Sounds like cathode poisoning. This is a very important thing that everbody using nixies must know: Just as running a nixie tube with too much current, is bad. Running a nixie with too little current flowing thru it, is also a bad thing.
There may not be enough current flowing thru the tube, to allow the "ON" cathode, to shake off the crud that coated it, when another cathode was ON. Eventually, that crud keeps the really nasty coated sections, of that cathode, from glowing. A few months of running at "UNDERcurrent" (too little current) will do what you're seeing. I'd just change out the anode resistors, with lower values. If its direct drive, measure the voltage drop, and calculate the current. Find a datasheet for that tube, and see what the minimum current is. Assume the voltage drop will be the same for the replacement resistor. Use Ohms Law, to calculate a resistance value that will meet that minimum current. Pick a real resistor value that's ~20% smaller, and use that for the new resistors. You can measure the supply voltage too. Maybe it was too low from the start, and it would have delivered the correct current, had it been at the proper voltage. Absolute minimum supply voltage for direct drive nixies, is 170V. For multiplexed operation, you want a higher voltage. The higher the voltage, the faster, the tube turns ON. Typically, nixie tubes take between 15 to 50uS to start conducting, after voltage is applied. On Thursday, September 11, 2014 9:38:51 PM UTC-7, Dman777 wrote: > > Well, I guess I have really bad luck. My clock is only like 3 months old. > > What is weird is that this issue, for this particle tube, is random. It's > not specific to just some digits. Sometimes it goes away and sometimes it > comes back....doesn't matter which digit. > > Is this the tube itself or the clock circuitry causing this? > > > -- 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/f99b5787-cd57-4bdb-b031-910a63935652%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
