@Matt_H:
The only thing I did to make both my previous IBM 9GB and my current IBM 18GB (DPSS) work with my CSPPC was to jumper the "enable auto spin" and "term power" (as the CSPPC manual stated that the CSPPC didnt supply termination power) jumpers and put termination at both ends of the cable and it worked directly. I have though read from other users that the CSPPC does indeed supply termination power so that last jumper was probably not necessary.
(edit):
One thing that can cause problems though with SE scsi running at high speeds like 20MHz as the CSPPC/MK3 can do is to keep the cable length down - I think the max is 1.5m at those speeds which means you should keep it even shorter.
@alext:
I had some problems getting the above kind of drives to work in my A2000 with a GVP HC8 though. At first I tried with a narrow->wide adapter with the upper byte active terminated and a passive terminator at the drive end of the cable, but that didnt work. Later when I got hold of a GVP GForce030 I tried the same drive again with the GForce's onboard scsi using the same narrow->wide adapter but with a scsi-cable with an active terminator at the end and it worked directly. The scsi-controller of both the HC8 and the GForce should be the same, so I assume that the active termination made the difference. Other than that I had also jumpered the "enable auto spin" jumper on the drive, but it should work nevertheless, just needing more time to spin up.
/Patrik
