27 May
2026
27 May
'26
6:05 p.m.
On 5/27/26 18:56, Ethan Dicks via cctalk wrote:
On Tue, May 26, 2026 at 9:38 PM Jon Elson via cctalk
<cctalk(a)classiccmp.org> wrote:
OK, I assume with the box laying flat and the top cover on
top, and all labels right side up, then slot 1 is at the top
of the backplane. So, I had the KA730AA in the top slot,
and had moved the QD21 to the left connectors just below
it. I was able to access the 2 registers just as the
diagnostic instructions said, but then did not get anything
in memory at location 80.
Now, I have screwed UP! I thought maybe I didn't know what
was slot 1, and moved the KA630 to the bottom slot. Now,
the board does not pass POST. It counts down from F to C
and then hangs there, with no serial output. Of course, I
moved the board back to slot 1, but same result.
I have no additional memory boards (seem to have sold them
all at the last VCFMW). Years ago, I did run VMS 4.7 just
fine on the on-board one MB.
When it was partially working, I tried several DIP switch
options on the QD21 but got the same no transfer to main
memory problem.
Anybody know what parts I popped by having the KA630 in slot
8? (I used to have a KA630 schematic set but sold that years
ago.)
I don't know for sure this KA630 was good, as somehow it got
swapped with my trusty old one from 40 years ago. This one
came from a junker. But, it mostly worked, except for maybe
the DMA. And, I have no idea if this backplane in the BA23
was good.
Thanks,
Jon
On 5/26/26 17:50, Ethan Dicks via cctalk wrote:
So the H9278-A is standard in the BA23 IIRC. Forgive me if I'm
going
over things you know but that means that the first three slots are
Q22/CD slots, so you rightly put the QD21 into the Q22 (AB) side of
slot 2. The usual KA630 uVAX II board has 1MB on it, which should be
enough to noodle around with, but we always ran those with at least an
8MB board in slot 2 (with the PMI cable). You didn't say what your
board configuration is, but might well ask now what _do_ you have
stuffed in there? A specific board buildout would be helpful at this
point.
Normally, it's CPU and memory (essential in the top 3 slots), then
peripheral cards in a certain order (low-latency cards over
high-latency cards, and unbuffered interfaces over buffered
interfaces, and the RQDXn, if any, at the end).
On Tue, May 26, 2026 at 6:45 PM Jon Elson via
cctalk
<cctalk(a)classiccmp.org> wrote:
Yes, first I had the QD21 in slot 4, and then realized if I
didn't have any memory boards in slot 2 or 3, I needed to
move the QD21 up to the A-B connectors on slot 2...
This is in a DEC H9278-A backplane that originally had an
LSI-11 in it. I am trying to get an Emulex QD21 configured on a
MicroVAX-II...
So, somehow the QD21 is not copying the diagnostic program
to the VAX memory.
I would ensure your NPR Grant Chain above the QD21 is intact.
I don't know if I need to do anything to the
backplane to make it work for a uVAX-II.
For a standard BA23, you don't need to
do anything. It's happy with a
KDF11-B (11/23+) or KDJ11 (11/53 etc) or a MicroVAX (KA610, KA630).
The only trick is where to stuff the CPU and memory when it's PMI
memory (above slot 4) (vs Qbus (more flexible). Someone can come
along and correct me, but I don't _think_ there's usually anything you
have to do with backplane termination when moving from a PDP-11 to a
MicroVAX CPU.