Filter
Top Products
11
3-3 Fault Diagnosis by Symptom
3-3-1 No Power (completely dead)-Initial diagnosis
1) Checklist :
(1) Is input voltage normal?
(2) Is AC power linked correctly?
(3) Is output voltage of DC regulator IC KA7805 (IC02) normal? (4.5VDC-5.5VDC)
2) Troubleshooting procedure
Replace
PCB display
Is DC voltage of PCB
display normal?
Remove power cord and plug in
again in approx. 5 seconds
Is operation lamp blinking?
Does operation start when
run/stop button on the remote
controller unit pushed?
Is transmission display of the
remote controller unit blinking?
Is "beep"sound heard from the
main unit?
Is DC voltage of the PCB module
normal?
5VDC Is voltage of #60 (indoor fan)
of the micom normal?
Is rating voltage ±10%
range applied to the
primary side (~,~)
of the “BD71”
•Check linkage between
power cord and
terminal tap
•Check fuse
Is 14~18VAC appear in
the secondary side (+, -)
of “BD71”
Replace
SMPS PARTS
YES
NO
YES
NO
YES
YES
YES
NO
YES
YES
DC5V
10ms
10ms
250ns
NO
OK
YES
YES
YES
YES
NO
NO
YES
Normal
Refer to remote control
unit fault diagnosis
Replace PCB module.
Is output voltage of ICO2 normal?
Check connections
compressor 4-way
valve, outdoor fan and
indoor fan.
DC12V
Is voltage at SS71(indoor fan)
Replace RY71,
RY73, RY72 and
SS71
NO
NO
NO
Is voltage output terminal of
TLP180(PC02) normal?
Replace ICO2
Check PCB pattern.
Replace main PCB.
Replace TLP180(pc02)
Replace micom
Is voltage at #52 terminal of the
micom normal?
Are voltage at #48 and #49 of the
micom normal?
NO
NO
NO
YES
NO
NO
NO
YES
OK
Is operation normal?
Replace resonator (X301)
DB98_05645A(1)_1 5/30/02 7:04 PM Page 11