The Burroughs SD-11 sphericular display has historically been a pretty mysterious device... it has incandescent bulbs and looks like a projection display, but produces numbers using a dramatically different system. Normally SD-11s are glued shut and can't be dissembled, but I had a damaged one so I cut it open and and made a page with lots of pictures explaining how this very strange device works. Enjoy!
How very unusual! I've never seen or even heard of this type of display before. Thanks to your pictures and write-up I understand how it work. Very clever and strange design, gotta wonder who thought of it.
Look into it later when the dust is clearing off the crater.