HP 400D Operating And Service Manual

T.O. 33A1-12-349-1 Section V
Paragraphs 5-1 to 5-8
SECTION V
MAINTENANCE
procedures. If an adjustment or replacement of parts
is made without following instructions or understanding
the effects, further trouble shooting may be complicated.
5-1. SCOPE.
5-2. This section contains complete instructions for
repairing and calibrating the voltmeter. This material
is
covered
in
the
following
groups
of
paragraphs:
b.
Do
not
remove
tubes
when
the
voltmeter
is
turned
on. Before replacing tubes refer to paragraph 5-10.
Lead F
Paragraph
tals
5-5.
TEST
EQUIPMENT
REQUIRED.
5-3.
Precautions
5-6.
The
test
equipment
required
for
complete
testing
5-5.
Test
Equipment
Required
of
the
voltmeter
is
listed
in
figure
5-1.
Equivalent
5-7.
Meter
Zero
Adjustment
instruments
may
be
substituted
for
those
listed.
5-9.
Cabinet
Removal
5-10.
Tube
Replacement
5-7.
METER
ZERO
ADJUSTMENT.
5-13.
Replacement
of
Special
Parts
5-17.
Trouble
Shooting
5-8.
The
meter
is
properly
zero-set
when
its
pointer
5-20.
Testing
the
Power
Supply
rests over
the zero
calibration
mark on the
meter scale
5-22.
Testing
Voltmeter
Performance
when
the
instrument
is
1)
at
normal
operating
tempera-
5-24
Calibration
and
Frequency
Response
ture,
2)
in
its
normal
operating
position,
and
3)
turned
Adjustments off. Adjust the zero-set if necessary, as follows:
5-3. PRECAUTIONS. a. Allow the voltmeter to operate for 20 minutes so
that the meter movement will reach normal operating
5-4. Observe the following precautions: temperature.
b. Turn the voltmeter off and allow one minute for all
capacitors to discharge.
a. Make no adjustments and replace no parts in the
voltmeter except as described in one of the following
Electronic
Multimeter
0 to 300 a-c and d-c volts;
accuracy of +3% or better;
input impedance 100 megohms.
Voltage and resistance ME-26B/U or
measurement. H-P 410B
Oscillator 10 cps to 300 kc; 3 volts Signal source for
Voltmeter Calibrator
(Precision Voltage
Source)
Frequency
Response
Test Set
Oscilloscope or
AC Voltmeter
Variable
Transformer
D-C Current
Test Set
(Milliammeter)
00102-3
output into 50-ohm load,
400-cps output voltage;
0.001 to 300 volts
in 10-db steps +0.2%; 0.1 to
1.0 volt in 0.1 volt steps +0.2%.
300-ke to 4-mc range;
3 volts output into 50-ohm load;
10-db steps, 0 to 70 db.
10-cps to 4-mc range.
Adjust line voltage between 103
and 127V ac with 1-amp load.
Clip-on type measurement;
current range up to 100 ma.
testing and calibration
Calibrating voltmeter
at mid-frequencies.
Calibrating voltmeter
frequency response.
Trouble shooting by
signal tracing.
Checking voltmeter
operation with
varying line
voltage.
Checking load on
power supply.
Figure 5-1. Test Equipment Required
160B or
400D
CN-16/U or
Ohmite VT2
5-1
;
1

HP 400D Specifications

General

Brand	HP
Model	400D
Category	Measuring Instruments
Language	English