You may require to review jumper settings if you have dual zip drives in single US.
Consider dual zip drives:
Your SCSI cable originating from EPDG I/O board shall connect to a zip drive first (say ZIP1) and then to second zip drive (say ZIP2).
Observe the SCSI address pinning (jumpers) next to the SCSI cable connector pins on the zip drive.
ZIP1 shouldn't have any pin shorted for address 0. [::::] left most.
ZIP2 should have the first & last pair shorted using a jumper, for address 1. [::::] left most & right most.
The SCSI address pinning actually is set by the last 3 pins, while SCSI bus end-termination is done using the first pin.
So the ZIP2, should be the last zip and terminated.
Refer the bernoulli drive to zip drive upgrade instruction manual, IF YOU ARE UPGRADING FROM BERNOULLI, AS IT WILL ALSO CALL FOR REPLACING EPDG/EPDG2 firmware EPROMS.
