17 Oct
1999
17 Oct
'99
1:18 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: Saturday, October 16, 1999 6:52 PM
Subject: Re: DEC boards unearthed
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
memory and G231/G110 core drivers.. The 11/05 uses that for it's own memory.
The older 11/05 backplane did not use +15V either!
Which CPU boards do you have. It's easy to tell. Does one of them have a
rotary switch to set the baud rate?
To get an 11/05 running you need:
M7260
M7261
G231 X 2
G110 X 2
H214 X2
G727 (grant)
You don't need a console serial board (M7800) as that was built into the CPU
board.
You can tell the year of the PDP 11/05 CPU set by:
74 - if the back of the boards are green (solder masked)
72/73 - if there is no baud selection switch
72 (beta) - hand stamped date before June 72, and a different layout of the
M7261 (with loads of wires)
I have restored many PDP 11/05s for "collectors" - yes, at $875 a pop!
I have about 5-6 cpu sets, 1 is beta.
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
>
> Finally, we come to an RK11D board set... M7254 through M7257. What else
is
> needed to make a working controller? A custom
backplane? Paddle cards?
I
Again you need the right backplane. Apart from that, not a lot -- the
cabling is the standard BC11 Unibus cables (both for the Unibus and to
link up the RK05 drives).
> think I've got an RKV11 box attached to an 11/03 (I haven't pulled it out
of
IIRC 3 of the 4 cards in that box are the same as the ones for the
RK11-D. The bus control is different (I think).
> the corner yet) If I'm missing too much of it, I can probably fix the
RK11C
> that I got with my first RK05 drives. I've
never used it and neither did
the
Oh, RK11-Cs are fun to fix (for suitable values of 'fun'). I learnt about
hard disk controllers, Unibus DMA cycles, etc while tracking down a dead
chip in mine. Having the printset is _essential_, though!
I have prints for the RK11-C and RK11-D, and the PDP11/05. I don't think
I have the RKV11-D set anywhere, but it can't be that hard to figure out.
I have two sets of these and run 8 RK05s, again, restored many of these. You
need a RK11-D backplane. You can hand wire one (yes I know many who have)
for UNIBUS operation - PDP 11/05.
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 completely
hand wired the RK11-D on it. Yikes. It works and I still have the plane if
you are interested in the wire list to do that.
The PDP 11/05 needs AClow, DClow,5V, -15V.
The newer ones required +15V.
-tony