TB 9-6625-1999-35
(2) Set MODULATION SELECTOR switch to CW.
(3) Adjust ATTENUATOR VERNIER control for a 0 DBM indication on R.M.S.
VOLTS meter. Record true
rms voltmeter indication.
(4) Rotate FREQUENCY control throughout range while maintaining a constant
output voltage indication on true rms voltmeter. Record maximum and minimum dBm
indications on R.M.S. VOLTS meter. If recorded indications are not between -1 and +1
dBm perform b below.
(5) Repeat (3) and (4) above at each RANGE switch setting.
b. Adjustments
(1) Select maximum and minimum value from values recorded in a (4) and (5) above
and determine average of the two values.
(2) Set RANGE switch and adjust FREQUENCY control until average value
computed in (1) above is indicated on true rms voltmeter.
(3) Adjust ATTENUATOR VERNIER control for a 0.9 V indication on true rms
voltmeter.
(4) Adjust OUTPUT CAL R37 (fig. 1) for a 0.9-V indication on R.M.S.
VOLTS meter (R).
28. Modulation Output
Distortion
a. Performance Check
(1) Connect audio analyzer to MODULATION INPUT-OUTPUT.
(2) Set MODULATION SELECTOR switch to INT. 1000∼. Audio analyzer will
indicate less than 1 percent distortion.
(3) Set MODULATION SELECTOR switch to INT. 400∼. Audio analyzer will
indicate less than 1 percent distortion.
b. Adjustments. No adjustments can be made.
NOTE
Do not perform power supply check if all other parameters are
within tolerance.
a. Performance Check
(1) Set POWER switch to off.
(2) Connect multimeter to 300 V test point (fig. 4).
(3) Set POWER switch to ON and allow 10 minutes for warm-up and stabilization.
If multimeter does not indicate between 288 and 312 V dc, perform b below.