> > I have acquired some Burroughs B6844A tubes, but I'm > > having trouble getting them to light properly. > > > > Are my tubes dead, or is there a hope for them? > > I bought a bunch of those tubes ... They exhibited the > symptoms you described. > > I'd recommend trying some different tubes. > > David Forbes, Tucson AZ
Given that nixie tubes are no longer made, I'd try to resolve the problem, before turning them into "non-operating museum pieces", or BB- gun targets. Light up a single numeral, with the offending 'glowing lead', and keep it lit for a couple of days. Do it at the rated or maybe twice the rated current (2-5mA). See if the 'lead-in' wire stops glowing within that time frame. If it does, go to the next offending digit, and repeat until the whole tube is cleared. It still might be a 'sub-set' of cathode poisoning. If the tube still has problems, buy some BBs. Most of the time tubes can be salvaged, but on occasion, some are just past redemption. I have a dekatron like that. It would not count properly within the specified operating current range (300uA - 600uA). Its a Sylvania 6476A. These tubes can usually be 'fixed' by running them at 2mA for a couple of hours. At 2mA it does count reliably. But once, its brought back down to a lower current, it stalls. I've run that thing for a day (@2mA) then bring it down, then a week, a month ... and so on. It still won't run in the normal range. Its been running now, 24-7, for the last two years, at 2mA, and it still won't behave at lower currents. Its running in a simple 'pendulum' circuit that's clocked at 10Hz. At this frequency it'll probably run for several more years. At this elevated current, it probably won't count at anywhere near the advertised rate of 4KHz. Fortunately, it won't have to. So give it a shot. Either way. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
