On my Williams IJ, I totally restored the game and once back together all was good except the DMD had a few odd lines / garbage and game played fine. I reseated all ribbon connectors and cleaned terminals of each ribbon connectors and DMD was alot better but not 100% without misc. garbage/lines on screen.
After playing the game a little while the DMD is now totally black, nothing on screen.
What could it be or what to check?