Very likely, the infamous "blue dot". The unused cathodes are clamped to 62V. I believe those unused cathodes, at that potential work somewhat like the beam plates, in beam power tubes, like the 6L6. The blue, at or near an anode, seems dependent on current density. The greater it is the more likely you'll see the blue glow. On one of my "blue dot" experiments, I used the decimal point of a NL-841 as the anode, and it glowed a nice bright blue.
Crossing my fingers, knocking on wood, and rubbing my rabbits foot, I've yet to see it on one of nixie thermometers. They are clamped to 47V, and I even have one clamped to 24V ! Maybe, the nixie tubes used on that circuit (ZM1000, IN-14, IN-8-2) aren't prone to blue dot. On Friday, June 30, 2017 at 11:58:14 AM UTC-7, Roddy Scott wrote: > > Folks, > > I put a set of XN-11s into a PV Electronics QTC board and I am getting > some weird things happening. > Blurred and missing numerals and a spot on the anode mesh. > > > <https://lh3.googleusercontent.com/-vp6qwGh3E2k/WVafNzO_R-I/AAAAAAAABLQ/tERqS6oG-CUtgQaMqm01SugFAA52TSp2gCLcBGAs/s1600/IMAG1452a.jpg> > Any ideas on this as I am totally in the dark as to why? > -- 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/9e14852b-c569-4930-857a-6a0dccc7724b%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
