Samsung LT20A350, Service Manual

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4-7
4. Troubleshooting
4-1-4. No video (HDMI 1, 2, 3, 4 - Digital signal)
Symptom
-
Audio is normal but no picture is displayed on the screen.
Major
checkpoints
-
Check the HDMI source.
-
Check the HDMI switch, 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
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) ?
Does the digital data appear at
TP-, E_TXCLK- ?
Yes
Yes
Yes
Yes
Check a set in the 'Stand-by mode'.
Input the HDMI signal properly.
Please, Contact Tech support.
Check CN601, CN604
CN602, CN603.
Check HDMI 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 HDMI source and
check the connection of HDMI cable ?
Check the LVDS cable?
Replace the LCD panel?
3
2
Caution Make sure to disconnect the power before working on the IP board.