VAXBI fun continues - seeking DEBNT installation docs

From: Ethan Dicks <>
Date: Fri Mar 15 01:54:31 2002

--- "Carlini, Antonio" <> wrote:
> > Ethan Dicks wrote:
> >
> >No DMB32... (not that I would mind locating
> >one of _those_ either).
> If only you'd asked 18 months ago :-)

Sigh. Woe is me. Ah well... perhaps another one will float to the
top, now that I'm using mine again. As I've said, I need a Unibus-
equipped VAX, and once I get a DWBUA on it, I'll be all set. The
goodies I mentioned here are most definitely optional.

> If you can get three KA820s (or KA825s)
> you should be able to get that to work too!

Three CPUs on the BI bus? Does that work? I thought it maxed out at
two. Perhaps they work, but they spend more time tripping over each
other than performing useful tasks?

> (But you cannot mix KA820 & KA825).

I knew that. Also, you can't mix boards of the same type with different
microcode revs. I had to juggle my KA820s when I got them because they
were nowhere near the same rev. Fortunately, I still have the microcode
floppies I used back then. Should be useful for dumping/loading any
KA825s I find, unless they come as a matched set.
> The only funny I remember with ethernet is
> that you need to cable up a little bit extra
> for the power required by the AUI in
> the bulkhead. But that may well have been
> the VAX 6000 ...

OK... I think mine came out of an 8xxx (a Nautilus-class machine,
not a Scorpio (82xx/83xx)). Don't know anything about an extra

I know that 12V is available to the bus in a BA-32 - we sent +/-12VDC
down our wires to power the 1488s and 1489s on the I/O bulkhead for
the COMBOARD-BI. Caused us no end of headache - I tried to tell the
design engineer that DEC stuff was designed for reverse-oriented cables;
stuff might not work, but it wouldn's smoke. If a customer swaps our
cables left-right _and_ installs them 180 degrees turned around (not
as difficult to do as it sounds), it sends +12VDC into one of the 74AS645
chips on the bulkhead PCB. We had just about every customer try it once.
Even if they guessed correctly the first time, if things didn't work
perfectly, they tried it the other way. :-( The only installs that
went smoothly were the ones I did. :-P

Anyway... I know 12V is available. I don't know if it's run down the
pipe properly with a DEBNT or not in a BA-32.

Any additional data would be handy. I guess I can go check the proper
pins on the AUI connector for voltage. No voltage is a bad sign. It
means I have to kludge up or locate a cable.


Do You Yahoo!?
Yahoo! Sports - live college hoops coverage
Received on Fri Mar 15 2002 - 01:54:31 GMT

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:35:11 BST