Samsung LN40A550P3R - No Power Troubleshooting

4-2
4. Troubleshooting
4-1-1. No Power
Symptom
The LEDs on the front panel do not work when connecting the power cord.
The SMPS / IP Board relay does not work when connecting the power cord.
The units appears to be dead.
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Major
checkpoints
The SMPS / IP Board 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 B12VS, B5V, B12V
appear at C2060, C1011, C1008_DE ?
Does proper DC A3.3V appear at C1006?
Check IC1002 Change the Main Ass’y
(Code Number refer to each model’s
BOM)
No
Yes
Does proper DC B1.26VD, MT_
DDRV18, B1.8V, B3.3V, B1.5VA
appear at C1037, C1045, C1042,
C1024, C1041?
No
Yes
Lamp(Backlight) Off, power indicator
LED on?
Yes
No
Check a connection power cable.
(Code Number refer to each
model’s BOM)
Does proper Stand-By DC
A5V appear at C1002?
No
Change the Main Power assembly
(Code Number refer to each model’s
BOM)
Yes
No
Does proper Inverter DC 12V appear at
CN1001 in SMPS?
Yes
No
Check IC1019, IC1008, IC1009, IC1005,
IC1007 Change the Main Ass’y
(Code Number refer to each model’s
BOM)
A power is supplied to panel
appear at C1025_DE?
Check a other function (No picture part)
Replace a LCD Panel
(Code Number refer to each model’s
BOM)
No
Caution
Make sure to disconnect the power before working on the SMPS / IP Board board.