Model 42PF9631D/37green light turns red and TV gose off

The power supply board answer is correct. However, depending on your model, the part may not be available or maybe you don;t want to spend a couple hundo and have some basic electronic skills. The following is an inexspensive and effective alternative.

I have a NEC 61" plasma with the same problem. However, I couldn't find the part I needed (the power supply board) except at NEC and they wouldn't sell me one since I was not azn authorized repair center.

So I checked the board, by simply measuring the resistance between connections, and discovered that 2 MOSFETs on the board,used for power switching, were defective. These transistors have been discontinued but were available still from the manufacturer. I replaced 3 of them for .75/ea and the TV is working beautifully now. The part number for the MOSFETs is FS20SM-5 and available directly from Powerex. I suspect many plasmas use this series (FSXXX-X) of discontinued transistors on their power boards thus the mulitudes of similar complaints and the discontinuation.

You have a defective power supply,this is a common problem with this set, go to shopjimmy.com and you will find it; the price is about $200.00 dollars. it not hard to replace i believe you can do it yourself. good luck