PDP-11/34A rebuild project Was: Re: Post-move diary

From: Christian Fandt <cfandt_at_netsync.net>
Date: Tue Mar 30 09:23:33 1999

Upon the date 01:09 AM 3/30/99 -0500, Megan said something like:
>Okay, since it has been a long time since I last did anything with a real
>pdp-8, and since I did pdp-11s for some 20+ years, I decided to start with
>what I knew... so I started examining the pdp-11/34a I got in the recent

Hi Megan,

Great choice to start with! (Uhh, actually, I'm trying to get my own 11/34A
 running and this will open up our list colleagues' assistance for benefit
of both of us ;-)

>Turns out that the system box has the cpu backplane, one DD11-DK (9 slot
>backplane for taking 'small peripheral controller' (SPC) boards), and
>one VT11 backplane.

The 11/34A CPU backplane (slots 1-9) has to be a DD11-PK.

Does the ID label on the outside, right side panel of the system box say
1134A xx or is it BA11 xx?

>Unfortunately, there is no power harness on the backplane, no boards in
>the backplane, and no cable to attach the boards to the VR14 that I did
>I think I may have a VT11 backplane with power harness and boards
>somewhere in my 'warehouse' (a couple of closets).

Can't help with the VT11. Sorry. Sounds quite cool though.

>The machine has the programmers console, but no memory.

Should have three cables connecting to the console panel: a two-wire
shielded cable going to the M9312 (P/N: 70-11413-3F), a four-wire twisted
cable going to the H765 PSU (P/N: 70-11992-0-0) and a 20 cond. flat cable
(P/N: 70-12214-2D) which goes to the M7859 Programmer's Console module.

>In one of the boxes I got in the move, I got a couple of MS11-LB memory

These are M7891-xx. My MS11-LB (M7891-BC) is 64KW -half filled w/RAM. The
MS11-LD I have (M7891-DH) is 128KW, fully stuffed.

>boards, so I'll use one of them. I think I also got an FPU, but I'll need

The FPU is M8267. (The FP11-A option)

>to see if I got prints for the 11/34a to see where it goes and how it gets
>connected (if it does). I don't have a cache board, so I'll be looking
>for one of those.

Cache board # M8268 (the KK11-A option)

Important to find the over-the-top jumper boards which go between the
various modules and possibly dependent upon whether you have the FPU in or
out. I'm assuming you got a box with a rat's nest of cables and misc parts.
If so, dig for small PC boards with dual-row, 0.1" center connectors. Part
numbers on white paper labels are H8821 with dual 40-pin connectors and
(hopefully for addition of your planed FP option) the H8822 with three
40-pin conns.

If you do not have the 11/34A printsets and KK11-A Cache tech manual please
get back to me and I'll give you more P/N's and some details on what goes
where based on my system and 11/34A printsets. This can get confusing with
just simple, brief statements.

I have not found an FP11-A tech manual and printset and Cache printset as
of yet (hint-hint anybody! :)

Two other important cables to root around for in the box, which go between
the M8266 and M7859, are two 10-conductor flat cables P/N 70-11411-1D. When
the M8367 FPU board is plugged-in, they run between the M8267 and the M7859
(this is where the docs are *real* handy) and a over-the-top board connects
the M8266 and M8267.

The board lineup in my machine is as follows (going from slot #1 to the
left) and the first five must be adhered to:

#1 M8266, 11/34A Control Module (KD11-EA)
#2 M8265, 11/34A Data Path Module (KD11-EA)
#3 M8267, 11/34A Floating Point Processor
#4 M9312 (slot A-B), Bootstrap/Terminator;
#4 M7859 (slot C-D-E-F), Programmer's Console I/F (KY11-LB)
#5 M8268, 11/34A Cache (1kbyte) (KK11-A)
The following can now be any MUD module . . .
#6 M7891-BC, 64KW MOS memory
#7 M7762, RL01/2 controller (RL11)
#8 G727A, buss grant jumper
#9 M9202, backplane jumper to next backplane . . .

For you Megan, the first three slots shall be M8266, M8265 and M8267 with
the H8821 over-the-top jumper between the 8265 and 8267. So, the H8821 is
the hot item to find to get your FPU lit up.

If you find an M8268 Cache module, then do either of the following:

1. Take out the M8267 and the over-the-top connector between it (P/N
5412416 printed in the etch underneath) and the M8266 and insert the M8268
and H8821. Plug the two 10-pin flat cables into the M8266.

2. Leave the 8267 in slot three and put the M8268 into slot five and use
the H8822 over-the-top connector. That 8822 would be another hot item to
find in your parts box. But, I suppose a ribbon cable/IDC connector kluge
could be made *if* the lines are straight thru. I haven't traced the
connections on my 8822 yet but can if you need me to. Same for the 8821 and

Jeez, I'm getting confused with all these numbers :-) But I believe I got
it right although I'm in a hurry here.

Incidentally, my system box has several of the module numbers printed on
the slot number label strip going across the top of the backside of the
slot cage. Yours may if it is indeed an 11/34A box instead of a generic BA11-K.

>I think I have an RL11 somewhere... but I'll need an RL drive. I may,
>for the time-being, take one of the RL01s from the -8 system racks. I
>also have an RUX50 controller and some RX50 disks, so I may try to get
>that working... I might be able to boot the XXDP+ RX50 kit that I have
>and do some system diagnostics.

Oh, I am salivating at the RUX50 controller! :) Can you clone that module?
:-) :-)

>That's it for now...

If you have more questions please holler! I have sever other printsets and
tech manuals which may help.

I was planning to talk to the list for help on mine in a couple of weeks or
less. I've got a real stumper I think.

Hope this helps you along with the "11/34A reconstruction".

Regards, Chris
-- --
Christian Fandt, Electronic/Electrical Historian
Jamestown, NY USA cfandt_at_netsync.net
Member of Antique Wireless Association
        URL: http://www.ggw.org/awa
Received on Tue Mar 30 1999 - 09:23:33 BST

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