TM 55-1510-219-10
Figure 3-7.HF Control Panel (718 U-5)
(2) RF TEST lamp check (system not keyed).
1. Set the function selector to RF TEST.
Do not key the system. Observe the RF
TEST lamp.
a. If the RF TEST lamp does not light,
the
lamp
is
defective
or
the
receiver-exciter is faulty.
b. If the RF TEST lamp blinks for more
than 1 minute, the receiver- exciter
is faulty.
c. If the RF TEST lamp lights
immediately or after an initial period
of blinking, the RF TEST lamp and
fault circuits are operational.
d. Repeat RF TEST lamp check, as
required, by selecting RF TEST with
the function selector.
(3) Tune check (system keyed).
1. Set the function selector to RF TEST.
Change frequency selection to any
frequency
and
key
the
system
momentarily. Observe the RF TEST
lamp during the tune cycle. Normal
tune time is 3 to 8 seconds.
NOTE
RF TEST lamp indications, during
tune, are only valid for 3 to 8
seconds
after
initial
key
is
applied. To repeat the tune
check, key the HF system with the
microphone switch.
a. If the RF TEST lamp stays on
continuously, the receiver-exciter is
faulty.
b. If the RF TEST lamp blinks on and
off, the PA-coupler is faulty.
c. If the RF TEST lamp extinguishes
after a nominal tune time, and
sidetone is heard when audio input
is supplied through the microphone,
the system is tuned and operating
correctly for the selected frequency.
3-15
