On a similar but not identical boxes I know, SCSI cable is either a loop
from the main board or a cable off the main board to the drives and then to
an external connector. No drive should have internal terminator on (it may
be a jumper or a pack of resistors that can be installed or removed) , but
an external terminator may be needed on the connector. That is the way it
should be. Everything else is not the way SCSI was designed - may work but
may be unreliable. Very short cables have better chance but in those
configurations any change (heat, location, swap of supposedly identical
devices) may break things and I would recommend against it. If the system
has 2 independent SCSI busses,  it is commonplace not to put a terminator
on an unused bus.