Thanks for choosing JustAnswer for your TV question!
missing parts of the picture, especially half the screen or in blocks as you describe , Is usualy a flaky buffer. The buffers seperate the picture into "zones" each of which is controlled by a buffer (or drive board). It can only be diagnosed in person by a technician, anything else is basically guesswork.
From the sound of your problem you should probably call for service. There are too many variables involved to diagnose a problem such as yours over the internet. Modern TV's have thousands of parts, it can take a seasoned veteran up to an entire day to track down troublesome problems IN PERSON.
Please understand that by opening a TV you are exposing youself to many dangers, including electrocution. Be sure that the set is un-plugged and keep one hand behind your back whenever possible to avoid a shock through the heart as this CAN KILL YOU. If you have zero electronic experience I would not attemp this repair. OK, public service announcement over.
Basic electrical knowledge is a must to get inside your TV and fix it.
Your TV will need some parts and it is best to either leave it to a technician to diagnose.
If you call for service prepare to part with $200-$450 depending on the damage in the TV.
You can call Your manufacturers customer support at the phone number in your manual to find a local repair center. They do this for free so you can get your set repaired.
Wish I could be of some more help to you.
Hope that helps!
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