I admire the holy purity of your art, Grahame, to make a tube regulated PSU. I'm afraid the presence in my junk box of a small mains transformer with 200V and 24V secondaries but no suitable heater voltage led me to stray from the path of righteousness and yield to the cheap seduction of semiconductor rectifiers.
I recall my friend from Hivac mentioning that the XC15/CV2486 was radioactive doped, and they had a relationship with Harwell to supply isotopes. They probably used Krypton 85, which has about a ten year half-life. My tubes all have a 78 date code so the activity will only be 12% of when they were new. Tomorrow I'm going to change the 50 minute tube, since I can't tame it. It now consistently gives me a 10 minute hour. What's very strange is that it always hands over to the 00 minute tube as it should, but then takes the glow back on the next minute pulse at 01. I suspect it's getting electrical noise from the adjacent unit minute track, since the tens ring doesn't get a pulse at that time. Or, it could be board contamination - I've had some trouble with that because of the small clearances. The clock has an annoying tendency to light several tubes in the same ring when I'm trying to set it - probably switch bounce. It's sometimes recoverable by working the switch, but the totally reliable solution is a push button for each ring, discreetly hidden away on the back out of sight, that directly grounds one cathode. It's not needed very often but it beats having to power down, wait for all the glows to go out, and then start over. I'm taking it to the local Maker Faire at the weekend. It's totally unrelated to the booth I'll be minding, but I'm going to hang it on the wall to attract some extra visitors. They'll probably ask whether I'm running it with an Arduino or a Raspberry Pi. };> -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/355e7891-af40-44b0-bf1e-26a0d1ab36af%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
