TV went out.

This is neither the power supply.
Replacing a transistor will not solve the problem either.

The smoke comes - most of the time - from a Y sustain buffer board; Betleano above tells you one small thing that's needed to be done on the Y sustain board, but it is MOST CERTAINLY not the only thing that will need to be done.

At the very least you will need to replace a buffer board or you risk burning another transistor and possibly more.

There are two sane approaches to this: have the Y sustain board repaired and replace the two buffers; or replace all three (the Y sustain board and the two buffers) together.

While theoretically possible that your problem might be elsewhere, 99% of all 42'' plasma Magnavoxes that come to our shop have that problem.

www.coppelltvrepair.com

Hi,
replace a transistor in the power supply and a diode that has shorted out near this transistor,this transistor is located near other in the same heat sink,and check the tall caps for swollen top,thanks everyone!!!

U have a dead power supply board,burn componnents parts on the power supply board.Replaced the power supply board,u will get ur power back as normal function as before.Tries websites like Shopjimmy.com,Ebay.com to buy a refurbish power supply board for the replacement.