Section IV. TESTING PROCEDURES

TM 11-6625-444-14-1

e. Turn off the voltmeter and remove the buffer

Table 6-10. Buffer (A11) Resistor Values

assembly (A11).

f. Install the resistor selected in accordance

with step das R22 or R25 in the buffer assembly

(A11).

g. Solder a jumper across the unused resistor

position of R22 or R25.

h. Disconnect the shorting jumper across R28.

i. Install the buffer assembly (A11) in the

voltmeter.

j. Turn the voltmeter on. Insure that the VDC,

FILT, and 10V range are selected.

k. Adjust A11R28 (COARSE DC ZERO) for a

digital readout of 0.0000.

l. Disconnect the shorting jumper from the

INPUT terminals.

NOTE

The voltmeter requires total recalibration

in accordance with paragraph 6-16 after

selection of R22 or R25.

.................

Section IV. TESTING PROCEDURES

6-15. General

meter to ac line power and set the controls as

follows:

a. This section contains performance testing

POWER . . . . . . . . . . . . . . . . . . . . . . . . . ON

and alignment procedures for the voltmeter.

FUNCTION. . . . . . . . . . . . . . . . . . . . . VDC, FILT

Performance testing shall be conducted prior to

RANGE . . . . . . . . . . . . . . . . . . . . . . . . .10

p e r f o r m i n g any maintenance or alignment.

SAMPLE RATE . . . . . . . . . . . . . . . . . Full cw

Alignment of the voltmeter is required after any

DC ZERO . . . . . . . . . . . . . . . . . . . . . . . Midrange

RATIO FULL SCALE Midrange

maintenance affecting alignment accuracy is

performed or if unsatisfactory results are ob-

b. DC Volts Accuracy Checks.

tained from performance testing. Alignment,

(1) Connect a shorting jumper between the

however, should only be attempted if the volt

INPUT terminals.

meter is out of alignment but is fully operational

(2) Adjust the front panel DC ZERO control

b. All testing shall be conducted in a clean

for a digital readout of 00.0000 ± .0001.

d r a f t free environment having an ambient

(3) Connect a dc voltage calibrator to the

temperature of 730 ± 90 F. and a relative

INPUT terminals, observing polarity.

h u m i d i t y of less than 70%. Required test

(4) Apply each of the input voltages shown

equipment is listed in table 6-7.

in table 6-11 to the INPUT terminals. The digital

6-16. Performance Testing

readout shall be as specified.

a. Preliminary Operation. Connect the volt-

6-27