8-2. HOW
TO
FIND
SHORT BETWEEN T-LINE AND R-LINE
If the shorted condition between T-line and R-line is not
corrected for a long time, it may burn out the guard re-
sistor (330ft 1/2W)
on
the
LMU
board. Therefore,
find
the shorted line according to the following procedure:
1. Turn off the privacy switch on all stations in the
system.
2. Turn
on
the
power
switch of the system for several
seconds, then, turn it off.
3. Watch the lamps on the LMU panels. The lamps on
normal lines will go off after approximately 0.5
second. The lamps on the shorted lines will stay
on more than 0.5 second.
Power ON
OFF
Normal
Abnormal
(Short)
Lamp ON
0.5 sec
Lamp ON
(Brighter than normal)
Lamp goes off gradually
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