I have just about the same problem man. The things I've tried include switching out and trying with different PSU, ram, cpu board, harddrives, cdroms, all kinds of ide cables, I also tried cutting the wire1 (red wire) from the IDE cable - which very interestingly made it boot up the first time I tried it from HD, but then wouldn't reboot when I tried that. My board also have no corrosion whatsoever anywhere, no battery leakage (new battery was inserted long before the old one sprung leak), I tried with a new IDE controller, didn't work. Now I'm getting my ppc card back from repair so I'll try a scsi disk over the weekend to see if that works. If not I will buy a new mainboard- but reading that you have tried that I'm a bit discouraged, however I suppose our problems could be of a slightly different nature, yet somehow perhaps related. Anyway just sharing some experiences, I will post if I get scsi drives working. Good luck in the meantime.
