PDP 11/23 help needed

From: John R. Keys Jr. <jrkeys_at_concentric.net>
Date: Wed Apr 22 19:58:56 1998

I picked up a digital Micro PDP-11 model 11C23-F in a tower case with
nothing else for $5 yesterday. Have not tried to fire it up yet. John
At 12:16 AM 4/22/98 -0700, you wrote:
>Well, folks, it looks like I lied in my recent post about not having
>a PDP-11.
>Actually, I _do_ have one. I simply forgot that I had, stashed
>away, an 11/23 CPU and some boards ("common as houseflies" was the
>term Allison used? :> ) Since it was not in a rack, and since
>the pieces have never been assembled, and since I have no disks for
>it, I pretty much forgot about it, and I've never had it working.
>But it appears I have a fairly nice, complete system, board-wise.
>Here's what I have:
>Chassis: DBA11-N
>1. M8186 (KDF11-AA) 11/23 CPU with KTF11-AA (MMU), sockets for FP11
>2. M8047-CA (MXV11-AC) 16-Kword RAM, 2 async EIA SLU, w/ 2 24-pin ROMs
>3. M8047-CA (MXV11-AC) 16-Kword RAM, 2 async EIA SLU, sockets for ROMs
>4. M8044-DB (MSV11-DD) 32-Kword 16-bit MOS RAM
>5. M8044-DC (MSV11-DD) 32-Kword 16-bit MOS RAM
>6. M7269 (RKV11) RK05 controller
>7. Data Systems Design 818836-01 REV B -- RX01, RX02, or RX50 controller??
> (25-pin ribbon-cable connector)
>So, in order to get this whole thing working again, I have a
>WHOLE SLEW of questions to ask folks, in no particular order.
>Here goes.
>1) The M8047-CA boards need to be wire-wrapped to assign their
> address vectors -- they're combination MOS RAM and Async EIA,
> and I have no docs for them. Can anyone guide me to some info,
> or tell me how to jumper one of them to be console serial
> port, and the other to be next in line on the bus?
> The wire-wrap pins have absolutely no markings on them, not
> even any single-letter or number labels, so this one could
> require ASCII-art to describe :)
>2) Same as above, but for the M8044-DB boards. I could put one
> of these in with the M8047's to get a full 64Kword of RAM, yes?
> Does anyone know what the DIP-switch settings for these boards
> are?
>3) I'd love to have the RK05 controller in there, in the hopes
> that someday I'll have an RK05 to play with. Just like the
> above... How do I jumper it, and where (physically) in the
> Bus should I put it?
>4) Actually, that raises a good question. All of these boards
> are single-height (1/2 the width of the Q-bus backplane).
> I know there is some special physical layout the boards should
> use when they populate the backplane, but what is it?
> My best (probably wrong) guess right now is:
> CPU in row 1, slot 1 (is that left or right?),
> M8047's in row 2, slots 1 and 2,
> M8044 in row 3, slot 1,
> M7269 in row 4, slot 1, DSD controller in row 4, slot 2.
> Does that make any sense? Should the CPU only live in the
> first row, not RAM? I seem to remember something like this
> from the darkest depths of my mind, but I don't remember
> for sure.
>5) OK, simple question, one I've wondered about but never bothered
> getting answered because I felt like a complete idiot moron
> asking it: Does the QBUS need to be terminated by a special
> card in any way, in order to work?
>6) What's the pin-out on the M8047 EIA ports? They're 9-pin Berg
> connectors, and I need to build a cable for them to connect
> either to 9-pin or 25-pin PC-style serial in order to set up
> any kind of console terminal.
>7) Anyone know what the Data Systems Design board is? It has
> "RX" stensiled onto the board near the jumper block, among
> other things like "BOOT", so I assume it's some sort of RX01
> or RX50 controller or some such.
>WHEW, that's _too_ many questions. Anyone who can tackle one of them
>gets my respect, and you may award yourself one cookie.
>I'd like to piece this system together and get it working to the
>point where I can play with it and at least fiddle with the monitor
>again, playing with Octal. And I'd dearly love to put it in a
>proper DEC desk-side rack with an RK05, but that comes later...
>Thanks much,
Received on Wed Apr 22 1998 - 19:58:56 BST

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