From the fine people at PVElectronics, my wife bought me for Christmas a Nixie Clock kit! There’s nothing quite like 170 Volts to make you careful and to short those capacitors!
Total build time was about 3 hours, plus 2 hours of debugging a problem with the high-voltage transistors on the anode of one the tubes:
But some quick email support with Pete at PVElectronics (thank you SO MUCH for being around to offer support the day after Christmas!) and I got the problem isolated to one of the MPSA92 transistors. Since this clock is a multiplexed cathode design using the anodes to select the active tube, the 4th tube was displaying the digits from the other tubes because the suspect MPSA92 was shorted always-on. I swapped it out with one that I had in my parts bin and voila! A shot of the finished board:
And some close-ups of the tubes themselves. Very neat old technology.
You can see the individual digit elements inside the tubes “stacked” on “top” of each-other.
Very cool little clock. Next project is to build a wooden case for it!