Some time ago John Taylor (Tayloredge) converted a wall wart into a Nixie PSU and showed the result here on the forum, after that I started to experiment with other small switching power supplies. In the answers to my questions John mentioned better rectifier diodes and also that he used two in series. I tested two UF4007s in series and found that the switcher worked a lot better, with one it sometimes blew up and caused a lot of collateral damage to the rest of the switcher. At the same time I pulled out a few switchers I had lying in a box like the ones here and I added a second rectifier diode to those too and they also worked a lot better. I can't explain this as I know too little about electronics in this area but I am sure that others can. I also discussed snubber and found that I could skip those if I used two UF4007s in series as it looked good enough on a scope then. The result with two diodes in series was that they didn't blow up but I also got a lot cooler inductors which also led to less heat in the switching transistor so there was a lot less power loss in the switcher. I tested this change on both switcher with a single inductor and also on switcher which uses an isolated transformer. I wish I knew more about this so that I could explain it properly but unfortunately I don't.
Don't forget to replace the mosfet if you have blown the inductor as the mosfet has seen a lot of stress during these situations and is probably partially damaged. I have had to replace the mosfet on several occasions even though it at first seems to work well. /Martin On Thursday, 1 September 2016 19:51:45 UTC+2, MichaelB wrote: > > Had another TubeHobby clock start blowing fuses the other day and I know > others on this forum have had similar issues. I have 4 of these muxed > clocks and 2 that drive IN-18’s, the others use smaller tubes like the > Z566M and the Z574M and have been fine. However, I have had issues now with > both of the IN-18 clocks where the 1st blew C6 (see attached PS > schematic) and now this one has eaten (shorted, or darn near, measures > .3ohms) the 270uf inductor. Replaced it and the clock has run fine now for > 3 days, so its fixed for now. Not sure what it is about this clock's power > supply driving IN-18’s and so wondered if others have noticed this problem > and what a long term cure might be? Included the power supply schematic for > review. > -- 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/87afc7fc-66cc-4882-9fcf-f346dd026fd4%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
