Samsung LN52B550K1F - No Power

4-2
4. Troubleshooting
4-1-2. No Power
Symptom
The LEDs on the front panel do not work when connecting the power cord.
The SMPS relay does not work when connecting the power cord.
The units appears to be dead.
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Major
checkpoints
The IP relay or the LEDs on the front panel does not work when connecting the power cord if the cables are
improperly connected or the Main Board or SMPS is not functioning. In this case, check the following:
Check the internal cable connection status inside the unit.
Check the fuses of each part.
Check the output voltage of SMPS.
Replace the Main Board.
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Diagnostics
Yes
Does proper Main
DC B12V, B13V, B5V appear at
BD104, BD108, BD106?
Does proper DC B3.3V, B9V, A1.2V,
DDR1.9V appear at
R171, R173, C122, R527?
Change the LVDS cable
32”/37” : BN96-10076A
40”/46” : BN96-10075A
52” : BN96-10074A
No
Yes
Does proper DC B12V
appear at LVDS connector Pin #1~5
of T-con b’d?
No
Yes
Lamp(Backlight) Off,
power indicator LED on?
Yes
No
Change 30p power cable
32” : BN39-01099H
37” : BN39-01099J
46”/46”/52” : BN39-01099K
Does proper Stand-By DC
A5V appear at BD102?
No
Change the Main Assy
550 32” : BN94-02518A
550 37” : BN94-02518B
550 40” : BN94-02518A
550 46” : BN94-02518D
550 52” : BN94-02518E
540 40” : BN94-02510A
540 46” : BN94-02510B
540 52” : BN94-02510C
Yes
Does proper DC A3.3V
appear at R102?
Yes
Does proper DC B12V
appear at F1 of T-con b’d?
No
Yes
Change the T-con b’d
32” : BN81-02345A
37” : BN81-02368A
40” : BN81-02390A
46” : BN81-02381A
52” : BN81-02342A
No
No
A power is supplied to set?
No
Check a other function (No picture part)
Replace a LCD Panel
32” : BN07-00640A
37” : BN07-00643A
40” : BN07-00661A
46” : BN07-00647A
52” : BN07-00678A
Caution
Make sure to disconnect the power before working on the IP board.