17 Apr
2020
17 Apr
'20
12:52 p.m.
I have been sorting thru a bunch of stuff in an effort to
clean the place up (Aren't we all doing that now with all
this time on our hands?) I found a backplane. It says
Digital on it but does not have an H- number. I also
don;t find it listed in any of the lists I can find on
the web.
It has 8 A-B slots and 4 C-D slots. the Four C-D are on
the bottom half of the backplane. I am assuming it is
18 bit and the C-D were intended for things like the 2
board RL controller.
Anybody familiar with this and able to identify it?
Anybody interested in it? It should fit in a USPS
Medium Flat Rate Box.
bill
17 Apr
17 Apr
12:57 p.m.
Just curious - in all the backplane photos I've seen, it appears the
fragile wire wrapping is always exposed without a cover protecting it from
other components, fallen screws and wayward fingers in the computer cabinet.
Was it ever standard practice to put a cover over these? I couldn't imagine
debugging or repairing a backplane...
--
Anders Nelson
www.erogear.com
On Fri, Apr 17, 2020 at 12:52 PM Bill Gunshannon via cctalk <
cctalk at classiccmp.org> wrote:
I have been sorting thru a bunch of stuff in an effort to
clean the place up (Aren't we all doing that now with all
this time on our hands?) I found a backplane. It says
Digital on it but does not have an H- number. I also
don;t find it listed in any of the lists I can find on
the web.
It has 8 A-B slots and 4 C-D slots. the Four C-D are on
the bottom half of the backplane. I am assuming it is
18 bit and the C-D were intended for things like the 2
board RL controller.
Anybody familiar with this and able to identify it?
Anybody interested in it? It should fit in a USPS
Medium Flat Rate Box.
bill
1:04 p.m.
On 4/17/20 12:57 PM, Anders Nelson via cctalk wrote:
Just curious - in all the backplane photos I've
seen, it appears the
fragile wire wrapping is always exposed without a cover protecting it from
other components, fallen screws and wayward fingers in the computer cabinet.
Was it ever standard practice to put a cover over these? I couldn't imagine
debugging or repairing a backplane...
This particular backplane is soldered and has a rather heavy steel cover
over it.
bill
1:33 p.m.
Smart!
--
Anders Nelson
www.erogear.com
On Fri, Apr 17, 2020 at 1:04 PM Bill Gunshannon via cctalk <
cctalk at classiccmp.org> wrote:
On 4/17/20 12:57 PM, Anders Nelson via cctalk wrote:
Just curious - in all the backplane photos
I've seen, it appears the
fragile wire wrapping is always exposed without a cover protecting it
from
other components, fallen screws and wayward
fingers in the computer
cabinet.
Was it ever standard practice to put a cover over these? I couldn't
imagine
debugging or repairing a backplane...
This particular backplane is soldered and has a rather heavy steel cover
over it.
bill
4:05 p.m.
On Fri, Apr 17, 2020 at 9:52 AM Bill Gunshannon via cctalk
<cctalk at classiccmp.org> wrote:
I have been sorting thru a bunch of stuff in an effort to
clean the place up (Aren't we all doing that now with all
this time on our hands?) I found a backplane. It says
Digital on it but does not have an H- number. I also
don;t find it listed in any of the lists I can find on
the web.
It has 8 A-B slots and 4 C-D slots. the Four C-D are on
the bottom half of the backplane. I am assuming it is
18 bit and the C-D were intended for things like the 2
board RL controller.
Anybody familiar with this and able to identify it?
Anybody interested in it? It should fit in a USPS
Medium Flat Rate Box.
Sounds similar to a BA123 backplane which has 4 Q22/CD slots and 8
Q22/Q22 slots.
But the BA123 is rather distinctive with a gap then a 13th slot where
the M9058 Signal Distribution Board for the M7555 RQDX3 is installed.
For example BA123 backplane part number 54-17507-01 / 50-17506-01
https://www.ebay.com/itm/DEC-QBUS-BACKPLANE-BA123-DEC-54-17507-01-PDP-11-MI…
https://i.ebayimg.com/images/g/LygAAOSwrP9Z2V7z/s-l1600.jpg
4:37 p.m.
On 4/17/20 4:05 PM, Glen Slick via cctalk wrote:
On Fri, Apr 17, 2020 at 9:52 AM Bill Gunshannon via
cctalk
<cctalk at classiccmp.org> wrote:
Definitely not that. Very small. Just big enough for the
slots I mentioned above. Power strip on one edge and berg
pins for control on the other.
bill
I have been sorting thru a bunch of stuff in an effort to
clean the place up (Aren't we all doing that now with all
this time on our hands?) I found a backplane. It says
Digital on it but does not have an H- number. I also
don;t find it listed in any of the lists I can find on
the web.
It has 8 A-B slots and 4 C-D slots. the Four C-D are on
the bottom half of the backplane. I am assuming it is
18 bit and the C-D were intended for things like the 2
board RL controller.
Anybody familiar with this and able to identify it?
Anybody interested in it? It should fit in a USPS
Medium Flat Rate Box.
Sounds similar to a BA123 backplane which has 4 Q22/CD slots and 8
Q22/Q22 slots.
But the BA123 is rather distinctive with a gap then a 13th slot where
the M9058 Signal Distribution Board for the M7555 RQDX3 is installed.
For example BA123 backplane part number 54-17507-01 / 50-17506-01
https://www.ebay.com/itm/DEC-QBUS-BACKPLANE-BA123-DEC-54-17507-01-PDP-11-MI…
https://i.ebayimg.com/images/g/LygAAOSwrP9Z2V7z/s-l1600.jpg
4:41 p.m.
On Fri, Apr 17, 2020 at 1:37 PM Bill Gunshannon via cctalk
<cctalk at classiccmp.org> wrote:
Definitely not that. Very small. Just big enough for the
slots I mentioned above. Power strip on one edge and berg
pins for control on the other.
I thought you meant 4 rows of Q/CD slots plus 8 rows of Q/Q slots.
So it is actually 4 rows of Q/CD slots plus 4 rows of Q/Q slots?
8:20 p.m.
On 4/17/20 4:41 PM, Glen Slick via cctalk wrote:
On Fri, Apr 17, 2020 at 1:37 PM Bill Gunshannon via
cctalk
<cctalk at classiccmp.org> wrote:
Can't send a picture, so lets try this:
A B C D
|--------|--------|
| | |
| | |
|--------|--------|
| | |
| | |
|--------|--------|
| | |
| | |
|--------|--------|
| | |
| | |
|--------|--------|--------|-------|
| | | | |
| | | | |
|--------|--------|--------|-------|
| | | | |
| | | | |
|--------|--------|--------|-------|
| | | | |
| | | | |
|--------|--------|--------|-------|
| | | | |
| | | | |
|--------|--------|--------|-------|
That's what it looks like.
bill
Definitely not that. Very small. Just big enough for the
slots I mentioned above. Power strip on one edge and berg
pins for control on the other.
I thought you meant 4 rows of Q/CD slots plus 8 rows of Q/Q slots.
So it is actually 4 rows of Q/CD slots plus 4 rows of Q/Q slots?
8:36 p.m.
Hm. Plessy backplane?
On 4/17/2020 8:20 PM, Bill Gunshannon via cctalk wrote:
On 4/17/20 4:41 PM, Glen Slick via cctalk wrote:
On Fri, Apr 17, 2020 at 1:37 PM Bill Gunshannon
via cctalk
<cctalk at classiccmp.org> wrote:
Can't send a picture, so lets try this:
??????? A??????? B???????? C?????? D
??? |--------|--------|
??? |??????? |??????? |
??? |??????? |??????? |
??? |--------|--------|
??? |??????? |??????? |
??? |??????? |??????? |
??? |--------|--------|
??? |??????? |??????? |
??? |??????? |??????? |
??? |--------|--------|
??? |??????? |??????? |
??? |??????? |??????? |
??? |--------|--------|--------|-------|
??? |??????? |??????? |??????? |?????? |
??? |??????? |??????? |??????? |?????? |
??? |--------|--------|--------|-------|
??? |??????? |??????? |??????? |?????? |
??? |??????? |??????? |??????? |?????? |
??? |--------|--------|--------|-------|
??? |??????? |??????? |??????? |?????? |
??? |??????? |??????? |??????? |?????? |
??? |--------|--------|--------|-------|
??? |??????? |??????? |??????? |?????? |
??? |??????? |??????? |??????? |?????? |
??? |--------|--------|--------|-------|
That's what it looks like.
bill
Definitely not that.? Very small.? Just big enough for the
slots I mentioned above.? Power strip on one edge and berg
pins for control on the other.
I thought you meant 4 rows of Q/CD slots plus 8 rows of Q/Q slots.
So it is actually 4 rows of Q/CD slots plus 4 rows of Q/Q slots?
9:40 p.m.
I remember the VT72 had a non-standard backplane in it, but I don't
remember the details.
Paul
On Fri, Apr 17, 2020 at 8:10 PM Bill Gunshannon via cctalk <
cctalk at classiccmp.org> wrote:
On 4/17/20 8:36 PM, Chris Zach via cctalk wrote:
Hm. Plessy backplane?
No name on the phenolic board part but the QBUS sockets are labeled
"Digital Equipment Corporation".
bill
9:48 p.m.
The actual sockets were always labelled with Digital's trademarks, but
they sold them to OEMs to do what they like with them.? We OEM'd for the
Components Group, at one time placed a million dollar order of stuff
including boxes of those backplane sockets!
cheers,
Nigel
On 17/04/2020 21:40, Paul Anderson via cctalk wrote:
I remember the VT72 had a non-standard backplane in
it, but I don't
remember the details.
Paul
On Fri, Apr 17, 2020 at 8:10 PM Bill Gunshannon via cctalk <
cctalk at classiccmp.org> wrote:
> On 4/17/20 8:36 PM, Chris Zach via cctalk wrote:
>> Hm. Plessy backplane?
> No name on the phenolic board part but the QBUS sockets are labeled
> "Digital Equipment Corporation".
>
> bill
>
>
--
Nigel Johnson
MSc., MIEEE, MCSE
VE3ID/G4AJQ/VA3MCU
Amateur Radio, the origin of the open-source concept!
You can reach me by voice on Skype: TILBURY2591
If time travel ever will be possible, it already is. Ask me again yesterday
This e-mail is not and cannot, by its nature, be confidential. En route from me to you, it
will pass across the public Internet, easily readable by any number of system
administrators along the way.
Nigel Johnson <nw.johnson at ieee.org>
Please consider the environment when deciding if you really need to print this message
10:08 p.m.
We had a few third party backplanes arranged like this.? This allowed
them to put a small MFM hard drive or 8 inch floppy in empty? area next
to the 4x2 (2x4?) slots of rack-mount 3U or 4U sized unit.? I don't
recall any that were a mix of A-B, C-D.? Ours were A-B, A-B.
??? Jerry
On 4/17/20 8:48 PM, Nigel Johnson via cctalk wrote:
The actual sockets were always labelled with
Digital's trademarks, but
they sold them to OEMs to do what they like with them.? We OEM'd for
the Components Group, at one time placed a million dollar order of
stuff including boxes of those backplane sockets!
cheers,
Nigel
On 17/04/2020 21:40, Paul Anderson via cctalk wrote:
I remember the VT72 had a non-standard backplane
in it, but I don't
remember the details.
Paul
On Fri, Apr 17, 2020 at 8:10 PM Bill Gunshannon via cctalk <
cctalk at classiccmp.org> wrote:
> On 4/17/20 8:36 PM, Chris Zach via cctalk wrote:
>> Hm. Plessy backplane?
> No name on the phenolic board part but the QBUS sockets are labeled
> "Digital Equipment Corporation".
>
> bill
>
>
18 Apr
18 Apr
7:50 a.m.
This is an interesting discussion. I may have to dig thru my
boxes and see if I still have the box this backplane came in.
Lots of time to do it.
But, on another note, I was planning on sending it to
someone when the thought occurred to me last night. I
can't. I don't even know if the Post Office is still
open other than for picking up mail from PO Boxes.
Haven't been anywhere near it in weeks and don't
anticipate going anywhere in that direction for several
more weeks.
But, I have other things that will need to go, too, Some that
can't be practically sent. Like a currently non-functioning
RX02 box. Might need to find someone close enough to pick
this stuff up when life returns to something closer to
normal.
bill
4:25 p.m.
On 17/04/2020 17:52, Bill Gunshannon via cctalk wrote:
I found a backplane.? It says
Digital on it but does not? have an H- number.? I also
don;t find it listed in any? of the lists I can find on
the web.
It has 8 A-B slots and 4 C-D slots.? the Four C-D are on
the bottom half of the backplane.? I am assuming it is
18 bit and the C-D were intended for things like the 2
board RL controller.
Is it quad height or hex height? Is there a picture anywhere?
It sounds a bit like an H9278-A, which is a 22-bit 4 x 8 (ie quad
height, 8 rows) backplane for a BA23 box. That has a mixture of Q22 and
CD in part and Q22 on the rest, but the rows with CD are the top rows.
http://www.dunnington.info/public/PDP-11/QBus_chassis
--
Pete
Pete Turnbull
1506
days inactive
1507
days old
15 comments
8 participants
participants (8)
-
anders.k.nelson＠gmail.com -
bill.gunshannon＠hotmail.com -
cz＠alembic.crystel.com -
glen.slick＠gmail.com -
jsw＠ieee.org -
nw.johnson＠ieee.org -
pete＠dunnington.plus.com -
useddec＠gmail.com