I see this a lot in some Dekatron types/brands that have been stored for a long time, some brands have fared better while being stored compared to others and some very´seldom experience this problem. I usually just increase the current either by raising the Anode voltage or decreasing the Anode resistor and then let them sit for a few hours up to a day or so and they usually start to run again past the sticky point. In those that you can reverse the rotation I sometimes switch the direction back and forth so I know that they run well in both directions.
/Martin On Wednesday, 23 February 2022 at 09:37:58 UTC+1 Paolo Cravero wrote: > Hello. > I am stuck with a stubborn WE-6167 dekatron ( > http://www.tube-tester.com/sites/nixie/dat_arch/6167.pdf seems to be the > only document available). > > The tube is NIB made in 1958. I understand it is a single guide dekatron, > and the stepping cathodes are split in two groups 1-5 and 6-10. > > I built the circuit as per Mike's diagram ( > http://www.tube-tester.com/sites/nixie/dat_arch/6167.pdf) and it span > correctly. I let it run for few minutes and then it got stuck at K10. > Through the glass I can see that it attempts to jump ahead, but the main > glow stays on K10. Fiddling with wires I could get it have one round up to > K10. The more it runs the more it gets stickier. The relaxation oscillator > never stops. > > I suspected some resistor overheating or changing value, but even after > hours of power-off, it doesn't go beyond K10. Or it simply powers up at K10 > and doesn't step over, while it does visually try to jump. > > Voltages are 450V/225V (input at 12V is 220 mA). Anode current is 1 mA (I > increased the anode resistor to 250k) while the current coming out of the > active cathode(s) is 1.5 mA. Stepping goes from 200V down to 2V (green > trace). Anode voltage (450 V) doesn't sag noticeably and inductor+IRF get > barely warm. The yellow trace in the oscilloscope shot is measured at the > "+58V" point (yes, I did try to move that voltage up and down with no > difference). > > > Then I opened a second new in box WE-6167. It ran correctly for a minute, > perhaps 100 rounds, then it started hiccupping (I think between K5 and K6) > and finally got stuck on K10 with the flicker towards the stepping cathode. > > It must be something with these tubes. Does anyone remember a similar > behaviour in never used dekatrons? I've read of deks needing a high current > "preparation", but not of them failing after a good start. I would like to > get out of the K10 position! > > Thanks, > Paolo > > -- 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 view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/34adcb73-2abb-4bc5-bfe6-08d9d192b142n%40googlegroups.com.
