If Ice Room Fan Does Not Operate - Samsung RF28R7201 AA Series Service Manual

4-2-3. If ICE Room Fan does not operate

This refrigerator has BLDC FAN motor. BLDC motor is driven by DC7~12V.
When COMP ON, normally operates with F-FAN motor.
If there is any trouble, you should select the self-diagnostic function to check the trouble before power off.
- When pressing the ICE TEST S/W for a certain period of time (over
1.5sec), the function is accomplished. After beginning of TEST mode,
Ice maker heater turns on for initial 2 minutes, if the ice making
temperature is below 0℃.
- If it exceeds 0℃, Ice maker heater turns on for initial 30 seconds.
- After Ice maker heater turns on for 30 seconds, it turns off and then
Ice maker motor turns on.
- As the Ice maker motor turns on, TEST MODE COUNT operates.
(6 minutes count)
Condition
- Ambient temperature : 32℃/75%
- Notch : 2℉/38℉(-19.0℃/3.3℃)
Initial full of ice bucket capacity : 794 g, 58ea
Ice Room control temperature
Ice ON
Ice OF
Reference
CN20 "20" will generate the pulse signal when motor
rotates.
These signals will be input into MICOM.
Unless signals are not input during motor operating, will be
ON 10seconds after fan OFF. But if signals are not still taken,
the above operation will be retried four times more. If
signals are not taken continuously, the motor will be
restarted after 10 minutes.
This function is against the case that motor movement
would be restrained by foreign matters like ice.
FAN pulse voltageCN76-"6"(Pink)
The voltage is variable due to pulse signal but
measured about 2~3V with the Multi-Meter.
☞ Display for checking the self-diagnostic function
Ice Room FAN ERROR
8.6℉(-13℃)
26.6℉(-3℃)
Does DC7~12V alternate with below DC2V
between MAIN PCB Ground CN20-"24"(W/GRN)
※ Predicted Cause
① FAN-MOTOR troubles itself.
② Bad wiring connections.
③ Wrong Input of the fan motor rotation pulse.
☞ Checking method of Ice Room FAN Motor Voltage with the voltage between Ice Room FAN :
CN20-"24"(W/GRN) and CN20-"22"(RED) shall be less than DC 7~12V.
83
TROUBLESHOOTING
Start
Is COMPRESSOR ON ?
Yes
Is the voltage between MAIN PCB
Ground CN20-"24"(W/GRN) and
CN20-"22"(RED) around DC7~12V?
No
Is the Ice
Room temperature suitable for
the Fan working?
Yes
and CN20-"22" (RED)?
Yes
No
Execute manual operation
Yes
FAN works normally
No
Operation
temperature/ready
No
Replace MAIN PCB Ground
PIN Number