Hello There. When working with SCSI Equipment, if you Remember that the First SCSI Device & The Last SCSI Device are the Only devices that Need Terminartion, It will save you alot of headache.
Also be very familiar with the SCSI Controller Catd.
Some SCSI Controllers auto-terminate the first device.
Generally when you have troubles with the scsi chain it's do to Extra termination in the scsi chain where it does not belong.
I generally read up on all of my scsi equipment before setting up the scsi chain. I make sure to know if the SCSI Controller has auto-termination or not.
Knowing if your SCSI Controller has auto-termination or not will help to avoid alot of headaches in the long run.
Take care.