(1) The A-RT call lamp does not light and no alarm beeps are heard in
the handset.
With this symptom there may be a power or squelch disable
problems, or the KY-57 is bad.
To determine which problem is occurring,
move the handset to the KY-57 audio connector and listen for the alarm beeps
in the handset. If alarm beeps are heard, the squelch disable circuit is
bad (open). If no beeps are heard, there may be no power. Measure voltage
at the KY-57 audio connector pin A to pin C.
If no voltage is measured,
power is the problem and would be checked according to para 14.
If 5.2
volts DC is measured, the KY-57 is bad.
(2) The A-RT call lamp lights, but no alarm beeps are heard in the
handset.
With this symptom there may be an audio (receive signal path)
problem or the KY-57 is bad. Move the handset to the KY-57 audio connector
and listen for the alarm beeps. If no alarm beeps are heard, the KY-57 is
bad. If alarm beeps are heard, the audio (receive signal path) is bad.
b. Squelch disable circuit possible bad items (lamp does not light).
The symptom A-RT call lamp does not light and no alarm beeps are heard at
J5, is observed. Alarm beeps are heard when the handset is moved to the KY-
57 audio connector, indicating the squelch disable circuit is bad.
This
symptom is caused by an open circuit. Trace the squelch disable circuit and
identify the following possible bad items of equipment: RT, MT-1029, J-
3513/U, CX-13061/U, and KY-57 (Figure 102).
Figure 102.
Squelch disable circuit (possible bad items).
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