I've only seen 2 types of functional failures in 7971's - One completely-dead segment (A gift to me; that's how I got started with 7971's) - Adjacent segments shorted together (it just happened one-day on my 8-tube clock w/o warning; very peculiar)
I have one exhibit-only device with a crack in the base, but that's from mishandling. The same tube has two black spots on the mica right next to rivets, and I dont know what to conclude from that. They are pretty rugged, especially considering their massive size /mechanical complexity, and versatile because you can display numerals, text, and a few special characters. That said, they are butt-ugly and getting expensive. With 9 tubes that all work, you're in great shape to build a 6-tube clock and have spares. On Monday, April 24, 2023 at 2:23:53 PM UTC-7 Nicholas Stock wrote: > I have a variety of B7971's with different micas, 'burn' marks, pins in > the top of the envelope etc etc. I have yet to have a tube fail on me in > day to day use after many years. I don't think it's an indication of any > life expectancy for these tubes.... they appear to be built like tanks. > > Now that I have said that, I await the inundation of messages talking > about B7971 failures...... LOL > > Cheers, > > Nick > > On Mon, Apr 24, 2023 at 10:42 AM Robert Norman <[email protected]> > wrote: > >> I have 9 tubes, 5 show no sign of any marks, 2 show marks on a couple of >> the connections and 2 show more extensive marks, all work perfectly. >> >> Are the ones with marks more likely to have a shorter life? >> >> Rob >> >> -- >> 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/17DE8F39-16DF-4E6D-8D4D-6D434E8558E3%40gmail.com >> . >> > -- 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/71bd4fcd-33fc-40de-ab45-2367f2905615n%40googlegroups.com.
