TM 11-6625-3053-14
STEP
OPERATION
NORMAL INDICATION
CORRECTIVE ACTION
9
MODE BALANCE ALINEMENT, OR BALANCING OUTPUT OF AT1 AND AT2 ON A5
Remove instrument dust cover if on. If dust cover is already off, and sig gen energized, set
modulation switch to RF OFF.
Connect test set up for output power check as in para 6-14 step 7.
Set sig gen to initial settings of para 2-4, and FREQUENCY at about 1680 MHz. Set ext power
meter to +5 dBm range.
Energize ext power meter and sig gen if off.
Set MODULATION switch to CW if sig gen was on or wait 2 mins before doing so if just energized.
Set ALC switch to ON and adjust ALC SET to SET on POWER MONITOR METER.
Observing ext power meter, tune upward in frequency through the mode switching frequency
to about 1720 MHz.
The steady state level of power measured before the mode switching
should equal the power measured after the mode switching within 0.2 dB.
If this is not the case, position and
turn circuit card A3 into vertical
position. Adjust A3R24 until the
condition is met. Replace A3 card
to its permanent hor position.
NOTE
Adjustment of A3R24 balances output of both halves
of A5 assy by sending the output of AR4 Leveling
and Modulating Amplifier in equal parts to AT-1 and
AT-2 sections of A5 assy. This compensates for
changes in power levels generated as frequency is
changed. Being inverted, the output of AR4 opposes
the direction of the power level change, and thereby
restores the level to its original value. See para 6-12
for a more complete explanation of this process.
If alinement ends here:
Deenergize sig gen.
Replace dust cover (para 6-20).
6-45