I'm scrapping a homemade control circuit that appears to have been intended as a turns counter for a coil winding setup on a lathe.
The circuit has a magnetic sensor, a bunch of hand-wired logic and a set of nixie tubes. The only power supply recognizable is clearly five volts. I don't see any hint of a higher-voltage supply to run the tubes, which I thought would need close to 100 volts to drive the gas dischrage elements.
The display tubes are labeled "RCA NUMITRON" and the logic date codes seem to range widely, from 73xx to 0001 (not sure how the codes jumped the Y2K gap).
Am I missing a HV power supply? The circuit is mechanically rather a mess, so it seems unwise to just plug it in. It isn't useful to me but I'd rather not wantonly destroy it. Each tube appears to have a single driver IC, RCA2501E with no obvious date code. The tubes and drivers sit on a production grade circuit board with an edge connector, probably salvaged out of something much older.
It's just a puzzle I'd like to understand.
Thanks for reading,
bob prohaska