Abnormal Diagnosis By Symptom - Samsung AQ18A9(0)RCF Service Manual

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Troubleshooting (cont'd)

2 Abnormal diagnosis by symptom

1. No Power - Initial diagnosis
1. No Power - Initial diagnosis
1) Checklist :
(1) Is input voltage normal? (voltage rating within ±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 the rating Voltage ±10%
Replace
range applied to the between
PCB display
YES
appear in the input side
of the DC regulator IC
Replace PCB
module
Refer to page 21
Replace resonator (X501)
Is operation normal?
16
NO
Does it start operating when you
Is DC voltage of PCB
display normal?
NO
#1 and #3 of CN78
NO
NO
Check linkage
between
a power cord and
a terminal tap
Check fuse
#7(IC04 : 4way valve) and #6(IC04 : outdoor fan)
Does 11~12.5VDC
KA7805(IC02)?
NO YES
Is voltage of #33 terminal of Micom (IC04)normal?
Is voltage of #18 terminal of Micom (IC04)normal?
NO
NO
YES
OK
Remove the power cord and plug
it in again in approx. 5 seconds
Does the lamp blink?
YES
push the On/Off button of the
remote control?
NO
Is transmission display of the
remote control unit blinking?
YES
Does the 'beep' sound from
the main unit?
YES
Is DC voltage of the PCB
module normal?
YES
Are voltages of #8(IC04 : compressor),
of Micom normal? 5VDC is voltage
of #60((IC04 : indoor fan) of Micom normal?
DC5V
10ms
NO
0VDC
5VDC
YES
Is voltage of #52 terminal of
Micom (IC04)normal?
10ms
YES
Are voltage of #48 and #49 of
Micom (IC04)normal?
100ns
YES
Replace
Micom
YES
Normal
NO
Refer to remote control unit
abnormal diagnosis
Replace PCB module
NO
Refer to page 21
Are voltages at RY71(Compressor)
and RY72 (Outdoor fan) normal?
YES
; DC12V
Is voltage at SS71(indoor fan)?
YES
Check connections
Replace RY71,
compressor, outdoor
RY73, RY72
fan and indoor fan
NO
Is output voltage of ICO2 normal?(DC5V)
YES
Check PCB pattern
Replace PCB module
Refer to page 21
NO
Is voltage output terminal of
D101~D105(IN4007) normal?
YES
Replace IN4007
OK
NO
and SS71
NO
Replace
IC02
NO