Samsung PL50P5HX/STR Service Manual page 88

6-2-2 When the unit is repeatedly turned on and off
Symptom - The SMPS relay is repeatedly turned on and off.
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
Major Checklist output is correct.
- If the symptom continues even when SMPS is operated alone, replace the SMPS.
- If the symptom is not observed when operating the SMPS alone, find any defective ASSYs by connecting the cables one by
one.
Troubleshooting
Does the symptom continue after
Procedures
removing the CN800 cable from
Does the symptom continue after
removing the CN800 cable from
When separating and connecting the cables such as CN809 of the Main SMPS, CN1, CN2, CN3, CN4 and CN5 of DC-DC
Caution SMPS, CN of the X Drive Board, and CN of the Y Drive Board, a spark may be generated by the electric charge of the high
capacity capacitor. Therefore, wait some time after separating the power cord from the unit.
Samsung Electronics
No
connecting the power and
the Main SMPS?
Yes
connecting the power and
the Main SMPS?
Yes
Replace the Main SMPS
Does the symptom continue when
connecting the power after connecting
the CN800 cable and removing the
CN1, CN2, CN4 and CN6 cables from
the DC DC SMPS?
Does the symptom continue when
connecting the power after removing
the CN4 cable from the DC DC SMPS?
Does the symptom continue when
connecting the power after removing
CN2 from the DC DC SMPS?
Does the symptom continue when
connecting the power after removing
CN810 from the Main SMPS?
Troubleshooting
Replace the
DC DC SMPS
Replace the
X Drive Board
Replace the
Y Drive Board
Replace the
Logic Drive Board
6-3