Or perhaps it is a termination issue. Something else to look at (if I can - no resistor packs, so need an external terminator plug?)
(kb/TA27743)
... The Macintosh has an internal hard drive
If the Macintosh in the SCSI chain DOES have an internal hard drive, terminate only the other end of the SCSI chain. (All Apple internal SCSI hard drives have built-in terminators).
... The Macintosh has a third party SCSI device
If you have a third-party (non-Apple) SCSI device, check the manual to find out if it is internally terminated. If the device is not internally terminated, follow the directions in the 2nd, 3rd, and 4th items directly above under the section "Terminating the SCSI Chain."
(kb/TA27743)
... The Macintosh has an internal hard drive
If the Macintosh in the SCSI chain DOES have an internal hard drive, terminate only the other end of the SCSI chain. (All Apple internal SCSI hard drives have built-in terminators).
... The Macintosh has a third party SCSI device
If you have a third-party (non-Apple) SCSI device, check the manual to find out if it is internally terminated. If the device is not internally terminated, follow the directions in the 2nd, 3rd, and 4th items directly above under the section "Terminating the SCSI Chain."