TB 9-4931-488-24
Table 26. Demodulated Output Accuracy (A26A8S1 set to DC).
True rms voltmeter
Measuring receiver % AM indications (%)
Indications (V Ac)
Min
Max
0.800
78.4
81.6
0.700
68.6
71.4
0.600
58.8
61.2
0.500
49.0
51.0
0.400
39.2
40.8
0.300
29.4
30.6
0.200
19.6
20.4
(22) Adjust AM control fully ccw. Set RANGE MHz switch to 512 - 256 and adjust
FREQUENCY TUNE control for a FREQUENCY MHz display indication of 333 MHz.
(23) Repeat technique of (15) through (21) above.
(24) Return A26A8S1 to AC position. Reduce all outputs to minimum. If there were
no failures re-install top cover.
b. Adjustments
NOTE
Disconnect all equipment before proceeding.
(1) Position controls as listed in (a) through (i) below.
(a) LEVEL VOLTS pushbutton pressed.
(b) AM switch to OFF.
(c) RANGE MHz switch to 256 - 128.
(d) FREQUENCY TUNE control for FREQUENCY MHz display of 190 MHz.
(e) AM control to mid range.
(f) OUTPUT LEVEL 10 dB switch to 0 dBm.
(g) OUTPUT LEVEL 1 dB switch to 0 dB.
(h) OUTPUT LEVEL vernier control to CAL.
(i) RF OFF/ON switch to OFF.
to AC.
(3) Connect multimeter to A26A8TP1 (BUFFER DET, fig. 2) and chassis ground.
Adjust A26A8R3 (BUFFER OFFSET, fig. 2) for a 0.000 0.001 V dc multimeter indication.
a 0.000 0.001 V dc multimeter indication.
(5) Disconnect ground from A26A8TP2 (fig. 2). Disconnect multimeter from
A26A8TP3 (fig. 2). Set multimeter to measure AC voltage and connect to AM IN
A26A2TP1 and GND (fig. 2).
(6) Connect pulse generator OUT 1 to TI AM input. Adjust pulse generator for a
100 Hz, 0.52 V ac output.
32