Why does RCA TV has a blank black square on the screen?

Black square appears at the center of my flat screen TV?

• Answer:

  Sounds like a defective circuit-board. It doesn't fail until it heats up which could be indicative of a hairline crack somewhere in a solder line/connection. It could be fine enough to prevent you from seeing it with even a magnifying glass. When the area containing the connection gets hot it expands and breaks the connection. When it cools it contracts and goes back to normal. That's why it works okay for the first few minutes after you turn the set on. If you have a set of schematics for your set you might be able to identify the problem module and replace it yourself. Otherwise you'll need a technician to diagnose and fix whatever is wrong. If your set is under warranty you should take it to an authorized Samsung facility otherwise I would visit Samsung's website (especially the FAQ's) and do a little research before taking it to a repair shop.