It is most likely the Small Signal Module. There is a module that is plugged into the main board on the left hand side. It plugs in like memory boards in a computer. You release the tabs and push it sideways and out. You have to remove the plastic holder over the top ot it to get it out though. I changed one to repair the same problem you have and it worked. That part is not cheap though. It's a couple hundred dollars so you may want to consider if it's worth the gamble.

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Posted by vasqdd (My Page) on Sat, Dec 1, 07 at 1:01

Hello i hope you can help me i have a 55''magnavox rear projection tv.model number 55p8288a. chassie number PTV910.My problem is my tv will come on for aprox. one hour and then turn off.If i trun it back on it will stay on for a couple of secounds then turn back off.i realy dont want to have to replace my tv any help would be greatly appriciated

I wonder where one can find that "Small Signal Module" if they are willing to part with the couple hundred bucks?
Magnavox 55'' projector tv (model # 55p8288a)