Samsung PN50A650T1FXZC, Service Manual

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Troubleshooting
Samsung Electronics 4-3
■ 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 operated 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.
Troubleshooting
Procedures
1
Check that the Va,Vs voltage of SMPS
match the voltages marked on the module
label
Replace the SMPS
①
Did problem improve?
Did problem improve?
Did problem improve?
Yes
No
Did problem improve?
Did problem improve?
Replace the Main Board
Replace the Y Main Board
Replace the X Main Board
Replace the Logic Board
Replace the X, Y Buffer Board
No
No
No
No
No
Yes
Yes
Yes
Yes
Caution
When separating and connecting the cables such as CN800,CN801,CN802,CN803, CN804,CN805 of the
MAIN SMPS,CN4005 of the X MAIN Board, and CN5005 of the 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.