Samsung RS68N Series Service Manual page 88

PRECAUTIONS(SAFETY WARNINGS)
4-5-6. When Fan does not operate
- This model has BLDC FAN motor. BLDC motor is driven by DC7~12V
- F-Fan motor usually runs together with the Compressor. Once the door is open and closed at high
ambient temperature, F-Fan motor put off its operation for one minute. Therefore, you are advised not to
take it as an error.
- When fridge door is open, the F-Fan motor stops.
For R-Fan
The voltage
between GND in Main PBA and
CN74 #3 is 7-12Vdc
NO
Fridge Door S/W is
closed.
Reading with Door
Plug in again after
closed.
5 minutes from
-.OPEN 5V, CLOSE 0V the power off.
For R-Fan
The voltage between
GND and CN74 #3 repeats the change from
7-12VDC to lower than 2VDC.
YES
Note
Pulse signal(FG) generated from the Fan motor rotation is transmitted through CN74 #9(F), #10(R), #11(C)
Micom senses these signal.
If Micom senses no signal, Micom make Fan Motor stop for 10 sec and try to operate it again.
Micom keeps doing the same procedure 4 times until Micom receive the signal.
If it still fails, MICOM stop trying for 10 minutes.
This procedure prevents the motor from overload when foreign substances such as ice built up
around the motor restrict motor rotation.
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For C-FAN
The voltage
between GND in Main PBA and
CN74 #2 is 7-12Vdc
Upon the initial power on,
Compand F/C Fan operate
for 5 minutes regardless
of the conditions.
For C-FAN
The voltage between
GND and CN74 #2 repeats the change from
7-12VDC to lower than 2VDC.
For F-Fan
between GND in Main PBA and CN74
NO
Freezer Door S/W is closed.
Reading with Door closed.
-.OPEN 5V, CLOSE 0V
For F-FAN
GND and CN74 #4 repeats the change from
YES
88
Start
NO
COMP is on?
YES
The voltage
YES
#4 is 7-12 VDC
NO
NO
YES
Plug in again after
Upon the initial power on,
5 minutes from
Comp and F/C-Fan operate for
the power off.
5 minutes regardless of the
conditions.
The voltage between
NO
7-12VDC to lower than 2VDC.
YES
◆ Possible Causes
1. Defective FAN-MOTOR
2. Contact problem at the terminal
3. FG signal error (Refer to Fan-Motor circuit in this manual)
☞ Checking method of C-Fan motor voltage
- Read the voltage between MAIN PBA GND and CN74 #2
- If it has 7~12 voltage, It's normal.
(Same method is applied to other Fan Motor)
Run Forced Operation.
FAN operates normally.
Check after closing the
Door. When there is Door
alarming, repair the Door
S/W connector.
Replace MAIN PBA.