55 inch lg55la6200 tv turns on quick flash of lg symbol and screen go black. it has sound just not picture after lg symbol disappears. Came back on for 3 minutes then stayed black for last few days

SOURCE: no sound or picture now

The set may have shorted the horizontal out put transistor since it kept coming on sometimes. This could be cause by the driver transformer arcing causing a "spike" in voltage going to you horizoltal out put transistor. Stargazer

SOURCE: TV Picture Goes Black

I had the same exact problem.
I removed the bulb and cleaned it. There is a small screen at the top of the bulb and it was covered with dust. Once it was cleaned I replaced the bulb and it solved the problem.
Thanks to those who posted the solutions

SOURCE: Black box showing up in center of tv

your closed caption feature is turn on and in the text mode. either turn off the closed captions or change it from text to cc1

SOURCE: Sound stays on, but no picture- goes black and stays that way.

This unit should still be under warranty and should be taken in for warranty service. Any attempt to access the interior will void the warranty. It is important that a complete description of the problem like you entered here be taken along when you bring the set in for service. This will insure that the servicer be able to reproduce the problem and resolve it.

From your description (and as a servicer), I would be looking for a component that is heat sensitive. These types of problems are fairly easy to locate and resolve.

Please take this in for warranty service and update this when you find out the details.

Thanks,
Dan

SOURCE: my tv picture and sound turn on and then after a

Hi,
There are two possible causes for this problem, either back light inverter board stop working thus screen goes black as lcd screen needs back light to show its image OR if sound remains while screen goes black then it seems firmware issue.
Let me know is it Insignia NS-LCD42HD tv or any other model?
Do you get sound in tv while no picture?
Does screen show any on-screen display when tv lose picture?
Above info will help me to diagnose problem in tv and to suggest some solution.
Thanks.