Is your harddrive powered by the PSU or the SCSI board? I know in mine it's powered from my GVP HC+8. A quick way to test the PSU would be to plug the harddrive into it directly.
If it doesn't spin up that way, your PSU is the likely culprit... If it DOES spin up that, and not via the power connection on the SCSI card, your board is likely fried.