Samsung RS257BABB Service Guide - 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 ZoneTM 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). Start For C-FAN Is the voltage between GND of the main-PCB and pin No. 4 of CN72 around DC 8-10V? NO 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 COMP OFF? YES 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 YES Is the voltage DC 0V between NO CN30 No. 1 and No. 2 in the main-PCB DC 0V? YES Execute Forced operation. (See page 34 in the manual) Fan works normally. Troubleshoot the connections of door S/W. For C-FAN Measure with the door closed. - door open: DC 5V - door close : 0V Apply power around 5 minutes after the power OFF. (Prevent overload on compressor.) For R-RAN For F-FAN In the first application of power, the freezer/fridge/compressor fans work for 5 minutes regardless of the condition. Does DC 8-10V alternate with below DC 2V between GND of the main-PCB section and CN72 pin No. 4? YES Does DC 10V alternate with below DC 2V between GND of the main-PCB sectionand CN72 pin No. 5? YES Does DC 9-11V alternate NO with below DC 2V between GND of the main-PCB section and CN72 pin No. 6? YES Exchange or troubleshoot the main PCB. 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. 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.) 52