e. Release slide rail latches and remove
downconverter from rack.
f. Replace the downconverter by performing steps
a through e above in reverse order.
g. After replacement, perform the gain adjustment
Section X. MAINTENANCE OF AMPLIFIER/MIXER AM-6704/TSC
Place the STATUS MONITOR switch to
each of the following positions and observe the STATUS
a. This section covers instructions and procedures
MONITOR meter for a correct indication.
for testing and fault isolation, adjustment, and removal
incorrect indication is observed, proceed to step (4)
and replacement. The test procedures are based on the
below. If a correct indication is observed, proceed to
use of built-in-test equipment (BITE) and the associated
step (5) below.
electronic frequency converter CV3199/TSC as a signal
source, and no additional suppoort or test equipment is
+ 30 V
+ 15 V
- 15 V
(4) Replace power supply module PS2 for the
amplifier/mixer adjustments, modules, and other
(5) Place the STATUS MONITOR switch in
the IPA MA position.
(6) If an FET amplifier is being used proceed
of the amplifier/mixer drawer.
to step (7) below. If a TWT is being used operate and
hold the FAULT RESET switch to ON (up) until the
DANGEROUS VOLTAGES EXIST IN
STATUS MONITOR meter starts up scale and release
THIS EQUIPMENT. Do not attempt
the switch. If the meter does not move up scale, replace
any removal or replacement unless
the equipment is in a non-operating
condition and all power circuit
breakers on the power distribution
(7) Observe the STATUS MONITOR meter
panel are in the OFF position.
for an indication of 16 to 32 ma. If the indication is
normal, proceed to step (8) below. If the indication is
5-35. Testing and Fault Isolation
a. Testing the Amplifier/Mixer.
perform the gain adjustments.
The SHF amplifier in this unit may be
(8) Place the SHF MONITOR switch to the
an FET or TWT. These procedures
reflect the use of either item and the
(9) Place the SHF MONITOR channel
replacement by either item.
selector switch to each of the channels that have a
(1) If necessary, interconnect a modem,
CV3199/TSC upconverter cable connected to them.
upconverter and power amplifier with the amplifier/mixer
(10) Observe the SHF MONITOR meter for an
suspected of being faulty and place in normal operation.
indication of 7.5 to 8.5 for each channel selected. If the
(2) Observe the indication on the PA
indication is correct, proceed to step (12) below. If the
MONITOR meter on the power amplifier. If the PA
indication is incorrect, proceed to step (11) below.
MONITOR meter is indicating a normal output power
(11) Disconnect the cable from the SHF
level and the FAULT lamp is illuminated on the
channel which does not give a correct indication, and
amplifier/mixer, the fault or metering circuit in the
connect the cable to another channel on the SHF
amplifier/mixer is giving an erroneous indication; perform
combiner module. Place the SHF monitor channel
steps b(10) through b(16) below. If the indication on the
selector switch to the selected channel, if the indication is
PA MONITOR meter is abnormal, proceed to step (3)
incorrect, disconnect. If the indication is still incorrect,
the problem is with the upconverter or interconnecting