It can be a result of out gassing. I had a ZM1082 that got damaged and slowly outgassed. Towards the end, this is exactly what it did.
A neon test using some high voltage source doesn’t tell you what the pressure is in there, or how much other gas there is. I have another tube that passes this test, but will nit light up at all no matter what voltage and current I use. Conversely I have some planar displays that do not pass that test, but light up just fine. On Tuesday, November 24, 2020 at 11:38:06 PM UTC-5 Pramanicin wrote: > That would appear to be a logical conclusion....I wonder if there's a poor > anode connection that separates after heating? Odd for sure....looking > forward to your results! They're rare tubes.... > > Sent from my iPhone > > On Nov 24, 2020, at 20:25, Kevin A. <[email protected]> wrote: > > > > He picked up the two problem tubes as spares for his black emerald 8971 > clock. The original 6 8971 tubes work just fine in the clock, no matter > what socket they are in. Only when one of these two problem 8971s are > popped in place, does this issue occur. This leads me to believe it is a > problem with the tube rather than the psu or driving circuit. > > I'll ask for a video and will definitely be making measurements once I get > a hold of them for experimenting. > > On Tue, Nov 24, 2020 at 11:21 PM Nicholas Stock <[email protected]> wrote: > >> I know this is a very obvious question, but the power supply your friend >> is using isn't doing something strange instead? That's certainly odd >> behaviour for a nixie... >> >> Nick >> >> Sent from my iPhone >> >> On Nov 24, 2020, at 20:14, Kevin A. <[email protected]> >> wrote: >> >> >> I will definitely make some measurements once he has a chance to hand >> them over. From what he told me, the whole tube just self extinguishes >> during this phenomenon. Very odd. >> >> On Tue, Nov 24, 2020 at 10:53 PM gregebert <[email protected]> wrote: >> >>> Can you monitor the voltage and current of the tube while it's running ? >>> I cant help wondering if higher voltage will keep it on. >>> >>> I made my own nixie bench supply which has variable voltage and current, >>> so I usually set the voltage above 200V, and limit the current to the >>> datasheet value, which is 4.5 to 6mA per segment for the 8971. >>> >>> Do all segments show the same behavior, or just some of them ? >>> >>> On Tuesday, November 24, 2020 at 6:11:58 PM UTC-8 Kevin A. wrote: >>> >>>> Hi all, >>>> >>>> A friend of mine, also purveyor of cold cathode and other unique >>>> displays, has collected two 8971 nixies that seem to be having an odd >>>> failure. >>>> >>>> When powering the tube on, it ignites normally and begins to operate. >>>> However, after a period of 30 seconds or so, none of the cathodes can stay >>>> ignited and they fizzle down into a state of very faint partial >>>> illumination. >>>> >>>> Has anyone experienced this before? The most common failure mode has to >>>> be outgassing, but the tube is still full of neon as far as I can tell. It >>>> just does not stay ignited for more than a period of seconds. Can this be >>>> remedied by applying some kind of high current or high(er) voltage pulse >>>> the same way cathode poisoning sometimes can? >>>> >>> -- >>> 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/9ca0e0f5-53b7-49c7-a654-a817ca45bfd9n%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/neonixie-l/9ca0e0f5-53b7-49c7-a654-a817ca45bfd9n%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 [email protected]. >> To view this discussion on the web, visit >> https://groups.google.com/d/msgid/neonixie-l/CALcVLK%2Biu8W%2BbKELTYenrkvgMHeGp%3Dxk4_PbrgK3VnQUmKP_jQ%40mail.gmail.com >> >> <https://groups.google.com/d/msgid/neonixie-l/CALcVLK%2Biu8W%2BbKELTYenrkvgMHeGp%3Dxk4_PbrgK3VnQUmKP_jQ%40mail.gmail.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 [email protected]. >> To view this discussion on the web, visit >> https://groups.google.com/d/msgid/neonixie-l/63B7ED85-D391-4AC2-9170-274EE3B10DE5%40gmail.com >> >> <https://groups.google.com/d/msgid/neonixie-l/63B7ED85-D391-4AC2-9170-274EE3B10DE5%40gmail.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 [email protected]. > > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/CALcVLKLDxVKzDu7bAEgLLhBNWEeFbdjKi0NnBwc%2BqeAsWQcs1A%40mail.gmail.com > > <https://groups.google.com/d/msgid/neonixie-l/CALcVLKLDxVKzDu7bAEgLLhBNWEeFbdjKi0NnBwc%2BqeAsWQcs1A%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. 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