Paul - Do any of your failed NOS units have a black or silvery coating inside the glass ? I'm hoping that is caused by sputtering, and not simple aging.
On Friday, December 11, 2020 at 6:32:45 AM UTC-8 Paul Andrews wrote: > I have about 12 6844A, all NOS, none of them work - they show the same > symptoms that you described. > > On Friday, December 11, 2020 at 1:45:30 AM UTC-5 gregebert wrote: > >> I have not been able to figure that out for years. You would think the >> internal leads were coated with an insulator so they dont glow, or perhaps >> they use a different metal with a higher workfunction than the actual >> cathodes, so they would not glow in normal circumstances. But when the >> cathodes are still visible, I dont understand why they have no glow. I >> doubt they would be selectively plated with another metal, which completely >> sputtered away, leaving them unable to glow. >> >> I have a bag of dead nixies, mostly 5031/6844, took 2 out, and >> microwaved them for 2 seconds. Got a brilliant crimson glow. One of them >> shows some cathodes working, so now I have to go back thru the bag to make >> sure I find the totally dead ones, or at least the ones that have glowing >> only on the bondwires, and nuke them in the microwave oven. I have other >> boxes for dying nixies, and so-so nixies, so I'm really surprised anything >> in the "body-bag" of dead ones actually glowed. Unless perhaps the zap from >> the microwave oven did something to the internal metal. >> >> I have some more experimenting to do. >> >> On Thursday, December 10, 2020 at 4:57:40 PM UTC-8 Chuck wrote: >> >>> Burroughs 6844A is domed not flat. I also have some National >>> Electronics NL-6844A tubes. Frankly, I have had much better >>> >>> luck with the National Electronics brand. This recently purchased >>> batch of (8) Burroughs 6844A tubes is a bad batch. >>> >>> The boxes all are stamped MAR 4 1968. The tubes themselves are >>> date-coded 6750 F20. In white letters stenciled on the glass: >>> >>> "Burroughs 6844A NIXIE". >>> >>> >>> >>> The test I did was that the anode got connected to +170 volts DC through >>> a 15k resistor. Then the digit cathodes were selectively >>> >>> grounded to the negative side of that power supply. On all (8) of >>> these Burroughs tubes, most of what is seen is an intense glow concentrated >>> >>> around the tiny internal wires which connect the digit cathodes of the >>> stack, to the pins. These tiny wires pass closely to the outside of the >>> >>> Anode casing which surrounds the digit stack. The glow strikes in the >>> wrong place. The glow is around the lead wires instead of being >>> >>> around the digits. I am very confident from the way these tubes were >>> in those boxes, that only one of the batch had even ever been out of the >>> box. >>> >>> >>> >>> So I am curious what causes the glowing lead wires. >>> >>> >>> >>> Chuck >>> >> -- 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/2f0a455d-a6ae-44bb-bc40-d5eeda5028d1n%40googlegroups.com.
