Here’s a couple shots of the inside. It’s a Delhi III motherboard from eMachines, which has an ATI Rage 3D chip for a video processor. It’s running DOS, ArcadeOS as a frontend and a custom compiled Mame .96 to remove a couple of the warnings (like Galaga’s “not quite right” message). IIRC the hard drive is 200M, more than enough for the smattering of games installed. There is also an Ultimarc video amp.
Since the number of inputs required is very low, instead of a dedicated keyboard encoder I hacked a keyboard instead.
I know it’s not fancy, I should tie the wiring back and secure things within, but until I have to move it it’ll be fine for now.