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 [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/e3118260-0301-48a9-b39f-20d9055f6e86%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
