Samsung RS257BABB Service Manual page 52

Diagnostics
11-7) If fan doesn't work:
Reference
� The refrigerator has been applied with the BLDC fan motor for RS253BA, 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 will 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 Fridge 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 get entered pulse signals which are generated when the motor rotates. These
signals will be inputted into MICOM. Unless signals are not inputted in the rerun of motor, it will be ON 10
seconds after the fan OFF. But If signals are not still entered, the above operation will be rerun 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 between
GND of the main-PCB and pin No. 4
of CN72 around DC 10V?
NO
Is the voltage DC 10V 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 nand
CN72 pi n No. 5?
YES
52
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
DC 9-11V?
NO
Is the voltage DC 0V between
CN30 No. 1 and No. 2 in the main-PCB
DC 0V?
YES
Apply power around 5 minutes
after the power OFF. (Prevent
overload on 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 for 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 at page 47.)
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 application of power, the
freezer/fridge/compressor fans
work for 5 minutes regardless of the
condition.
Exchange or troubleshoot the
main PCB.