HP 3400A Service manual

OPERATING AND SERVICE MANUAL
RMS VOLTMETER
3400A
,J- MOO* »« VOLIWIt* -^
HEWLETT MPACKARD
J

HEWLETT-PACKARD
M
CERTIFICATION
Hewlett-Packard Company certifies that this instrument met its published
specifications at the time of shipment from the factory. Hewlett-Packard
Company further certifies that its calibration measurements are traceable to the
United States National Bureau of Standards, to the extent allowed by the
Bureau's calibration facility, and to the calibration facilities of other
International Standards Organization members.
WARRANTY AND ASSISTANCE
This Hewlett-Packard product is warranted against defects in materials and
workmanship for aperiod of one year from the date of shipment, except that
in the case of certain components, if any, listed in Section 1of this operating
manual, the warranty shall be for the specified period. Hewlett-Packard will, at
its option, repair or replace products which prove to be defective during the
warranty period provided they are returned to Hewlett-Packard, and provided
the proper preventive maintenance procedures as listed in this manual are
followed. Repairs necessitated by misuse of the product are not covered by this
warranty. NO OTHER WARRANTIES ARE EXPRESSED OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR APARTICULAR PURPOSE.
HEWLETT-PACKARD IS NOT LIABLE FOR CONSEQUENTIAL DAMAGES.
If this product is sold as part of aHewlett-Packard integrated instrument
system, the above warranty shall not be applicable, and this product shall be
covered only by the system warranty.
Service contracts or customer assistance agreements are available for
Hewlatt-Packard products.
For any assistance, contact your nearest Hewlett-Packard Sales and Service
Office. Addresses are provided at the back of this manual.

fMANUAL CHANGES
Model 3400A
RMS VOLTMETER
Manual Part No. 03400-90008
|New or Revised Item
ERRATA:
Page 5-3, Paragraph 5-12 d and f. Change reference from
0.707 volts to 0.707 millivolts.
Page 6-5/6-6, Figure 6-2. Change value of C403 to
0.1 uF.
Page 6-9/6-10, Figure 6-4. Change Part No. on A7
schematic to 03400-66510.
Page 7-3, Table 7-1. Change C403 to Part No. 0160-0269,
C:fxd 0.1 uF 500 V.
Page 7-4. Change C427 to a selected component, C427*.
Page 7-5. Change R403 and R404 to R403* and R404*.
Change R419* to Part No. 0683-3315, R:fxd 330 «±5%
1/4W.
Page 7-6. Change R426 and R429 to R426* and R429*.
CHANGE NO. 1: For All Serial Numbers.
Page 7-8. Add Part No. 1200-0077, lnsulator:transistor
mica, TQ =3to Miscellaneous Parts.
CHANGE NO. 2: For Serial No. 1218A14726 and
Greater.
Page 7-6. Change R207 to Part No. 0757-0848.
CHANGE NO. 3: For Serial No. 1218A16126 and
Greater.
Page 6-9/6-10, Figure 6-4. Change value of A7R708 to
24.
Page 7-4. Change CR704 to Part No. 1901-0701
.
Page 7-5. Change Q1 to Part No. 1853-0063 Tstr:Si PNP.
Page 7-7. Change R708 to Part No. 0683-2405 R:fxd
24 «±5%1/4W.
CHANGE NO. 4: For Serial Numbers 1218A16126 thru
1218A16425.
If C71 1,R701 or R702 require replacement, replace with
part number listed above. If unable to obtain above part
numbers, replace all three components with part numbers
specified in Table 7-1. This is necessary to maintain the
same oscillator frequency provided by the above
component values.
CHANGE NO. 5: For Serial Numbers 1218A18576 and
Greater.
Page 6-9/6-10, Fig. 6-4. Change T1 lead designation color
codes as follows:
OLD
Primary Side- YEL(L)
BLU
GRN(L)
VIO
NEW
BLK
BLK/GRN
BLK/YEL
BLK/RED
Secondary Side-RED(S) pin 16BLU
ORN(L)pin8 VIO
ALL OTHER SECONDARY COLOR CODES RE
MAIN THE SAME.
Page 7-2, Fig. 7-1. Change Index No. 6, Rear Panel, to
Part No. 03400-00205.
CHANGE NO. 6applies to serial numbers 1218A18776
'and greater.
Page 7-8, Miscellaneous. Delete Insulator, 1200-0043 and
1200-0077.
Add InsulatonTransistor, 0340-0580.
CHANGE NO. 7applies to serial numbers 1218A19076
and greater.
Page 6-3/6-4, A2 Schematic. Change A2C208 from
.01 mF to .02 mF.
Page 7-3, Table 7-1. Change the -hp- Part Number and
description of C208 to 0150-0024,0.02 mF-
CHANGE NO. 8applies to all serial numbers.
Page 1-0, Table 1-1. Change the POWER specification to:
115or 230 Vac ±10%, 48 to 66 Hz, 15VA max.
Page 6-5/6-6, Figure 6-2. Change R433 from 24 Kto
249 K.
C711 is 0170-0019 C:fxd 0.1 uF 200 VR701, R702 are
0757-0852 R:fxd 47.5 K1%.
Page 6-7/6-8, Figure 6-3. Change R617 from 1800 to
1.82 Kand R3* from 1200 to 1210.
10 October 1977 Supplement Afor 03400-90008

»qge 2MANUAL CHANCES Mode! 3400A
Page 6-9/6-10, Figure 6-4. Change R704 from 36 Kto
36.5 K.
Page 7-5 and 7-7, Table 7-1. Change the -hp- Part Num-
bers and descriptions as shown in Table MC-1
.
Table MC-1.
R3*
R433
R434, R435
R617
R703
0757-0734
0698-3217
0757-0739
0757-0738
0757-0765
1,21 kfi ±1%
24.9 kS2 ±1%1/4W
2000 nt1%1/4W
1.82 kn ±1%
36.5 kJ2 ±1-%
CHANGE NO. 9applies to all serial numbers.
Page 1-1. Add the following new paragraphs.
1-16. OPTIONS AVAILABLE.
1-17. Option 910. An additional Operating and
Service Manual may be ordered, part number
03400-90008.
CHANGE NO. 10 applies to Serial Number 1218A20341
and greater.
Page 7-5, Table 7-1. Change the part number of Q401,
402, 403 and 405 to 1853-0288.
Change the part number of Q404 and 406 to 1854-0354.
Page 7-6 and 7-7. Show the following reference designa-
tors as starred value components.
R403*
R404*
R426*
R429*
CHANGE NO. 11 applies to all serial numbers.
Delete all "RMS" designations throughout the entire man-
ual.
Page 73, Table 7-1.
Delete: P. C. Assy -ATTEN 03400-66501 1ea.
Add: P. C. Assy -ATTEN 03400-66511 1ea;
The P.C assemblies are completely interchangeable.
CHANGE NO. 16 (09-14845) applies to serial numbers
1218A21281 and greater.
Page 7-5.
Delete: Q2, Q3 XSTR-GE SP1822 1850-0038 2ea.
Add: Q2, Q3 XSTR PNP 2N5875 1853-0305 2ea.
Page 7-8, Table 7-1.
Delete: R731 R-F 5360 OHM .01 0698-3258 1ea.
R730 R-F 11.3 KOHM .01 0698-4121 1ea.
Add: R730 R-F 10.5 KOHM .01 0698-4477 1ea.
R731 R-F 5620 OHM .01 0757-0200 1ea.
'age 7-4, Table 7-1
.
Delete: CR706 DIO-S1 1910-0025 1ea.
Add: CR706 DIODE-SILICON 1910-0701 1ea.
CHANGE NO. 12 (09-14504) applies to all serial num-
bers.
Page 1-1, Table 1-2. Change item number 1under IDEN-
TIFICATION NUMBER from 10110A to 10110B.
CHANGE NO. 13 (09-14494) applies to serial numbers
1218A21041 and greater.
Page 7-3, Table 7-1. Change part number of C201 from
01 70-001 9to 01 60-2671.
CHANGE NO. 14 (09-14530) applies to all serial num-
bers.
Page 7-6, Table 7-1. Change part number of R104 from
121 00-01 28 to 5061-1101.
CHANGE NO. 15 (09-14840) applies to serial numbers
1218A21121 and greater.

^
OPERATING AND SERVICE MANUAL
(HP PART NO. 03400-90008)
MODEL 3400A
RMS VOLTMETER
SERIALS PREFIXED: 1140A*
*Appendix C, Manual Backdating Changes, adapts this
manual to instruments with serial numbers 0979A13725
and below, and serials prefixed: 322-, 401-, 528-,
and 714-.
Copyright Hewlett-Packard Company 1965
P.O. Box 301, Loveland, Colorado, 80537 U.S.A.
Printed: JUNE 1972

Table of Contents Model 3400A
TABLE OF CONTENTS
Section
I
Page
GENERAL INFORMATION 1-1
1-1. Introduction 1-1
1-3. Description and Purpose 1-1
1-8. Specifications 1-1
1-10. Instrument Identification 1-1
1-12. Equipment Supplied 1-1
1-14. Accessory Equipment Available ... 1-1
Section Page
HINSTALLATION 2-1
2-1. Introduction 2-1
2-3. Initial Inspection 2-1
2-5. Power Requirements 2-1
2-8. Installation 2-1
2-10. Combining Case(-hp- Models 1051A
or 1052A) 2-1
2-12. Adapter Frame (-hp- Part No.
5060-0797) 2-1
2-14. Repackaging for Shipment 2-1
Section Page
mOPERATING INSTRUCTIONS 3-1
3-1. Introduction 3-1
3-3. Controls and Indicators 3-1
3-5. Turn On Procedure 3-1
Operating Instructions 3-1
Applications 3-1
RMS Value of AC Signals with DC
Component 3-1
3-13. RMS Current 3-1
3-15. RMS AC-to-DC Converter 3-1
Section Page
IV THEORY OF OPERATION 4-1
4-1. Introduction 4-1
4-3. General Description 4-1
4-11. Detailed Description 4-1
3-7.
3-9.
3-11.
4-12.
4-15.
4-19.
4-22.
4-27.
4-37.
4-40.
4-48.
Input Attenuator Assembly Al ...4-1
Impedance Converter Assembly A2. 4-1
Second Attenuator Assembly A3. .4-2
Video Amplifier Assembly A4 ... 4-2
Photochopper Assembly A5,
Chopper Amplifier Assembly A6,
and Thermocouple Pair
(part of A4) 4-2
Power Supply Assembly A7 . . ..4-3
Regulator Operation 4-3
Neon Lamp Drive Oscillator .... 4-3
Section
VMAINTENANCE
5-1. Introduction
5-3. Test Equipment
5-5. Performance Checks
5-7. Accuracy, Linearity, and DC Out-
put Check
5-9. Frequency Response Check . . ..
5-10. Input Impedance Check
5-13. Crest Factor Check
5-14. Output Noise Check
5-15 Adjustment and Calibration
Procedures
5-17. Mechanical Meter Zero
5-19. Power Supply Checks
5-21. Low Frequency Calibration ...,
5-25. High Frequency Calibration ...
5-29. Troubleshooting Procedure
5-34. Checking Thermocouples TC401
andTC402
5-37. Thermocouple Replacement ....
5-39. Checking Photochopper Assembly
A5
5-41. Replacement of Neon Subassembly
-hp- Part No. 1990-0224 ... .
5-43. Servicing Etched Circuit Boards . . .
Page
5-1
5-1
5-1
5-1
5-1
5-2
5-2
5-3
5-4
5-4
5-4
5-5
5-5
5-6
5-6
5-7
5-14
5-15
5-15
5-16
Section Page
VI CIRCUIT DIAGRAM 6-1/6-2
6-1. Introduction 6-1/6-2
6-3. Schematic Diagrams 6-1/6-2
6-6. Parts Location Diagrams 6-1/6-2
Section
VII REPLACEABLE PARTS. .
7-1. Introduction
7-4. Ordering Information
7-6. Non- Listed Parts
Page
7-1
7-1
7-1
7-1
Appendix
ACODE LIST OF MANUFACTURERS
Appendix
BSALES AND SERVICE OFFICES
Appendix
CMANUAL BACKDATING CHANGES
LIST OF TABLES
Number Page
1-1. Model 3400A Specifications 1-0
1-2. Equipment Supplied 1-1
1-3. Accessory Equipment Available 1-1
5-1. Required Test Equipment 5-0
5-2. Accuracy, Linearity, and DC Output
Check Data 5-1
Number Page
5-3. Frequency Response Check 5-2
5-4. Power Supply Checks 5-5
5-5. Front Panel Symptoms 5-7
5-6. Troubleshooting Procedure 5-9
5-7. Factory Selected Components 5-16
7-1. Replaceable Parts 7-3

Model 3400A Table of Contents
LIST OP ILLUSTRATIONS
Number Page
1-1. -hp- Model 3400A RMS Voltmeter .... 1-0
3-1. Model 3400A Controls and Indicators . . 3-0
4-1. Block Diagram 4-0
5-1. Accuracy, Linearity and DC Output
Test Setup 5-2
5-2. Frequency Response Test Setup 5-2
5-3. Input Impedance Test Setup 5-3
5-4. Crest Factor Test Setup 5-4
5-5. Troubleshooting Tree 5-8
5-6. Input to Demodulator 5-9
5-7. Input to Demodulator (feedback loop open) 5-10
5-8. Output of Demodulator (feedback loop open) 5-10
5-9. Neon Drive Voltage 5-11
5-10. Collector of Q602 (feedback loop open) ..5-12
5-11. Base of Q604 (feedback loop open) .... 5-12
Number Page
5-12. Base of Q601 (feedback loop open) ... 5-13
6-1- Input Attenuator Al, Impedance
Converter A2, and Second Attenuator
A3 Schematic and Parts Location
Diagram 6-3/6-4
6-2. Video Amplifier A4, Schematic and
Parts Location Diagram 6-5/6-6
6-3. Photochopper Assembly A5, Chopper
Amplifier Assembly A6, and
Thermocouple pair Schematic and
Parts Location Diagram ..6-7/6-8
6-4. Power Supply A7, Schematic and
Parts Location Diagram .... 6-9/6-10
7-1. Modular Cabinet 7-2
iv

Section IModel 3400A
UM00» RMSVOLTMETtR /->.
oe
-10
VOLTS
.3
RANGE VOLTS
1
OB
-M .1 v/S10
-M 03 ^J L- io 20
-40 .01 -^ m30 JO
-so .003 'W100 «0
-60 .001 ——300 so
40 ^*
Table 1-1. Model 3400A Specifications
VOLTAGE RANGE: 1mV to 300 Vfull scale, 12
ranges.
DB RANGE: -72 to +52 dBm (0 dBm 1mW in
600 n).
FREQUENCY RANGE: 10 Hz to 10 MHz.
RESPONSE: Responds to rms value (heating value)
of input signal.
METER ACCURACY: %of Full Scale (20°C to
30°C)*
10 Hz 50 Hz 1MHz 2MHz 3MHz 10 MHz
±5% ±1% ±2% ±3% ±5%
AC-to -DC CONVERTER ACCURACY: %of Full
Scale (20°C to 30°C)*
10 Hz 50 Hz 1MHz 2MHz 3MHz 10 MHz
±5% ±0. 75% ±2% ±3% ±5%
OUTPUT: Negative 1Vdc into open circuit for
full-scale deflection, proportional to meter
deflection; 1mA maximum; nominal source
impedance lOOOfi.
OUTPUT NOISE: <1mV RMS.
CREST FACTOR: (ratio of peak-to-rms ampli-
tude of input signal): 10:1 at full scale (except
where limited by maximum input), inversely
proportional to meter deflection (e. g. ,20:1 at
half -scale, 100:1 at tenth-scale).
INPUT IMPEDANCE: 0. 001 Vto 0. 3Vrange;
10 Mfi shunted by <50 pF: 1. Vto 300 V
range; 10 MS2 shunted by <20 pF. AC -coupled
input.
AC OVERLOAD: 30 dB above full scale or 800 V
peak, whichever is less, on each range.
MAXIMUM DC INPUT: 600 Von any range.
RESPONSE TIME: For astep function, <5
seconds to respond to final value.
POWER: 115 or 230 V±10%, 48 to 440 Hz.
approximately 7watts.
WEIGHT: Net 71/4 lbs. (3, 3kg); shipping 10 lbs.
(5 kg).
OVERALL DIMENSIONS: 61/2" high; 51/8" wide;
11 11/16" deep.
•
Temperature Coefficient: ±0. 1% over range of Qoc to 20°C and 30°C to 55°C.
It
1-0

Model 3400A Section I
SCOPE OF MANUAL
This manual contains the information necessary for oper-
ating and servicing the standard Model 3400A RMS Voltmeter
and the Model 3400A/Option 01 RMS Voltmeter (DB scale
uppermost).
SECTION I
GENERAL INFORMATION
1-1. INTRODUCTION.
1-2. This section contains general information about
the Model 3400ARMS Voltmeter (Figure 1-1). In-
cluded are: description of instrument, purpose, in-
strument identification, equipment supplied and
accessory equipment available. Also included is a
table of instrument specifications.
number on your instrument does not agree with those
on the title page of this manual, change sheets supplied
with the manual will define the differences between your
instrument and the Model 3400A described in this man-
ual. Some serial numbers may have a letter separating
the two sections of the number. This letter indicates
the country in which the instrument was manufactured.
1-12. EQUIPMENT SUPPLIED.
1-3. DESCRIPTION AND PURPOSE.
1-4. The Model 3400A RMS Voltmeter measures the
actual root-means-square (RMS) value of ac voltages
between 100 microvolts and 300 volts. Frequency
range is from 10 Hz to 10 MHz. Full scale
measurements of nonsinusoidal waveforms with crest
factors (ratio of peak voltage to rms voltage) of 10
can be made.
1-5. Ac voltages are measured with aspecified full-
scale accuracy of ±1% from 50 Hz to 1MHz, ±2%
from 1MHz to 2MHz, ±3% from 2MHz to 3MHz,
and ±5% from 10 Hz to 50 Hz and 3MHz to 10 MHz.
Asingle front panel control selects one of 12 voltage
or decibel ranges.
1-6. The Model 3400A crest factor rating is 10:1
which enables full scale readings for pulses which
have a1% duty cycle. At l/10th of full scale, pulse
trains with 0. 01% duty cycle (100:1 crest factor) can
be accurately measured.
1-7. The Model 3400A provides adc output which is
proportional to the front panel meter reading. By
using this voltage to drive auxiliary equipment, the
Model 3400A functions as an rms ac-to-dc converter.
1-8. SPECIFICATIONS.
1-9. Table 1-1 contains the specifications for the
Model 3400A.
1-10 INSTRUMENT AND MANUAL
IDENTIFICATION.
1-11. Hewlett-Packard uses atwo-section serial num-
ber. If the first section (serial prefix) of the serial
1-13. The equipment supplied with each Model 3400A
is listed and described in Table 1-2.
Table 1-2. Equipment Supplied
IDENTIFICATION
NUMBER QUANTITY DESCRIPTION
10110A 1Adapter (BNC to
dual banana jack)
8120-1348 1Power Cord
03400-90008 1Operating and
Service Manual
1-14. ACCESSORY EQUIPMENT AVAILABLE.
1-15. The accessory equipment available is listed
in Table 1-3. For further information contact your
local -hp- Sales and Service Office. (See Appendix B
for office locations.
)
Table 1-3. Accessory Equipment Available
IDENTIFICATION
NUMBER DESCRIPTION
10503A Cable (Male BNC to male
BNC, 48 inches)
11001A Cable (Male BNC to dual
banana plug, 45 inches)
11002A Test Lead (dual banana plug
to alligator clips, 60 inches)
11003A Test Lead (dual banana plug to
probe and alligator clip, 60 in.
)
456A Current Probe
01768-4 1-1

Model 3400A Section II
SECTION II
INSTALLATION
2-1. INTRODUCTION.
2-2. This section contains information and instructions
necessary for installation and shipping of the-hp- Model
3400A RMS Voltmeter. Included are initial inspection
procedures, power requirements, installation infor-
mation, and instructions for repackaging for shipment.
2-3. INITIAL INSPECTION.
2-4. The -hp-Model 3400A RMS Voltmeter received a
careful mechanical and electrical inspection before
shipment. As soon as the Model 3400A is received,
verify that the contents are intact and as ordered.
Although the instrument should be free of mars and
scratches and in perfect electrical condition, it should
be inspected for any physical damge which may have
been incurred in transit. Also test the electrical
performance of the instrument using the procedures
given in paragraph 5- 5.If any physical damage or
electrical deficiency is found, refer to the warranty
on the inside front cover of this manual. Should
shipping of the instrument become necessary, refer
to paragraph 2-14 for repackaging and shipping
instructions.
2-5. POWER REQUIREMENTS.
2-6. The Model 3400A can be operated from any ac
source of 115- or 230- volts (±10%), at 48 to 440 cycles.
With the instrument disconnected from the ac power
source, move the slide switch (located on the rear
panel) until the desired line voltage value appears.
The ac line fuse is a0. 25 amp, fast blow type for 115-
or 230-volt operation. Power dissipation is approxi-
mately 7watts.
2-7. The Model 3400A is equipped with athree-prong
power cord. To protect operating personnel, it is
necessary to preserve the grounding feature of this
plug when using atwo contact ac outlet. Use athree-
prong to two-prong adapter and connect the green
pigtail lead on the adapter to ground.
2-8. INSTALLATION.
2-9. The Model 3400A is asubmodular unit suitable
for bench top use. However, when used in combination
with other submodular units it can be bench and/or
rack mounted. The -hp- combining case and adapter
frame are designed for this purpose.
2-10. COMBINING CASE (-hp- Models 1051A or 1052A).
2-11. The combining case is afull-module unit which
accepts various combinations of submodular units.
Being afull-module unit, 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. For additional information, address
inquiries to your -hp- Sales and Service Office. (See
Appendix Bfor office location.
)
2-14. REPACKAGING FOR SHIPMENT.
2-15. The following paragraphs contain ageneral
guide for repackaging for shipment. Refer to para-
graph 2-16 if the original container is to be used;2-17
if it is not. If you have any questions, contact your
local -hp- Sales and Service Office.
•NOTE-
If the instrument is to be shipped to
Hewlett-Packard for service or
repair, attach a tag to the instrument
identifying the owner and indicate the
service or repair to be accomplished;
include the model number and full
serial number of the instrument. In
any correspondence, identify the
instrument by model number, serial
number, and serial number prefix.
2-16. If original container is to be used, proceedas
follows:
a. Place instrument in original container if avail-
able. If original container is not available, one
can be purchased from your nearest -hp- Sales and
Service Office.
b. Ensure that the container is well sealed with
strong tape or metal bands.
2-17. If original container is not to be used, pro-
ceed as follows:
a. Wrap instrument in heavy paper or plastic
before placing in an inner container.
b. Use packing material around all sides of
instrument and protect panel face with cardboard
strips.
c. Place instrument and inner container in a
heavy carton or wooden box and seal with strong
tape or metal bands.
d. Mark shipping container with "DELICATE
INSTRUMENT, ""FRAGILE, "etc.
2-1