Since i'm not getting any kind of positive effect by software changes (time, pattern etc),i looked at the circuit and found a small problem (V-Screen was connected to Vbias) which was fixed, sadly this changed also nothing to the problem, so i searched my old pandicon calculator in the lab and took measures.
The first very odd thing i noticed is that they don't bias the anode! They just apply high voltage on the and then go straight back to 0V at the anode. The next very strange thing is that the driver of that calculator doesn't seem to be "on" all the time, it looks like the HV turns on for a short time, and then decays to 0V "slowly". In the first screen of the scope here you can see a few anode pulses that turn on quickly and then decay to 0V, the duration of this pulse is around 2ms. In the second pic you can see one pulse magnified in time were its visible that the "steady" HV is only active for around 200uS before starting to fall I also checked what the cathode drivers do, which turned to be exactly what i thought, the ARE biased with around 75V as specified in the datasheet and are pulled low and then return to bias. In the Screenshot you can see cathode "0 digit" (green) following anode 1 (blue) and cathode "1 digit" (yellow) following anode 2 (red). For the test i set "10" on the calculator which meant 2 cathodes have a value to display, and 6 have not! Its very interesting how the "processor" works with that. If you look at the yellow trace, which is the second cathode (which display the 1 of 10), it does not return to bias after the anode turns off, it just stays LOW for the rest of the switching cycle. Thereby the processor saves some operation to not go back to HIGH again. Very insteresting to see what kind of logic they already had at that time. My conclusion now is that maybe i can try to not even turn anodes on that don't have to display anything, just leave it off. Currently i'm turning them on, but don't activate any cathode since i've have nothing to display. Could it be possible that a "charge" is trapped in the tube by that? I also will make a experiment with no Anode bias, as in the calculator If anyone here knows more about panidcons and there use i'm happy to hear about! - Jonathan -- 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 post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/5466a70e-8d75-4cc5-812a-f13ce3aac555%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
