HP 4001, Организационное, ДС, ГС и ремонтное руководство на уровне базы, Страница: 33 / 73

TM 11-6625-1514-15
Section V
Figure 5-6. Test Setup for Calibration Check and Adjustments
meter reading; it must not be higher than the residual The residual reading on voltmeter must be no higher
than the residual reading obtained with voltmeter INPUT
terminated with a 10-megohm resistor and shielded to
prevent stray pickup. If the residual reading is higher
when connected to the calibrator, refer to paragraph 3-12.
e. Set the voltmeter RANGE switch to .001. Set the
voltmeter calibrator to provide. 001 volt rms (400 cps)
output. Record deviation of voltmeter reading from 1
on the voltmeter scale.
f. Set the voltmeter RANGE switch to 1. Set the
voltmeter calibrator to provide 1 volt rms output. Re-
cord deviation of voltmeter reading from 1 on the volt-
meter scale.
g. Still using the voltmeter l-volt range, reduce the
voltmeter calibrator output in 0.1 volt steps. Record
deviation of voltmeter readings from each 0.1 volt cali-
bration mark.
h. Compare recorded deviations with the permissible
errors listed in the performance specifications in
figure 1-2.
i. Connect the voltmeter as shown in figure 5-7
and set line voltage to 115. (This setup measures
calibration accuracy at low and high frequencies.)
j. Set voltmeter RANGE switch to .001. Set frequency
response test set OUTPUT ATTENUATOR to .001 to
measure the lowest voltmeter range; initially set
AMPLITUDE control for 0 volts output. Then note volt-
00102-3
reading noted in step d.
k. Turn the frequency response test set RANGE
SELECTOR to EXTERNAL. Set the external oscillator
frequency to 400 cps; adjust the oscillator output level
to obtain a reading of .9 on the 0 to 1 VOLTS scale of
the voltmeter. Then adjust the METER SET control on
the frequency response test set to obtain a standard
meter indication at the SET LEVEL mark on the test
set meter.
l. Tune the external oscillator to 10 cps and adjust
its output level to keep the frequency response test set
meter reading at SET LEVEL. Do not adjust the METER
SET control as this would alter the fixed monitoring
point of the meter. Record the voltmeter deviation
from .9 on the scale. This reading must be between
0.85 and 0.95 to be within specifications.
m. Set the RANGE SELECTOR on the test set to 3-10
mc, set the FREQ. TUNING dial to 4, and adjust the
AMPLITUDE control to keep the frequency response
test set meter reading at SET LEVEL. Record the
voltmeter deviation from .9 on the scale. This reading
must be between 0.85 and 0.95 to be within specifications.
The gain and frequency response of the basic voltmeter
amplifier is now tested.
n. Repeat step m using line voltages of 103 and 127.
Record voltmeter deviation from .9 on the scale.
o. Set voltmeter RANGE switch to .003 and also set
the frequency response test set OUTPUT ATTENUATOR
to .003 to check this voltmeter range. Repeat steps k
and m. Record voltmeter deviation from .9 on the scale.
5-7