Bill, I'm by no means an expert on this, but from what I've gleaned with the IN-13 tubes is that they sometimes need a little bit of over current to get them 'settled/conditioned'..after which you can use them full scale according to specs..try burning one in for a while then reducing the current and seeing what happens...
Cheers, Nick On Sat, Jul 4, 2015 at 1:07 PM, Bill Esposito <[email protected]> wrote: > Hey everyone -- It's been a long time since I've posted to this group (or > played with Nixies for that matter). > > I've built an IN-13 driver circuit, using a topology that seems to be the > "canonical" one most commonly floating around the web, using an opamp and > an MPSA42 -- see the linked schematic: > > http://puu.sh/iNgTq/3f60ecf956.jpg > > All values are measured full scale indication conditions. I'm using a > Taylor Edge supply module set at 146V (as indicated on the schematic; I > know my handwritten 4s looks like 9s to some people). I originally had it > set at 140V, but one of my tubes wasn't reliably striking at 140V, so I > changed the set resistance. > > Thing is, all the documents on the IN13 that I've seen indicate that the > control current should be on the order of 0-5mA. With the tubes I've got on > hand (I've tried this on 3) the control current required has been on the > order of 13mA to get the bargraph to indicate full scale. > > The question is, why to I need 3x the rated current to get full scale? It > seems like I MUST be doing something wrong, but I'm not seeing what it > could be. I suspect this isn't good for the tubes long term, but I'm also > not sure how bad it is. > > As an aside, I tried 392k resistors on the cathodes and those gave me a > slightly less linear sweep but overshoots the full scale indication > slightly, which is nice. If there's no long term harm in upping that > resistance, I'll probably go back to the 392k resistors. > > Thanks! > -Bill > > -- > 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 email to [email protected]. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/CABKLWSFP%3DrReVhHnWMORsRKQxBU2rjuHZw2nL-fG3Gn0V%3DBWcw%40mail.gmail.com > <https://groups.google.com/d/msgid/neonixie-l/CABKLWSFP%3DrReVhHnWMORsRKQxBU2rjuHZw2nL-fG3Gn0V%3DBWcw%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- 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/CAOX%2BRHL-5%3D%3DEDfeVemBe7b2N%3DoTDR1-aFnqQLhRQ42hZ%2BzdimA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
