[Apologies for following up my own message]
Sounds like
some variant of the 9817 / 9000/210
It sure looks like a 9817, and the backplane has a 09817- part number,
which would indicate that it came from that machine. The mainboard has a
50960- part number, but it's on a stuck-on (HP printed) label, not in the
etch or silk-screen. There doesn't appear to be any other number under
the label, though.
Alas, having looked at the manuals on
hpmusuem.net, I think the machine
is somewhat different. The main logic board of the 9817 would seem to
include an HP-HIL port and a sound circult as standard (there was an odd
hole in the intneral metalwork of my machine, from the diagrams in the
manual it would appear this was for an internal speaker). Those are on
one of the expansion cards in my machine.
I've still not powered it up. I am hoping there is some what to make it
do something other than act as an SRM server (since I have no more SRM
stuff...)
-tony