7.21
Troubleshooting
KMSD field service repairs are limited to subsystem and circuit board replacement. All defective printed circuit
boards and modules should be returned to factory service for repairs. Refer to Table 7-1.
a.
If (Lb) Power Supply No. 1 trouble light is on, check fuses F1, F2; relay KR1 ; contacts 5, 4 and 1, 3; fuse F4:
transformer T1: bridge rectifier A7; fuse F7; relay K2: connections P7. P6. Replace main electronic board.
b.
If (16) Power Supply No. 2 trouble light is on, perform step 1 above before replacing main electronic board.
c.
If (L9) alarm bell trouble indicator is on, check fuse F9, F10; relay K5; connector P15.
d.
If (L8) main panel light is on, check reset switch (S6); relay K5 coil; common alarm front panel (T2).
e.
If blower failure indicator (L7) is on, check fuse F6; relay K7; contacts 6, 7; timer board; connector P3. Other
possible causes are defective pressure switch, motor failure in blower cabinet or restricted air flow.
f.
If (L-11) ground fault trouble light is on, check the DC resistance with an ohmmeter (TURN OFF POWER TO
SYSTEM) between +24VDC and cabinet frame and between -24VDC and cabinet frame. The readings
should both be no less than 50,000 ohms, adjust the ground fault potentiometer R50 located on the
supervisory control electronic printed circuit board per test procedure 153621. If test procedure 153621 is not
available, cut ground fault defeat jumper.
g.
If (L-16) timer disconnect trouble light is on, the blower timer cycle printed circuit board is unplugged from its
connector. Check connector P17.
h.
If (L-15) clock high speed trouble light is on, test switch (S1) is in the test position. Return to normal position
to the right.
i.
If smoke lamp light (1-10) is on, check repeater cabinet common alarm lamp DS-26.
j.
If the smoke detector module zone trouble light is on, check corresponding zone alarm lamp at repeater
cabinet;
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