23 Jan
2012
23 Jan
'12
6:35 p.m.
Wolfgang Eichberger wrote:
Nice system.
But that's not a BA23, it's a BA11-N. Standard rackmount CPU box for a
PDP-11/03 or early 11/23 systems so what you have may be a box that's
had a CPU upgrade (maybe not though, 11/03s would have had RLV11 not
RLV12, whereas 11/23s usually had RLV12). It's an 18-bit backplane,
which matches your 256KB memory (of which 248K is usable, 8K being
reserved for the I/O page). It's fairly easy to upgrade the backplane
to 22-bit, though, by removing the card cage and soldering a few wires.
Wire-wrap wire is best for that. Your MSV11-P is 22-bit capable, as are
all the other cards you listed.
What backplane
do you have? For example you might have one of the DEC
backplanes below:
hi glen, a little inventory:
# 11/23 BA23 Box S/N AG07072
-in there is a H786 Rev.C PSU - after quick measurements it's clear that
this PSU needs some work
-H9273 11/03L Rev.B Backplane is installed
-Cardcage is not bent but needs some of this plastic-PCB-guides, many are
broken due to age. The Distribution Panel is absent, but it should not be
too hard to
substitute it with something else. I'm looking forward to fin a M7555, they
seem to be quite common. But first I have to repair the PSU and check
everything.
The panel Glen was referring to is a large circuit board that's part of
the middle of a BA23 chassis, behind the backplane, and it has a 50-way
connector for an RQDX controller, along with some sets of 34-way and
20-way connectors for RDxx and RX50/RX33 drives.
Distribution panels for BA11-N boxes are small things for the likes of
DB225 serial connectors and DA15 Ethernet AUI connectors -- you've got a
good example with the panel attached to the DELQA. They fasten onto a
metal back panel, which (if present) is hinged to the back edge of the
BA11 box. They're really just small connector panels, not at all like
the distribution panel Glen meant.
As Allison suggested, an M9058 out of a BA123 is a very good thing to
use with an RQDX, but if you only want one hard drive and a floppy, all
you need is something to split out the signals passively. If you want
to make your own, there's a schematic and PCB layout on my website. I
have a BA11 system very similar to yours, hooked to up a small box that
used to be a TK50 case, and now has a hard drive, an RX50, and that
disti board in it. http://www.dunnington.u-net.com/public/RQDX/
--
Pete Peter Turnbull
Network Manager
University of York