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

TROUBLESHOOTING

4-2-2. If FAN does not operate

The refrigerator of this model has BLDC FAN motor. BLDC motor is driven by DC 7~12V.
On the normal condition of COMP ON, it operates together with F-FAN motor. If door is opened and closed once at a high
ambient temperature, it will be operated after 1 minute delay. Therefore, you are advised not to taken it for an error.
If there is a trouble, you should select the self-diagnostic function to check the trouble before power off.
Is the voltage between MAIN
PCB Ground CN40 "15" (W/GRY) and CN 40 "13" (S/
BLU) around DC7~12V?
Is the external temperature
above 66.2℉(19℃)?
Recheck after 7 minutes (Time
could be delayed depending
on the temperatures. If the
temperature is lower, It may
not operate : about 59℉
(below 15℃)
Does DC7~12V alternate with below
DC 2V between MAIN PCB Ground CN40 "15"
(W/GRY) and CN 40 "13" (S/BLU) ?
F FAN pulse voltage CN20 "14"(PNK)
The voltage
measured around
2~3V with multi-
meter though the
voltage is very
weak because of
pulse signal
☞
Display for checking the self-diagnostic function
R FAN ERROR
F FAN ERROR
(Option)
Is the voltage between MAIN PCB
Ground CN20 "17" (BLK) and
CN 20 "15" (S/BLU) around DC7~12V?
Is the voltage between MAIN PCB
Ground CN20 "3" (GRY) and CN 20 "1" (PRP)
around DC0V?
Door & MICOM State
F MICOM R MICOM(#58)
Door
(#60)
Right and Left
Close 0V(Low) 0V(Low)
Open 5V(High) 5V(High)
Does DC7~12V alternate with below below
DC 2V between MAIN PCB Ground CN20 "17"
(BLK) and CN 20 "15" (S/BLU) ?
Reference
CN20-13(R), 14(F), CN40-11(C)will generate the pulse signal when motor
rotates. These signals will be inputted into MICOM.
Unless signals are not inputted during motor operating, will be ON 10
seconds after fan Off. But if signals are not still entered, the above operation
will restart four times more. If signals are not entered continuously, the motor
will be restarted after 10 Minutes. This function is effective when the normal
operation of motor would be restrained by foreign matters such as ice.
C FAN ERROR
Start
Is COMPRESSOR ON ?
Is the voltage between MAIN PCB
Ground CN20 "18" (W/BLK) and CN 20 "16"
(S/RED) around DC7~12V?
Is the voltage between MAIN PCB
Ground CN20 "4" (FLAT_WHT) and CN 20 "2"
(FLAT_ORG) around DC4.5~5V?
Power ON with 7 minutes delay
after power OFF.
For preventing the over load of
compressor)
Does DC7~12V alternate with"3" (Yellow)
below DC 2V between MAIN PCB Ground CN20
"18" (W/BLK) and CN 20 "16" (S/RED)?
The voltage between PCB typical Ground CN20 "17" Pin and
F FAN : CN20 "16" (S/RED) shall be less than DC 7~12V.
R FAN : CN20 "15" (S/BLU) shall be less than DC 7~12V.
C FAN : CN 40 "13" (S/BLU) shall be less than DC 7~12V.
- Recheck if resistance values are different after measuring.
PIN Number
82
Execute manual
operation
FAN work normally
Repair the connection
of Door switch
In initial power to appliance, the compressor
and fans of fresh food/ freezer, compressor fan
operate. If freezer temperature is sensed of
41℉ by momentary power failure, fans will
operate after 7 minutes.
Replace MAIN PCB Ground
• Expected causes
① Check that if FAN-MOTOR has failure itself.
② Check that if wiring connection has bad contact.
③ Check the input of the fan motor rotation pulse when motor fan
operates.