If an LCD TV has sound but no picture do the following:
Use the source button to ensure that source is not set to the wrong input.
Try unplugging power cord for ten minutes, to ensure it is not a setting problem.
Check all the video cables at the back of TV.
Check Light /Color settings.
If problem persist and does not depend on external receiver or settings, then it is likely an internal fault.
If it has sound but no picture then one of the following parts is faulty, and must be tested and replaced:
inverter is the high voltage board that provides variable power to the
backlight lamp. This is the most common. When inverter is faulty you
can get no picture, or a very dim picture that can only be seen by
pointing a torch light with a 45 degree angle on the LCD surface from
very near distance.
The inverter must be tested by reading voltages with a multimeter.
The LCD ribbon cable/LCD display and connectors.
is quite uncommon, but happens. If the TV had been hit or moved the LCD
cable may have slipped out, or the LCD connector may be damaged.
The LCD controller board.
is the board that controls the video signal, it is difficult to test,
as there is need to read determined values on IC pins. To test this
board you need to purchase a service manual and follow the
troubleshooting diagrams on service manual.
Input/Output Signal boards.
This are the boards where you connect the video and audio cables, if a signal board is defective, then you
may get no picture on particular inputs located on faulty board.
Generally, when the screen has no light at all, it is the inverter, rarely the main board.
When the screen is blank, inverter is OK, and it may be any of the other faults listed.
If under warranty contact the manufacturer ringing the number on the user manual.
If you want to repair at your own expenses, just locate any good qualified repairer.
If you want to DIY you find parts here,
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