What leads you to think caps are the culprit, Macdrone? Just curious.

This sounds a lot like a SCSI chain issue to me. I assume the SE/30's internal drive is terminated, but who knows, plugging an external terminator into the rear SCSI port might help. SCSI is weird like that. And it's a cheap, plug-and-play fix, if it works.

My next guess would be that the drive itself is on its way to drive heaven.