Thank you for the suggestion... That is essentially what I was thinking as well, simply leakage current C-E. I've ordered 300V transistor pairs from Digikey.
Good news is the wife brought home a wonderful vintage Tek scope today, with a cart, -- digital, 150 MHz, early but with lots of capabilities for its' day. Model 2340A in perfect working order. $5 as it was being dumpsterized soon... I may well end up with a few more. I think I can safely retire my 15 MHz analog Hitachi scope now. Terry On Friday, November 11, 2016 at 3:47:41 PM UTC-6, gregebert wrote: > > What might be happening in your clock is the PNP driver is damaged, and > only allowing a tiny amount of current through. That can still result in > ~170V across the tube with no visible glow. I wonder if the PNP's Vceo > rating is less than 170V, and it suffered from long-term exposure. > -------- > I've observed erratic behavior on 7971 nixies when the current is limited > to a few uA. I was attempting to measure the ionization voltage, but the > behavior was so erratic I cant get consistent readings. But I did notice > the voltage was significantly higher in this pre-ionization phase, versus > normal operation. For example, I would measure around 140V across the nixie > at 100uA (dim segment); during pre-ionization I'd see 160-180V and faint > erratic glowing. > > I'm sure other nixies show similar behavior. > > BTW, I used my nixie bench supply to plot I-V data in Excel for my 7971 > nixies (7tubes * 15 segments * 7 currents = lots of data) and came across > this behavior. > > > -- 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 post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/d9a8dbfc-8ec7-4651-b6a7-cf78031c41ca%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
