In order to assess what is happening with your circuit, we need more information. Schematic, bill of materials, and pictures of your pcb artwork (showing copper and component placement) and the actual test prototype. All of that information is critical if you want a serious response about potential problems and how to move forward.
On Mon, Aug 31, 2020, 6:55 AM Massimo Di Noi <[email protected]> wrote: > Hi all, > > I'm been following this group for a while and finally decided to go back > to a hoppy that I had 15-20yrs ago or so, to brush up my old knowledge and > to build my personal nixie watch starting from what David at Cathode Corner > kindly shared, but looking to improve its efficiency with new chips and to > add functionalities similarly to Kopriso watch or else. I like the > capacitive buttons etc. > > This is all very steep for me. I have however managed to learn to use a > CAD software to design the PCBs (still haven't worked out to properly > solder an ADXL335 by hand, I find that challenging even with a microscope > but what I have done so far seems fine for a prototype project. > > I have put it all together and it works! Almost: only issue I have is the > voltage clamping, which I don't understand well. > > I couldn't find B5870 Nixies, so for now while testing I'm using chip Q27 > Nixies. > > I do get a stable 158V from the power supply. I believe I need 180V as per > descriptions on Cathode Corner's webpage. Looking at the resistor divider, > I should be getting 163V, so the HV circuit seems to work, I think. Not > sure why David says it should give 180V. So I may be doing something wrong > or the values of the resistor divider on the schematics are incorrect (I > very much doubt so!). I calculated 1.22V*[1+(510k+510k)/(7.5k+150)]=163.8V > as per datasheet of the LT 1308B. > > Thing is, the whole things works, keeps the time etc but if I connect the > VCLAMP (to clamp the 083A darlingtons to 51V - see link to schematic > below), then nothing happens, only one of the Nixies goes on, but it's very > fainted. > > What am I missing? > > This is what I am looking at: > http://www.cathodecorner.com/nixiewatch/theory/theory.html > http://www.cathodecorner.com/nwl/NWLD5schem.pdf > > Obviously I could experiment with different values of the resistor divider > but I don't understand why I should do that as I'm sure Dave's design is > proven by many years and many watches he sold. So, I'm guessing I'm doing > something wrong here. Or it's as simple as the Q27 tube needs a higher > maintaining voltage than the B570? I cannot find a datasheet for the Q27. > But then again, why Dave talks of 180V out of his HVPS? I'm going in a > loop... > > Any help would be much appreciated. > > Thanks, > Max > > > -- > 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 view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/d0451e2f-a7ec-470a-a268-eecedd2ffc3en%40googlegroups.com > <https://groups.google.com/d/msgid/neonixie-l/d0451e2f-a7ec-470a-a268-eecedd2ffc3en%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- 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 view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/CALcVLKKMeOXY-7NDj5hEzUTZA%3DkZ-avfr5KuNeLc%2BfoBt808kA%40mail.gmail.com.
