tv turns off and then back on

Unplug the TV from the power outlet, remove all video input sources. Hold the power button down for 30-60 seconds. Then plug the TV back in and connect only one video source. Best is a local source like a game console or DVD player. See if that resolved the issue. If not then the issue could be caused by either a faulty IR board or a bad motherboard (shortened power transistor etc.) If you are going to take a look at it you do want to go ahead and post some images of all of your board with your question. That way we can see what you see

Adding images to an existing question