Centipede Problem - Yellow screen

[cornishHen]

I'm involved with yet another centipede restoration, and i've ran into an odd problem.  The machine plays fine after turned on, but after it sits for a few hours it freezes up and the screen goes yellow with maybe a couple of red mushrooms.  Restarting machine/reset has no effect..putting in test mode just gives constant beeping.  I was initially thinking the machine was overheating, but this problem remains after letting it sit overnight.  This has happened a couple of times and resolves itself days later it seems.  Any ideas?

[Level42]

Did you do the basics ?

[cornishHen]

Sorry for the ultra slow response.. I'm getting married next month and alot of little wedding planning tasks keep popping up...

My troubleshooting for this issue has been very basic as i'm really not sure where to start with this one.  I've checked voltages going in to the pcb(only when in a working state) and visually inspected wiring.  I suppose I should check voltages after the problem begins?  Any other pointers on where I should start looking?  This is the first machine that i've ran into that has an intermittent problem..

Thanks!

[Level42]

The most problems are caused by simple things. Check the connectors, wires, pins inside the connectors. If it's always after warming up there could be an issue on the PCB.

With basics I meant replacing the Big Blue on the Power Brick and capkitting the ARII board.