have a look and check the jumpers, there may be a jumper configuration on the drive that will either disable the top 8 data lines, or switch ON auto termination.
(only problem being that you have to have the drive at the end of a narrow scsi chain, not too much of an issue for PC people as they usually only have one or two SCSI drives, or a stack of drives sat on an ultra SCSI bus)
if that doesn't work, then it can't handle not having the top 8 data lines unterminated, so the less cable you have between it and the controller the better. other than that, and you have a duff 68-50 way adapter. mate of mine had a duff one and fried my optiplex 2.6G removable optical drive. yay
other than testiong it on something with a 68pin scsi bus, i'm out of suggestions.
