Samsung LT20A350 Service Manual page 36

4-1-4. No video (HDMI 1, 2, 3, 4 - Digital signal)
Symptom
- Audio is normal but no picture is displayed on the screen.
- Check the HDMI source.
Major
- Check the HDMI switch, Check the Main Chipset.
checkpoints
- This may happen when the LVDS cable connecting the Main Board and the Panel is disconnected.
Diagnostics
3
2
Caution Make sure to disconnect the power before working on the IP board.
SMPS BOARD
Power indicator LED is off.
Lamp(Backlight) on, no video ?
Yes
Check the HDMI source and
check the connection of HDMI cable ?
Yes
Does the signal appear at
CN601 (Pin#12 , #7 )(HDMI1)
CN604 (Pin#12 , #7 )(HDMI2)
CN602 (Pin#12 , #7 )(HDMI3)
CN603 (Pin#12 , #7 )(HDMI4)
(HDMI RX_Clk , RX_Data) ?
Yes
Does the digital data appear at
TP-E_TXCLK+, E_TXCLK- ?
Yes
Check the LVDS cable?
Replace the LCD panel?
MAIN BOARD
No
Check a set in the 'Stand-by mode'.
No
Input the HDMI signal properly.
Check CN601, CN604
CN602, CN603.
No
Check HDMI cable.
Change the Main Assy.
No
Check IC1111 (X5).
Change the Main Assy.
No
Please, Contact Tech support.
4. Troubleshooting
4-7