28 Sep
2014
28 Sep
'14
10:21 p.m.
I know a lot of people who have wire wrapped their 18 bit backplanes to 22
bit. I also know of RK11-Ds that have been upgraded to either 18 or 22 bit
( I forgot which).
I have backplanes, power supplies, boxes and boards here if you need
anything.
On Sun, Sep 28, 2014 at 11:26 PM, Noel Chiappa <jnc at mercury.lcs.mit.edu>
wrote:
From: David
Riley
I think most if not all Qbus backplanes were
PCBs. But some of them
(notably the H9270) are PCBs with wire-wrap posts for the connector
terminals. Makes it very handy to, say, modify the H9270 for 22-bit,
which I did .. with no problem.
This reminds me of something I'm looking into. I have a BA11-N (Q18/CD)
which
I'd like to upgrade to BA11-S (Q22/CD). (Yes, yes, I know, the -S has a
oomphier power supply, which I won't have, but I'm not trying to run a lot
of
power-hungry cards.)
I've tried finding an H9276-A backplane (Q22/CD) to go in it, to replace
its
existing H9273-A (Q18/CD), but _every_ place I called which had one listed
reasonably cheap (<$100), and which claimed their internal stock database
(i.e. not just their lame, useless, Web-site) showed they had one... when
they
checked the actual shelf, they did not in fact have any.
So now I'm thinking, maybe I'll just add the BDAL19-22 lines to the
existing
H9273-A. It doesn't have wirewrap pins, but there's enough pin showing
that I
can get two wires onto each pin, and solder them; does not look to be
difficult at all.
I have verified that the CD part of the backplane is identical in both (the
1983-84 Microcomputer Interfaces Handbook, EB-23144-18, has pinouts for
the CD
part for both, and they are indeed identical). Alas, I cannot find detailed
data on the rest of the H9273-A: neither the BA11-N Technical Manual, nor
the
Print Set, is available online. (I found some old list email which
indicates
that someone named David Powell had a copy of the TM - does anyone know
him?)
So, has anyone tried to upgrade an H9273-A to H9276-A, and are there any
pitfalls? From what I can see, there shouldn't be a problem, but I'd like
to be 100% sure before I start plugging cards into it...
Noel