>I used a crappy PC powersupply on my jamma boards and >it would cause some of my games to lock up. I asked one >of the electrical engineering professors here at UVA, and >they seemed to believe that cheap pc power supplies >prone to "power spikes."
Thats probably the problem. Although professors are very knowledgeable when it comes to theoretical information, when it comes to practical knowledge they are usually pretty lacking, as most have zero experience working in industry and in the real world.
The problem is not so much "power spikes" as you call them, but more likely a problem of output ripple or the fact that you didn't preload your cheap pc power supply. It definitely not power spikes (peak voltage transients) as this would definitely affect the sensitive power equipment they are driving. I have an arcade power supply and this particular one is designed with a switching topology that doesn't require a minimum load. Perhaps, you never put a preload on your pc power supply therefore weren't getting the proper regulation.
Also, output ripple is a real problem with all switching power supplies. Linear supplies have very clean outputs, but the drawback to them is they are much larger, much heavier (big transformer), and more expensive. If you have a multimeter, you can measure the output ripple simply by switching the meter to Volts AC and seeing what the output voltage is.
And with output ripple, your JAMMA boards probably do not have enough filtering on them (capacitors in the simplest sense) to provide the filtering necessary for those boards.
Another problem is grounding. YOU NEED TO PROVIDE a good ground path between your computer and the JAMMA card, and the power supply powering the JAMMA board, otherwise you could have all kinds of problems.
(I don't know much about electronics, so I can't provide you with details). Anyway, all I meant was, buying a cheap pc power supply is not the best route to go....