Fairchild Channel F system II issues.

[Jerilock]

Hey guys. Just picked up a Fairchild channel f system II but it's giving me some issues. Right now if it's been sitting for a while it comes up and works great. But if I leave it on for a few mins the screen goes blank with white diagonal lines going all over the place. If I turn it off and let it sit it goes back to working ok but the problem returns once it's been running. I opened it up and checked for any hot to the touch components or shorts. Around the voltage regulators the 7812 does feel somewhat hot to the touch and thought this might be the issue but when I checked it my meter showed it was giving the correct voltage, same with the 7805 (this one doesn't get warm though). Any other spots to check? My next thought is to just recap it and swap the regulators but don't want to just pull and replace parts I'd that's not the source of the problem.