Fault Diagnosis By Symptom - Samsung AQA24C5ME Service Manual

5-2 Fault Diagnosis by Symptom

5-2-1 No Power (completely dead)-Initial diagnosis
1) Checklist :
(1) Is input voltage normal? (the rating voltage ±10% range)
(2) Is AC power linked correctly?
(3) Is input voltage of DC regulator IC KA7805 (IC02) normal? (11.5VDC-12.5VDC)
(4) 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 input rating ±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 11.5~12.5VAC appear in
the input side of the DC
regulator IC KA7805(ICO2)?
NO
Refer to replace
PCB Module
Replace resonator (X501)
Is operation normal?
OK
5-2
Remove power cord and plug in again
Is operation lamp blinking?
NO
run/stop button on the remote
NO
Is transmission display of the remote
Is "beep"sound heard from the main
NO
NO
Is DC voltage of the PCB module
Are voltages of #40 (compressor),
#43 (4 way valve) and #41 or #42 (out-
door fan) of the micom normal? (5VDC)
Is voltage of #39 (indoor fan) of the
DC5V
YES
Is voltage at #17 terminal of the Micom normal?
Is voltage at #16 terminal of the Micom normal?
Is voltage at #10 terminal of the micom
Are voltage at #18 and #19 of the
NO
NO
YES
in approx. 5 seconds
YES
Does operation start when
controller unit pushed?
NO
controller unit blinking?
YES
unit?
YES
normal?
YES
micom normal?
10ms
NO
; 0VDC
; 5VDC
YES
normal?
10ms
YES
micom normal?
100ms
YES
Replace
micom
YES
Normal
NO
Refer to remote control
unit fault diagnosis
Refer to Replace
NO
PCB module.
Are voltages at RY71(Compressor)
RY73 (4 way vale) and RY 72 (Outdoor fan)
YES
normal? (DC12V)
Is voltage at SS71(indoor fan)
YES
Check connections
compressor 4-way
valve, outdoor fan and
indoor fan.
NO
Is output voltage of ICO2 normal?(DC5V)
YES
Check PCB pattern. Refer to
Replace nidule PCB.
NO
Is voltage output terminal of
D101~D105(IN4007) normal?
YES
Replace IN4007
OK
Samsung Electronics
NO
Replace
RY71, RY73,
RY72 and
SS71
NO
Replace ICO2
NO