10 Jul
1998
10 Jul
'98
2:49 a.m.
AFAIK all DEC unibus peripheral controllers work here.
There *might* be an ancient SPC that doesn't, but yes, all DEC cards
I've ever seen work in a MUD slot.
Here's what's going on.
On an original Unibus slot, connectors A,B were either Unibus In/Out...
C-F were not changed AFAIK on any slots.
AFAIK, that is all correct.
On a MUD slot, there were memory signals on connectors
A,B. Originally
these were just the Unibus address and data lines, wired almost the same
as a Unibus In or Out connector. However some grounded pins on the Unibus
connector were assigned to extra power lines (battery backed, etc) on the
MUD slot, so plugging a terminator or Unibus cable into an MUD slot
shorts out the PSU. Bad idea.
Right. Some bozo vendor shipped me a 11/725 (11/730 CPU, different case)
with no grant cards and the terminator in a MUD slot. Stupid me turned on
the power without checking the cards. Stupid vendor did replace the PSU.
For this reason no peripheral card should ever do
anything but take power
from A and B unless you know exactly what you are doing.
True, but that third-party board I used to make was designed by Real
Engineers (tm). They just *knew* that the Unibus signals were on A and B
and didn't worry about those C and D fingers. You should see the mod
to make that board work in a MUD slot - bunches of wires.
What ever you
do, don't install the M9202 terminator in a higher slot than
THe M9202 is a bus jumper, isn't it? The terminator is the M9302.