"Lectrascan" information?

[SWISSNIXIE - Jonathan F.]

Hello!

By browsing around, i found this site: https://www.glaver.org/mod-6-nixie/

On the bottom of the page, there is a huge device with B7971 tubes. Its called lectrascan. Sadly, i can't find any information about it like datasheet or something like this. Would be very interesting to read about the function or see images of the thing in use, if it was ever in use.


It would be amazing to rebuild that thing, but i'm counting 48 tubes!  :( i only have 18... but yeah well

[Jeff Walton]

The description on the page that you referenced is actually very good.  They Lectrascan was used to show stock and commodity prices in large modular displays that were mounted end-to-end so there were far more tubes in a row than are shown with just the single bank of tubes.  I saw one of these actually working on a job interview in 1972 and they were already obsolete at that time.

 

If you look at the back of the B7971 tubes, you will find a large number of them that are marked with the Ultronic part number rather than the Burroughs B7971 marking.  While I don’t know this with certainty, I believe that Ultronic was the largest user of the Burroughs tube but the window of use was just a few years.  

 

Every so often, the tubes are auctioned with the modular board that is shown on the page that you referenced.  I have a bunch of them that I never bothered to do anything with and they are full of discrete transistors and resistors with hardwired sockets.  I think that if you look on eBay for tubes, you will often find tubes with sockets where the sockets have just been cannibalized from the Lectrascan boards.  About four years ago, I bought some tubes from a surplus dealer that said that he had some of the complete Lectrascan units in his storage barn and he was just taking the tubes & boards out of his displays and periodically posting them on ebay.  He had purchased the displays as part of a large lot of various products at a bankruptcy auction.  For historical purposes, I should have asked him if he had any of the displays that were still complete just to get photos.  My interest was just the tubes.  There have been some auctions of the modular boards with and without the tubes and I’ve not seen the empty boards ever sell but I’ll bet that there are a number of folks in this group that have the empty boards sitting around if you were looking for one.  Most anyone that has built a MOD-SIX has likely come across the boards in a quest for tubes.  I bought (8) of the B7971 tubes in 1972 from either Burnstein-Applebee or Poly-Packs for a senior project in college and never got around to using them until a few years ago in my MOD-SIX.  They came with the tubes still plugged into the boards.  I should have bought more!

 

The Lectrascan was a product of the 1960’s and the 48 tube modular display sections were driven by remote systems that filled large rooms with a ton of wire harnessed cables that were really primitive by today’s standards.  They did not last for long as other computer and display technology quickly developed and displaced it.   Read the referenced PDF file at https://www.glaver.org/mod-6-nixie/Ultronic_Systems.pdf for a good history of where this unit got its start.  

 

Jeff

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[Quixotic Nixotic]

On 20 Nov 2016, at 19:22, Jeff Walton wrote:

The description on the page that you referenced is actually very good.  They Lectrascan was used to show stock and commodity prices in large modular displays that were mounted end-to-end so there were far more tubes in a row than are shown with just the single bank of tubes.  I saw one of these actually working on a job interview in 1972 and they were already obsolete at that time.

[MichaelB]

This is Terry Kennedy's site. One of our Forum members. Nice site!

[Nick]

That's actually a Quotron rather than a Lectrascan unit - they were competitors...

See thread https://groups.google.com/d/msg/neonixie-l/MDn6HDUbiN8/hEZMgDKVGa4J 

EDIT: Should have read my own posts - it's probably a single height Lectrascan unit but the photo is a composite...

Nick

[gregebert]

Were these multiplexed, or direct-drive units ? Anyone know what the MUX ratio was ? I doubt it was 24:1 or 48:1

I remember visiting an EF Hutton brokerage around 1970, and I recall their display used incandescent bulbs to form characters about 12" tall. When messages were scrolling, there was a noisy whoosh sound, which I assume was a fan to keep the heat from going into the office.  Lectrascan/Quotron was definitely a big improvement.

[Terry Kennedy]

On Monday, November 21, 2016 at 11:56:36 AM UTC-5, gregebert wrote:

Were these multiplexed, or direct-drive units ? Anyone know what the MUX ratio was ? I doubt it was 24:1 or 48:1

 

I could pull out one of the boards, but I believe the display board just had drive transistors. The Lectrascan systems came in whatever size was needed for a particular installation, so there was probably some sort of bank addressing for each 48-tube section. Since these date from the mid to late 60's and the design was likely done a year or two before the units appeared, it is almost certainly built out of discrete components. I'm not even sure what they would have used for a character generator, but it could have been a diode matrix. I doubt they used any of the more esoteric storage methods (IBM CROS, Bell Twistor, etc.) but magnetic core (either R/O or R/W) is a possibility. I wonder if the patent applications for the Lectrascan disclose anything about the drive mechanism?

Terry Kennedy

https://www.glaver.org