Vizio P50HDM - No picture or sound, works 4w later

[DarwinIcesurfer]

I have a Vizio P50HDM

About a month ago, we turned on the TV, but there was no picture and no sound. There were a couple 1 pixel high green lines shown on the screen one near the top and the other near the center of the screen. We took the TV out of service.

It has been about 4 weeks since we took the TV out of service. I started the tv again today with nothing plugged into the inputs and observed the green lines again. After sitting for about 10 minutes, I pressed the input key and a box was displayed with random red/green pixels where the 'no input signal' message would normally appear. I continued to press the input key and eventually the 'no input' box was shown, but you couldn't read the text because random lines were shifted horizontally 'smearing' the text.

After another 5 minutes or so, I plugged in a DVD player into the S-Video source and a picture was displayed, but again, the picture was 'smeared'. It appeared that the lines didn't all start at the left side, some would start part-way into the screen. It appears like there are 3 to 4 different 'start points' for the various lines. I'd estimate that 80% of the lines started correctly at the left side so you could make out the picture. I then plugged in the audio cables from the DVD and could get the audio signal.

After playing the 'smeared' picture for about 5 minutes, I turned the TV off and back on again and now the picture is fine!

From this description, can you suggest what boards or components may need to be replaced?