My Magnavox started showing Green and Blue Lines in between the Picture going white and the Picture would narrow Horizontally for 3-5 minutes before adjusting to fit the Television Screen. Now I have no Picture and the Screen is just Black. The light comes on to let me know that it has Power. The Model is a 9P6031C102 and the Chasis is a PTV835. I believe this is a 60inch TV. I bought it used and it's a rear Projection Television.
If your screen shrinks and expands over and over or if you have lost the audio and video competely you may need to replace the opt IC chip. You can get a repair kit and service manual from www.magnavoxhelp.com