RCA 50" smart tv model RWOSQU5050-B

Sorry I can't help but I have a similar issue that I hope someone can provide an answer. I have a 50 inch RCA UHD TV .....(same model) that has a new t-con board and new main board. The picture is perfect for 10 or 15 minutes after turning on, then it begins to produce horizontal lines and distortion in the middle section of the screen. After which it keeps getting worse until I turn it off and let it cool. Any ideas of the cause?

I haven't left the TV on when it is experiencing this issue but I will try that to see if similarly my TV, clears up.

UPDATE: I had the TV on for an hour. The bottom half of the screen started doing weird things after about 20 minutes ... like going all white, or freezing or showing the picture, lagging behind the top half of the TV ... the picture looked normal in the top half. A few times the entire picture looked like it was clearing up but it hasn't so far. I will leave it on for a while longer.