Samsung LT20A350, Service Manual

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4-4
4. Troubleshooting
4-1-3. No Video (Analog PC signal)
Symptom
-
Audio is normal but no picture is displayed on the screen.
Major
checkpoints
-
Check the PC source
-
Check the Arsenal, Check the Main Chipset.
-
This may happen when the LVDS cable connecting the Main Board and the Panel is disconnected.
Diagnostics
MAIN BOARD SMPS BOARD
Does the signal appear at
PIN - R, G, B, HS, VS (R, G, B, H, V) ?
Does the digital data appear at
TP-, E_TXCLK- ?
Yes
Yes
Yes
Yes
Check a set in the 'Stand-by mode'
or 'DPMS mode'
Input the analog PC signal properly.
Check CN401, PC cable.
Change the Main Assy.
Check IC1111 (X5).
Change the Main Assy.
No
No
No
No
No
Power indicator LED is off.
Lamp(Backlight) on, no video ?
Check the PC source and
check the connection of D-SUB ?
Please, Contact Tech support.
Check the LVDS cable?
Check the T-Con B'd?
Replace the LCD panel?
1
2
Caution Make sure to disconnect the power before working on the IP board.