I forgot to mention that when I am "un-sticking" a Dekatron I just connect all cathodes together so they don't have differing potentials, with or without one common cathode resistor for all cathodes.
/Martin On Wednesday, 23 February 2022 at 23:56:50 UTC+1 Tidak Ada wrote: > Thanks John, that is useful information! > Yes, you confirm my fear. Fortunately I bought the tube as am collecting > item, > Eric > > Verstuurd vanaf mijn iPhone > > Op 23 feb. 2022 om 23:21 heeft Jon <deka...@nomotron.com> het volgende > geschreven: > > To Eric's question on the N3... > > > These are also rather tricky tubes. My experience is similar to Martin's - > unfortunately many examples of N3 are non-functional in that they won't > even strike a glow - outgassed or similar. I fear that if you can't raise a > glow with a violet ray unit or plasma globe then yours may be dead :( > > But if you do find a working N3 or N4, then the conditions below work for > me: > > - Va = +350V with respect to main cathodes > - Transfer pulses 30V amplitude from a resting bias +15V with respect > to main cathodes > - Anode current 1.6mA (82K anode resistor, 8K2 cathode resistors) > > It's quite an unusual design with relatively low anode and transfer > electrode voltages. If the anode voltage or current is too high, it's easy > to get multiple cathodes glowing instead of just one which can mess up the > stepping. > > Jon. > > > On Wednesday, February 23, 2022 at 10:04:53 PM UTC Jon wrote: > >> The sticking on K10 specifically is a peculiarity of the 6167 in my >> experience. I believe it's distinct from the sleeping sickness effect that >> Martin describes as that is essentially random in which cathodes are >> affected (and as he says, working the tube, possibly at elevated current, >> in both directions where possible, is usually an effective cure). >> >> I mostly saw K10 sticking when I was exploring a circuit that makes use >> of the unique auxiliary anode connection (pin 5) which of course lies >> adjacent to K10. What seems to be happening was that when the glow gets to >> K10 there is current flow from both the main anode and auxiliary anode. The >> next transfer pulse moves the glow onto the transfer electrode, but when it >> terminates the auxiliary anode-K10 gap is still sufficiently primed so that >> the glow mostly steps back to K10 rather than forward to K1. I was able to >> mitigate this by reducing the auxiliary anode potential below what I'd >> originally understood it needed to be from the datasheet (the datasheet is >> really opaque on this point), and also by lengthening the transfer pulse to >> allow more deionisation time. >> >> However, if I understand Paolo's post, he's using Mike Moorrees's circuit >> (https://threeneurons.files.wordpress.com/2011/09/we6167ckt.gif) which >> leaves the auxiliary anode disconnected. When I ran 6167s in this >> configuration they were generally much more reliable in not sticking on >> K10, though I was using rather different circuit conditions: >> >> - Va = +400V with respect to main cathodes >> - Transfer pulses 60V amplitude from a resting bias +30V with respect >> to main cathodes >> - Anode current 1.3mA >> >> >> Paolo, can you confirm you have indeed left pin 5 unconnected? If so, >> given that the sticking effect seems to be increasing with tube use, I >> wonder if we're seeing the floating auxiliary anode gradually charging up >> and eventually reaching a potential which is disrupting the stepping >> operation. Maybe use a potentiometer or potential divider to pin the >> auxiliary anode at some moderate voltage positive to the main cathodes (say >> +100V as a starting point) and see if that helps? >> >> They're funky tubes... >> >> Jon. >> >> >> On Wednesday, February 23, 2022 at 8:37:58 AM UTC 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 neonixie-l+...@googlegroups.com. > > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/561cd232-4426-40a5-aa4d-8945868ccd0bn%40googlegroups.com > > <https://groups.google.com/d/msgid/neonixie-l/561cd232-4426-40a5-aa4d-8945868ccd0bn%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > -- 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 neonixie-l+unsubscr...@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/74ca55ad-287f-4de5-a70a-06f9a9fb08aan%40googlegroups.com.
