Samsung RS757LHQESR/ Series Service Manual page 59

DISASSEMBLY AND REASSEMBLY
8) When Fan does not operate
• This refrigerator uses the BLDC Fan Motor. The BLDC Motor operates with DC 7~12V.
• Under Comp On conditions, the F-Fan operates generally. But, the F-Fan Motor may not work due to various conditions (such as the operating
condition of Cool Select Pantry, etc) ,and when the ambient temperature is high or when you open and close the Door once, it operates after one
minute delay. So, don't get misled by it. It is normal.
• Also, when the Fridge Door is open, the Freezer Fan Motor stops together with the Fridge Fan Motor (for the purpose of performance improvement).
C - FAN
Voltage betweenPCB
CASE CN7 #10-#11 is measured
betweenDC7~12V?
▶
Freezer Door CN7 #10-#11
-. DC 7~12V
-. Check other Fans with the same method
C - FAN
Does it repeatingbetween
DC7~12and DC2V on PCBCASE
CN7 #10-#11?
YES
Note_reference of PCB CASE
Pulse signal is input to CN7 #12(C), CN2 #3(F), CN3 #5(R) when the Motor spins.
This signal enters to MICOM and if there is no signal entering when the Motor spins, the
Fan goes off and works again in 10 seconds. If there is still no signal entering, it repeats
the above operation 4 more times. If it keeps not sending the signal, the Motor operates
in 10 minutes.
This is a function to overcome the case that there is a restriction in the Motor due to
foreign substances around the Motor.
R - FAN F - FAN
Voltage between
PCB CASE CN3 #3-#4 is
PCB CASE CN2 #1-#2 is measured
measured between
DC7~12V?
Voltage between
PCB CASE CN7 #7-#9 is PCB CASE CN7 #6-#9 is
measured between
DC0V?
Measure it with the Door closed
- DOOR OPEN : 0V
- DOOR CLOSE : DC5V
Apply power in 7 minutes after
turning off the power. (to prevent
Compressor overload)
R - FAN F - FAN
Does it repeatingbetween
Does it repeatingbetween
DC7~12and DC2V on PCBCASE
DC7~12and DC2V on PCBCASE
CN3 #3-#4?
YES
58
START
YES
Comp is off?
NO Turn on Forced Operation.
(Refer to the Manual)
Voltage between
YES
between
DC7~12V?
Fan operates normally → Only when
NO
Voltage between
YES
measured between
DC0V?
Repair Door S/W Connection
NO
Upon the initial power on, the
Compressor and the Freezer / Fridge /
Compressor Fans operates for 3
seconds regardless of the conditions.
NO
CN2 #1-#2?
- Check the wire connection Between
PCB CASE and MAIN PCB
YES
- Replace MAIN PCB
Expected Causes
① Defective Fan-Motor
② Contact error at wire connection
③ When the Fan Motor operates, check the input of
the Motor Spinning Pulse.
(Refer to the Fan Motor Drive Circuit in this manual)
④ peration Error due to Motor Fan Restriction
the Motor is normal