Agilent Technologies 4338B User manual

Agilent 4338B Milliohmmeter
Service Manual
SERIAL NUMBERS
This manual applies directly to instruments with serial number prex JP1KD
.
F
or additional important information about serial numbers, read
\Instruments Covered by This Manual" in Chapter 1of
this manual.
Agilent Part No. 04338-90033
Printed in JAPAN March 2001

Notice
The information contained in this document is subject to change without notice
.
This document contains proprietary information that is protected by copyright. All rights are
reserved. No part of this document may be photocopied, reproduced, or translated to another
language without the prior written consent of the Agilent T
echnologies.
Agilent T
echnologies Japan, Ltd.
Component T
est PGU-Kobe
1-3-2, Murotani, Nishi-ku, Kobe-shi,
Hyogo
,651-2241 Japan
c
 Copyright Agilent Technologies Japan, Ltd. 1996, 2000, 2001

Manual Printing History
A
ugust 1996
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: First Edition (part number: 04338-90033)
June 2000
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::
: Second Edition (part number: 04338-90033)
March 2001
::::::::::: :: :: :: ::::
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Third Edition (part number: 04338-90033)
iii

Safety Summary
The following general safety precautions must be observed during all phases of operation,
service
,and repair of this instrument. F
ailure to comply with these precautions or with specic
W
ARNINGS
elsewhere in this manual may impair the protection provided by the equipment.
In addition it violates safety standards of design, manufacture, and intended use of the
instrument.
The A
gilent T
echnologies assumes no liability for the customer's failure to comply with these
requirements
.
Note
4338B complies with INST
ALLA
TION CA
TEGORY II and POLLUTION DEGREE 2
in IEC1010-1. 4338B is INDOOR USE product.
Ground The Instrument
T
oavoid electric shock hazard, the instrument chassis and cabinet must be connected to a
safety earth ground by the supplied power cable with earth blade
.
DO NOT Operate In An Explosive Atmosphere
Do not operate the instrument in the presence of ammable gasses or fumes
.Operation of any
electrical instrument in such an environment constitutes adenite safety hazard.
K
eep Away From Live Circuits
Operating personnel must not remove instrument covers
.Component replacement and internal
adjustments must be made by qualied maintenance personnel. Do not replace components
with the power cable connected. Under certain conditions
,dangerous voltages may exist even
with the power cable removed. T
oavoid injuries
,always disconnect power and discharge
circuits before touching them.
DO NOT Service Or A
djust Alone
Do not attempt internal service or adjustment unless another person, capable of rendering rst
aid and resuscitation, is present.
DO NOT Substitute P
arts Or Modify Instrument
Because of the danger of introducing additional hazards
, do not install substitute parts or
perform unauthorized modications to the instrument. Return the instrument to a Agilent
Technologies Sales and Service Oce for service and repair to ensure that safety features are
maintained.
Dangerous Procedure W
arnings
Warnings , such as the example below
, precede potentially dangerous procedures throughout
this manual. Instructions contained in the warnings must be followed.
Warning
Dangerous voltages, capable of causing death, are present in this
instrument. Use extreme caution when handling, testing, and adjusting
this instrument.
iv

Certication
Agilent T
echnologies certies that this product met its published specications at the time
of shipment from the factory
.Agilent T
echnologies further certies that its calibration
measurements are traceable to the United States National Institute of Standards and
T
echnology
,to the extent allowed by the Institution's calibration facility
,or
to the calibration
facilities of other International Standards Organization members.
W
arranty
This Agilent T
echnologies instrument product is warranted against defects in material and
workmanship for aperiod of one year from the date of shipment, except that in the case of
certain components listed in
General Information
of this manual, the warranty shall be for the
specied period. During the warranty period, Agilent Technologies Company will, at its option,
either repair or replace products that prove to be defective
.
F
or warranty service or repair
,this product must be returned to aservice facility designated by
Agilent Technologies
. Buyer shall prepay shipping charges to Agilent T
echnologies and Agilent
T
echnologies shall pay shipping charges to return the product to Buyer
.However
,Buyer shall
pay all shipping charges
,duties
,and taxes for products returned to Agilent T
echnologies from
another country
.
Agilent T
echnologies warrants that its software and rmware designated by Agilent
T
echnologies for use with an instrument will execute its programming instruction when
property installed on that instrument. Agilent T
echnologies does not warrant that the operation
of the instrument, or software
,or rmware will be uninterrupted or error free
.
Limitation Of W
arranty
The foregoing warranty shall not apply to defects resulting from improper or inadequate
maintenance by Buyer
,Buyer-supplied software or interfacing, unauthorized modication or
misuse
,operation outside the environmental specications for the product, or improper site
preparation or maintenance
.
No other warranty is expressed or implied. A
gilent T
echnologies specically disclaims the
implied warranties of merchantability and tness for aparticular purpose
.
v

Exclusive Remedies
The remedies provided herein are buyer's sole and exclusive remedies
.A
gilent T
echnologies
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 agreements are available for
Agilent T
echnologies products
.
F
or any assistance
,contact your nearest Agilent Technologies Sales and Service Oce
.
A
ddresses are provided at the back of this manual.
vi

Safety Symbols
General denitions of safety symbols used on equipment or in manuals are listed below
.
Instruction manual symbol: the product is marked with this symbol when it is
necessary for the user to refer to the instruction manual.
Alternating current.
Direct current.
On (Supply).
O (Supply).
Frame or chassis terminal
This
W
arning
sign denotes ahazard. It calls attention to a procedure
,practice
,
condition or the like
,which, if not correctly performed or adhered to
,could
result in injury or death to personnel.
This
Caution sign denotes a hazard. It calls attention to aprocedure
,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
denotes important information. It calls attention to aprocedure
,
practice
,condition or the like
,which is essential to highlight.
vii

Documentation Map
Operation Manual
Operation Manual (Agilent P
art Number: 04338-90030 for English edition, 04338-97030 for
Japanese edition) explains specications
,basic measurement explanations
,andhow to verify
conformance to published specications
.
Service Manual
Service Manual (Agilent P
art Number: 04338-90043) explains how to adjust, troubleshoot, and
repair the 4338B.
How T
oUse This Manual
This is the Service Manual for the 4338B Milliohmmeter
.This manual contains adjustments and
repair information, and consists of the following four chapters
.
Chapter 1General Information
Chapter 1gives general information for servicing the 4338B .This chapter lists the
recommended equipment for adjustments and troubleshooting.
Chapter 2A
djustments
Chapter 2describes the adjustments
,required to ensure that the 4338B is within its published
specications after it has been repaired, or it fails the performance tests
.
Chapter 3Assembly Replacement
Chapter 3provides the information on replacing the 4338B assemblies. The information
includes replaceable assembly lists
,and removal and installation procedures.
Chapter 4Troubleshooting
Chapter 4provides the information on troubleshooting the 4338B.The information includes
theory of operation and information on faulty assembly isolation.
Appendix A Manual Changes
Appendix A contains manual changes and provides information for using this manual with
4338Bs manufactured before the printing date of the manual.
Appendix B Default Jumper and Switch Settings
Appendix B describes the settings of the jumpers and switches on the 4338B A2 CPU Board
Assembly. The information is required when the A2 assembly is replaced.
viii

Contents
1. General Information
Introduction ....................
..
..
.........1-1
Instruments Covered by This Manual ................
..
..
. 1-1
Required Equipment ...................
..
..
..
....1-2
2. A
djustment
Introduction ................
..
..
..
...........2-1
Safety Consideration ................. .. .. .......2-1
Required Equipment .................
..
..........2-1
A
djustment T
ools .....................
.........2-2
Adjustable Components . .......................
..
. 2-2
F
actory-Selected Components ................
..
..
.....2-2
EEPROM Write Protect Switch ...............
..
..
..
...2-2
Related A
djustment .................... .........2-2
A
djustment Program ..................
..
.........2-3
Program Installation ..................... .......2-4
Making aW
orking Copy .........................2-4
Program Execution .............
...............2-4
A
djustment Procedure References ............
..........2-5
Resistance Measurement A
djustment .............
.......2-5
Equipment ...............................2-5
Setup .................. ................2-5
3. Assembly Replacement
Introduction ......
..
..
..
..................... 3-1
Ordering Information .......
..
..
.................3-1
Restored Exchange Assemblies ........ ..
..............3-1
Replacing the A2 CPU Board Assembly . ................... 3-2
Replaceable Assembly List ..
..
..................... . 3-2
Replaceable Mechanical P
arts List ..
..
..
............... .. 3-5
Disassembly Procedures .........
............
......3-9
Tools and F
asteners ............. .. .. .. .. .. .. .. . 3-9
Cover Removal .. .. .. .. .. .. .. .. .. .. .......... 3-9
A1 Main Board Removal ....................
...... 3-10
Removal Procedure ...... .. .. .. .. .. .. .. .. . .. .. 3-10
A2 CPU Board Assembly Removal ..................... 3-10
Removal Procedure .... .. .. .. .. .. .. .. .. .. . .... 3-10
A5 A
C Inlet Board Assembly Removal . . . . ................ 3-10
Removal Procedure ...... .. .. .. .. .. .. .. .. . .. .. 3-10
Keyboard Assembly Removal . . . . . . . . . . . . . . . . . . . . . . . . 3-11
Removal Procedure ...... .. .. .. .. .. .. .. .. . .. .. 3-11
LCD Assembly Removal ... .. .. .. .. . .. .. .. .. .. .. .. 3-11
Removal Procedure ...... .. .. .. .. .. .. .. .. . .. .. 3-11
BNC Connector Removal . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
Removal Procedure ...... .. .. .. .. .. .. .. .. . .. .. 3-11
Contents-1

4. Troubleshooting
Introduction ..
.............
..
..
..
..
..
..
......4-1
Safety Considerations . .............
..
..
..
..
..
..
.4-1
Required Equipment . ............... .. .. .. .. .. ...4-1
After Service Product Safety Checks .............
..
..
..
.. 4-2
Theory of Operation ...............
..
..
..
..
..
....4-3
Overall Measurement Theory .............
..
..
..
.....4-3
Overall Block Diagram ............... .. .. ........4-4
Analog Section .................. .. ..........4-5
Signal Source Section ...............
..
..
.......4-6
Range Resistor and Current Sense Amplier Sections ...........
. 4-7
V
oltage Sense Amplier and Process Amplier Sections ......
..
.. 4-8
Digital Section ............
..
..
..
.............4-9
P
ower Supply Section ..........
..
..
..
...........4-10
Troubleshooting .............
..
..
..
............4-11
Check Procedure References ............. .. .. .......4-13
Check 1, DC-DC Converter Output V
oltage .......
..
..
..
...4-13
Check 2, LCD Displays Anything? .......
..
............4-14
Check 3, LCD Operates Correctly? ....................4-14
Check 4, Any Error Message on LCD? ...................4-14
Check 5, CPU Related Error Message? .......
..
..
........4-14
Check 6, CPU P
ower LED Lights? ......
..
..
..
.........4-14
Check 7, Any Error Code on LED? ..
..................4-15
Check 8, CPU Fuse High Lead V
oltage . ..................4-16
Check 9, Fuse and Line Switch . .. ...................4-16
Check 10, DC-DC Converter Input V
oltage .................4-17
Check 11, DC-DC Converter Open Output V
oltages . ............4-18
Check 12, Transformer Secondary V
oltage .................4-19
A. Manual Changes
Introduction ..
..
.......................
..
....A
-1
Manual Changes . ..
......................... ...A
-1
B
.Default Jumper and Switch Settings
Introduction ...................
..
..
..........B-1
Jumper and Switch Settings .................. .. .....B-1
Index
Contents-2

Figures
1-1. Serial Number Label ...................
..
..
.....1-1
2-1. A
djustment Program Flow ..................
..
..
...2-3
2-2. Range Resistor A
djustment Setup ................... .. .2-5
3-1. Cover Removal . ................... .. .. .. ....3-9
4-1. V
oltage Current Ratio Measurement Principle ................ 4-3
4-2. 4338B Overall Block Diagram ................ .. .. ....4-4
4-3. Analog Section Block Diagram ..............
..
..
..
...4-5
4-4. Signal Source Section Block Diagram .............
..
..
..
.4-6
4-5. Range Resistor and Current Sense Amp
.Block Diagram ........... 4-7
4-6. V
oltage Sense Amp
.and Process Amp
.Block Diagram ............4-8
4-7. Digital Section Block Diagram .......................4-9
4-8. P
ower Supply Section Block Diagram .................. .. 4-10
4-9. Troubleshooting Flow .................... .. ..
..
.4-12
4-10. DC-DC Converter Output V
oltage Check ...................4-13
4-11. CPU Board Assembly LED Light Sequence .................. 4-15
4-12. Location of High Lead of A2F1 Fuse .................
..
.4-16
4-13. T
est Pin Locations ..............
...............4-17
4-14. DC-DC Converter Output Connector ..............
......4-18
4-15. Transformer Secondary V
oltage Check ..............
.....4-19
B-1. Jumper and Switch Settings ................
........B-1
Tables
1-1. Required Equipment ..........
..
..
..............1-2
1-2. Required Language Extensions ........... .. .. ........1-2
2-1. Related A
djustment ........... .. .. .............2-2
3-1. Replaceable Major Assembly List ......
..
..
..
...... ....3-3
3-2. A2 CPU Board Assembly
,Replaceable Assembly List ............. 3-4
3-3. Replaceable Assembly List .. .. .. .. ................. 3-4
3-4. Replaceable Mechanical P
arts List 1 . . . . . . . . . . . . . . . .... .. 3-5
3-5. Replaceable Mechanical P
arts List 2 . . . . . . . . . . . . . . . . ..... 3-6
3-6. Replaceable Mechanical P
arts List 3 . . . . . . . . . . . . . . . . . .. .. 3-7
3-7. Replaceable Mechanical P
arts List 4 . . . . . . . . . . . . . . . . . . ... 3-8
4-1. DC-DC Converter Output V
oltage(Connected) .... .. .. .. .. .. .. 4-13
4-2. DC-DC Converter Open Output V
oltages . . . .. .. .. .. .. .. .. .. 4-18
A-1. Manual Changes by Serial Number ....
... . .. .. .. .. .. .. . A-1
Contents-3

1
General Information
Introduction
This chapter provides information on instruments covered by this manual and required
equipment for the adjustment and troubleshooting.
Instruments Covered by This Manual
Agilent T
echnologies uses atwo-section, nine character serial number which is printed on
the serial number label (Figure 1-1)attached to the instrument's rear panel. The rst ve
characters are the serial prex, and the last ve digits are the sux.
Figure 1-1. Serial Number Label
An instrument manufactured after the printing date of this manual may have a serial
number prex that is not listed on the title page
.This unlisted serial number prex indicates
the instrument is dierent from those described in this manual. The manual for this new
instrument may be accompanied by ayellow Manual Changes supplement or have adierent
manual part number
.This sheet contains \change information" that explains how to adapt the
manual to the newer instrument.
In addition to change information, the supplement may contain information for correcting
errors (Errata) in the manual. T
o keep this manual as current and accurate as possible
, Agilent
Technologies recommends that you periodically request the latest Manual Changes supplement.
The supplement for this manual is identied by this manual's printing date and its part number
,
both of which appear on the manual's title page
. Complimentary copies of the supplement are
available from Agilent T
echnologies. If the serial prex or number of an instrument is lower
than that on the title page of this manual, see
Appendix A, Manual Changes
.F
or information
concerning, a serial number prex that is not listed on the title page or in the Manual Change
supplement, contact the nearest Agilent Technologies oce.
General Information 1-1

Required Equipment
T
able 1-1 lists the required equipment for adjusting and troubleshooting the 4338B . Table 1-2
lists the required language extensions to be used with the adjustment program.
T
able 1-1. Required Equipment
Equipment Requirements Recommended Model Qty
.Use
Multimeter DC VA
ccuracy:
<
1% 3458A 1 T
1
Standard Resistors No Substitute 42030A 1 A
2
Open T
ermination No Substitute 42090A
3
1 A
Short T
ermination No Substitute 42091A
3
1 A
Computer No Substitute HP 9000 series 200 or 300
4
RAM

4M bytes
1 A
Operating System B
ASIC 5.1 or higher 98616A 1 A
A
djustment Program No substitute Agilent PN 04338-65005 1 A
1
Troubleshooting
2
A
djustment
3
This model is also included in the 42100A, F
our T
erminal P
air Resistor Set
4
Excluding the 9826A
T
able 1-2. Required Language Extensions
Name V
er
.
CLOCK 5.0
COMPLEX 5.1
CRT
A5.1
CRTX 5.1
Name V
er
.
CS80 5.0
1
EDIT 5.1
ERR 5.1
FGPIB 5.0
Name V
er
.
GRAPH 5.2
GRAPHX 5.2
GPIB 5.0
IO 5.1
Name V
er
.
KBD 5.1
MA
T5.1
MS 5.1
PDEV 5.0
1
This language extension depends on the mass storage type used.
1-2 General Information

2
A
djustment
Introduction
This chapter describes the adjustment required to ensure the 4338B is within its published
specications after it has been repaired. The adjustment should be performed along
with periodic maintenance to keep the 4338B in optimum operating condition. If proper
performance cannot be achieved after adjustment, proceed to Chapter 4.
Note
T
oensure proper results and correct instrument operation, a30 minute
warm-up and stabilization is required before performing the adjustment.
Safety Consideration
This chapter contains
NO
TE
s
,
CA
UTION s
,and
W
ARNING
swhich must be followed to ensure
operator safety and to maintain the instrument in asafe and serviceable condition. The
adjustment covered in this chapter should be performed only by aqualied person who is
aware of the hazards
.
W
arning
Any interruption of the protective ground conductor (inside or outside
the instrument) or disconnection of the protective ground terminal can
make the instrument dangerous
.Intentional interruption of the protective
ground system for any reason is prohibited.
Required Equipment
T
able 1-1 lists the equipment required to perform the adjustment. Use only calibrated
standards when adjusting the 4338B .
Adjustment 2-1

Adjustment Tools
No hand tools are required for the adjustment.
A
djustable Components
There are no adjustable components
,such as variable capacitors or variable resistors
,in the
4338B.A
djustment is performed by updating the adjustment data stored in the EEPROM.
Factory-Selected Components
No factory-selected components are used in the 4338B
EEPROM W
rite Protect Switch
There are no EEPROM write protect switches in the 4338B.
Related A
djustment
There is only one adjustment for the 4338B.T
able 2-1 lists the adjustment that must be
performed if an assembly has been replaced.
T
able 2-1. Related A
djustment
Assembly Replaced Required A
djustment
A1 Main Board Assy Resistance Measurement A
djustment
A2 CPU Board Assy without ROM None
1
A5 A
CInlet Board Assy None
LCD Assembly None
DC-DC Converter Unit None
Keyboard Assembly None
1
If the EEPROM, A2U1, is replaced, the Resistance Measurement A
djustment is required.
2-2 Adjustment

Adjustment Program
The adjustment program listed in T
able 1-1 is required for the adjustment. Using the program,
the computer controls the 4338B to obtain the adjustment data, and stores the data in the
4338B internal EEPROM, A2U1.
The adjustment program runs on the computer listed in T
able 1-1 .The
program should be
installed into your computer according to the procedure described in \Program Installation
". T
o
start the program after it has been installed, refer to \Program Execution
".
Figure 2-1 shows the adjustment program ow.The following lists the brief explanation for
each menu item.
Figure 2-1. A
djustment Program Flow
INITIAL SETUP denes the standards' calibration values
. Update the standard's calibration
values if necessary
.
Resistance
Measurement
A
djustment
obtains the data to adjust the actual measurement resistance to the
standards' value
,and writes the data both to the 4338B internal EEPROM
and to the unit-serial-number dependent le on the disk. This adjustment
should be performed if the Impedance Measurement A
ccuracy performance
test fails
.
Rewrite EEPROM writes the adjustment data, which is stored in the unit-serial-number
dependent le
, to the EEPROM.
Note
Make sure that the correct line frequency (50 or 60Hz) has been selected in the
\UUT: 4338B" window preceding the Main Menu. This selection will improve
the adjustment data accuracy.
Adjustment 2-3

Program Installation
The adjustment program must be installed in the computer using the following procedures.
Making aW
orking Copy
Copy the content of the adjustment program disk to a working disk or to the harddisk to
prevent the program le from accidental deletion or destruction. Use the working disk or
harddisk and store the original disk in asafe place
.
Program Execution
P
erform the following steps to start the adjustment program.
Note
Install the program prior to execution. Refer to \Program Installation
".
1. Turn on the computer and bring up the BASIC system. Refer to the T
able 1-2 for the
required language extensions
.
2. Set the Mass Storage Unit Specier to the drive/directory where the adjustment program
exists using the
MSI
command.
3. Load the program, \
ADJ4338B
"by pressing
LOAD "ADJ4338B"
4
Return
5
(or
4
Enter
5
).
4. Execute the program by pressing
RUN
.
Note
In the program, the 4338B is referred as \UUT".
Note
If the adjustment being performed follows right after EEPROM replacement,
change switch A2SW1-1 to \CLOSE", so that the 4338B will ignore the self test
errors at power-on. (Return the switch to \OPEN" when the adjustment has
been completed.) Refer to Figure B-1 for the switch location.
2-4 Adjustment

Adjustment Procedure References
This section provides supplemental information for the adjustment which is performed by the
program. Connection instructions and some additional explanations are provided. Use this
chapter as areference when performing the adjustment.
Resistance Measurement A
djustment
This adjustment updates the data to adjust the measurement resistance to the standard values
.
Equipment
Standard Resistors 42030A
Open T
ermination 42090A
Short T
ermination 42091A
Setup
This setup obtains the range resistor adjustment data and the process amplier attenuator
adjustment data.
Figure 2-2. Range Resistor A
djustment Setup
Perform the following steps as the program instructs
.
1. Connect the specied termination or standard resistor directly to the 4338B UNKNOWN
Connectors.
2. Repeat step 1 as instructed.
Adjustment 2-5