Chrisprols:
...
Among those, here is a power supply which is using them.
... I might have messed it up: I only get 90V, but I'll try again some time soon
First of all, under what conditions are you measuring 90 Volts?
I didn't try to go through the narrative on the web site that you referenced (dumb, lazy mono-lingual American that I am), but here's how it looks to me:
I think that when processor outputs are high, if the power supply is giving 170 Volts at the point labeled "B+" on the schematic, the anode drivers (Q6-Q9) are supposed to apply something in the neighborhood of 100 Volts to the Nixies. (The voltage dividers in the bases of the anode drivers cause them to operate as emitter followers with an output about 60% of B+.)
Then, when one of the processor outputs goes low, that anode's driver goes into saturation and it applies the full B+ voltage (minus Vcesat) to the Nixie. (Al cathodes driven by the decoded active-low output of the 74141 will be at ground potential, but only one of the anodes will be high enough to illuminate a Nixie tube.)
Applying a voltage that is a little lower than the strike voltage of the Nixie tube (a keep-alive voltage) makes it faster to illuminate when the full voltage is applied. With just the right setting of R20 (and with proper software driving Q1-Q4), one and only one of the Nixies will be illuminated at any given time and the others will have a voltage just below their ionization value. It seems like a good plan to me, and I don't see any glaring errors on the schematic. (But I might have overlooked something.)
Anyhow...
How are you testing? What voltage are you supplying to the '555? If the load is disconnected from the power supply (disconnect one of the leads to R14) what voltage are you measuring at the cathode end of diode D1? Adjust the 1K potentiometer (R20) from one end to the other. By my reckoning, the voltage should go from something between 90 and 100 Volts when the wiper contact of the pot is at the R19 end and should be something over 160 Volts when it is at the R21 end.
If none of this helps you, then I have some other questions for you:
Did you use component values indicated on the schematic or did you substitute?
What kind of 1 millihenry inductor did you install at L1?
What kind of test equipment do you have? In addition to a voltmeter, a simple oscilloscope that can look at 100 Volt pulses at a frequency of something like 20-30 kHz would be cool.
Regards,
Dave