Hi Jeff, I guess it is a leak along one of the pins, dumet seals can corrode (it is a copper plated nickel-iron wire). I would be interested to do a leak test on a helium leak detector. Of course if you can miss the tube.
Just a very small (tiny tiny!) amount of air is enough to ruin the balance of the gas inside a nixie tube. Less than one would actually think. Regards, Dalibor Dne pátek 8. července 2016 20:48:04 UTC+2 Jeff Walton napsal(a): > > I recently had a IN-18 failure in a clock after about 2.5 year operation. > Over a (4) day period, the digits in one of the tubes stopped working in > PWM dimmed mode. At full brightness, the digits in the affected tube > slowly lost percentages of digit coverage to where only portions of each > digit would illuminate. At the end of the observed period, the digits in > the failing tube went completely dark and even higher voltage on the bench > would not illuminate any of the cathodes. The tube date code was 8505. > > I am guessing that absent of any other signs of damage, a seal around one > of the pins has failed and allowed the tube to leak. It was surprising how > quickly it failed and none of the other tubes in the same clock have > exhibited any signs of trouble and look as good as the first day of > operation. Has anyone experienced similar failures with the IN-18? Is > this a typical failure mechanism? Have there been any particular date > codes that others have found to be problematic? > > The tube has been since been replaced and the clock is happy again but > curiosity leads me to ask about this experience to the rest of the members > of the group. FYI - these tubes have not been rotated since the clock was > initially put into operation (no handling). There was never any evidence > of cathode poisoning during the operation of the clock. > -- 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/0ec52c6e-eefb-43f8-8e61-349fa55a8e54%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
