TB 9-6695-261-35
b. Adjustments
(1) Connect oscilloscope to test point AO (fig. 1) located on PC418 card using probe.
(2) Position FREQUENCY Hz pushbuttons to indicate 1-0-0 and press
MULTIPLIER 1 pushbutton. If square wave component in the signal present at test point
AO is not less than 10 mV, adjust P331 (fig. 1) for minimum signal (R). Typical oscilloscope
(3) Position FREQUENCY Hz pushbuttons to indicate 0-9-0 and press
MULTIPLIER .1 pushbutton. If
square wave component (fig. 3) in the
signal present at
test point AO is not less than 100 mV p-p, adjust P421 (fig. 1) for minimum signal (R).
(4) Press MULTIPLIER 10 pushbutton, and adjust R142B (fig. 1) for a 0 V dc
output level (R).
Figure 2. AO at
100 Hz
(vertical sensitivity - 20
mV/cm).
Figure 3. AO at 9 Hz
(vertical sensitivity 50
mV/cm).
a. Performance Check
(2) Turn RMS VOLTS vernier control fully ccw.
(3) Press FREQUENCY Hz pushbuttons to indicate 1-0-0 and press
MULTIPLIER 10 pushbutton. If true
rms voltmeter does not
indicate between 8.818 and
9.182 V rms, perform b below.