LG Plasma TV no picture

[phantom27]

I have an LG 60PA5500-UG

I was watching TV the other day and the TV just turned off on it's own. I turned it back on and I had sound but no picture. I left the TV off for a few hours and tried it again. It came one picture and all for about 15 mins and went off again. I turned it back on again and had sound but no picture. About a week later I decided to take it out to my shop and work on it, I plugged it in and it worked just fine. I connected my laptop via HDMI to all 3 ports and the darn TV worked just fine for 7 hours straight with not even a glitch. I turned it off and back on a few times and it worked just fine. The next day I tried it again, the TV came on just fine and about 12 mins in the TV turned off on its own again. I turned it back on and it came on with sound and picture for about a min and went off again. I turned it back on and now I'm getting sound and no picture.

Can someone please help me with this

 

[Robert Ban]

Seems like on mainboard which converts signal has been damaged from use. For how long do you have it? If you have it from over 6-9 years it did its job, but as i've typed in ebay parts are 60$-100$ (in US and EU).
Does it still have warranty?
You could take it to repair shop, maybe just a converter or capacitor went bad.