I've checked the driving circuit before posting with oscilloscope and there is absolutely nothing incorrect visible up to MMBTA92s collectors. I've taken photos of the bases of PNP transistors - the signal is clean, as visible below: <https://lh3.googleusercontent.com/-e7kYKgtZ5g0/WmDgB921u-I/AAAAAAAAC4k/MnGzGEuIcqoi4-QkLHEddY0fCnSVnM5MQCLcBGAs/s1600/IMG_20180118_184655%255B1%255D.jpg>
There are only three channels shown, because I've actually shorted something while soldering pieces of wire to the bases, so one of the transistors ended up its life in a spectacular and loud way :) and I can't find the bag with more of these. So I desoldered it. So, if there was a problem with capacitive coupling between wires leading to the board, some loose connections or capacitive coupling, it should be visible in here. All the bad stuff happens INSIDE of the MMBTA92s. This is the signal at anodes of the tubes: <https://lh3.googleusercontent.com/-Sv6-DkDwlzk/WmDg1enXQCI/AAAAAAAAC4s/UJbkcWqalqAnD9EcIRJqnA2AS_Um-IHbQCLcBGAs/s1600/IMG_20180118_185202%255B1%255D.jpg> As you can see, there is no glitch while the channel with removed PNP transistor should be on, so it again narrows the problem to PNP transistor - if any other part of the circuit would be the one creating glitches, the glitch would happen at this time as well. I've also added 10nF decoupling directly to HV input pins of my PCB, with no effect. Noise on HV rail is about 30mVpp and doesn't look like it is correlated with switching frequency. I'm starting to think that I might have received a bad batch of transistors or they are just counterfeit - which would be sad news, because I consider the supplier (TME) as rather reliable. -- 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/831d7192-f611-4b27-87c9-ac988c059ac4%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
