So I decided to insert two 32K core memory
backplanes
32KW, those would be MM11-U backplanes, right?
Here is a closeup. I have have related docs.
http://vintagecomputer.net/digital/pdp11-40/32Kx16-MemoryBackplane_5010344C…
My plan is to replace the solid-state RAM card
with core, and this
will
free up a slot on the 4-slot backplane for a
terminator.
Terminators all only go in the last slot of the last backplane anyway
(either
that, or a UNIBUS 'out' cable), so adding extra backplanes shouldn't give
you
"a slot .. for a terminator".
Thanks for clarifying.
Also, Paul's point is a good one: the hex
memory cards need so-called
'MUD
slots' (hex), not SPC slots (quad), and only
(IIRC) the DD11-C/D have MUD
slots. (Those came in with the 11/04-34, IIRC).
It is 3011-cf / 70-12445 1979
the
serial card seems to have stopped working. It appears that the
console program is being loaded and runs from the M9312 but nothing
is
> appearing on the terminal. I cannot send an "A" to the terminal,
the
most
basic test I can think of.
Hmm. You can read/write the console registers from the console, though,
it
sounds like? My guess would be that if your
serial port is EIA, somehow
you're missing -15V or something on the DD11 in its new location. Study
the
-11/35-40 system manual to learn about which
'bricks' supply which
voltages
to which system units.
OK, but will always watch this.
And while you're at it, check that you have
the right 'bricks' for the
MM11-U.
The -11/35-40 system manual has lots of text on how to support the
MM11-U.
> Can you only use the core backplanes for core memory (assume yes),
or
are they
capable of holding other types of cards temporarily?
AFAICR, the MM11-U backplane does _not_ have an
SPC slot in it. IIRC, the
16KW MM11-U board set is a quad controller board, and 3 hex boards (core,
X-Y
and something else). So two sets (the backplane holds two) would be 8, so
one
empty slot - which IIRC is blank. Check the MM11-U manual, it's
available.
Came with M7891 RAM installed in the 3011-cf backplane.
I have
one slot that needs the npg, it's in place.
??? _Every_ SPC/MUD slot which does not have a DMA device in it _must_
have
the jumper on the backplane (or the _double_
width UNIBUS grant card,
whose
> number escapes my memory, which contains a NPG jumper). Not sure if that
> was the import of what you wrote there.
Note - System came to me as thus, after the CPU, the 3011-cf backplane had
the following:
I have no idea what "3011-cf" is. Isn't it just a a DD11-C backplane with
power-wring entering from the back, rather than through small circuit
boards?
UNIBUS 10 A-B (LEFT SIDE OF UNIBUS)
M7856 10 F-C (RS232 WITH 19.2 OPTION?)
G7273 11 C-D
7891 12 A-F (64k MEMORY)
M9312 13 A-B (ROM CARD)
672A 13 D (GRANT CONT.)
That looks like a reasonable setup provided that jumpers W1- W5 are
installed on the M9312. You should be able to install the RL11 in slot 11
when you remove the G7273. Make sure that the wire-wrap between CA1-CB1 is
cut on slot 11 if you install the RL11 there. Also make sure that CA1-CB1
wire-wrap jumper is installed in slot 13 (or install G7273 card in 13C-D)
I am going to switch to another backplane and start over. Don't know what
I am doing yet to be honest. I have to read the manuals and get better
educated to properly get these parts working together correctly.
But all this still doesn't now explain the problem that you cannot access
(or send characters to) the serial port. It could very well be the power
problem as Noel suggested. If I were you I would try to get back to the
state where it worked, shortening the Unibus to just include the 4-slot
back plane and the CPU backplane and also remove the RL11 for now. Then
install the RL11 in slot 11 when everything is working.
/Mattis
Bill
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