Samsung AS24A2RC Service Manual page 9

3-2 Fault Diagnosis by Symptom
3-2-1 No Power(completely dead)-Initial diagnosis
1) Checklist :
(1) Is input voltage normal? (rating voltage ±10% range)
(2) Is AC power linked correctly?
(3) Are connections between primary side, secondary side of the power transformer and PCB good.
(4) Is input voltage of DC regulator IC KA7805 (IC02) normal? (11VDC-12.5VDC)
(5) Is output voltage of DC regulator IC KA7805 (IC02) normal? (4.5VDC-5.5VDC)
2) Troubleshooting procedure
YES
Is DC voltage of PCB
display normal?
Is the rating Voltage ±10%
Replace PCB
range applied to the
display
between #1 and #3 of CN78
•Check linkage between
power cord and
terminal tap
•Check fuse
Is 11~12.5VDC appear in
the input side of the DC
regulator IC KA7805(IC02)?
NO
refer to
replace
PCB module
Replace resonator (X501)
Is operation normal?
YES
OK
8
Remove power cord and plug in again
in approx. 5 seconds
Is operation lamp blinking?
NO
Does operation start when
run/stop button on the remote
controller unit pushed?
NO
Is transmission display of the remote
controller unit blinking?
Is "beep"sound heard from the main
NO
NO
Is DC voltage of the PCB module
Are voltages of #8 (compressor), and#6
(outdoor fan) of the micom normal? ; 5VDC
Is voltage of #60 (indoor fan) of the micom
DC5V
YES
Is voltage at #33 terminal of the Micom normal?
Is voltage at #18 terminal of the Micom normal?
Is voltage at #52 terminal of the micom
Are voltage at #48 and #49 of the
NO
NO
YES
YES
NO
NO
YES
unit?
YES
NO
normal?
YES
YES
normal?
10ms
NO
; 0VDC
; 5VDC
YES NO
normal?
10ms
YES
NO
micom normal?
100ns
YES
Replace
micom
Normal
Refer to remote control
unit fault diagnosis
Refer to Replace PCB
module.
Are voltages at RY71(Compressor)
and RY72 (Outdoor fan) normal? ; DC12V
Is voltage at SS71(indoor fan)
YES
Check connections Replace
compressor, outdoor RY71, RY72
fan and indoor fan. and SS71
Is output voltage of ICO2 normal?(DC5V)
YES
Refer to replace PCB
Replace ICO2
module
Is voltage output terminal of
D101~D105(IN4007) normal?
YES NO
Replace IN4007
OK
NO
NO