5 Jun
2003
5 Jun
'03
1:13 a.m.
Hello people. Is there any way to tell if a backplane is QQQQ or QQCD by
looking at it, and without having to pull the backplane out of the
chassis? What if I can find the model number of the chassis?
Peace... Sridhar
5 Jun
5 Jun
2:33 a.m.
--- vance(a)neurotica.com wrote:
Hello people. Is there any way to tell if a backplane
is QQQQ or QQCD by
looking at it, and without having to pull the backplane out of the
chassis?
Not from the slot-side... all the connectors look exactly the same.
Well... not _visually_ You could sit down with a VOM or a continuity
tester and probe a couple of selected pins to determine the wiring
scheme. In practice, though, it's ordinarily done by other means.
In some older chassis, you can see the backplane wiring, but not on
boxes like the BA23 or BA123.
What if I can find the model number of the chassis?
That's useful... The model numbers that look like BA-23, BA-11N, BA-11M,
etc., are the ones you want.
Also, remember in newer boxes, it's three slots of Q22-CD, with the rest
Q22-Q22. Older boxes can be wired for either 18-bit or 22-bit addressing,
which may or may not involve Q-CD slots. I _think_ the BA-11N is a 18-bit
Q-CD box... that's what I remember my 11/23 is in (but I added the extra
wires some time ago to make it Q22).
-ethan
6:15 a.m.
Also, remember in newer boxes, it's three slots of
Q22-CD,
with the rest Q22-Q22. Older boxes can be wired for either
IIRC that's true of the BA23 but the larger BA123 is four slots
of Q-CD and then serpentine Q-Q.
The even newer BA200 series (BA213/BA214) and probably everything
after that (which is mostly just the BA400 stuff) is AFAIK all
Q-CD.
Antonio
--
---------------
Antonio Carlini arcarlini(a)iee.org
8:08 a.m.
On Thu, 5 Jun 2003, Antonio Carlini wrote:
Are you sure? I believe my BA215 has at least 5 Q-CD slots (well, I think
anyway) as I have the cpu board and 4 memory boards in it. Come to think
of it, don't these only have 6 slots?
-Toth
Also, remember
in newer boxes, it's three slots of Q22-CD, with the
rest Q22-Q22. Older boxes can be wired for either
IIRC that's true of the BA23 but the larger BA123 is four slots of Q-CD
and then serpentine Q-Q.
The even newer BA200 series (BA213/BA214) and probably everything after
that (which is mostly just the BA400 stuff) is AFAIK all Q-CD.
8:48 a.m.
On Thu, 5 Jun 2003, Antonio Carlini wrote:
Are you sure? I believe my BA215 has at least 5 Q-CD slots
(well, I think
anyway) as I have the cpu board and 4 memory boards in it.
Come to think of it, don't these only have 6 slots?
Sure about which bit? I'm reasonably sure that the BA123 (old style
world box most often used for the MicroVAX II) is four slots of
Q22-CD and then serpentine Q22-Q22. I'm fairly sure the BA23 (smaller
box, same size as the Rainbow) has one less Q22-CD slot (hence it has
3).
I'm sure that the BA200 series boxes are all Q22-CD, and the BA200
Series Module Design Guide agrees with me there. In fact, I think
you were agreeing with me too, unless you meant BA123 where you typed
BA215.
Antonio
--
---------------
Antonio Carlini arcarlini(a)iee.org
> Also, remember in newer boxes, it's
three slots of
Q22-CD, with the
rest
Q22-Q22. Older boxes can be wired for either
IIRC that's true of the BA23 but the larger BA123 is four slots of
Q-CD and then serpentine Q-Q.
The even newer BA200 series (BA213/BA214) and probably everything
after that (which is mostly just the BA400 stuff) is AFAIK all Q-CD.
9:14 a.m.
On Thu, 5 Jun 2003, Antonio Carlini wrote:
No disagreement, I just misread your comments.
The only major issue I've had with the BA215 is the lack of slots. I guess
a BA213 might suit me better, but I haven't been able to obtain one just
yet. By the time I maxed out the ram with 4 boards and installed a TK70
controller, all the slots in my BA215 were gone :)
Since we are on the subject of VAXen...
What would be the most likely problem with a BA123 MicroVAX II that powers
up, but sometimes totally locks up during the diagnostics? (I'm not even
sure it can boot, as some of the RD53s sound a little sick.) I've pretty
much eliminated the boards as the cause, and the only things left are the
backplane and power supply. It does have those older power supply to
backplane wiring harness cables, which I guess I need to replace before I
put many boards in the card cage.
-Toth
On Thu, 5 Jun
2003, Antonio Carlini wrote:
Sure about which bit? I'm reasonably sure that the BA123 (old style
world box most often used for the MicroVAX II) is four slots of Q22-CD
and then serpentine Q22-Q22. I'm fairly sure the BA23 (smaller box, same
size as the Rainbow) has one less Q22-CD slot (hence it has 3).
I'm sure that the BA200 series boxes are all Q22-CD, and the BA200
Series Module Design Guide agrees with me there. In fact, I think you
were agreeing with me too, unless you meant BA123 where you typed BA215. IIRC that's true of the BA23 but the larger
BA123 is four slots of
Q-CD and then serpentine Q-Q.
The even newer BA200 series (BA213/BA214) and probably everything
after that (which is mostly just the BA400 stuff) is AFAIK all Q-CD.
Are you sure? I believe my BA215 has at least 5 Q-CD slots (well, I
think anyway) as I have the cpu board and 4 memory boards in it.
Come to think of it, don't these only have 6 slots? 
9:38 a.m.
On Thu, 5 Jun 2003, Antonio Carlini wrote:
Sure about which bit? I'm reasonably sure that the
BA123 (old style
world box most often used for the MicroVAX II) is four slots of
Q22-CD and then serpentine Q22-Q22. I'm fairly sure the BA23 (smaller
box, same size as the Rainbow) has one less Q22-CD slot (hence it has
3).
My BA23's and BA123's are like this, yes.
--fred
3:59 a.m.
Hello Sridhar,
yes, if you can see the traces, you can tell from the shape: CD
interconnect consists of point-to-point leads from one slot's A side to
the next one's B side, which should look quite different from Qbus,
which (except for few grant or other daisy-chained signals) consists of
bused connections between "same" pins (A side of one slot to A side of
next slot).
If you cannot inspect visually, your continuity checker is your friend.
Layout of Q vs. CD slots may be different between DEC and third-party
backplanes even if both are, say, 4*9 shape, beware...
Andreas
vance(a)neurotica.com wrote:
Hello people. Is there any way to tell if a backplane
is QQQQ or QQCD by
looking at it, and without having to pull the backplane out of the
chassis? What if I can find the model number of the chassis?
Peace... Sridhar
--
Andreas Freiherr
Vishay Semiconductor GmbH, Heilbronn, Germany
http://www.vishay.com
7871
days inactive
7871
days old
7 comments
6 participants
participants (6)
-
Andreas.Freiherr＠Vishay.com -
arcarlini＠iee.org -
erd_6502＠yahoo.com -
tothwolf＠concentric.net -
vance＠neurotica.com -
waltje＠pdp11.nl