My ABC TV reception became bad two weeks ago with the pictures and!sound breaking up. All other stations were fine. Tonight ABC ceased to operate at all and the no signal sign is displayed.

SOURCE: Problems with TV

Our 37 inch Sanyo LCD HDTV has a problem with the picture distorted by being too wide. This has beenia problem for the duration since we bought the TV about three months ago. The PIX Shape button on he remote does not adjust this problem. We need help in solving the problem. Thank you.
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SOURCE: tuning problem

The tuner is bad. Could also be the video process, since the hi-def is decoded there

SOURCE: Panasonic TV-Sound but no picture.

Hi,
    According to the symptoms, There is a problem in vertical out section.Just check it there must be a capacitor that has been burst or leak.And second one reason could be the malfunctioning of vertical IC.Which is also in the vertical section.

Thanks for using fixya.

SOURCE: LG 42LG30 TV will not scan in DTV stations

Sounds like you're having a problem with your main board assembly. The main board is what processes all your audio/video signals. So if it's not scanning DTV you've probably got a bad card. Call LG's customer support line at 1-800-243-0000 and have them schedule you a service call. Request a DMST if there's one available in your area as they actually work for the factory. Otherwise you may get an ASC(authorized service center) which can be less than reliable at times when it comes to customer support and satisfaction. 

Remember to have your proof of purchase handy as well as the full model and serial number. And by model number, I don't just mean 42LG30. On the side or back of the unit there will be a manufacturer's code. The first part is indeed the model#. However, it will appear something along these lines:
42LG30-UA.AUSRMJR or something similar to that. 

Have that ready definately. Any tech worth their salt will call you a few days beforehand to try to get that data so they can order boards before coming out there, saving them, and you, an extra trip when they have to come and order boards. Without that extended manufacturer's code, LG techs have a hard time with a lot of models trying to order parts as different revision codes and such use slightly different circuit boards. 

SOURCE: The picture blinks on for just a second, then goes

The most likely the TV has a power supply related problem. The most common thing to go out is the circuit board that supply power to the screen. Commonly called a Backlight Inverter Board.
I can't say it's 100% the problem because I can't actually look at the tv over the internet.
If by chance the TV is still under warranty, go that route.
If not under warranty and If you have some electronic experience, you can purchase a Service Manual over the internet and diagnose the source of the problem and fix it by soldering in the new part. The Service Manual will give you circuit diagrams, test points, and part# lists. Usually, cost under $20.

I hope I shed some light on the subject for you.