Samsung RM255BABB, Training Manual

Page: 69 / 88

DIAGNOSTIC
71
Is the COMP OFF State?
Start
Execute Forced operation.
Is the voltage DC 0-1V between GND of the
main-PCB section and CN76 pin No. 2?
Fan works normally.
Is the voltage DC5V between the main PCB
section CN No.2 and No.7?
Troubleshoot the connections
of door S/W.
In the first power application, the
freezer / refrigerator / compressor
fans work for 5 minutes regardless
of the condition.
Apply power around 5 minutes
after the power OFF. (to prevent
overload of compressor.)
Expected causes :
1. Fan motor has failure itself.
2. Wire connections have a trouble of contact.
3. Check : Input of the fan motor rotation pulse in operation of fan motor.
(See the details of Fan Motor Drive Circuit section.)
NO
YES
YES
NO
NO
YES
Is the voltage DC 0-1V between GND of the
main-PCB section and\ CN76 pin No. 5?
Is the voltage DC5V between the main
PCB section CN No.9 and No.14?
NO
YES
Does DC 0V alternate with DC 12V between
GND of the main-PCB and CN76 pin No. 2?
Exchange or troubleshoot the
main PCB.
Measure with the closed door.
- Door Open: DC 0V
- Door Close : DC 5V
NO
YES
CN76 No. 3(C/F-FAN), pin no.6(C/R-FAN) will get pulse signals
which is generated when the motor rotates.
These signals will be inputted into MICOM.
Unless signals are not inputted in the motor operation, it will be ON
10 seconds after the fan OFF. But if signals are not still entered, the
above operation will be performed four times more. Without signals
entered continuously, the motor will get restarted after 10 minutes.
This function is effective to secure normal operation where the motor
would be restrained due to foreign matters such as ice. Ref
Reference
Does DC 0V alternate with DC 12V between
GND of the main-PCB anf cn76pin NO.5?
YES
FOR R-RAN FOR F-FAN
FOR C/R-FAN FOR C/F-FAN
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