Have you tried booting from an external floppy? (Assuming you have one).
edit:
rev 7.0
no SCSI termination is mounted on the motherboard, just sockets for three 8 pin resistor packs
cannot boot without at least one SCSI device attached
from amiga hw db
I'm guessing you have no scsi devices attached and a rev 7 motherboard. I suppose that could also explain the long seek time if it is trying to search the scsi bus all the time.
