Sounds like a multiplexing issue to me. I am guessing that this particular tube in question is getting cooked for quite a bit longer than the others.
Chuck > > >---- Original Message ---- >From: jwalton...@gmail.com >To: neonixie-l@googlegroups.com >Subject: Re: [neonixie-l] One slot on my clock keeps burning out >tubes, whilethe others have been good for years. Thoughts? >Date: Tue, 16 Aug 2016 21:28:09 -0700 > >> >> >>When all of the cathodes in a single tube lose large patches of >coverage in a short period of time, it still seems that it would be a >failure of the gas mixture. Over driving the cathodes for a period >of time would cause an eventual loss of brightness but it should >cause variations among the cathodes and not a sudden loss of coverage >on all cathodes. >>GregEbert suggested to look at the socket to make sure that pins >aren't stressed, which seems to match your description of how the >tube failed... Three failures in the same socket does seem to be >more than coincidence and it would be a good question to determine >whether mechanical or electrical. You should follow up with the >group regarding future failures and/or findings as it is >interesting. >> >> >>-------- Original message -------- >>From: Nicholas Stock <nickst...@gmail.com> >>Date: 8/16/2016 8:26 PM (GMT-07:00) >>To: neonixie-l@googlegroups.com >>Subject: Re: [neonixie-l] One slot on my clock keeps burning out >tubes, while the others have been good for years. Thoughts? >> >>Could the photocoupler at HC2 be the culprit at all? When you change >the tubes, is the brightness of the IN14 at that position the same as >the rest? >>On Tue, Aug 16, 2016 at 8:10 PM, gregebert <gregeb...@hotmail.com> >wrote: >>Since it's multiplexed, it might be worth comparing the 'on' time of >each tube (I'm guessing it's H2 on the schematic ?). You'll need a >scope. Maybe there is a quirk in the controller firmware that leaves >this particular tube on longer ?? There's also a slight difference in >the circuit around tubes H2, H3, and H4 though nothing pops out as a >possible culprit. >>Any chance there's a source of heat next to tube H2 ? >> >>Only other thing I can think of is if the particular socket puts >more stress on this tube. >> >> >> >>-- >> >>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 post to this group, send email to neonixie-l@googlegroups.com. >> >>To view this discussion on the web, visit >https://groups.google.com/d/msgid/neonixie-l/14912c65-1aa1-46a3-b2dd- >f2320a6d966c%40googlegroups.com. >> >>For more options, visit https://groups.google.com/d/optout. >> >> >> >> >> >> >>-- >> >>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 post to this group, send email to neonixie-l@googlegroups.com. >> >>To view this discussion on the web, visit >https://groups.google.com/d/msgid/neonixie-l/CAOX%2BRHJ4H9qTzQ0OrEh2L >YmrN%2Bn7nVhCjfc9coGRKwFy9yyQwA%40mail.gmail.com. >> >>For more options, visit https://groups.google.com/d/optout. >> >>-- >>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 post to this group, send an email to neonixie-l@googlegroups.com. >>To view this discussion on the web, visit >https://groups.google.com/d/msgid/neonixie-l/5hnpmx7sytvq69mp5yfocrcp >.1471406207133%40email.android.com. >>For more options, visit https://groups.google.com/d/optout. >> $4.95/mo. National Dialup, Anti-Spam, Anti-Virus, 5mb personal web space. 5x faster dialup for only $9.95/mo. No contracts, No fees, No Kidding! See http://www.All2Easy.net for more details! -- 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 post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/380-220168317142733655%40all2easy.net. For more options, visit https://groups.google.com/d/optout.
