Many thanks to everyone who responded to my question! The site at
http://www.sphere.bc.ca/ has a lot of older type displays and the
Minitron Seven Segment Displays were among them *including* a datasheet!
The pricing I've seen ranged from about $7.00 to $44.00 each used and
tested but so far, I haven't seen any prices for NOS parts. I do like
the $100.00 per digit though :).
The name
'minitron' seems to be floating in my brain for some reason...
They could well be incandescent. I've seen such devices in a 16 pin DIL
package, in a smaller package with 9 socket contacts on the back arranged
like a miniature DE9 connector (those are used in the ICL Temiprinters
for the column display, for example), and in a wire-ended valve-shaped
envelope.
I have a bunch of them too. Four are in a counter I made back in 73,
the rest are spares for it. Actually they are fairly nice and at about
10MA brighter than leds of the time (I must ahve a dozen MAN-x series
LED 7 segments as well).
FYI: those things are considered rare as hens teeth as most systems
that use them have burnt them out. One series of ARC (used in cessna
aircraft) radios had them as they were bright enough for day use
and I hear they cost about 100$+ per digit to replace.
Allison