MAINTENANCE CONTROLS AND INDICATORS. (CONT)
FUNCTION OR USE
CONTROL OR INDICATOR
Permits monitoring of voltage, automatic gain control
(age), and power functions of radio set. Scale is 0 to
100 in 10 equal divisions.
Six position rotary switch, used to connect TEST METER
to various circuits of radio set to be checked.
Position 1 Connects 24-volt dc supply to TEST METER.
Position 2 Connects regulated 16-volt dc supply to
Position 3 Connects agc circuits to TEST METER.
Position 4 Connects rf output circuit (RF FWD) to TEST
Position 5 Connects antenna circuit (RF REFL) to TEST
Position 6 Disconnects meter from all circuits.
Selects nominal transmitter power output. In HI
XMTR HI-LO (transmitter
position, power output level is 10 watts. In LO posi-
power output switch)
tion, power output level is 1 watt.
Keys transmitter without depressing microphone button
XMTR TEST (transmitter
or press-to-talk button. When TEST SWITCH is set to
position 3 and XMTR TEST is depressed, agc is measured
on TEST METER. When TEST SWITCH is set to position 4
and XMTR TEST is depressed, forward or rf output power
is measured. When TEST SWITCH is set to position 5 and
XMTR TEST is depressed, rf reflected by antenna circuit
Permits adjustment of carrier squelch.
SQ ADJ (squelch
Disables squelch circuits to allow hearing of back-
SQ DIS (squelch disable
ground noise to adjust control unit VOL control setting.
The operational check provides a step by step procedure for evaluating the operational readiness of
the Radio Set AN/ARC-131. It specifies tests and checks for the receiver- transmitter, mounting, and
The operational check is normally performed with the radio set installed in aircraft. At a minimum,
the operational check is done as part of PMCS. At the discretion of the maintenance supervisor,
the operational check could be done more often than the scheduled PMCS. After replacement or
adjustment of any component, the portion of the operational check that applies shall be repeated to
ensure that the malfunction has been corrected and that no others exist.