TB 9-6625-1966-24
9. Dial Accuracy and Stability
a. Performance Check
(1) Disconnect calibrator from equipment setup.
(2) Connect shorting strap between FREQ DIAL and FREQ CONTROL
(rear panel).
(3) Position controls as listed in (a) through (c) below:
(a) FREQUENCY dial to 1.
(b) RANGE switch to X100.
(c) CHANNEL A function switch to SINE.
(4) Measure frequency. If frequency counter does not indicate between 9.090 and
11.111 ms, perform b below.
(5) Repeat (4) above at autotransformer settings of 105 and 125 V.
(6) Adjust autotransformer for 115 V output.
(7) Repeat technique of (4) above at RANGE and FREQUENCY settings listed in
table 3. If frequency counter does not indicate within limits specified, perform b below.
b. Adjustments
(1) Set FREQUENCY dial to 1 and RANGE switch to X100.
(2) Loosen FREQUENCY dial from shaft.
(3) Rotate shaft until frequency counter indicates 10 ms (R).
(5) Set FREQUENCY dial to 10.
(6) Adjust A13R17 or R6 (fig. 2) until frequency counter indicates 1 ms (R).
(7) Repeat (1) through (6) above for best in-tolerance condition.
(8) Set RANGE switch to X1K and FREQUENCY dial to 10.
(9) Adjust A13C19 (fig. 2) until frequency counter indicates 10 kHz (R).
Table 3. Dial Accuracy
Test instrument
Frequency counter indications
FREQUENCY dial
RANGE switch settings
Min
Max
settings
X100
5
1.96 ms
2.04
ms
X100
10
0.99 ms
1.01
ms
X0.01
10
9.90
s
10.10
ms
X0.01
5
19.6
s
20.4
s
X0.01
1
90.90
s
111.11
X0.1
1
9.09
s
11.11
s
X0.1
5
1.96
s
2.04
s
X0.1
10
0.99
s
1.01
s
X1
10
99
ms
101
ms