Jorg - Regarding the dead tube, have you compared the filament resistance of the bad tube to the others ?
NIMO tubes have 2 parallel filaments, so if one is open, the resistance will be TWICE the value of a good tube. I think the cold resistance is around 3 ohms. If 1 filament is out, you can still get 5 numerals to work. I would be surprised if both filaments are burned-out, unless someone put way too much voltage on it, or the tube is cracked around the pins. If the filaments are OK, power-up the tube and make sure you get around 180mA of current. Then try varying the voltage between the filament and the logic driving the grids. If a grid is about 6 V more positive than the filament, you should get a numeral to turn on. On Thursday, October 1, 2020 at 1:44:20 PM UTC-7 jörg wrote: > Short update of my nimo project. > I've got 5 tubes running. The sixt is unfortunately DOA. > The tubes filaments are driven with three power supplies, with soft start > IC (load switch). > So the filament gets started very smooth. > I've made some experiments with multiplexing the tubes. > Which work nice, using the method described in the manual. The bias > voltage is changed for every tube, that should be on/off. > In the actual approch, I'm using direct driving the tubes via 74HC595 > shift registers. Got a plenty of problems at the beginning. > The power and signal lines for the 595 were messed with switching noise. > Some caps did the trick. > Really nice to view the working tubes. > > Video: https://www.youtube.com/watch?v=JbwfZhYhnlo > > jörg schrieb am Mittwoch, 15. Juli 2020 um 18:01:18 UTC+2: > >> I‘m using Eagle to layout. >> It takes time for me to feel comfortable with it. >> And Fusion360. >> >> -- 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 view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/2ad71412-6a32-4a5f-91b4-5eb597c9e3ffn%40googlegroups.com.
