I didn't look at your waveforms (or schematics), but if your switching speeds are very fast, this can cause transistors to turn on when they should not. The inter-element capacitance can pull the control element to the active state, even if it's not reflected on the pin itself.
Terry On Wednesday, January 17, 2018 at 3:25:33 PM UTC-6, Tomasz Kowalczyk wrote: > > I'll be able to check it in few days. > Power supply won't be overloaded for sure, it's a 0-300V 1A lab power > supply :) > > W dniu środa, 17 stycznia 2018 22:03:24 UTC+1 użytkownik gregebert napisał: >> >> Can you check the signals on all 4 of the NPN bases at the same time? >> Neglecting blanking, they should look like 4 pulses, each 25% duty-cycle, >> with no overlap. >> >> The 4th picture looks like this sequence: >> >> - Anode 1 on >> - Anode 1 & Anode 2 both on >> - Anodes 1,2, and 3 on >> - Anodes 1,2,3, and 4 on >> >> The anode voltage progressively decreases, which looks like heavier >> loading on the power supply as more tubes are simultaneously on. >> >> I checked the datasheets, and these transistors have plenty of margin, >> low-leakage, and decent switching speeds so no parasitic effects should be >> causing problems. >> > -- 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/53e33485-9f90-4795-acf3-cbf018fdbbfe%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
