Chad to my knowledge takes broken boards and does surface mount solder work to repair them. the CPUs on these are very fragile. what frequently happens is board flex or some dickhead decided to pull the heatsink off the CPU and wound up breaking legs in the process.
alternatively, the large cabinet fan was not only intended to cool the hard drive (which I doubt those 2.5" drives ever really got hot anyway) but was for cooling the CPU. without that fan active, I hear that the CPUs can overheat and burn out.
now there's one more chance at fixing the white bar error, and that's a corrupt U98 boot rom. you can take a gamble on rewriting that to see if it fixes it, but to my knowledge that's mostly caused by either a bad CPU or one of those Altera chips going bad.
also to the guy that sold me my first KI board that was "untested", fuck you. you deal games and you couldn't test a JAMMA game? yeah, fuck you.
you'll usually find these boards in scrapheaps in "untested" condition because of the same problem you've got. sometimes on ebay you'll find some chodes listing boards with bad hard drives, including the blue/black screen signifying a bad drive and you can score them on a bargain on a slow day... most bidders are privy to this though and bid the fuck out of them.
I happened to buy my first board from quarterarcade for a pretty penny at around $230, and the second from dj dns for an incredible price.
/KI