I switched the faulty internal HDD to an internal Iomega Z100Si (SCSI ZIp) and used the same SCSI cable that previously was connected to the internal HDD. And made sure that the cable was connected correctly, pin 1 to nr 1 on the cable.
I set the SCSI id to 0, (termination; on) on the Internal drive.
The only mod I did was to only connect the +5V cable for the power supply, as only +5V was stated on the ZIP-drive. So the +12V line was left unused.
I loaded a floppy with the Plus OS and made sure that the SCSI Id was 0 (by holding transpose-button).
But - I only get "HD format error" when trying to acces the drive (which I have loaded with a pre-manufactured ZIP-disk with Emax-sounds bought of Ebay http://www.ebay.com/itm/301299193629?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT)
Any suggestions? Could it be the 12V-line?
Niklas