Samsung PN50C450B1DXZC, Service Manual

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4-4 Samsung Electronics
Troubleshooting

When the unit is repeatedly turning on and off
Symptom The SMPS relay is repeatedly turning on and off.
Major
Checklist
In general, the SMPS relay repeatedly turns on and off by the protection function due to a defect
on a board connected to the SMPS.
- Disconnect all cables from the SMPS, operate the SMPS alone and check if the SMPS works
properly and if each voltage output is correct.
- If the symptom continues even when SMPS is operating alone, replace the SMPS.
- If the symptom is not observed when operating the SMPS alone, find any defective
assemblies by connecting the cables one by one.
Caution
When separating and connecting the cables such as SMPS and X-Main Board, Y-Main Board
a spark may be generated by the electric charge of the high capacity capacitor. Therefore, wait
some time after disconnecting the power cord from the unit.
Yes
When the unit is repeatedly turning on
and off
Replace the Y Main Board
No
Replace the Logic Board
No
Yes
2
Does the symptom continue when
connecting the power after removing
CN802 from the SMPS?

Refer to image of
Fig. 4-2.
1
Does the symptom continue when
connecting the power after removing
CN804 from the SMPS?
Replace the SMPS

Refer to image of
Fig. 4-2.