Panasonic plasma TV intermittent

I have a Panasonic Viera TH58PX600U Plasma TV since 2007. During the last 6 months it has developed an annoying trait. When I turn the TV on it shows picture and sound for about 10 seconds, then those go off for about 5 seconds and then come back on again. The power light stays on and does not blink. This occurs no matter what input to the TV is being used (TV, Cable, DVD, etc.).

I have tried unplugging the TV and tried a different power outlet. When the TV is plugged back in I hear a click and then a few seconds later (with the TV still off) another click. If I power the TV on it shows the "First time setup" menu until the screen goes black and sound goes off as described above. When the sound and picture come back the menu is off.

One of the things I am wondering is whether this has anything to do with the unavailability of TVGOS that was discontinued in 2013. I am not able to access the TVGOS setup screen to try and bypass any of its functions. When I try to access TVGOS I get a black screen for about 5 seconds and then the picture and sound return.

Is there a diagnostic that I can run to troubleshoot this problem? Panasonic Support could only tell me that they did not know what the problem could be and referred me to a local service center.

 

Does it stay on normally after it does that ?

If it does.... it sounds like the TV is looking for something. I'll check further and your reply will help me.

 

Yes it stays on and operates normally.

That's why I mentioned TVGOS. I thought it might be looking for the listings or the feed, which since 2013 no longer exist.