Facit 1131J Nixie Tube Calculator

Tour of the Facit 1131J Nixie tube calculator, from approx. 1971. This machine is a weird combo of 1960's and 1970's technology, with lots of pretty Nixie tubes and LSI integrated circuits from Rockwell. It actually is a modified Sharp Compet machine. I finally tease out what the 5/4 key does at the end of the video...
This model post-dates the 1123/1124 machines, see:
http://www.cs.ubc.ca/~hilpert/eec/calcs/Facit1123.html
and:
http://www.johnwolff.id.au/calculators/Facit/1124/Facit1124.htm
that had lower level integration 74xx circuitry, but a similar keyboard and Nixie display, but pre-dates the later high-level integration machines with VFD displays like the 1185:
http://www.curta.com.ar/curta/database/brand/facit%5CFacit%201185/index.html
So it has a curious mix of rather modern LSI circuitry and very vintage Nixie tubes into it. A very solidly built calculator with a great vintage Nixie display, a mysterious 5/4 key and whimsical overflow indications. Mystery gets solved at the end of the video...

Видео Facit 1131J Nixie Tube Calculator канала CuriousMarc