On Thu, Sep 23, 2021 at 6:41 PM Jonathan Stone via cctalk
<cctalk at classiccmp.org> wrote:
  I've read that there is circuitry in the expansion
base (BA40A?) has circuitry .  Does anyone know what the circuitry does?  Is it required
for SCSI operation?  (I hope not, or I'll have to kludge one up to make use of pk2k
SCSI boot-roms!) 
IIRC the DHT32 has a small board in the skirt and the external RD
interface may have a board as well.  SCSI (for a TK50Z-FA, originally)
is just a cable.  The 50-pin connector on the mainboard is correctly
wired for SCSI. It may well have TERMPWR active and not
current-limited though, if it matters to your target.
-ethan