4-2-4) When Defrost Does Not Work (F Def Heater) - Samsung RB31FEJNB Series Service Manual

4. TROUBLESHOOTING
4-2-5) When Defrost does not work (F DEF Heater)
- When there is a trouble in defrosting, select the Self-Diagnosis function before turning off the unit.
And, check if there is any defect in the Defrost Heater. If not, plug out the unit and do the Trouble-Shooting.
(Refer to the Self-Diagnosis function and check the details)
** Heater Resistance Reading Location **
F-DEF : Resistance between CN70 #5 (BRN) ↔
CN77 #3 (ORG) should be 260 ohm ± 10%.
** 0Ω : Short / ∞Ω : Open
(Bimetal / Thermal Fuse / Heater Defect)
** Sensor Resistance Reading Location **
F-DEF : Between CN30 #4 (RED) ↔ CN30 #7 (GRU)
** 0Ω : Short / ∞Ω : Open
Temp vs. Resistance Table
30℃ 4.22㏀
20℃ 6.05㏀
For more
10℃ 8.87㏀
detail data,
0℃ 13.29㏀ refer to
DATA1. Temp
-10℃ 20.42㏀
Table
-20℃ 32.23㏀
-30℃ 52.41㏀
** Sensor Voltage Reading Location **
F-DEF : Between PCB COMMON Ground
and CN30 #4 (or SEN_2)
** 0V : Short / 5V : Open
After pressing the Freezer and the Fridge
buttons simultaneously for 4 seconds,
push the Freezer button to enter the
Test Mode. And then, when any one of
the buttons is pressed twice, the Forced
Defrost will start and the relevant LED
Lamp will light up on the display panel.
Check the related sensors
if they are defective.
Note When the temperature of the F DEF Sensor
goes over 8℃ with the Defrost Heater heating up, it
stops heating and it goes back to Cooling Operation.
Start
All Defrost Heaters
are normal?
Yes
Defrost Sensor is normal?
(Check it with Self-Diagnosis)
Yes
The Sensor Temperature Value
is lower than 8℃.
Yes
Do Forced Defrost
Power is applied to
F-Defrost Heater.
Yes
After heating up
No
for a while, it goes back to
Cooling Operation
Yes
Normal
MAIN PCB
Connection is normal?
Yes
Check Bimetal, Heater Wire Cut or
Wire Contact
Repair Defective Relay or
replace PCB Assy
68
☞ When checking with the Self Diagnosis
No
Check Bimetal, Heater
Continuity or Wire Connection
No
Replace the Sensor
Refer to Self-Diagnosis
No
Forced Operation for a while
No
No
Repair Connector