HP 3400A Service manual

A biciano
Model 3400A
RMS Voltmeter:

[iz]
MANUAL
CHANGES
-hp- MODEL 3400A
RMS VOLTMETER
Manual! Part Number 03400-90013
CHANGE NO. 1. Applies to Serial Numbers 2415A31171 and Above.
Section VII, Table 7-3 (Replaceable Parts). Do the following
changes in the table:
Reference
Desigestion Description
Change:
C102 0121-0457 CAPACITOR-V TRMR-PSTN .8-8.5PF
CHANGE NO. 2. Applies to-All Serial Numbers.
Page 1-3/1-4, Table 1-2 (Equipment Supplied). Change the -hp- part
number of the power cord from ”8120-1348” to
“8120-1378.”
CHANGE NO. 3. Applies to All Serial Numbers
Section V, Paragraph 5-8. Add the following note to the
paragraph.
If in the following procedure the HP 3400A appears to
be non-linear, it could be caused by ground loops. If this
is noted, isolate the HP 3400A from the ac power line
by using an isolation transformer between the ac power
line and the Mode! 3400A.
CHANGE NO. 4. Applies to Serial Numbers 2415A31801 and Above
Section Vi, Figure 6-1 (A1, A2, and A3 Schematic). Do the
schematic changes in Figure 6-1 as shown in Figure CS-1
(in shaded area).
Figure CS-1. Figure 6-1 Changes (Change #4)
Section Vii, Table 7-3 (Replaceable Parts). Do the following
changes in the table:
0160-3402 CAPACITOR-FXD 1UF
25% SOVDC POLYE
CAPACITOR-FXD 12PF
=5% SOOVDC CER
RESISTOR 3.3K S%
.25W FC TC =-400/ +800
RESISTOR 3.3K 5%
.25W FC TC =-400/ +800
0160-2259
0683-0335
0683-0335
1 December 1986
CHANGE NO. 5. Applies to All Serial Numbers.
Section V. Paragraph 5-13. The 410C Voltmeter called for in
the Crest Factor Test has been discontinued. If a 410C
Voltmeter is not available an oscilloscope may be used
to set up the puise trains. The pulses should have an
amplitude of 10.1 Volts for a Crest Factor of 10, and an
amplitude of 10.0 Volts for a Crest Factor of 20. These
amplitudes require that the puise widths and spacings
given in steps c and e remain unchanged.
ERRATA
Section Vi, Figure 6-1 (A1, A2, and A3 Schematic). Change the
word ‘’VIDIEO”’ to ‘“VIDEO”’ at the AC INPUT point.
Section Vil, Table 7-3 (Replaceable Parts). Change the check digit
of CR402 from ‘’3”’ to ‘’*1’’ and add a quantity of ’1’’.
Section Vil, Figure 7-5 (3400A Rear View). Change the -hp- Part
Number of S2 in the table located in Figure 7-5 from
*°3103-1234” to “°3101-1234"’.
CHANGE NO. 6. Applies to Ail Serial Numbers
Add the attached ‘’Deciaration’’ to the manual.
OTS LIBRARY
OTS LIBRARY
2400011662
Supplement A for 03400-90013
ACGN

Page 2 of 2 MANUAL CHANGES HP 3400A
(03400-63402) i
|
!
l
}
[ AR [SECOND ATTENUATOR ASSEMBLY
!
i
if
i
2
D
Livy
a o
jI--
DO Oo
nN
49.4K
w
AC INPUT
epee i
cecs
100
th
70
VIOZEC AMPL.
(Ac)
|.
pt
cR206
Ret2
2.75K aoe
coe
Figure CS-1. Figure 6-1 Changes (Change #4)
7
: | |
Nyt Rote arr

(I eackaro
Herstellerbescheinigung
Hiermit wird bescheinigt, da8 das Ger&t/System HP 3400A
in Ubereinstimmung mit den Bestimmungen von Postverfiigung 1046/84 funkentstdrt ist.
Der Deutschen Bundespost wurde das Inverkehrbringen dieses Gerates/Systems angezeigt und
die Berechtigung zur Uberpriifung der Serie auf Einhaltung der Bestimmungen eingeraumt.
Zusatzinformation fur Mef- und Testgerate
Werden Me§- und Testgerate mit ungeschirmten Kabeln und/oder in offenen MeSaufbauten
verwendet, so ist vom Betreiber sicherzustellen, da8 die Funk-Entstérbestimmungen unter
Betriebsbedingungen an seiner Grundstiicksgrenze eingehalten werden.
Manufacturer's deciaration
This is to certify that the equipment HP 3400A
. Is in accordance with the Radio Interference Requirements of Directive FTZ 1046/84. The Ger-
_man Bundespost was notified that this equipment was put into circulation, the right to check
the series for compliance with the requirements was granted.
Additional Information for Test- and Measurement Equipment
If Test- and Measurement Equipment is operated with unscreened cables and/or used for
measurements on open set-ups, the user has to assure that under operating conditions the Radio
Interference Limits are still met at the border of his premises.

(0) eackano
OPERATING
AND
SERVICE
MANUAL
MODEL 3400A
RMS VOLTMETER
SERIAL NUMBERS
This
manual
applies
directly
to
instruments
with
a
serial
number
prefix
of
2415.
To
help
minimize
the
possibility
of
electrical
fire
or
shock
hazards,
do
not
expose
this
instrument
to
rain
or
excessive
moisture.
Manual! Part Number 03400-90013
Microfiche Part Number 03400-90063
RESTRICTED RIGHTS LEGEND
Use,
duplication,
or
disclosure
by
the
Government
is
subject
to
restrictions
as
set
forth
in
subdivision
(6)(3)(ii)
of
the
Rights
in
Technical
Data
and
Computer
Software
clause
at
52.227-7013.
Hewlett-Packard Company
3000 Hanover Street, Palo Alto, California 94304
Printed in U.S.A.
© Copyright Hewlett-Packard Company 1965
P.O. Box 301, Loveland, Colorado 80537 U.S.A.
Printed: August 1984

HEWLETT
|G | PACKARD
CERTIFICATION
Hewlett-Packard Company certifies that this product met its published specifications at the time of shipment from the
factory. Hewlett-Packard further certifies that its calibration measurements are traceable to the National Institute of
Standards
and
Technologies,
to
the
extent
allowed
by
the
the
Institute's
calibration
facility,
and
to
the
calibration
facilities
of other International Standards Organization members.
WARRANTY
This
Hewlett-Packard
instrument
product
is
warranted
against
defects
in
materials
and
workmanship
for
a
period
of
one
year
from
date
of
shipment
{,except
that
in
the
case
of
certain
components
listed
in
Section
I
of
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
a
service
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.
Duration and conditions of warranty for this instrument may be superceded when the instrument is integrated into
(becomes a part of) other -hp- instrument products.
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 specifica-
tions 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 A PARTICULAR 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.
3/11/83

) HEWLETT
() PACKARD
SAFETY SUMMARY
The
following
general
safety
precautions
must
be
observed
during
all
phases
of
operation,
service,
and
repair
of
this
instrument.
Failure
to
comply
with
these
precautions
or
with
specific
warnings
elsewhere
in
this
manual
violates
safety
standards
of
design,
manufacture,
and
intended
use
of
the
instrument.
Hewlett-Packard
Company
assumes
no
liability
for
the
customer's
failure
to
comply
with
these
requirements.
This
is
a
Safety
Class
1
instrument.
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
piugg-
ed
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
mating
plug
of
the
power
cable
meet
International
Electrotechnical
Commission
(IEC)
safety
standards.
DO 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
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
con-
nected.
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
perform
any
unauthorized
modification
to
the
instrument.
Return
the
instrument
to
a
Hewlett-Packard
Sales
and
Ser-
vice
Office
for
service
and
repair
to
ensure
that
safety
features
are
maintained.
DO NOT OPERATE A DAMAGED INSTRUMENT
Whenever
it
is
possible
that
the
safety
protection
features
built
into
this
instrument
have
been
impaired,
either
through
physical
damage,
excessive
moisture,
or
any
other
reason,
REMOVE
POWER
and
do
not
use
the
instrument
until
safe
operation
can
be
verified
by
service-trained
personnel.
If
necessary,
return
the
instrument
to
a
Hewlett-Packard
Saies
and
Service
Office
for
service
and
repair
to
ensure
that
safety
features
are
maintained.
;
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,
are
present
in
this
instrument.
Use
extreme
cau-
tion
when
handling,
testing,
and
adjusting.

SAFETY SYMBOLS
General Definitions of Safety Symbols Used On Equipment or in Manuals.
iF
bo O-P
abel
ie
al
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 a fault. Used with field wiring terminals to in-
dicate the terminal which must be connected to ground before
operating 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 a 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 (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).
The WARNING sign denotes a hazard. It calls attention to a pro-
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 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.
The NOTE sign denotes important information. It calls attention
to procedure, practice, condition or the like, which is essential to
highlight.

TABLE OF CONTENTS
Section Page
I. GENERAL INFORMATION
1-1. Introduction ........................ 1-1
1-3. Description and Purpose............. 1-1
1-8. Specifications ....................... 1-1]
1-10. Instrument and Manual Identification. .1-1
1-12. Equipment Supplied............0.... 1-1
1-14. Accessory Equipment Available....... 1-3
Section Page
I. INSTALLATION
2-1. Introduction ........................ 2-1
2-3. Initial Inspection.................... 2-1
2-5. Power Requirements................. 2-1
2-8. Installation ......................0.. 2-1
2-10. Combining Case (-hp- Models 1051A or
LOS 2A) Soni cieee Casta Se wins Me ies tees 2-1
2-12. Adapter Frame (-hp- Part No.
5060-0797)... 0... eee eee eee 2-2
2-14. Repackaging for Shipment............2-2
Section Page
III. OPERATING INSTRUCTIONS
3-1. Introduction ...................022.. 3-]
3-3. Controls and Indicators.............. 3-1
3-5. Turn on Procedure.................. 3-1
3-7. Operating Instruction........... eae edel
3-9. Applications ...................00... 3-2
3-11. RMS Value of AC Signals with DC
Component...................000. 3-2
3-13. RMS Current..........0.0...00...... 3-2
3-15. RMS AC-to-DC Converter........... 3-2
Section Page
IV. THEORY OF OPERATION
4-1. Introduction ...........2..0........... 4-1
4-3. General Description.................. 4-]
4-11. Detailed Description................. 4-2
4-12. Input Attenuator Assembly Al....... 4-2
4-15. Impedance Converter Assembly A2...4-3
4-19. Second Attenuator Assembly A3..... 4-3
4-22. Video Amplifier Assembly A4........ 4-3
4-27. Chopper Op Amp Assembly A6 and
Thermocouple Pair (Part of A4)....4-4
4-36. Power Supply Assembly A7.......... 4-5
4-39. Regulator Operation................ 4-5
4-41. +75 Volt Supply....2..0..00...0... 4-5
4-43. —17.5 Volt Supply.........0020.00.. 4-5
Section Page
V. MAINTENANCE
5-1. Introduction ........................ 5-]
5-3. Test Equipment..................... 5-1
5-5. Performance Checks................. 5-1
5-7. Accuracy, Linearity, and DC Output
Check 3 3 este a esate ate §-1
5-9. Frequency Response Check.......... 5-4
5-10. Input Impedance Check............. §-5
5-11. Resistance Check...................5-5
5-12. Capacitance Check.................545
5-13. Crest Factor Check................. 5-6
5-14. Output Noise Check................ 5-7
5-15. Adjustment and Calibration
Procedures................00cceees 5-7
5-17. Mechanical Meter Zero.............. 5-7
5-19. Power Supply Checks............... 5-8
5-21. Low Frequency Calibration.......... 5-8
5-22. Amplifier Offset Adjustment......... 5-8
5-23. Amplifier Gain Adjustment.......... 5-8
5-24. 1/10 Scale Adjustment.............. 5-8
$-25. 1 Volt Adjustment.................. 5-9
5-26. High Frequency Calibration......... 5-10
5-27. Amplifier Gain Adjustment......... 5-10
5-28. Input Attenuator Adjustment....... 5-10
5-29. Second Attenuator Adjustment...... 5-11
5-30. Troubleshooting Procedures......... $-11
5-35. Checking Thermocouples TC410 and
ST C402 Seta coheed wae ae 5-11
5-38. Thermocouple Replacement......... 5-14
5-40. Servicing Etched Circuit Boards...... 5-15
5-43. A6 Assembly (03400-66512) Retrofit
PROCEGUIC:: S45 end soda al owetts 5-16
Section Page
VI. CIRCUIT DIAGRAMS
: 6-1. Introduction ..................0000.. 6-1
6-3. Schematic Diagrams................. 6-1
6-6. Parts Location Diagrams............. 6-1
Section Page
VU. REPLACEABLE PARTS
7-1. Introduction ...............0...002.. 7-1
7-4. Ordering Information................ 7-]
7-6. Non-Listed Parts.................... 7-1
7-8. Parts Changes.....................0.. 7-2
APPENDIX
A. BACKDATING

LIST OF TABLES
Table Page
1-1. Model 3400A Specifications............... 1-2
1-2. Equipment Supplied...................... 1-3
1-3. Accessory Equipment Available............. 1-3
5-1. Required Test Equipment................. 5-2
5-2. Accuracy, Linearity, and DC Output
Check’ Datan2c. 22 ei isda nie vee en 5-3
5-3. Frequency Response Check................ 54
5-4. Power Supply Checks.................-... 5-9
5-5. Front Panel Symptoms..............-.-.. 5-12
5-6. Troubleshooting Procedure............... 5-13
5-7. Factory Selected Components............. 5-15
7-1. List of Abbreviations..................... 7-2
7-2. Code List of Manufacturers............... 7-2
7-3. Replaceable Parts..............-.2..--.-. 7-3
LIST OF ILLUSTRATIONS
Figure Page
j-1. 3400 RMS Voltmeter.................-.6. 1-2
3-1. Model 3400A Controls and Indicators...... 3-3
4-1. Block Diagram................-2---2.-06- 4-2
5-1. Accuracy, Linearity, and DC Output Test
StU isos Bea be eae eS hers weed os 5-3
5-2. Frequency Response Test Setup............ 5-4
5-3. Input Impedance Test Setup............... 5-5
5-4. Crest Factor Test Setup................... 5-6
5-5. Testing the Thermocouples............... 5-13
5-6. Troubleshooting Tree.................... 5-13
5-7. Input to Demodulator................... 5-13
6-1. Input Attenuator Al, Impedance
Converter A2, and Second Attenuator
A3 Schematic and Parts Location
Diagram ss oe sce ts eee stesso dae 6-3
6-2. Video Amplifier A4, Schematic and
Parts Location Diagram................. 6-5
6-3. Chopper Amplifier A6 and Thermocouple
Pair (Part of A4) Schematic and Parts
Location Diagram.........-..........-. 6-7
6-4. Power Supply A7, Schematic and Parts
Location Diagram...............2....-. 6-9
7-1. Modular Cabinet.......................-. 7-3
7-2. 3400A Top View..................-2---6- 7-8
7-3. 3400A Bottom View............... 002-065 7-9
7-4. 3400A Bottom View with Shield
RemOVEO 0.5 ok da ieiorgre eb a waco icles ie 7-10
7-5. 3400A Rear View................. 2000005 7-11
7-6. 3400A Left Side View................--.. 7-12
7-7. 3400A Right Side View.................. 7-13
A-1. Figure 6-3 Component Locator
Changes (Change #1)............-...-.- A-5
A-2. Figure 6-3 Schematic (Change #1).......... A-5
A-3. Input Attenuator Al, Impedance
Converter A2, and Second
Attenuator A3 Schematic
and Parts Location Diagram............ A-7
A-5. Figure 6-4 Schematic Changes
(Change #2)..............222-.0--0-0-5 A-9

SECTION |
GENERAL INFORMATION
1-1. INTRODUCTION
1-2.
This
section
contains
general
information
about
the
Model 3400A
RMS
Voltmeter
(Figure
1-1).
Included
are:
description
of
instrument,
purpose,
instrument
identification,
equipment
supplied
and
accessory
equipment
available.
Also
included
is
a
table
of
instru-
ment
specifications.
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
a
specified
full-scale
accuracy
of
+1%
from
50
Hz
to
1
MHz,
+2%
from
1
MHz
to
2
MHz,
+3%
from
2
MHz
to
3
MHz,
and
+
5%
from
10
Hz
to
50
Hz
and
3
MHz
to
10
MHz.
A
single
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
a
1%
duty
cycle.
At
1/10th
of
full
scale,
pulse
trains
with
0.01%
duty
cycle
(100:1
crest
factor)
can
be
accurately
measured.
1-7.
The
Model
3400A
provides
a
dc
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-dce
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
a
two-section
serial
number.
If
the
first
section
(serial
prefix)
of
the
serial
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
in-
strument
and
the
Model
3400A
described
in
this
manual.
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
1-13.
The
equipment
supplied
with
each
Model
3400A
is
listed
and
described
in
Table
1-2.
I-]

General Information
Model 3400A
Table 1-1. Model 3400A Specifications
VOLTAGE RANGE: 1 mV to 300 V full scale, 12 ranges.
DB RANGE: -72 to +52 dBm (0 dBm = 1 mW in 6009).
FREQUENCY RANGE: 10 Hz to 10 MHz.
RESPONSE: Responds to rms value (heating value) of input
signal.
METER ACCURACY:”* from 1/10 scale to full scale is % of
Full Scale (20°C to 30°C)**
10Hz 50Hz 1MHz 2MHz 3MHz 10MHz
[=5% | =1% | =2% | +3% J =5%|
AC-to-DC CONVERTER ACCURACY: % of Full Scale (20°C to
| 30°C)*
10Hz 50Hz IMHz 2MHz 3MHz 10MHz
[=5% | =0.75%
OUTPUT: Negative 1 V dc into open circuit for ‘full-scale
deflection, proportional to meter deflection; 1mA maximum;
nomina! source impedance 10000.
OUTPUT NOISE: < 1 mV RMS.
thy
**
Temperature
Coefficient:
=.15%/°C
over
range
of
0°C
to
20°C
and
30°C
to
55°C.
papok OWS VOLTMCTER re)
neeser?
CREST FACTOR: (ratio of peak-to-rms amplitude 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).
IMPUT IMPEDANCE 0.001 V to 0.3 V range; 10 MQ shunted
by <50 pF: 1.0 V to 300 V range; 10 M@ shunted by <20
pF. AC-coupied input.
AC OVERLOAD: 30dB above full scale or 800 V peak,
whichever is less, on each range.
MAXIMUM DC INPUT: 600 V on any range.
RESPONSE TIME: For a step function, <5 seconds to respond
to final value.
POWER: 115 or 230 V + 10%, 48 to 440 Hz. approximately
7 watts.
WEIGHT: Net 7 1/4 Ibs. (3, 3kg); shipping 10 ibs. (Skg).
OVERALL DIMENSIONS: 6 1/2’’ high; 5 1/8°° wide; 11
11/16" deep.
STORAGE TEMPERATURE: — 10°C to +60°C.
* The 3400A may show a zero offset with no voltage applied to the input terminalis.
+ pacman
RANGE
-
“7
-30 «03
Figure 1-1. 3400 RMS Voltmeter
1-2

Model
3400A
General
Information
1-14, ACCESSORY EQUIPMENT AVAILABLE
1-15.
The
accessory
equipment
available
is
listed
in
Table
1-3.
For
further
information
con-
tact
your
local
-hp-
Sales
and
Service
Office.
Table 1-2. Equipment Supplied
identification
: Number Description
101108 Adapter (BNC to
dual banana jack)
8120-1348 ee ee ae | Power Cord |
03400-90011 Operating and
Service Manual
Table 1-3. Accessory Equipment Available
10503A Cable (Male BNC to male BNC,
48 inches)
11001A Cable (Male BNC to dual ba-
nana 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.)
Current Probe
1-3/1-4

SECTION Il
INSTALLATION
2-1. INTRODUCTION
2-2. This section contains information and instructions necessary for installation and ship-
ping of the -hp- Model 3400A RMS Voltmeter. Included are initial inspection procedures,
power requirements, installation information, and instructions for repackaging for ship-
ment.
2-3. INITIAL INSPECTION
2-4. The -hp- Model 3400A RMS Voltmeter received a careful mechanical and electrical in-
spection 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 damage 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 instru-
ment 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 a 0.25 amp, fast blow type for 115- or 230-volt GpetsHon: Power dissipation is ap-
proximately 7 watts.
2-7. The Model 3400A is equipped with a three-prong power cord. To protect operating per-
sonnel, it is necessary to preserve the grounding feature of this plug when using a two con-
tact
ac
outlet.
Use
a
three-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
a
submodular
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
a
full-module
unit
which
accepts
various
combinations
of
sub-
modular units. Being a full-module unit, it can be bench or rack mounted and is analogous
to any full-module instrument.

Installation Model 3400A
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.
2-14. REPACKAGING FOR SHIPMENT
2-15. The following paragraphs contain a general guide for repackaging for shipment. Refer
to paragraph 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 sérvice
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, proceed as follows:
a. Place instrument in original container if available. 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, proceed 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 card-
board 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.

SECTION Ill
OPERATING INSTRUCTIONS
3-1. INTRODUCTION
3-2.
This
section
consists
of
instructions
and
information
necessary
for
the
operation
of
the
-hp-
Model
3400A
RMS
Voltmeter.
This
section
contains
identification
of
controls
and
in-
dicators,
turn-on
procedures,
and
operating
instructions.
Also
included
is
a
discussion
of
the
applications for the Model 3400A.
3-3. CONTROLS AND INDICATORS
3-4.
Each
operating
control,
connector,
and
indicator
located
on
the
Model
3400A
is
iden-
tified
and
described
in
Figure
3-1.
The
description
of
each
component
is
keyed
to
an
illustra-
tion
of
that
component
which
is
included
within
the
figure.
3-5. TURN ON PROCEDURE
3-6.
To
turn
on
the
Model
3400A,
proceed
as
follows:
a.
Set
115/230
switch
(7,
Figure
3-1)
to
correct
position
for
input
line
voltage.
b.
Apply
ac
voltage
to
Model
3400A
by
plugging
power
cord
into
input
power
jack
(8)
ac
receptacle.
c.
Operate
power
switch
(4)
to
ON;
ensure
that
LINE
indicator
(3)
lights.
NOTE
Allow
five
minutes
for
the
Model 3400A
to
warm
up
and
stabilize
before
making
a
reading.
3-7. OPERATING INSTRUCTION
Do
not
measure
signal
above
80
volts
with
10
to
1
crest
Jactor.
Otherwise,
the
maximum
input
rating
(800
volts
peak)
will
be
ex-
ceeded.
When
measuring
signals
up
to
80
volts
RMS
with
a
10
to
1
crest
factor,
use
the
BNC
to
dual
banana
jack,
accessory
10110A,
Supplied
with
the
instrument,
or
other
input
test
leads
and
connec-
tions
that
will
withstand
the
maximum
input
of
800
volts
peak.
3-8.
To
operate
the
Model
3400A
as
an
rms
voltmeter
proceed
as
follows:
a.
Attach
test
lead
to
INPUT
connector
(6,
Figure
3-1).
(See
Table
1-3
for
a
list
of
test
leads
available.)
3-1]

Operating
Instructions
Model
3400A
b. Set RANGE switch (5) to 300 VOLTS position.
When measuring an ac signal superimposed on a DC level, always
set the range switch to the 300 volt position. A high voltage tran-
sient due to the application of a DC voltage will damage the input
circuitry.
c. Connect test lead to point to be measured.
d. Rotate RANGE switch counterclockwise until meter (1) indicates on upper two thirds
of scale.
3-9. APPLICATIONS
3-10.
The
Model
3400A
can
be
used
in
conjunction
with
other
test
instruments
to
measure
the
rms
value
of
ac
signal
with
a
dc
component,
measure
rms
current
and
act
as
an
rms
ac-to-
dc
converter.
For
additional
informatidn
on
special
applications,
contact
your -hp-
Sales
and
Service
Office.
3-11. RMS Value Of AC Signals With DC Component
3-12.
Since
the
3400A
is
an
ac
device
it
will
measure
only
the
rms
value
of
the
ac
component.
If
it
is
necessary
to
include
the
mms
value
of
the
dc
component
when
measuring
a
signal
use
an
-hp-
Model
3468A
Digital
Multimeter
to
measure
the
dc
component.
Substitute
the
reading
from
the
Model
3468A
and
Model
3400A
in
the
following
formula:
The
ac
signal
(up
to
800V
peak)
may
be
superimposed
on
a
dc
level
of
up
to
600
V.
mms =/ Sacer + Sae-
3-13. RMS Current
3-14. To measure rms current, use an -hp- Model 456A AC Current Probe. This probe clips
around the current conductor and provides an output voltage that is proportional to the cur-
rent
being
measured.
Using
this
method,
rms.currents
of
one
milliampere
to
one
ampere
can
be measured.
3-15. RMS AC-To-DC Converter
3-16.
Since
the
Model
3400A
is
provided
with
a
dc
output
(10,
Figure
3-1)
which
is
propor-
tional
to
the
meter
deflection,
it
can
be
used
as
a
linear
rms
ac
to
de
converter.
The
dc
output
can
be
used
to
drive
an
-hp-
Model
3468A
Digital
Multimeter
for
high
resolution
measurements
and/or
an
-hp-
Model
680
Strip
Chart
Recorder.
External
loading
does
not
affect
the
meter
accuracy
so
that
both
the
meter
and
dc
output
can
be
used
simultaneously.
A
plug
for
DC
OUT
jack
may
be
purchased
under
-hp-
Part
No.
1251-0067.
3-2

Model 3400A
Oresers
sev sate
Direct reading meter: dc meter which indicates rms
voltage level of input signal.
Mechanical zero adjustment: screwdriver adjustment for
zero of direct reading meter.
LINE ON pilot lamp: neon lamp which indicates when
power is applied to instrument and power switch is ON.
Power switch: two-position toggle switch which applies
115- or 230-volts ac to instrument.
RANGE switch: 12-position rotary switch which selects
various attenuation ranges available within Model 3400A.
INPUT connector: BNC jack which enables application of
input signal to instruments measuring circuits.
®Oo ©
Operating Instructions
115/230-volt switch: two-position slide switch which
sets
instrument
to
operate
from
either
a
115-
or
230-volt
ac source.
Input
power
jack:
three-prong
jack
which
enables
ap-
plication
of
line
voltage
to
instruments
power
supply
cir-
cuits.
115V/230V .25A FUSE: 0.25 ampere fuse which
provides protection against line voltage surges.
DC OUT jack: telephone-type jack which provides
negative
1-volt
de
out
at
full
scale
deflection,
output
is
°
Proportional
to
meter
deflection.
Output
impedance
is
1000 ohms.
A
telephone
plug
for
the
DC
OUT
jack
may
be
purchased
under
-hp-
Part
No.
1251-0067.
Figure 3-1. Model 3400A Controls and Indicators
3-3/3-4

SECTION IV
THEORY
OF
OPERATION
4-1. INTRODUCTION
4-2.
This
section
contains
the
theory
of
operation
of
the
Model
3400A
RMS
Voltmeter.
In-
cluded
is
a
general
and
detailed
description
of
the
theory
of
operation.
4-3. GENERAL DESCRIPTION
4-4.
The
operation
circuitry
of
the
Model
3400A
consists
of
two
attenuators,
an
impedance
converter,
a
video
amplifier,
a
chopper
op
amp,
a
thermocouple
pair,
and
a
direct
reading
meter.
4-5.
A
signal
being
measured
with
the
Model
3400A
is
applied
to
input
attenuator
Al
through
the
INPUT
jack,
located
on
the
Model
3400A
front
panel.
The
input
attenuator
has
an
input
impedance
of
over
10
megohms
and
provides
two
ranges
of
attenuation.
The
out-
put
of
the
input
attenuator
is
applied
to
impedance
converter
A2.
The
impedance
converter
is
a
non-inverting
unity
voltage
gain
amplifier.
It
presents
a
high
impedance
to
the
input
signal
and
provides
a
low
impedance
output
to
drive
the
second
attenuator
A3.
The
second
attenuator
provides
6
ranges
in
a
1,
3, 10
sequence.
The
two
attenuators
are
switched
to
pro-
vide
12
ranges
of
attenuation.
4-6.
The
output
of
the
second
attenuator
is
amplified
by
video
amplifier
A4.
The
video
amplifier
is
a
wideband,
five
stage
amplifier.
The
overall
gain
of
the
video
amplifier
is
con-
trolled
by
an
ac
feedback
loop.
The
ac
output
of
the
amplifier
is
applied
to
TC401;
one
of
the
thermocouples
of
the
thermocouple
pair.
°
4-7.
The
dc
output
of
TC401
is
applied
to
the
chopper
op
amp
(U601)
which
modulates
the
voltage.
The
resultant
modulated
signal
is
then
amplified
and,
after
the
amplification,
the
signal
is
demodulated
back
to
de
volts.
This
voltage
is
the
output
of
the
chopper
op
amp.
The
value
of
the
voltage
is
proportional
to
the
dc
input
voltage.
4-8.
The
output
of
the
chopper
op
amp
is
applied
to
a
filter
and
also
to
TC402,
the
second
thermocouple
of
the
thermocouple
pair.
The
output
of
the
filter
is
applied
to
an
output
amp
(A4)
which
is
used
to
drive
the
meter
(M1).
4-9.
The
thermocouple
pair
TC401
and
TC402
acts
as
a
summing
point
for
the
ac
output
of
the
video
amplifier
(A4)
and
the
dc
output
of
the
chopper
op
amp.
The
difference
in
the
heating
effect
of
these
voltages
is
the
dc
input
to
the
chopper
op
amp.
This
difference
input
is
amplified
and
is
fed
to
TC402
and
also,
after
going
through
the
output
amplifier
(U602),
to
the
meter
(M1).
This
voltage
represents
the
rms
value
of
the
ac
Signal
applied
to
the
3400A’s
INPUT
jack.
By
using
two
“‘matched’’
thermocouples
and
measuring
the
dif-
ference,
the
output
of
the
chopper
op
amp
will
be
linear.
Using
two
thermocouples
also
pro-
vides
temperature
stability.
4]

Theory
of
Operation
Model
3400A
9 ==
a 7
¢ ¢
” v
7
Zc
'
INPUT
—
ee
TC40
|
| INPUT j | IMPEDANCE | SECOND ; | VIDEO +
>= OATTEN «CONVERTER ATTEN «= AMPLIFIER
1 i Al A2 mod A3 fo} 4
!
|
}
[ce
H
lene
ewww nnen
Figure 4-1. Block Diagram
4-10.
The
dc
voltage
driving
meter
M1
is
also
available
at
the
DC
OUT
jack,
located
at
the
rear
of
the
Model
3400A.
:
4-11. DETAILED DESCRIPTION
4-12. input Attenuator Assembly At
4-13.
The
input
attenuator
assembly
is
a
capacitive-compensated
attenuator
which
provides
two
ranges
of
attenuation
for
the
12
positions
of
the
RANGE
switch.
See
input
attenuator
schematic
diagram
illustrated
on
Figure
6-1.
4-14.
When
the
RANGE
switch
is
positioned
to
one
of
the
six
most
sensitive
ranges
(.001
to
.3
VOLTS),
the
attenuator
output
voltage
is
equal
to
the
input
voltage.
When
the
RANGE
switch
is
positioned
to
one
of
six
highest
ranges
(1
to
300
VOLTS),
the
input
signal
is
at-
tenuated
60
dB
(1000:
1
voltage
division)
by
the
resistive
voltage
divider
consisting
of
R101,
R103,
and
R104.
Trimmer
C102
is
adjusted
at
100
kHz,
and
R104
is
adjusted
at
400
Hz
to
provide
constant
attenuation
over
the
input
frequency
range.
4-2