Samsung AQ12A5(6)MB, Service Manual

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Samsung Electronics
5-2
5-2 Fault Diagnosis by Symptom
5-2-1 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
ON/OFF 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?
Are voltages of #8 (compressor),
#7(4 way valve) and #6 (outdoor fan)
of the micom normal? 5VDC
Is voltage of #60 (indoor fan) of the
micom normal?
Is voltage at #50 terminal of the Micom normal?
0VDC
Is voltage at #18 terminal of the Micom normal?
5VDC
Is rating voltage ±10% range
applied to the primary side(~,~)
of the “BD71”
•Check linkage between
power cord and
terminal tap
•Check fuse
Is 325VDC appear in the
secondary side (+, -)
of “BD71”
Replace
SMPS PARTS
YES
NO
YES
NO
YES
YES
YES
NO
YES
YES
YES
DC5V
10ms
10ms
250ns
NO
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
and indoor fan.
Are voltages at RY71(Compressor)
normal? DC12V
Is voltage at SS71(indoor fan)
Replace
RY71 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)
00181_TSHOO_9 11/6/00 5:17 PM Page 5-2