Samsung RS21 Service Manual page 59

Diagnostics
11-7) If fan doesn't work:
Reference
The refrigerator has been applied with the BLDC fan motor. For RS2533, R room Fan is AC motor used. The BLDC
motor is driven by DC 8-12V.
Under the normal condition of COMP ON, it is operated together with F-FAN motor. With operation of the CoolSelect
Zone TM function, the F-Fan motor may do not work. If the door is opened and closed once at a high ambient
temperature, the BLDC motor would be operated after a 1-minute or longer delay. Therefore, you' re advised not to
take it for an error.
When the refrigerator is open, the freezer fan motor will also stop working simultaneously with the fan motor. (for the
purpose of performance improvement).
For C-FAN
Is the vol t age between GND
of the mai n -PCB and pi n No. 4 of CN72
around DC 8-10V?
NO
For C-FAN
Does DC 8-10V al t ernate
wi t h bel o w DC 2V between GND of the mai n -PCB
secti o n and CN72 pi n No. 4?
YES
Reference
CN72 No. 3(F), 2(R),1(C) will be generated pulse signals when the motor rotates. These signals will be
inputted into MICOM. Unless signals are not inputted in the restart of motor, it will be ON 10 seconds after
the fan OFF. But if signals are not still entered, the above operation will restart four times more. Without
signals entered continuously, the motor will get restarted after 10 minutes. This function is effective where
the normal operation of motor would be restrained due to foreign matters such as ice.
For R-FAN
Is the voltage DC10V between
GND of the main-PCB and pin No. 4
of CN72 ?
NO
Is the voltage DC 0V between
CN30 No. 5 and No. 6 in the main-PCB
section?
YES
Measure with the door closed.
- door open: DC 5V
- door close : 0V
For R-RAN
Does DC 10V al t ernate
wi t h bel o w DC 2V between GND of the mai n -PCB secti o n and
CN72 pi n No. 5?
YES
59
Start
COMP OFF?
For F-Fan
NO
Is the voltage DC 9-11V between
GND of the main-PCB section and
CN72 pin No. 6?
NO
Is the voltage DC 0V between
CN30 No. 1 and No. 2
in the main-PCB?
YES
Apply power around 5 minutes
after the power OFF. (Prevent
overload of compressor.)
For F-FAN
NO
Does DC 9-11V al t ernate
wi t h bel o w DC 2V between GND of the mai n -PCB secti o n
and CN72 pi n No. 6?
YES
Expected causes :
1. Check if the fan motor has failure itself.
2. Check if the wire connections have a trouble of contact.
3. Check the input of the fan motor rotation pulse in the operation motor
fan. (See the details of Fan Motor Drive Circuit section.)
YES
Execute Forced
operation. (See page
34 in the manual)
YES
Fan works normally.
NO
Troubleshoot the
connections of door S/W.
In the first power application, the
freezer / fridge / compressor fans
work for 5 minutes regardless of the
condition.
Exchange or troubleshoot the
main PCB.