Apple Power Macintosh 7100/80AV - Manual (Page 48)

Troubleshooting Symptom Charts/Peripheral - 14
Peripheral
Works with internal
or external SCSI
device, but does not
work with both
1 Replace external SCSI cables.
2 Verify that there is only one terminator on external devices.
3 Verify that SCSI select switch on any external device is set
differently from any internal SCSI device.
4 Verify that the hard drive is terminated and the CD-ROM
drive is not terminated.
5 Replace the terminator on external SCSI device.
6 Replace the SCSI select cable on external SCSI device.