So, it turns out the power connectors (plastic female shell with metal male pins, etc) widely used in UNIBUS PDP-11's (e.g. to provide power to backplanes, etc) are still available, if anyone else wants any. (No doubt some of you already knew this; this is for those, like me, who didn't! :-) The 3-pin ones are used for the remote power on/off cables (used extensively in DEC gear, not just UNIBUS PDP-11's). They are 'Commercial Mate-n-Lok', now made by TE Connectivity, who bought AMP. Here are the current part numbers: 1-480305-0 3-pin female shell 1-480276-0 6-pin female shell 1-480277-0 9-pin female shell 1-480324-0 15-pin female shell 60620-1 14-20AWG male pin The 6- and 15-pin are for the backplane power connecters; the 9-pin were used to power backplanes in older machines (e.g. PDP-11/10). There's also a pin for smaller gauge wires, e.g. for the power control cables, but I don't have the number right here. I have checked, and these do plug into old DEC gear properly. I got mine from Digikey; their page for the line is here: https://www.digikey.com/products/en?FV=ffec0ef5 Go to the bottom, where it says 'Housings', and click on that, and they will all show up. (There are cross-links to the pins when you click on a particular shell.) Noel PS: I'm also tracking down the 8-pin connectors used in the H744/H745/etc regulator 'bricks'; an update on them in a day or so.