Qbus Backplanes

From: Tothwolf <tothwolf_at_concentric.net>
Date: Thu Jun 5 16:14:06 2003

On Thu, 5 Jun 2003, Antonio Carlini wrote:
> > On Thu, 5 Jun 2003, Antonio Carlini wrote:
> >
> > > 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?
>
> 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.

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
Received on Thu Jun 05 2003 - 16:14:06 BST