17 Oct
1999
17 Oct
'99
9:10 a.m.
-----Original Message-----
From: Tony Duell <ard(a)p850ug1.demon.co.uk>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Sunday, October 17, 1999 2:54 PM
Subject: Re: DEC boards unearthed - I have some info
There are at least 3 different backplanes, but the 11/05 and 11/10 can
use any of them. The 11/05 and 11/10 are really the same machine -- the
differences seem to be what was included when the machine was originally
shipped.
The first backplane goes in the 5.25" box. The CPU cards go at the bottom
(in slots 8 and 9).
No, CPU goes in slots 2&3, the maintenance board goes in slot 1.
The next 3 slots are for one set of core memory
> >> One of the other interesting items are a
M7260/M7251 pair, one marked
> >> "datapath", one marked "11/05 control". These are
clearly the CPU for
an
> >> 11/05, but will they go into an 11/04 or
short (not BA-11) 11/34
chassis
> >> for testing?
> >
> >You need the 11/05 (or 11/10 -- they're the same) backplane and
> >frontpanel for these. There was a 5.25" box versions and a 10.5" box
> >version with _different_ backplanes. They won't work in an 11/04 or
11/34
backplane, though
Actually the 11/05 and the 11/10 have two different backplanes (as I have
both) and the cards are fitted differently in each one. Keep your H214 boards. And then 4 SPC slots, with Unibus out on slot 1
(top of box --
yes, I do have this the right way round!).
The second backplane is similar, and also goes in the 5.25" box. Again
the CPU goes in the bottom. The next 6 slots are for 2 sets of core
memory, with a single SPC (and unibus out) at the top (slot 1)
The third backplane goes in the BA11-K 10.5" box. The CPU goes on the far
right (slots 1 and 2). Unibus out is on slot 9 (as you'd expect). One of
the A+B slots is for a paddleboard that connects to the the console
cable. I can't remember how many core memory sets you can put into it.
completely
74 - if the back of the boards are green (solder
masked)
72/73 - if there is no baud selection switch
Hmmm... They're strictly different systems -- the rotary switch implies
it's an 11/05S board set. This has 2 extra features, firstly you can
easily disable the on-board console port (if you want to use a DL11 for
some reason) and secondly you can disable the unibus arbiter so that the
CPU can be a slave device on the unibus of another machine.
>
> The best backplane I have is from someone who completely modified a PDP
> 11/05 (16K backplane).He took out the second core memory set and > hand wired the RK11-D on it. Yikes. It works and I
still have the plane
if
Seems reasonable. Modifying backplanes isn't _that_ hard if you are
careful. I've done a couple of major backplane mods. The best thing to do
is to make a wirelist and tick off each wire as you do it. Oh, and don't
bother with one of those slit-n-wrap tools -- the general experience of
those is that about 10% of the connections are actually good. Do the job
properly, and it will work.
-tony