integrator Output Waveform 8-16
8-27. Integrator Output Waveforms for
Different Input Voltage Levels 8-17
8-28. Simplified A/D Input and Reference
Diagram 8-17
8-29. Simplified A/D Convertor Diagram 8-18
8-30. Simplified Inguard Controller
Flowchart 8-19
8-31. Controller Data Transfer Circuit 8-19
8-32. Data Transfer Signals 8-20
8-33. Inguard Controller Reset Circuit 8-20
8-34. Simplified A/D Convertor Control Circuit8-21
8-35. Simplified Program ROM Circuit 8-22
8-36. Simplified Output Circuit 8-23
8-37. Simplified Main Controller Flowchart. ...8-24
8-38. Main Controller ROM Circuit 8-25
8-39. Main Controller RAM Circuit 8-26
8-40. Main Controller ALU Circuit 8-27
8-41. Main Controller Interrupt Circuit 8-28
8-42. Simplified Turn-On Interrupt Circuit 8-29
vi

LIST OF ILLUSTRATIONS (Cont'd)
8-43. Interface Connections and Bus Structure. .8-30
8-44. Simplified Block Diagram 8-3S
8-45. Inguard-Outguard Connections 8-37
8-B-l. Auto-Cal Constant #11 (10 VOffset) 8-44
8-B-2. Auto-Cal Constant #10 (10 VGain) 8-44
8-B-3. Auto-Cal Constant #9 (10 K. 100 K.
and 10 MOffsets) 8-45
8-B-4. Auto-Cal Constant #8 (10 K, 100 K.
and 10 MOffsets) 8-45
8-B-5. Auto-Cal Constant #7(100 VOffset #2). ..8-46
8-B-6. Auto-Cal Constant #6 (1000 VOffset) 8-46
8-B-7. Auto-Cal Constant #5 (100 VGain) 8-47
8-B-8. Auto-Cal Constant #4 (100 VOffset #1). ..8-47
8-B-9. Auto-Cal Constant #3 (.1 VOffset) 8-48
8-B-lO. Auto-Cal Constant #2 (1 VOffset I) 8-48
8-B-ll. Auto-Cal Constant#! (IV Offset <2)....8-49
8-B-I2. Auto-Cal Constant #0(1 VGain) 8-49
8-E-1. A/D Waveforms 8-68
8-H-l. Assemble and Test Point Loading 8-79
8-H-2. General Troubleshooting Procedure
Diagram 8-79
8-H-3. Inguard Troubleshooting Procedure
Diagram, Auto-Cal Circuitry
TEST 13 8-83/8-84
8-H-4. Inguard Troubleshooting Procedure
Diagram, Auto-Cal Circuitry
TEST 12 8-85/8-86
8-H-5. Inguard Troubleshooting Procedure
Diagram Auto-Cal Circuitry
TEST II 8-87/8-88
8-H-6. Inguart Troubleshooting Procedure
Diagram, Auto-Cal Circuitry
TEST 10 8-89/8-90
8-H-7. Inguart Troubleshooting Procedure
Diagram, Auto-Cal Circuitry
TEST 98-91/8-92
8-H-8. Inguart Troubleshooting Procedure
Diagram, Auto-Cal Circuitry
TEST 88-93/8-94
8-H-9. Inguart Troubleshooting Procedure
Diagram. Auto-Cal Circuitry
TEST 78-95/8-96
8-H-lO. Inguard Troubleshooting Procedure
Diagram, Auto-Cal Circuitry
TEST 68-97/8-98
8-H-l 1. Inguard Troubleshooting Procedure
Diagram, Auto-Cal Circuitry
TEST 58-99/8-100
8-H-12. Inguard Troubleshooting Procedure
Diagram, Auto-Cal Circuitry
TEST 48-101/8-102
8-H-13. Inguard Troubleshooting Procedure
Diagram, Auto-Cal Circuitry
TEST 3.
8-H-14. Inguard Troubleshooting Procedure
Diagram, Auto-Cal Circuitry
TEST 28-I05/8-I06
8-H-15. Inguard Troubleshooting Procedure
Diagram. Auto-Cal Circuitry
TEST 18-107/8-108
8-H-I6. Inguard Troubleshooting Procedure
Diagram, Auto-Cal Circuitry
TEST 08-109/8-110
8-H-17. Inguard Troubleshooting Procedure
Diagram, Inguard/Outguard Transfer
Circuitry 8-111/8-112
8-H-18. Inguard Troubleshooting Procedure
Diagram, Power Supply and
Controller Circuitry 8-113/8-114
8-H-19. Inguard Troubleshooting Procedure
Diagram. A-to-D Convertor
Circuitry 8-115/8-116
8-H-20. Preliminary Outguard Troubleshooting
Procedure Diagram 8-119/8-120
8-H-21. Outguard Troubleshooting Procedure
Diagram, Main Controller
Circuitry 8-121/8-122
8-H-22. Outguard Troubleshooting Procedure
Diagram, RAM Circuitry 8-123/8-124
8-H-23. Outguard Troubleshooting Procedure
Diagram, ALU Circuitry 8-125/8-126
8-H-24. Outguard Troubleshooting Procedure
Diagram, Device Select
Circuitry 8-127/8-128
8-H-25. Outguard Troubleshooting Procedure
Diagram, Interrupt Circuitry. ..8-129/8-130
8-H-26. Outguard Troubleshooting Procedure
Diagram, Display Circuitry 8-131/8-132
8-H-27. Outguard Troubleshooting Procedure
Diagram, HP-IB Circuitry 8-133/8-134
8-H-28. Detailed Block Diagram 8-135
8-H-29. Input and Auto-Cal Switching
Schematic 8-147/8-148
8-H-30. Average Responding AC Convertor
8-149/8-150
8-H-31. True RMS AC Convertor
Schematic 8-151/8-152
8-H-32. Ohms Convertor Schematic 8-153/8-154
8-H-33. Reference Assembly 8-157/8-158
8-H-34. Analog-to-Digital Convertor
Schematic 8-159/8-160
8-H-35. Inguard Controller Schematic 8-161
8-H-36. Main Controller Schematic 8-167/8-168
8-H-37. HP-IB Schematic 8-169/8-170
8-H-38. Front Panel Assembly 8-171/8-172
8-H-39. Power Supply Schematic 8-173/8-174
vii
8-103/8-104

TJS% HEWLETT
PACKARD
SAFETY SUMMARY
TIm failnviRQ Rtittral Mfaty pracMtiMt mutt ba abaarvad during all phaaaa af aparatian, aarvica. and rapair af thia
initrumant Failara ta camply with thasa praeaatiaaa ar with tpacrfic warnings alsawhara in this manual violatas
safaty standards af dasign, manafsetara, and intandad usa of tha instruawnt Hawlatt Packard Company assumas no
liability for tha customar's failara ta comply with thasa raqairamants. This is aSafaty Clau 1instramant
GROUND THE INSTRUMENT
To minimize shock hazard, the instrument chassis and cabinet must be connected to an elec-
trical ground. The instrument is equipped with athree-conductor ac power cable. The power
cable must either be plugged into an approved three-contact electrical outlet or used with a
three-contact to two-contact adapter with the grounding wire (green) firmiy connected to an
electrical ground (safety ground) at the power outlet. The power jack and mating plug of the
power cable meet International Electrotechnical Commission (lEC) safety standards.
00 NOT OPERATE IN AN EXPLOSIVE ATMOSPHERE
Do not operate the instrument in the presence of flammable gases or fumes. Operation of any
electrical instrument in such an environment constitutes adefinite safety hazard.
KEEP AWAY FROM LIVE CIRCUITS
Operating personnel must not remove instrument covers. Component replacement and internal
adjustments must be made by qualified maintenance personnel. Do not replace components
with power cable connected. Under certain conditions, dangerous voltages may exist even with
the power cable removed. To avoid injuries, always disconnect power and discharge circuits
before touching them.
DO NOT SERVICE OR ADJUST ALONE
Do not attempt internal service or adjustment unless another person, capable of rendering first
aid and resuscitation, is present.
DO NOT SUBSTITUTE PARTS OR MODIFY INSTRUMENT
Because of the danger of introducing additional hazards, do not install substitute parts or per-
form any unauthorized modification to the instrument. Return the instrument to aHewlett-
Packard Sales and Service Office for service and repair to ensure that safety features are main-
tained.
DANGEROUS PROCEDURE WARNINGS
Warnings, such as the example below, precede potentially dangerous procedures throughout
this manual. Instructions contained in the warnings must be followed.
Dangerous voltages, capable of causing death, ore present in this instrument Use ai-
trome caution whoa handling, testing, end adjusting.
A

SAFETY SYMBOLS
General Definitions of Safety Symbols Used On Equipment or In Manuals.
iOR
77*7 X
Instruction manual symbol: the product will be marked with this
symbol when it is necessary for the user to refer to the instruction
manual in order to protect against damage to the instrument.
Indicates dangerous voltage (terminals fed from the interior by
voltage exceeding 1000 volts must be so marked).
Protective conductor terminal. For protection against electrical
shock in case of afault. Used with field wiring terminals to in-
dicate the terminal which must be connected to ground before
opierating equipment.
Low-noise or noiseless, clean ground (earth) terminal. Used for a
signal common, as well as providing protection against electrical
shock in case of afault. Aterminal marked with this symbol must
be connected to ground in the manner described in the installation
(opierating) manual, and before operating the equipment.
Frame or chassis terminal. Aconnection to the frame (chassis) of
the equipment which normally includes all exposed metal struc-
tures.
Alternating current (power line).
Direct current (power line).
Alternating or direct current (power line).
WARNING 1
t
1
t
^caution}
The WARNING sign denotes ahazard. It calls attention to apro-
cedure, practice, condition or the like, which, if not correctly per-
formed or adhered to. could result in injury or death to personnel.
The CAUTION sign denotes ahazard. It calls attention to an
operating procedure, practice, condition or the like, which,if not
correctly performed or adhered to. could result in damage to or
destruction of part or all of the product.
NOTE: The NOTE sign denotes important information. It calls attention
to procedure, practice, condition or the like, which is essential to
highlight.