glitches

I bought ghost'n goblins japanese(makaimura) pcb. It worked well but, there is a problem. When I played 3,4,5, and 6 stages, background wall had changed to other background wall only 1 pixel. For example, when I played 3 stage, after charactor met first arima(red devil one), background wall...

When I got it, it was suicided. No sign of corrosion or leaks whatsoever, very clean board. Installed an Infinikey and it came back to life, but I'm seeing some weird rows of "dots" (pixels) almost in a grid pattern across the screen during startup, the warning screens, and the intro. However...