HP 4328A Service manual

OPERATir
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Return this manual to Kobe
Agilent Technologies International, Inc.
1-3-2 Murotani Nishiku Kobe Japan, 651-2241
Attention:
Ayumi Sakamoto
TEL:[phone]
MILLIOHMMETER
4328A
I 30 LINE
IQO 'ON OFF 'FAST
11
,~HAfiG£1,
'·.~'
HEWLETT
PACKARD

SAFETY SUMMARY
T~e following general safety precautions must be observed during all phases of op-
eration, service, and repair of this instrument. Failure to comply with these pre-
cautions or with specific warnings given elsewhere in this manual violates safety
standards of design, manufacture, and intended use of the instrument. Hewlett-
Packard Company e.ssumes no liability for the customer's failure to comply with
these requirements.
GROUND THE INSTRUMENT
To minimize shock hazard, the instrument chassis and cabinet must be connected to
an electrical ground. The instrument is equipped with a three-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) firmly connected to an electrical ground (safety ground) at
the power outlet. The power jack and the mating plug of the power cable meet
International Electrotechnical Commission (IEC) safety standards.
DO NOT OPERATE IN AN EXPLOSlVE ATMOSPHERE
Do not operate the instrument in the presence of flammable gases or fumes. Op-
eration of any electrical instrument in such an environment constitutes a definite
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, dan-
gerous 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 perform any unauthorized modification to the instrument. Return the in-
strument to a Hewlett-Packard Sales and Service Office for service and repair to
ensure that safety features are maintained.
DANGEROUS PROCEDURE WARNINGS
Warnings, such as the
throughout this manual.
example below, precede potentially dangerous procedures
Instructions contained in the warnings must be followed.
WARNING
Dangerous voltages, capable of causing death, are present in this instru-
ment. Use extreme caution when handling, testing, and adjusting.
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SAFETY SYMBOLS
General Definitions of Safety Symbols Used On Equipment or In Manuals.
~
~
..l...
oR@
-
~
rh OR .L
WARNING
CAUTION
Note
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 ex:ceeding 1000 volts must be so marked).
Protective conductor terminal. For protection against electri-
cal shock in case of a fault. Used with field wiring terminals
to indicate the terminal which must be connected to ground
before operating e4uipment.
Low-noise or noiseless, clean ground (earth) terminal. Used for
a signal common, as well as providing protection against elec-
trical shock in case of fault. A terminal marked with this
symbol must be connected to ground in the manner described
in the installation (operating) manual, and before operating the
equipment.
Frame or chassis terminal. A connection to the frame (chas-
sis) of the equipment which normally includes all exposed metal
structures.
Alternating current (power line).
Direct current (power line).
Alternating or direct current (power line).
A WARNING
denotes a hazard. It calls attention to a pro-
cedure, practice, condition or the like, which, if not correctly
performed or adhered to, could result in injury or death to
personnel.
The CAUTION sign denotes a hazard. 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.
A Note denotes important information. It calls attention to a
procedure, practice, condition or the like, which is essential to
highlight.
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I 1111
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Herstellerbescheinigung
Hiermit wird bescheinigt, daB das Geriit HP 4328A Milliohmmeter in Ubereinstimmung mit
den Bestimmungen von Postverfiigung 1046/84 funkentstort ist.
Der Deutschen Bundespost wurde das Inverkehrbringen dieses Gerates angezeigt und die
Berechtigung zur Uberpriifung der Serie auf Einhaltung der Bestimmungen eingeraumt.
Anm: Werden Mef3- und Testgedite mit ungeschiunten Kabeln und/oder in offenen
Me6aufbauten verwendet, so ist vom Bet rei her slcherzustellen, daB die Funk-
Entstorbestimmungen unter Betriebsbedingungen an seiner Grundstiicksgrenze eingehalten
werden.
GERAUSCHEMISSlON
Lpa < 70 dB
am Arbeitsplatz
normaler Betrieb
nach DIN 45635 T. 19
Manufacturer's Declaration
This is to certify that this product, the HP 4328A Milliohmmeter, meets the radio frequency
interference requirements of directive 1046/84. The German Bundespost has been notified
that this equipment was put into circulation and was granted the Iight to check the product
type for compliance with these requirements.
Note: If test and measurement equipment is operated with unshielded cables and/or used for
measurements on open set-ups, the user must insme that under these operating conditions,
the radio frequency interference limits are met at the border of his premises.
ACOUSTIC NOlSE EMISSION
Lpa < 70 dB
operator position
normal operation
per ISO 7779

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MANUAL
CHANGES
HP 4328A
MILLIOHMMETER
r-- MANUAL IDENTIFICATION -
Model Number: HP 4328A
Date Printed: MAR.
1989
Part Number: 04328-90008
Thl1 1upr.lomonl eontalno Information for correcting manual erron and for adapting tho manual to nowor lnotNmonle thai oonlaln lmprovomonto
or modH calion• not documented In tho oxletlng manual
fo uM thll •upplemont
1 .. Make all ERRATA correction•
2
.. Mako all appropriate .. rial-number-related change• listed below
SERIAL PREFIX OR NUMBER MAKE MANUAL CHANGES SERIAL PREFIX OR NUMBER MAKE MANUAL
CHANGES
ALL
1
1828J07291 and above 2
1828J07961 and above 3
1828J09594 and above 4
.., New Item
ERRATA
Page 5-7. Figure 5-3,
{900 + j1800) Impedance:
Change the Part Number for the INDUCTOR
to 9100-1686.
.., Page 3-6, Paragraph 3-43, NOTES ON OPERATION:
Add the followmg NOTE to paragraph 3-45 ..
NOTE
An erroneous measurement reading can occur if both leads 1n one probe and the
current lead
only on the other probe makes contact with the device under test.
Under this condition, the meter may mdicate approximately mid scale on any meter
range selected. You can verify i! the measurement readmg 1s correct by checking if
the resistance measurement at two different ranges differ by more than 50 % of the
indicated value.
NOTE
Manual change supplements are revised as often as necesury to keep manuals •• current and accurate •• ponlllle Hewlaii-Packard recommend•
that you periodically reqUII'SI the latest edition of lhls supplement Free copies are avallallle lrom all HP offices. When requullng coploa. quote
the manualldenllllcallon Information rrom your oupplement, or the model number and print dale from the IIIIo page of tho manual .
Oate/Div: MARCH 1 0, 1989/33
Page: 1
of 4
PRINTED IN JAPAN
Flp11HEWLETT
~~PACKARD

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• Page 5-2, Paragraph 5-13, 4328A PERFORMANCE CHECKS:
Add the following NOTE to paragraph 5-14.
NOTE
Before starting the Performance Check for the 4328A Option 001 , confirm that the
battery has enough charge by pressing the BATT. TEST button. If the pointer
of
meter is out of the BAT. CHARGED range on the meter scale, recharge the battery
following the instructions given in Paragraph 3-9. The 4328A Option 001 will not
operate properly, if the battery does not have enough charge.
CHANGE 1
..,. Section 6, Replaceable Parts, Table 6-2, Reference Designation Index:
See Table 1, Parts Information.
CHANGE 2
Section 6, Replaceable Parts, Table 6-2, Reference Designation Index:
See Table 1, Parts Information.
Page 4-7, Figure 4-5 and Page 8-19, Figure 8-17, A2 PHASE-SENSITIVE AMPLIFIER Assy.:
Change the value of R230" to 56k0.
Page 8-21, Figure 8-19:
Change the value
of R3 to 33k0.
Page 8-23, Figure 8-21:
Change the value
of R3 to 33k0.
CHANGE 3
Page 6-8, Table 6-2, Reference Designation Index:
See Table 1, Parts Information.
Page 8-17, Figure 8-14: A3 OSCILLATOR Assy.
Change the value
of R335 to 133kn.
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Page 6-5, Table 6·2, Reference Designation Index:
See Table 1, Parts Information.
Page 4-7, Figure 4-5 and Page 8-19, Figure 8-17, A2 PHASE-SENSITIVE AMPLIFIER Assy.:
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Change the value of R234 to 3.16kn-
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CHANGE
1
2
3
4
PAGE NOTE
6-7
... c
6-11
... c
6-5 D
A
6-11 D
A
D
A
6-8 D
A
6-5 D
A
"': NEW ITEM
A: Added
D: Deleted
C: Change
Table 1. Parts Information
REFERENCE HP
DESIGNATION PART NUMBER
A3Q312 1853-0314
F1
2110-0234
*
A2R230 0698-3161
*
A2R230 0698-5635
DS1
1450-0566
DS1
1450-0613
R3 0683-4735
R3 0683-3335
A3R335 0683-1545
A3R335 0698-3451
*
A2R234 0757-0439
*
A2R234 0757-0279
I
L -4-
DESCRIPTION
TRANSISTOR: SILICON
FUSE SLOW
BLOW 100mAT
R: FXD 38.3k!l 1% 1/8W
R: FXD 56k!l 1% 1/8W
LAMP: INDUCTOR
LAMP: INDUCTOR
R: FXD COMP 471<0 5% .25W
R: FXD COMP 33k0 5% .25W
R: FXD COMP 150k0 5% 1/4W
R: FXD COMP 1331<01% 1/8W
R: FXD 6.811<01% 1/8W
R: FXD 3.16k0 1% 1/8W

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OPERATING
AND
SERVICE
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MODEL 4328A
MILLIOHMMETER
SERIALS 18:.'8J06-t21 AIHJ ABO\/E
See Sect•on VII for Other Serial Prefixes.
"~' COPYRIGHT YOKOGAWA HEWLETT·PACKARD, LTD 1967
9-1, TAKAKURA.CHO, HACHIOJI-SHI, TOKYO, JAPAN
Manual Part No. 04328-90008
Microfiche Part No. 04328-90058
MANUAL
Prmted : MAR 1989
Ff/OW HEWLETT
~~PACKARD

Table o[ Contents
Model 4328A
TABLE OF CONTENTS
Section
Page
I GENERAL INFORMATION . . . . . . . . . 1-1
1-1. Description ...................... 1-1
1-9. Accessories Furnished ........... 1-9
1-11. Instrument Identification . . . . , .... 1-2
1-13. Manual Changes .... , ............. 1-2
U INSTALLATION .... , ...... , ............ 2-1
2-1. Introduction . . . . . . . . . . . . . . . . . . . . . 2-1
2-3. Unpacking and Inspection .. , ..... , 2-1
2-5. Storage and Shipment . . . . . . . . . . . . . 2-1
2-6. Packaging .................... ,. 2-1
2-7. Environment . . _...... 2-1
2-8. Installation , . . . . . . . . . . . . . . . . . . . . 2-1
2-10. Combining Case ...... , 2-1
2-12. Adapter Frame , . . . 2-1
2-14. Power Connection . , . . . . . . . . . . 2-1
2-15. Line Voltage . . . . .. . . . . 2-1
2-16. Power Cable . . . . . .. . . . . 2-1
III OPERATION .................. , . . . 3-1
3-1. Introduction . . . . . . .. . . . . . .. 3-1
3 -4.. Controls, Connectors, and
Indicators . . . . . _. . . . . . . . . . . 3-1
3-6. Battery Operation , .............. 3-1
3-10. Instrument Temperature
Range ...................... 3-1
3-12. Measurement 3-1
3-15. Operating Procedure . . . . . . . . . . . 3-1
3-17. Measuring Voltage on Samples . . . . . 3-1
3-21. Applied Current on Samples and
Ma..ximum Power Dissipation ..... 3-5
3-24. Effect of Series Reactance of
Samples .................... , _. . . 3-5
3-26. DC Bias Superimposed , . . . . . . ... 3-5
3-30. Recorder Output . . . . . . . . . .. . . . . . . 3-5
3-32. Probe Connection . . . . . _........ . 3-5
3-33. General .......... , . . . . . . . . . 3-5
3-35. Probe InstallatiOn . . . . . . . . . . 3-6
3-37. 16005A Clip-Type Probe . . . . . . 3-6
3-39. 16006A Pin-Type Probe . . . .. . . 3-6
3-41. 16007A B Test Leads .... _ .... 3-6
3-43 Notes on Operation .... , . . . 3-6
3-44 In using the 1 and 3m Ohm
Ranges, Connection o[
Current Terminals to the
Sample must be a Firm,
Positive Contact . . . . . .. . . . . . . 3-6
3-46. In using the 1 and 3m Ohm
Range, Large Electrically
Conductive Matedals should
not be placed close to the
Probe or their Cables 3-6
3-48. Changing Test Lead Length . . . . 3-7
IV THEORY OF OPERATION ............. _ 4-1
4-1. Introduction ,. _ ...... ,. . . . . . . . . .. . . 4-1
4-4. Simplified Functional DescriptiOn 4-1
4-7. Oscillator Circuit . , _. . . 4-2
4-10. Schmitt Trigger Cucuit . . . . . . 4-2
ii
Section
Page
IV THEORY OF OPERATION (Cont'd)
4-12. 20mV Peak Limiter . . . . 4-2
4-14. Phase Sensitive Voltmeter. . . . 4-2
V MAINTENANCE ................. , . . . . . . 5-1
5-l. [ntroduction . , ................... 5-1
5-3. Contents . . . . . . . . .. . . . . . . 5-1
5-4. Performance Checks .......... 5-1
5-6. Adjustments ..... _ ........... , 5-1
5-9. Test Equipment ...... , . . . .. . 5-1
5-11. Maintenance .......... ·-······. 5-2
5-13. 4328A Performance Checks . . . . . .. . 5-2
5-15. Mechamcal Meter Zero . . . .. . 5-2
5-17. Linearity Check ............ , . 5-2
5-18. Full Scale Check . .. . .. . . . 5-2
5-19.. Cover Removal and Replacement. 5-2
5-21. Top Cover Removal .. . . . . . . . . . 5-2
5-22. Top Cover Replacement . . . . 5-2
5-23. Bottom Cover Removal .. , ..... 5-3
5-24. Bottom Cover Replacement 5-3
5-25. Adjustment Procedures . . . . . . . . . . 5-3
5-27. Mechanical Meter Adjustment .. 5-3
5-28. DC Power Supply Check 5-3
5-30. Bias AdJustment , ... , ...... _ .. 5-3
5-32. T302 Adjustment ........... , _... 5-3
5-33. Oscillator Output Adjustment .. 5-3
5-34. Electrical Zero Adjustment . . . 5-3
5-35. Lmeanty Adjustment ......... 5-3
5-36. Full Scale Adjustment ........ 5-4
5-37. Recorder Output Adjustment ... 5-4
5-38. Reactance Component Offset
Adjustment ........ ,. . ... , , . . . . 5-4
5-39. Isolating Trouble in Transistor
Circuits ..... , . . . .. . . 5-5
5-40.. General . . . . . . . . . . . .. . . . , . . . 5-5
5-41. In Circuit Testing ............. 5-5
5-45. Out-of-Circuit Testing ........ 5-5
5-47. Component Replacement m
Etched Circuits ................. 5-5
5-48. General . .. . . .. . .. . 5-5
5-49. Axial-Lead Components , . . . . . . 5-5
5-51. Other Components 5-5
Vl REPLACEABLE PARTS . . .. .. . .. 6-1
6-1. Introduction ..... , . . . . . 6-1
6-4. Ordering Information _ .... , . . . . . . 6-1
VII MANUAL CHANGES AND OPTIONS . . . .. . .. 7-1
7-l. Options . . . .. . . ...... _ ............. 7-1
7-3. Special Instruments . . . .. . . . . . .. . . 7-1
7-5. Manual Changes .............. , . 7-1
7-7. Later Instruments . . . . .. . . . 7-1
7-8. Earlier Instruments . , . . . . . .. 7-1
VIIl TROUBLESHOOTING AND CffiCUlT
DIAGRAMS , ..... , . . . . . . . . . . .. 8-1
8 -1. Introduction . . . . . . . . .. . . . . .. 8-1
8 -5.. Troubleshooting 8-1
8-8. Schematics . . . . . . . . .. . . . . .. . .. . . . . 8-1
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Model 4328A
LLst of Tables
List of Illustration
LIST OF TABLES
Number
Title Page
1-1.
3-1.
3-2.
5-l.
5-2
5-3.
5-4.
5-5.
5-6.
5-7.
6-L
Specifications ...... , . 1-2
Characteristics of Applied Current
on Samples and Maximum Power
Dtssipation .............. ,. . . .. . . 3-5
Ma..ximum Values of Resistance and
Length of Lead Wire ....... , _. .. . . 3-7
Recommended Test Equipment .... , ... 5-1
Linearity Test ............ , .. , ...... 5-2
Full Scale Test , .............. , ... , . 5-2
Power Supply Test .......... _. . . . _ .. 5-3
Out-of-Circuit Transistor Resistance
Measurements ........... , ......... 5-6
Safe Ohmmeter Range for Transistor
Resistance Measurements 5-6
Etched Circuit Soldering Equipment .. , 5-7
Ltst of Reference Designators and
Abbreviations ..... , ... , . . . , ........ 6-1
Number Title
6-2.
7-1.
8-1.
8-2.
8-3.
8-4.
8-5.
8-6.
8-7.
8-8.
8-9.
8-10.
Reference Designation Index ....... , ..
Backdating Changes .. , ..... , ..... .
4328A Overall Troubleshootmg .... .
Oscillator P/0 A3 Troubleshooting .
Schmitt Trigger P,'O A3
Troubleshooting , .......... _ .... , -
Flip-Flop P/0 A3 Troubleshooting .
Limitter P/0 A3 Troubleshooting . , ....
AC Amplifier P/0 A2
Troubleshooting .. , ........... .
Phase Detector and DC Amplifier
P /0 A2 Troubleshooting .
Modulator P iO A2 Troubleshooting
Power Supply Troubleshooting .... , .. ,
Ni-Cd Power Supply Troubleshooting ..
Page
6-2
7-1
8-5
8-7
8-7
8-9
8-9
8-11
8-11
8-11
8-13
8-15
LIST OF ILLUSTRATIONS
Number
Title
Page
1-1.
3-1.
3-2.
3-3.
3-4.
3-5.
3-6.
3-7.
3-8.
3-9.
4-1.
4-2.
4-3.
4-4.
4-5.
4-6.
4-7.
5-l.
5-2.
5-3.
7-1.
7-2.
8-1.
8-2.
8-3.
8-4.
8-5.
8-6.
Model 4328A Milhohmmeter . . . . . . . . . . 1-1
Front Panel Controls and Connectors . . 3-2
Rear Panel Controls and Connectors... 3-3
Operating Procedure . . . . . . . . . . . . . . . . 3-4
Probe Combmation ..... , . . . . . . . . . . . . 3-5
Probe Installation ...... ,. . . . . . . . . . . . . 3-6
16005A Clip-type Probes . . . . . . . . . . . . . 3-6
16006A Pin-type Probes ..•.... , ...... 3-6
16007A
1B
Test Leads ................ 3-6
4-Terminal Device Measurement.... . . 3-7
Basic Low Resistance Measurement ... 4-1
SimphfLed Block Diagram,....... . . . . . . 4-1
Operation of Phase Detector .... _. . . . . 4-2
Model 4328A Oscillator Talking
Schematic .... , . . . . . . . . . . . . . . . . . . . 4-5
Model 4328A Phase-Sensitive
Amphher Talking Schematic . . . . . . . 4-7
Model 4328A Power Supply Talking
Schematic .... , _ ..... , ............ 4-9
Model 4328A Ni-Cd Power Supply .... .
Talking Schematic . . . . . . . . . . . . . . . . 4-11
Transistor Biasing CharacteristLcs ... , 5-4
(0. 9m.f2 + j 1. 8m0) Impedance ......... 5-7
(900 + J 180Q) Impedance .. , .......... 5-7
Partial Schematic of A2 Ass'y . . . . . . . . 7-1
Parhal Schematic of A3 Ass'y ........ 7-2
Schematic Diagram Notes... . . . . . . . . . . 8-2
Overall Block Diagram. . . . . . . . . . . . . . . 8-3
Model 4328A Waveforms . . . . . . . . . . . . . 8-4
Model 4328A Waveform Test Point
Locations . . . . . . . . . . . . . . . . . . . . . . . . 8-5
Model 4328A Left Internal VIew . . . . . . . 8-6
Model 4328A Bottom Internal V'lew . . . . 8-6
Number
Title
Page
8-7.
8-8.
8-9.
8-10.
8-11.
8-12.
8-13.
8-14.
8-15.
8-16.
8-17.
8-18.
8-19.
8-20.
8-21.
Model 4328A Rear Internal View ........ 8-8
Model 4328A Right Internal View ....... 8-10
Model 4328A Top lnternal View ....... 8-10
Model 4328A Power Supply PC Board ... 8-12
Model 4328A Ni-Cd Power Supply
PC Board ......................... 8-14
Oscillator Assembly A3 Component
Locations ........................ 8-16
Range Switch Assembly A4
Component Locations .............. 8-16
Oscillator Assembly A3 Schematic ..... 8-17
Range Switch Assembly A4 Schematic .. 8-17
Mother Board Assembly A5 Schemattc .. 8-17
Phase Sensittve Amplifier Assembly
A2 Component Locations .....•..•.. 8-18
Mother Board Assembly A5
Component Locations .............. 8-18
Phase Sensitive Amplifier Assembly
A2 Schematic ............ , ....... 8-19
Mother Board Assembly A5
Schematic ...•......•..........•.. 8-19
Power Supply Assembly Al .......... .
Component Locations .............. 8-20
Power Supply Assembly Al
Schematic ........................ 8-21
Mother Board Assembly A5
Schematic ........... , ............ 8-21
Ni-Cd Power Supply Assembly A6
Component Locations .............. 8-22
Mother Board Assembly A5
Schematic _ ......... _ ....... _ ..... 8-23
Ni-Cd Power Supply Assembly A5
Schematic . . . . . . ........... , ...... 8-23
iii

Section I
Paragraphs L-1 to 1-10
SECTION I
GENERAL INFORMATION
1-1. DESCRIPTION
1-2. The Model 4328A Milliohmmeter (Fig. 1-1) is
a portable instrument designed to measure low resist-
ance with speed and accuracy. Covering a resistance
range of. OOH2 to 100!1, the mstrument uses a Kelvin
Bridge method to obtain high sensitivtty Although
the 4 terminal method is used to insure accuracy,
only 2 probes placed on each end of the sample are
used m the actual measurement.
1-3. To avoid measurement errors due to thermal
emfs, contact potential differences and electrolytic
polarization, the measurement utilizes a 1kHz :::ilgnal
and is msensitive to d .. c errors. '
1-4. In the measurement of contact res1stance of
components used in low level s1gnal circuits, swttches.,
relays and connectors, the measurement voltage ap-
plied should be less than 20m V peak so that thm insu-
lating films are protected from breakdown With the
4328A, voltage across samples 1s less than 200t.tV
peak on any range (when proper range setting used).,
and a maximum voltage of 20mV if incorrect range
settings are used.
1-5. The 4328A can be used to measure heat-sensitive
__ . .-------
AIHIGE
I -.,'""!-
"'
':l
:.~.-----,.
-u,,
samples because the power dissipatwn in samples is
very low. Voltage applied to samples is automahcally
llm1ted to permit safe measurement of fuses and ex-
plosives
1-6. A unique phase dLscriminator in the meter cir-
cuit_ insures accurate measurement of samples with
senes reactance up to twLce full scale reststance ..
1-7. 150V superimposed de bias may be present on
samples durmg measurement. Thus, direct measur~
ment oi mcremental resistance of back biased diodes
may be performed, permithng use of the 4328A in the
design of semiconductor circuitry.
1-8.. Complete specifications of the Model4328A are
given in Table 1-1.
1-9.. ACCESSORIES FURNISHED
1-10 Model 16005A Clip-type probe, 16006A Pin-
type probe and 16007A B Test Leads are furnished;
these probes or test leads may be "mtxed or matched"
in any configurahon determined by the form of the
sample to be measured.. Also detachable power cord
is supplied with the .. Model 4328A Milliohmmeter ..
""•TTrrcr
'
LlliE
Figure 1-L Model 4_328A Milliohmmeter
1-1

Section [
Paragraphs 1-11 to 1-14
1-11. INSTRUMENT IDENTIFICATION
1-12. Hewlett-Packard uses a two-section nine-
character (OOOOJOOOOO) or eight-character (000-00000
or OOOJOOOOO) serial number. The first three or four
digits (serial prefix) idenhfy a series of instrument;
the last five dig'its identify a particular instrument in
that series. A letter placed between the two sections
identifies the country where the mstrument was manu-
factured. The serial number appears on a plate located
on the rear panel. All correspondence with Hewlett-
Packard Sales/Service Offices with regard to an in-
strument should refer to the complete serial number.
1-13. MANUAL CHANGES
1-14. This manual provides operating and service
information for the HP Model4328A a portable instru-
Model 4328A
ment for measurement of low resistances. Informa-
tion in this manual applies directly to instruments (as
manufactured) with serial numbers prefixed by the
three digits indicated on the title page. If the serial
prefix of the instrument is above that on the htle page,
a "Manual Change" sheet supplied will describe
changes which Will adapt this manual to provide
correct coverage. Techmcal correction (if any) due
to known errors in print are called Errata and are
shown on the change sheet.. And if the serial prefix
or number of the instrument is below that on the title
page, see SECTION VU MANUAL CHANGES AND
OPTIONS. For information on manual coverage of
any HP instrument, contact the nearest HP Sales i
Service Office (addresses are listed at the rear of
this manual)
Table 1-1. Specifications
Resistance Range: 0. 001 to 100 ohms in a 1, 3, 10
sequence.
Resolution rna...:, resolution 0 .. 02 on 0-1 scale.
0. 05 on 0-3 scale.
Accuracy: ±2% of full scale.. Accuracy is un-
affected by series reactance of samples with
magnitude of up to 2 times full-scale resistance
value.
Measuring Frequency: 1000Hz ±100Hz
Voltage across sample:: 200J.N peak at full scale.
Maximum voltage across sample: 20mV peak in
any case.
Measuring current and power dissipation in sample.
Range
*Applied ~* Ma..ximum Dissipation
(ohms) Current (rnA in Samples (J..lW)
0 .. 001 150 23
0.003
50
8
0.01 15 2. 3
0.03 5 0.8
0. 1
1.5 0.23
0. 3
0.5
0 .. 08
1
0.15 0 .. 023
3 0.05
0.008
10
0 .. 015
0.0023
30 0.005
0.0008
100
0.0015 0.00023
* Constant for each range.
** Proportional to meter deflection, full scale
values given.
Superimposed DC: 150V de ma..ximum may be
superimposed on samples from an external
source.
Recorder Output 0. 1V de output at full scale
meter deflection. Output resistance approx:. 1k
ohm.
Operating Temperature Range: 0 to 55°C,
Power:: 115 i230V ±10%, 50 to 60Hz, 2 W Op-
1-2
tional rechargeable battery provides up to 15 hours
continuous operation.. Automatic battery recharge.
Weight 7 lbs (3. 2kg)
Accessories Furmshed · 16005A Clip-type Probes
16006A Pin-type Probes
16007A Test Lead
160078 Test Lead
Detachable Power Cord
16143A Probe Cable
Accessories Available·
5060-0797 Rack Adapter Frame (holds three
instruments the size of the 4 3::!8A.
16459A Carrying Case
1L056A Handle Kit
Combining Cases.
l051A 11 - 1"4 in. (286mm) deep
1052A 16 - 3 8 in .. (416mm) deep
The combining cases accept the 1/3 -module HP
instruments for bench use or rack mounting. See
1051A data sheet for detail.
Options:
001: Rechargeable battery mstalled, provides
up to 15 hours continuous operatmg.
Dimensions:
hiOTE
OIMEI\I:SIOI~IS IN 11~1 HE5 ANIJ IMILLIMETEA:il
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Model 4328A
Section IT
Paragraphs 2- L to 2-16
SECTION II
INSTALLATION
2-1. INTRODUCTION
2-2. This section contains information for unpacking,
inspection, repackaging, storage, and installation of
the Model 4328A.
2-3. UNPACKING AND INSPECTION
2-4. If the shipping carton is damaged, ask that the
carrier's agent be present when the instrument is
unpacked.. Inspect the instrument for damage
(scratches, dents, broken knobs, etc .. ). If the instru-
mentis damaged or falls to meet specifications, notify
the carrier and the nearest Hewlett-Packard Field
Offlce (see List at back of thLs manual) Retain the
shipping carton and the padding material for the
carrier's inspection.. The held office will arrange
for the repair or replacement of your instrument
Wlthout waiting for the cla1m agamst the carrier to be
settled.
2-5.. STORAGE AND SHIPMENT
2-6. PACKAGING. To protect valuable electronic
equipment during storage or shipment always use the
best packagmg methods available. Your Hewlett-
Packard fleldoffice can provide packing matenal such
as that used for original factory packaging. Contract
packaging companies m many cities can provide de-
pendable custom packaging on short nohce.. Here are
a few recommended packaging methods:
a.. RUBBERIZED HAIR. Cover painted surfaces
of instrument with protective wrapping paper
Pack instrument securely in strong corrugated
contamer (350 lb sq in .. bursting test) with 2-
inch rubberized hair pads placed along all sur-
faces of the instrument. Insert fillers between
pads and contamer to ensure a snug fit.
b. EXCELSIOR. Coverpaintedsurfaces of instru-
ment with protective wrapping paper.. Pack
instrument in strong corrugated container
(350 lb sq in .. bursting test) with a layer of ex:-
celsior about 6 mches thick packed firmly agamst
all surfaces of the instrument.
2-7 ENVIRONMENT. Conditions during storage and
shipment should normally be limited as follows::
a. Ma..xLmum altitude, 20, 000 feet.
b .. Temperature, -40°F ( -40"CI to l67°F (75°C) ..
c .. Temperature (with Opt. 001), 32°F (0°C) to ll3°F
(45°C)
2-8. INSTALLATION
2-9. The Model4328A is a submodular unit, equipped
with plastic feet and tilt stand for bench operation as
sb1pped from the factory However, when used in
combination with other submodular units 1t can be
bench and, or rack mounted. The HP combinmg case
and adapter frame are designed for this purpose and
are available through your Hewlett-Packard Sales and
Service office ..
2-10. COMBINING CASE ( HP Models 1051A or
1052A)
2-11. The combining case is a full-module unit which
accepts varwus combinations of submodular units.
Being a full-module umt, it can be bench or rack
mounted and is analogous to any full-module instru-
ment ..
2-12. ADAPTER FRAME ( HP Part No. 5060-0797).
2-13.. The adapter frame is a rack frame that accepts
any combination of submodular units.. It can be rack
mounted only ..
2-14. POWER CONNECTION
2-15. LINE VOLTAGE. The Model 4328A may be
operated from either 115- or 230-volt (±1000) 50 or
60Hz power lines, which can supply approximately
2 watts. A slide switch on the rear panel permits
quiek conversion for operation from either voltage.
Insert a narrow-blade screwdriver in the switch slot
and slide the switch to the right for 230-volt operatwn
("230" marking exposed) or to the Left for l15-volt
operation ("115" markLng exposed). The Model 4328A
is supplied with aD. 1 ampere fuse for etther 115- or
230-volt operation ..
CAUTION
To avotd damage to the instrument, before
connecting the power cable, set the 115
230
switch for the line voltage to be used.
2-16. POWER CABLE. To protect operating per-
sonnel, the Natwnal Electrical Manufacturers' Asso-
ciation (NEMA) recommends that instrument panels
and cabinets be grounded.. Accordingly, the Model
4328A is equipped with a detachable three-conductor
power cable which, when plugged into an appropriate
receptacle, grounds panel and cabinet. The offset pin
of the three-prong connector is the ground pin Pro-
ceed as follows for power cable tnstallation.
a. Connect flat plug (3-terminal conneetor) to LINE
Jack at rear of instrument.
b. Connect plug (2-blade with round grounding pm)
to 3-wire (grounded) power outlet Exposed
portions of instrument are grounded through the
round pin on the plug for safety; when only 2-
blade outlet is available. use connector adapter
(HP P.1rt No 1251-8196) the connect the green ground-
ing tab to power !me ground
2-1

I
,,,, '' Model 4328A
Section m
Paragraphs 3-1 to 3-19
I"
,,
'I"
i
r"
!
SECTION Ill
OPERATION
3-L INTRODUCTION
3-2. The Model4328A IS effective in measuring con-
tact resistance such as in relays, switches, connec-
tors and incremental resistance of diodes, or lead
resistance of integrated circuits. Measurement is
made by the 4 terminal method, actually utilizing on
2 probes One current lead and one voltage lead are
incorporated in each probe. The probes are branched
off through a connector in the probe cord that leads
from the front panel and the user can rearrange the
different kinds of probes OT test leads at will, accord-
ing to the form of the sample. This section includes
a complete de scription of the Mill iohmmeter operating
controls, its accessories, characteristics and tech-
niques of uses ..
3-3. The range of 4328A extends from 1 milliohm to
100ohms full scale in a 1, 3, 10 sequence. Maximum
sensitivity IS 20p. ohms.
3-4. CONTROLS, CONNECTORS AND INDICATIONS
3-5. The front and rear panel controls, conneetors
and mdicators are explained in Figure 3-1 and 3-2,
The descriptions are keyed to the corresponding items
which are i.nd'lcated on the fi.gure
3-6. BATTERY OPERATION
3-7. The HP 4328A Option 001 can operate from a rechargea-
ble Nickel-Cadmium battery
or ac hne power. Continuous bat-
tery operation is poss1ble for approximately
15 hours after a
full charge
.. The 4328A automatically operates on 1ts mternal
batteries whenever the ac lme power IS disconnected,
and the
batteries are continually charging when the power cable
is con-
nected
to the power lme, when the LINE lamp is lit
3-8, Before operatmg the 4328A on battenes, check the bat-
tery voltage with the BATT.
TEST button .. When the BATT
TEST button is pressed, the pointer of mater indicates the in-
ternal battery voltage .. If the pointer is in the range of BAT.
CHARGED of the meter, the battery voltage is h1gh enough
to use
.. If the pointer IS out ot the range of BAT CHARGED,
the battery must be recharged first..
3-9, The battery can be charged using the following proce-
dure (when in the
BAT.. CHARGED range or out of the BAT
CHARGED range)
I) Connect the power plug to the ac hne, and set the LINE
sw1tch to FAST CHARGE.. The LINE lamp is lit and
mdicates the battery 1s charging ..
2) Charge the battery unul the pointer is in the range of
BAT. CHARGED by pressmg the BATT. TESL It takes
apprmumately 4 hours to charge up a full discharged bat-
tery mto the BAT
CHARGED range, and takes approx-
Imately 48 hours to fully charge
..
CAUTION
The four Nickel-Cadmium batteries in the
Option 001 are m hermetically-sealed con-
tainers Under high temperatures (above
50° C), hydrogen m the hermetically-
sealed battery container can build up to
high pressure causing damage to the bat-
teries and or the mstrument The user
must be cognizant of temperature ex:-
tremes while charging the batteries. Do
not charge batteries when temperature is
above 40°C ..
3-10 Instrument Temperature Range
3-11, Model4328AOption001 has certain temperature
limitations_ Operatmg temperature upper limits for
battery operation are lower compared with convention-
al ac operatwn (Oo C to 50° C). Internal temperatures
in ex:cess of 50° Care quite easy to obtain tf the instru-
ment is left m the sun, even if the air temperature is
quite moderate A good practice is to be certain that
the instrument IS not stored or operated in direct sun-
light to avoid the possibility of reduced performance.
Keep this limitatwn in mind when operating in field
conditions to obtam safe and stable operation.
CAUTION
Nickel-Cadmium cells in this instrument
are hermetically-sealed Damage to cells
may occur if exposed to extremely high
temperatures (above 50° C)
3-12. MEASUREMENT
3-13. Measurement is made by the 4 terminal method
to obtam accurate measurement of Low resistance,
actually two 2-termmal probes are used so that opera-
tton of the instrument is quite easy The probes fur-
nished in Model4328A are 16005A probe, 16006A probe
and 16007 A/B conventional 4 termmal test leads.
3-14. Under no conditions will voltage across the
sample exceed 20mV peak, even in the case of incor-
rect range settings. When the correct range setting
is used, voltage across the sample is less than 200f.1V
peak. For optimum use of the instrument, range
should be set on a higher range when making the mi-
tial connection followed by swttching the selector to
the appropriate lower range.
3-15. OPERATING PROCEDURE
3-16. Figure 3-3 illustrates operating procedure.
3-17. MEASURING VOLTAGE ON SAMPLES
3-18. When the voltage applied between the contact
is high, the oxidized film formed between the contact
is destroyed thereby, and the resistance value me as-
ured may be smaller than under actual use. More-
over, once this happens, it wi.ll never recover the
former conditwn even if the voltage or the current is
cut off
3-19. According to the recommended standard of IEC
(lnternahona Electrotechnical CommissLOn), meas-
urement of contact rest stance by ac should be conducted
3-1

Section III
Figure 3-1
..,._ ..... -
C@m HEWLETT PACitARD
1. LINE-ON/OFF.'FAST CHARGE: Instrument
power ON/OFF/FAST CHARGE toggle switch
connects either ac line or internaL battery
(option 001 only) to internaL voltage regulator
circuit and provides fast charge to the battery.
2 LINE lamp: This pilot lamp glows when the
instrument is turned ON. In optwn 001, the
pilot Lamp glows when power cord is connected
to ac 115 1 230V source when power switch is
in ON or FAST CHARGE positions. When the
pilot lamp glows ( Optwn 001 ) batteries are
charging continuously.
3. BATT. TEST: Push on~'off switch (non-lock) -
a
battery test Is made when the push button is
depressed irrespective of the position of the
ON 1 0FF·FAST CHARGE switch.
4. RANGE: Low resistance measurement range
selector; seLect ranges from lm!J fuLt scale to
1000 fuLl scale.
10
,.
•••
BATT .. TESr
3
~--~~------~2
LINE
OFF fAST
CHAitti:E
Model 4328A
5. PROBE: Cord, for measurement, divides into
2 probes at moduLar connector.
8_ CAUTION
Superimposed DC voltage limits are
as folLows:
(1)
Between High and Low terminals
±150Vdc maximum.
(2) Between Low terminal and GND
±500Vdc maximum.
Do not superimpose DC voltage above
sample limits.
6. MechanicaL Meter Zero: Sets meter suspension
so that meter indicates zero. To adjust the zero.
a. Remove power from the instrument.
b. Turn the adJustment screw cLockwise until
the indicator falls beLow zero and comes
back up to zero again.
,1,
I •
I
t·
c. Turn the adjustment very slightly counter- •
clockwise to free up the mechanism from
the adJUSti.ng peg.
Figure 3-1. Front Panel Controls and Connectors
3-2

Model 4328A
1. Line Fuse· Select fuse to match line voltage
m u.se. For 115V ac or for 230V ac use 0. 1
amp slow blow fuse ..
2.... Power Cord Input: Use power cord provided,
(HP 8120-1378) Line Power limits are 115/
230V ac, 50 -60Hz.. Check FUSE rating and
position of -Une voltage slide switch before
connecting power.
3 .... Line Voltage Slide Switch: Set to line voltage
available (115 or 230V ac, 50 -60Hz)
Section III
Figure 3-2
4 .. RECORDER OUTPUT· 0 ... 1V de output is ob-
tamed at full scale meter deflection directly
proportional to meter deflection Output
impedance is approximately 10000.
5. Cabinet Ground:: The recorder output is nor-
mally floating and Cabinet Ground termmal is
tied to earth ground... When recorder output 1s
connected to the input of the recorder and when
the recorder cabinet is not hed to earth ground,
the recorder cabinet should be connected to
th1s Cabinet Ground terminal.
Figure 3-2. Rear Panel Controls and Connectors
3-3

Section Ill
Figure 3-3
1. Choose the appropriate probes or test leads and
put them into connector on the cord.
2. Meter Mechanical Zero.
a. With the instrument turned off, rotate the
meter adjustment screw cLockwise until the
pomter approaches the zero mark from the
left.
b. Continue the clockwise rotation until the
pomter coinctdes with the zero mark. [f the
pointer overshoots, continue rotating the
adjustment screw c lockw1se until the pointer
once again approaches the zero mark from
the left.
c. Rotate the adJustment screw aboutthree de-
grees counterclockwise to disengage screw
adjustment from the meter suspension.
Model 4328A
3.. Turn 4328A LINE switch to ON .. The LINE lamp grows
when the instrument power is
ON ..
In Option 001: The 43~8A operate'> on Its mternal bat-
tery when the power cable is not connected to ac Ime
and the LINE switch IS ON. The 4328A operates and
charges the battery when the power cable IS connected
to ac !me
and the LINE switch is ON. The 4328A charges
the battery
and does not operate when the LINE switch
ism the FAST CHARGE position.
4 In
Option 001:: Press the BATT. TEST button When
the pomter of the meter is in the range of BAT..
CHARGED, the 4328A can operate .. When the pointer
is out of the BAT.. CHARGED range, the battery must
be recharged .. Even when the power cable i'> connected
to ac line,
and when the pomter is out of the BAL
CHARGED range, the 4328A cannot operate normally
until
the battery Is recharged .. Refer to paragraph 3-9
for details
5.
Connect the probes to the sample to be measured.
6. Rotate the range selector until the meter indi-
cator moves on scale.
7. Read the meter indication.
Figure 3-3. Operatmg Procedure
3-4

A
Model4328A
by means of measuring instruments with voltage peak
values of 20mV or less.
3-20. The instrument can not start oscillating H no
sample is connected between the probes .. When sam-
ple is connected between the probes, a positive feed-
back loop is formed, and the oscillator begins oscil-
lation. Since constant current flows in the sample (in
correct range setting), voltages across the sample
are proportional to sample resistance and are less
than . 2m V peak on any range, at full scale deflection.
When the resistance value of the sample is greater
than that of the set range, an "over-voltage" protec-
tion circuit ln the Model 4328A i.s called upon to pre-
vent any voltage higher than 20mV peak from belng
applied to the sample.. Thus, when an unknown sam-
ple IS measured without special preparation, contact
resistance is still accurately measurable without dis-
turbance to the contact points.
3-21. APPLlED CURRENT ON SAMPLES AND
MAXIMUM POWER
DISSIPATlON
3-22. With Model 4328A, the current and power ap-
plied to samples are extremely small, the maxima at
measurement (i. e, when the meter needle deflects
full scale) being as shown in the table below.
Table 3-1. Characteristics of Applied Cur-rent
on Samples and Maximum Power Dissipation
MEASURING *1
POWER
*2
RANGE
CURRENT DISSIPA TlON
(Ohm) (rnA)
(/lW)
0. 001
150
23
0. 003
50
8
0.01
15 2.3
0.03
5
0.8
0 1
1.5 0.23
0. 3
0.5 0 .. 08
l 0
.. 15 0
.. 023
3 0
.. 05
0.008
10 0. 015
0. 0023
30 0
.. 005 0.0008
100
0.0015
0.00023
*1 Constant to each range.
*2 Propo-rtional to meter deflection,
against full scale deflectwn ..
3-23. As shown in the above table, the power dissi-
pation at sample is so small that fuses, detonators
and semi-conductors can be safely measured.
3-24 EFF.Ii:CT OF SERlES REACTANCE OF
SAMPLES
3-25. The meter circuit of Model 4328A does not
(within limits) respond to the series reactance of --a
sample. The meter mdtcates only the correct value
of the pure resistance of the sample as long as the
series reactance of the sample at 1kHz is less than
twice full scale resistance value.
3-26. DC BIAS SUPERIMPOSED
3-27 DC bias may be present on samples, due to
Section III
Paragraphs 3-20 to 3-34
some source. Model4328A measures with ac (1kHz),
but its probe ctrcuits incorporate de blocktng capaci-
tors The mstrument will not burn out nor will any
measuring error will occur even when the probes come
in direct contact With a de circuit. The maximum de
voltage applicable between two probes is 150V.
3-28.. Also, as the probes are floating from the in-
strument case (able to Withstand voltage up to 500V
de; insulation resistance 10Mr2 or over), it is possible
to measure the resistance value of a sample having
de voltages relative to ground by connecting directly
to it.
3-29. The dynamic resistance of elements whose V-1
characteristics shownon-hnearittes, (such as diodes)
may be measured at an arbitrary DC bias pomt. In
this type of measurement, note that the maximum
voltage (1 kHz) applied to the sample is 0. 2mV peak
or less ..
3-30. RECORDER OUTPUT
3-31. A RECORDER termmal is provided on the rear
panel of the 4328A, providing a de voltage proportional
to the resistance of the sample permitting recording
of consecutive tests, etc.
3-32. PROBE CONNECTIONS.
3-33. General
3-34. In Model 4328A, measurement is made by the
4-terminal method; special two-terminal probes that
can make 4-terminal measurements (16005A Clip-
type Probes and 16006A Pin-type Probes), and con-
ventional4-terminal testleads (16007 A/B Test Leads)
are furnished, and can be mixed or matched depend-
ing on sample type For eKample, in the case of
measurement of the contact resistance of printed cir-
cuit board connectors, 1t is usually convenient to use
a combination of the clip-type probe and the pin-type
probe as shown in Figure 3-4.
Figure 3-4. Probe Combination
3-5

Section III
Paragraphs 3-35 to 3-46
3-35. Probe Installati.on
3-36.. Plug in the probes to the connector at the end
of 16l43A Probe Cable. Note that the probe plugs
must be oriented correctly before plugging m.
1) Connector at the end of probe cable has 4-
contacts Each pairof closely--spaced contacts
comprise one set of probe contacts.
2) Plug the probe pms in to the connector such
that the off set Side faces outwards.. Refer to
Figure 3-5.
t
16143A
Figure 3-5. Probe Installation
3-37. 16005A CLip-type Probe
3-38. General purpose, alligator-jaw contacts pro-
vide positive gripping of samples. Upper contact
(marked "V"l is voltage termmal and lower contact
is current terminal. When using this probe in 1 mn
range, It is not alway-s possible to measure the sample
because of extreme deflectwn of the meter. Figure
3-6 shows 16005A Clip-type Probes.
Figure 3-6. 16005A Clip-type Probes
3-39. 16006A Pin-type Probe
j
/
3-40. Probe tip is a voltage terminal and outer con-
ductor ts a current terminal. Probe tip is spring-
loaded, so that both terminals firmly contact the
sample under test. This probe LS usefulfor press-an
contact measurement such as printed board conduc-
tivity measurements. When using this probe m lmn
range, itis notalways possibleto measure the sample
because of extreme deflection of the meter. (See
Figure 3-7).
3-6
---.jo._--~-
.~- __ L+_,._-.._._,j...
Model 4328A
Figure 3-7.. 16006A Pin-type Probes
3-41. 16007A!B Test Leads
3-42.. These are provided for standard 4 -terminal
measurements.. Each pair of testlead has a separate
alligator clip voltage and current terminaL 16007A is
furnished with a red cover the 16007B with a black
cover.. The black test lead is the voltage terminal and
the grey test lead IS the current terminaL
(See Figure 3-8)
Figure 3-8.. 16007A/B Test Leads
3-43. NOTES ON OPERATION
3-44.. IN USING THE 1 AND 3m OHM RANGES,
CONNECTION OF CURRENT TERMINALS
TO THE SAMPLE MUST BE A FIRM,
POSITIVE CONTACT.
3-45.. With Model 4328A, the internal resistance of
the constant current generator is approximately-equal
to the set range x500 Therefore, at 1m ohm and
3m ohms ranges, the internal resistances are 500m
ohms and 1. 5 ohms respectively.. Excessive resist-
ance at the probe contact can therefore relatively
larger error than on other ranges, The quahty of the
connection of the probes to the sample may be deter-
rowed by applying pressure on the connection point
and noting if the meter needle deflects.. Very poor
contact or no contact whatsoever 1s mdicated by- a
deflection off-scale
3-46.. IN USING THE 1 AND 3m OHM RANGE
LARGE ELECTRICALLY CONDUCTIVE
MATERIALS SHOULD NOT BE PLACED
CLOSE TO THE PROBES OR THEIR
CABLES,