Need help with donkey kong

[zaxxonfan]

I've had the machine for a few years now. When playing, the image will shake and sometimes eventually become a horizontal blur. I cleaned the pcb contacts and that worked for about an hour then went back to shake. The shaking will get worse and worse when playing. What do you think I should do? Is there a proper way to clean a pcb or what? Thanks

[Dr Galaga]

Have you also tried cleaning the contacts on the monitor itself?

[zaxxonfan]

No I have not. How do I do so?