JAMMA PCB's

[kripp]

I've got a couple JAMMA PCB's that don't work the way they should, one has a bunch of corrosion on various components and the other has damaged components.

The PCB with the corrosion will boot, but the image is scrambled. I'm working on cleaning that one off, should be able to get it working. The other PCB is a dual board style, a mainboard and a soundboard. On the soundboard side of things there is one ceramic capacitor that has been crushed, and on the mainboard two electrolytic capacitors had been damaged but replaced.

This PCB will not boot, the speaker makes a hissing noise when powered on. No image comes up when its turned on, but when switched off the screen flashes and the speaker makes a bit of noise. Would a single damaged ceramic capacitor cause the board to not boot? Are all the components that critical to the PCB's operation?

One other question, should the mainboard be able to boot without the soundboard attached? Does the mainboard perform some kind of check to see if the soundboard is attached and then boots if all is ok?

Thanks.

[NFG]

How the PCB reacts without the sound board attached depends on the game.  

Normally a capacitor won't hurt things, but it is possible to have a cap that's vital to the operation of the game.