Hey folks, new to the cabinet world and I need some help. I have included pictures to show the issues, and to see the beauty that cost me $100

Recently purchased a Tekken 3 Jamma cabinet which turns out has a strange problem.
When you first turn the unit on the display that comes up is a flickering epileptic inducing nightmare. It looks like 5 or 6 rapidly scrolling compressed screens.
After a couple of hours sitting on, the display starts to looke like 2 scrolling images and then finally stabalizes into a nice clear game image.
When I first saw it I assumed it was the CRT failing and took the back off, did a visual inspection of the caps and what connectors I could get to without removing the CRT and everything looked ok.
The plot thickened when I finally got to play the game and I knocked the joystick a bit hard and the screen flicked to the rapid scrolling and a small hit restored it back to working.
I opened the drawer where the PCB is and checked the connections. Nothing unusual there. I removed the PCB, cleaned the JAMMA connector and checked the board for any noticeable problems. Again nothing. When I plugged everything back in and restored power the screen came up scrolling like I had just turned it on. Hitting the console didnt work (sounds so sad) and when I put some pressure on the JAMMA connector the display flickered but did not correct. After a couple of hours I came back and the game was ready to play.
So I am wondering if anyone has come across this issue. I am thinking it could be a cold solder joint in the JAMMA connector, but since there is very little heat there, why would it eventually start working? I was thinking it could still be the CRT but I have no idea why it would work after warming up, but then not work after just powering down the unit for a minute or two? Could the PCB be at fault? A cold solder joint on one of the chips?
Any help would be great and much appreciated.
Thanks.