-> On 12 Nov 2000, Frank McConnell wrote: -> -> > "Rick Bensene" <rickb(a)bensene.com> wrote: -> > > > in some sort of Genrad whatsit that he was getting ready to scrap. -> > > > (He's keeping the display digits though.) Each digit is a box with a -> > > > bunch of tiny incandescent bulbs mounted in the back; each bulb -> > -> > > Check out the following electronic calculator in my -> > > museum of old calculators: -> > > http://www.geocities.com/oldcalculators/canon161.html -> > > -> > > It uses this exact type of display. Pretty amazing stuff. -> > -> > Thanks. Yes, that is the same sort of thing. One difference (perhaps -> > an improvement) in the Genrad digit-display modules is that the -> > grain-of-wheat bulbs are just slid into tubes in the back of the -> > module -- their contacts poke out the back of the module and mate up -> > with spring-loaded contacts in the display chassis. Also, the modules -> > slide out from the front of the unit, so replacing the bulbs is fairly -> > straightforward and can be done without soldering. -> > -> > -Frank McConnell -> > -> Your description of the bulb mounting sounds more like the projection -> type display wherein each bulb projected the image of a digit or -> character onto a frosted plastic screeen at the viewed end. Each bulb -> had a small lens associated with it to focus the image on the screen. -> IIRC, they were typically about 1.5 x 2.0 x 4.0" and were constructed -> from an aluminum extruded(?) box. -> -> - don These were used heavily in the US Navy, in the Hughes Aircraft Company consoles, which were used with the NTDS systems. When I was stationed at the training center in Dam Neck, VA there were many OPS mockups. NTDS console operators were trained there, and software was also developed. I remember many a midshift spent replacing those bulbs and film. I still have one _somewhere_. Historical trivia: Who was the first NTDS program manager? Answer is at the end of this post. Speaking of the Navy, has anyone ever heard of the Univac Digital Trainer (UDT). It was developed in the mid 60's and had a Friden Flexowriter for I/O (with punch and reader). I remember we had a room full of them at Mare Island (Vallejo, CA) for training on. I guess my age is showing, but I'd sure wouldn't mind adding a Univac CP-642A (first production NTDS computer, the size of a large refrigerator) to my collection, since this was the first "real" computer I learned to repair and program. I imagine freight would be a killer, though. Anyone out there collecting these old beasts? Univac 642/A, Univac 642/B, AN/UYK-7, AN/UYK-20? Bill Answer: Seymour R. Cray was the first Univac NTDS program manager