TM 9-4935-282-34
803D
required; apply output DC supply to 540A and null
(b)
Apply 0.5 volt AC at 20 kilocycles to
galvanometer by adjusting internal reference supply voltage;
apply output of AC oscillator to 540A and null galvanometer by
(c) Adjust 0.5 VAC HF TRIM control C519
adjusting AC oscillator voltage; the output of the oscillator now
until meter needle is within +30 microvolts (1-1/2 small
equals the required voltage.
divisions) of needle position noted in (2).
(2) 0.5 VAC Converter Gain Adjustment.
(6) 0.5 VAC Converter Gain Check.
(a) Set RANGE switch to 0.5 volt position.
(a) Apply 0.5 volt AC at 400 cycles to
(b) Apply 0.5 volt AC at 400 cycles to volt
meter.
(b) If meter needle is not within 50
(c) Adjust 0.5 VAC GAIN COARSE ADJ
microvolts (2-1/2 small divisions) of null, adjust 0.5 VAC GAIN
control R536 and 0.5 VAC GAIN FINE ADJ control R545 until
FINE ADJ control R545 and then repeat (3), (4), and (5) before
meter needle is within +30 microvolts (1-1/2 small divisions) of
continuing with (7).
null. Use R545 for final touch up trying to keep control in
(7) 5 VAC Converter Gain Check.
center third of its mechanical range. Note position of meter
(a) Set RANGE switch to 5 volt position.
needle.
(b) Apply 5 volts AC at 400 cycles to
(3) 5 VAC Converter Gain Adjustment
(a) Set RANGE switch to 5 volt position.
(c) If meter needle is not within +50
(b) Apply 5 volts AC a 400 cycles to
microvolts (2-1/2 small divisions) of null, adjust 5 VAC GAIN
FINE ADJ control R541 and repeat (4) and (5) before
(c) Adjust 5 VAC GAIN COARSE ADJ
continuing with (8).
control R542 and 5 VAC GAIN FINE ADJ control R541 until
(8) 500 VAC Attenuator Adjustment.
meter needle is within +30 microvolts (1-1/2 small divisions) of
(a) Set RANGE switch to 500 volt position.
null. Use R541 for final touch up trying to keep control in
(b) Apply 500 volts AC at 400 cycles to
center third of its mechanical range. Note position of meter
needle.
(c) Adjust 500 VAC ATTEN COARSE ADJ
(4) 5 VAC High Frequency Adjustment
control R535 and 500 VAC ATTEN FINE ADJ control R544
(a) Apply 5 volts AC at 10 kilocycles to
until meter needle is within 30 microvolts (1-1/2 small
divisions) of null. Use R544 for final touch up trying to keep
(b) Adjust 5 VAC HF TRIM control C504
control in center third of its mechanical range. Note position of
until meter needle is within +30 microvolts (1-1/2 small
meter needle.
divisions) of needle position noted in (3).
(5) 0.5 VAC High Frequency Adjustment.
(a) Set RANGE switch to 0.5 volt position.
Figure 4-5. AC TO DC CONVERTER CALIBRATION SET-UP
4-7
