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Samsung Electronics
6-3 Fault Diagnosis by Symptom
6-3-1 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 the operation icon(
) lamp
flickering with the sound of "ting"?
<MH26– ; Doesn't it flicker but come
out the sound of "ting"?>
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 #48 (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 300V DC 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 IC02 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
PC814(PC02) normal?
Replace IC02
Check PCB pattern.
Replace main PCB.
Replace
PC814(PC02)
Replace
micom
Is voltage at #16 terminal of the
micom normal?
Are voltage at #23 and #24 of the
micom normal?
No
No
No
Yes
No
No
No
Yes
OK
Is operation normal?
Replace resonator (X301)
DB98_16045A(4)_1 1/29/04 4:56 PM Page 41
Содержание MH18AP1(P2)-09
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