4-13
4. Troubleshooting
4-1-6. No Video (Tuner DTV)
Symptom
-
Audio is normal but no picture is displayed on the screen.
Major
checkpoints
-
Check the DTV source.
-
Check the Tuner, 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 DC B5V_TU_PW, B33V_TU_PW
appear at #3, #5 Pin of Tuner ?
Check the 'signal strength' in Self Diagnosis
menu Strength is enough ?
Does the digital data appear at
TP-, E_TXCLK- ,
, O_TXCLK-?
Yes
Yes
Yes
Yes
Yes
Check a set in the 'Stand-by mode'
Input the RF source properly.
Please, Contact Tech support.
Change the Main Assy.
Check the D-TV source.
Check IC1111 (X5).
Change the Main Assy.
No
No
No
No
No
No
Power indicator LED is off.
Lamp(Backlight) on, no video ?
Check the RF source and
check the connection of RF cable ?
Check the LVDS cable?
Check the T-Con B'd?
Replace the LCD panel?
2
Caution
Make sure to disconnect the power before working on the IP board.
Summary of Contents for LT20A350
Page 34: ...4 5 4 Troubleshooting Main Board_Top Main Board_Bottom...
Page 35: ...4 6 4 Troubleshooting WAVEFORMS 1 PC input V sink H sink R G B 2 LVDS output...
Page 37: ...4 8 4 Troubleshooting Main Board_Top Main Board_Bottom...
Page 38: ...4 9 4 Troubleshooting WAVEFORMS 3 HDMI input RX_Data RX_Clk 2 LVDS output...
Page 40: ...4 11 4 Troubleshooting Main Board_Top Main Board_Bottom...
Page 41: ...4 12 4 Troubleshooting WAVEFORMS 2 LVDS output...
Page 43: ...4 14 4 Troubleshooting Main Board_Top Main Board_Bottom...
Page 44: ...4 15 4 Troubleshooting WAVEFORMS 2 LVDS output...
Page 46: ...4 17 4 Troubleshooting Main Board_Bottom Main Board_Bottom...
Page 47: ...4 18 4 Troubleshooting WAVEFORMS 4 CVBS OUT Grey Bar 2 LVDS output...
Page 49: ...4 20 4 Troubleshooting Main Board_Bottom Main Board_Bottom...
Page 50: ...4 21 4 Troubleshooting WAVEFORMS 5 Compnent_Y Gray scale Pb Pr Color bar 2 LVDS output...
Page 53: ...4 24 4 Troubleshooting WAVEFORMS 7 Speaker out...
Page 70: ...4 41 4 Troubleshooting TOP BOTTOM...
Page 72: ...4 43 4 Troubleshooting Model Inch CODE P N 24 27 BN44 00450A PD27A0_BDY...