Looks like a Kycon KPJ-3S or similar if this reference is to be believed: http://en.globtek.com/connectors/
Good call! Thank you.
I ordered a KPPX-3S which appears to be the correct plug.
Trying to charge the battery in a 25-year-old handheld computer. Chances are I'll need to have a new battery pack made, but either way I will need the plug.
The good news: connector arrived and fits the plug perfectly. The bad news: I didn't realize it comes in several pieces and you have to assemble it. No instructions. I have no idea how to do this. Might bring it to the next workshop. Next question: what kind of wall wart do I need? I've got to find out the battery specs before anyone can answer this. I removed the pack but it doesn't list any specs. It is five cells. They look like 1.2V/AA-size. I'd disassemble it (it's dead anyway!), but it has a hard shell, not a vinyl wrap. Thus I am not sure how to break it open. Tips? (Briefly considered using a Dremel. Then realized it could be dangerous if the tip hit a cell.)