Samsung LA37C630 Series, Service Manual

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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 relay does not work when connecting the power cord.
-
The units appears to be dead.
-
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.
-
Diagnostics
Does proper DC A3.3V appear at
C1131_NACH, C1132_NACH?
Check a IC1103_NACH.
Change a main PCB ass’y
No
Yes
Does proper DC 5V, 3.3V,
1.25V(B1.2VD), 1.5V, 1.8V(MT_DDRV)
appear at C1140, C1169,
C1163, C1167, C1174?
No
Yes
LAMP off, power indicator
LED red color?
Yes
No
Check a connection a power cable.
Does proper DC 13V appear at
pin21,22 of CN801?
No
Yes
A power is supplied to set?
No
Check a other function.
(No picture part)
Replace a lcd panel.
Change a Assy PCB Power.
Check a IC1108, IC1107, IC1109
Change a main PCB ass’y
1
2
3
Caution
Make sure to disconnect the power before working on the IP board.