TB 9-6625-1866-50
(5) Turn UUT polarity switch to - (negative).
(6) Repeat (1) through (3) above for negative indications on UUT meter.
(7) Adjust dc voltage standard for 0 (zero) indication on UUT meter and turn UUT
NULL switch to .01.
Table 8. Dc VTVM
Unit under test
Dc voltage standard indication (V)
Range switch
Meter indication
Min
Max
position
5
100
0.85
1.15
5
200
1.85
2.15
5
300
2.85
3.15
5
400
3.85
4.15
5
500
4.85
5.15
50
500
48.5
51.5
500
500
485
515
(8) Adjust dc voltage standard output until UUT meter indicates a negative 10 mV
(100 on lower scale). Dc voltage standard will indicate between 9.7 and 10.3 mV.
(9) Repeat technique of (7) and (8) above for settings and indications listed in table
Table 9. Null Range
Unit Under Test
Dc voltage standard
NULL
Meter indication
indication
switch position
(lower scale)
Min
Max
.1
100
97 mV
103 mV
1
100
0.97 V
1.03 V
10
100
9.7 V
10.3 V
(10) Turn UUT polarity switch to + (positive).
(11) Repeat technique of (7) through (9) above for positive indications on UUT meter.
(12) Turn UUT NULL switch to VTVM.
b. Adjustments
(1) Adjust dc voltage standard output to .500 volt.
(2) Adjust R219 (fig. 2) (rear of AN/USM -98B) until UUT meter indicates 500.
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