I picked up a dead Area 51 Site 4 kit with wiring, guns marquee and all. Previous owner reported it was DOA - nothing on screen.

Found out these boards are nothing more than a special JAMMA interface on a standard PC motherboard. The motherboard is a Cyrix P5GX-LG, and the interface board is referred to as an Atari "Jammit" board. They connect directly into each other via the VGA and parallel ports. In addition, there's an audio connector for sound, and a reset wire for a watchdog.

Looking the board over, I found the power led on the jammit board damaged. I don't think that's causing an issue but I'll prob replace it with a standard led. It was true that it is DOA, however the sound amps seem to work and the hard drive and motherboard are getting all the proper voltages.

Being a computer geek I focused on that first. There is a tiny speaker on the board and not hearing a bios beep - I knew it wasn't booting. I removed the jammit board and flipped it off to the side keeping the power wires connected. I connected a regular monitor to the VGA port, and plugged the jamma harness into the jammit board (for power). Fired it up, and sure enough, no boot or picture. I  reseated the RAM simms to no avail. Finally after doing some digging, I found some old ram simms and popped those in, and upon power up - the monitor now tells me it can't display the signal (arcade monitor res). YES!! Now getting a signal and bios beep means its functioning! Woohoo!

I put the jammit board back on, connect a monitor, and now have a boot picture/test menu. GREAT - it works! Now lets hook up some guns and set this up. Wait...guns not working...in fact, no data leds on jammit board...CRAP - still half dead

A minute after that - my bench switcher went up in smoke. Yay.

I moved the pile over to my Dynamo cab, and still getting the same results. Again I yanked the jammit board and went over it with a magnifying glass. I found one unused solder pad for a chip had a short, which I simply fixed with a dental pick. I found 1-2 crappy looking solder points on power connector that I resoldered, but alas, nothing that brings it back to life.

At this point I don't know where to go with it, other than look up a few of the chips (there's not a ton) and make sure each one is getting voltage. There are 4 leds that show data activity when the jammit board is communicating with the motherboard, and none are ever lit, so again that could indicate the jammit board is dead, or the parallel port is dead, or both. I shoudl be able to verify the parallel port with my oscope - the mobo looks like it tries to talk to the jammit as part of its bootup so hopefully that'll show some activity!