I then removed the M930C terminator card from drive 1
and
put it in drive zero, removed the card that had the
controller cable attached to it (M993 RK8E cable), and
I seem to recall (vaguely) that that card can assert one of the power
fail lines on the drive interface (there is a chip on it, after all) and
that this might well stop the spindle relay from pulling in.
-tony