Which PDP-11 parts to keep an eye out for?

[tech58761]

So, at my work, in a room adjacent to my work area, are these two PDP-11s and which are used to run some automated electronics assembly equipment. Back in the 1990s, this equipment ran 8 hours a day, but now, it is barely run 8 hours a quarter. I think the only reason they haven't scrapped these two pieces of equipment is that the one customer for which we still have active programs hasn't officially discontinued the remaining boards for which we need these machines. There's an old 486 box down below which is apparently used to upload the program to the PDP (one is a spare) which then runs the equipment.
We are starting a plant rearrangement over the next calendar year, and it occurs to me there may be a slight chance that these could finally be retired within the next year or so.

Is there a list somewhere of boards that are particularly sought-after for PDP-11 machines? I cannot and will not commit to any timeline of these being available, but if and when that decision comes down, I want to be able to rescue these (and any spares) that would come available at that time. These machines are big and bulky enough I doubt very much the company would try and sell these on to new owners - especially since the equipment is well-worn and the industry's current emphasis on SMT over through-hole.

 

[ftcnet]

Always commendable to try to avoid having DEC systems end up at recyclers or scrap yards. It might be worth letting the right manager know you'd be interested in acquiring the PDP11's "when the time comes". Or print a note along the lines of "Do not scrap - contact tech58761" and tape it to each PDP11 in case you're on vacation when they decide to move them out.
You could add your location to your profile - on the top menu bar, click on your name, then Account details.

 

[daver2]

We moved offices and I 'dispersed' PDP and VAX equipment to enthusiasts and museums. For the enthusiasts, I suggested a suitable donation (based upon what they took and the state) to the charity that our company supports. Win, win, win for everyone concerned!

There were a few companies interested in the high value cards and machines - but they were just going to mark them up and sell them on at a vast profit. Sorry, not interested...

Graphics cards and SCSI cards can be high value items. DEC also produced some unobtainium audio cards that never went into production...

Dave

 

[tech58761]

ftcnet: Fortunately my supervisor is one of those I'd need to talk to, and management has been good about updating us when they are bringing in or getting rid of major equipment at the quarterly all-plant meetings.

When I get a chance, I'll have to get a picture of what I think are spare chassis, these sit in the machines that are run by the PDPs, but I'm not sure if they're DEC or the company that built the equipment.

 

[pbirkel@gmail.com]

Graphics cards and SCSI cards can be high value items. DEC also produced some unobtainium audio cards that never went into production...

Note that both graphics and SCSI cards are easy to spot based on their attached cables :->. If the cables are missing then one wonders what those modules would be doing in an operational system. Anyway, record the PNs on all handles to start with. Then look at both sides of the module for possible further identification. In the case of third-party modules the distinguishing PNs may be on a label attached to a PROM. Good luck with your investigation.

 

[tech58761]

Here's the 'spare' chassis I mentioned... the handles are what makes me wonder whether any could be DEC.

 

[pbirkel@gmail.com]

Well the M8186 certainly is -- a KDF11 CPU (11/23). To its left (slot #2) a third-party memory. Further left an unknown third-party module, perhaps PROM. And finally (slot #4) a 4 line serial interface, also third-party. On the right end ("P/S") is a substitute for a DEC front-panel control. The "ROM BOOT STARTING ADDR." list is interesting as it implies some hardware that isn't evident (e.g., RX02 floppy disk controller & cabling); the other possibilities could be different serial lines with alternate protocols.

 

[pbirkel@gmail.com]

PS: What's that in the pink bubble wrap at the left end?

 

[tech58761]

So the official DEC cards would have the maroon card guides and white would signify 3rd-party compatible cards? That card in the bubblewrap is one of the equipment cards. Who knows, maybe these chassis were originally fitted with these RX02 controllers and were replaced by the 486 and serial cabling (there's an A/B switch box in the setup). I know there's a box of spare cards in that room as well, if I remember right when I nosed through them one day, half were equipment cards, and the rest was a mix of extender cards and cards like the ones in the rack. When things settle down after the holiday season and everyone's done burning off vacation time (including me), I'll start asking about this stuff.

 

[pbirkel@gmail.com]

So the official DEC cards would have the maroon card guides and white would signify 3rd-party compatible cards?

Generally speaking, yes (handles, not guides). DEC might have had some special-development modules on Qbus that used white handles; they certainly used green handles for analog-type modules ((uncommon) core memory, ADC, DAC, etc.). Most diagnostic will be the DEC PN on the handle and then DEC markings in the PCB etch (could be on either or both sides). When in doubt look at the PCB etch for markings, although I can't think of a case where DEC failed to put the module identifier on the handle. Third-party modules are idiosyncratic when it comes to markings; every manufacturer had their own system -- and at least to me some were inscrutable unless you can find a copy of their marketing literature from the right era.

 

[oktology]

It’s amazing to me how many PDP-11s are still in service in 2023.

Glad you’re trying to save these things from the scrap pile. I’m deeply interested in that 11/23 if it ever becomes available, even if it’s stripped of cards.

 

[tech58761]

I'm still keeping an eye on the system, and in fact, they ran those two machines yesterday for the first time in a few months.

Got a bit much on my plate lately tho', between our main customer deciding to clean their shelves of product needing to be returned and the other person in my department on indefinite medical leave (back / neck problems, trying to avoid the need for surgery)...

 

[tech58761]

Just a follow-on to another recent thread: the "spare" chassis in post 6 turns out to be a Universal Instruments 8222 controller.
The board in the P/S slot is a power-up sequencer which apparently has circuitry similar to that in the standard DEC power supply for the PDP-11.
Also partly visible in the picture of the 8222 is a small transformer that most likely powers the sequencer card through the SSpare6 and SSpare8 lines.