TM11-5895-846-14
If there is deflection, replace the amplifier/mixer drawer
a module has just been replaced, the front panel cables
and refer it to the next higher level of maintenance.
are disconnected, the amplifier/mixer is extended from
Return to step a(1) above.
the rack, and the AC POWER is turned off. Proceed as
(16) If the MONITOR meter on the PA and the
follows:
a. Preliminary.
SHF MONITOR meter on the amplifier/mixer have a
normal indication, but the amplifier/mixer FAULT lamp is
(1) Connect the SHF OUTPUT cable to the
on, attempt to adjust the fault threshold as in paragraph
amplifier/mixer drawer. It may be necessary to loosen
the captive screws and open the cable access covers to
and repeat the fault threshold adjustment. If still not
obtain enough cable slack to make the necessary
adjustable, replace A6CR1 and then perform the fault
connection with the drawer extended.
threshold adjustment in paragraph 5-36f below. Return
(2) Place the front panel AC POWER circuit
breaker to the ON position.
to step a(1) above.
(3) Place the STATUS MONITOR switch in
5-36. Amplifier/Mixer Adjustments
the IPA position. If using a TWT, operate and hold the
WARNING
FAULT RESET switch to the ON position until the
DANGEROUS VOLTAGES EXIST IN
STATUS MONITOR meter starts reading up scale and
THIS EQUIPMENT. Do not attempt
then release the FAULT RESET switch. Observe the
any removal or replacement unless
STATUS MONITOR meter for an indication of 16 to 32
the equipment is in a nonoperating
ma.
condition and all power circuit
b. Adjustments to Perform when SHF Combiner
breakers on the power distribution
Assembly A1 is Replaced.
panel are in the OFF position.
(1) Check that the input level adjustment AT1
The gain of the amplifier/mixer must be adjusted upon
for each of the four channels on the SHF channel
replacement of the SHF channel assembly Al, SHF drive
combiner are turned fully clockwise (fig. 5-20).
assembly A2, FET/TWT amplifier A3, or the SHF output
assembly A6. This is necessary to accommodate
individual module gain variation. It is assumed here that
5-56
