Emax

There's only one SCSI port, for both the internal and external drives. 
SCSI is notoriously picky about exactly how different bits can be
interconnected.  Ideally, the SCSI chain should be terminated at both
ends, but in practice you may find that it doesn't work unless one end
*isn't* terminated, or something in the middle *is*...

SCSI is in general a bit of a dark art, more so with samplers and stuff
for some reason.  You can't break anything by experimenting (unless you
terminate *everything, or plug stuff in or unplug it when it's switched
on).  Oh, and my Emax II hangs up for *ages* when you have dodgy SCSI
devices - sometimes I get an error after about 10 minutes.

HTH
  Gordon