Samsung UN HU7250F Series, Service Manual

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4-2-3. No Video (Tuner_CVBS)
Symptom Audio is normal but no picture is displayed on the screen.
Major
checkpoints
Check the Tuner CVBS source. •
Check the Tuner. •
This may happen when the LVDS cable connecting the Main Board and the Panel is •
disconnected.
Diagnostics
Power indicator LED is off.
Lamp(Backlight) on, no video ?
No Check a set in the ‘Stand-by mode’.
Yes
Check the RF source and check the
connection of RF cable.
No Input the RF source properly.
Yes
1
Check the Power of Tuner.
Pin #4 of Tuner : B1.8V_Tuner
-
Pin #1 of Tuner : B3.3V_Tuner
-
No Change the Main Ass’y.
Yes
1
2
Check the CVBS data out of IC1400.
L903 : Tuner CVBS_OUT
-
CVBS_OUT_TP : IC1400 CVBS_
-
OUT
No
Check IC1400(NT14U).
Change the Main Ass'y.
Yes
3
Check the LVDS clk signal at output of
Main Board. (TX)
TX6_CLK : TCON SDA
-
TX8_DATA : TCON SCL
-
No
Check IC1400(NT14U).
Change the Main Ass’y.
Yes
Check the LVDS cable?
Replace the T CON / LCD panel?
Yes Please, Contact tech support.
Caution Make sure to disconnect the power before working on the IP Board.
4-10
4. Troubleshooting