finally the final final nixie clock schematic

Discussion in 'The Projects Forum' started by magnet18, Aug 9, 2011.

  1. magnet18

    Thread Starter Senior Member

    Dec 22, 2010
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    I gave up on point to point wiring it, for some reason my power supplies are melting and smoking, I think I need to replace the transistors, and I really don't want to do that, so to stop all these problems I decided to just make a pcb (multiple, probably), so I decided to finish the schematic first.

    Anyway, I think it's done, does anyone see any problems?
    I'm mainly concerned about the features section and the signal/power section.
    Thanks!
     
    Last edited: Aug 9, 2011
  2. JDT

    Well-Known Member

    Feb 12, 2009
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    Well, looks OK. I haven't had more than a brief look though.

    I would have replaced all that logic with a micro-controller myself but nothing wrong with doing it your way.

    What transistors are you using to drive the nixies? Hopefully high voltage types.
    I like the 555 boost power supplies but why do you have 2? Is 1 not powerful enough on its own?

    You really need to find out why your power supplies are melting and smoking before you think about a PCB!
     
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  3. magnet18

    Thread Starter Senior Member

    Dec 22, 2010
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    Thanks, the nixies are being driven by mps-a42 transistors, which are high voltage.

    The thing with the pcb is I was trying to make this clock in two separate sections, and when I tried to connect them I fried my web-bought power supply because I drew too much current.
    After replacing it with 2 555 supply's (just in case) the first half of the clock still works fine (signal generator, seconds, 1/2 of minuets), but there's a problem somewhere with the second part, leading me to believe I fried some transistors or something, and since I had a whole bunch of problems before, I finally decided I'm fed up and I'm just making a pcb.
     
  4. magnet18

    Thread Starter Senior Member

    Dec 22, 2010
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    So, nobody sees any issues with the first or last schematic page?
     
  5. SgtWookie

    Expert

    Jul 17, 2007
    22,182
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    On the 1st page, what are D10 and D11? Did you mean 1N4148?
    Why not use a 1N5817 or other low-Vf Schottky instead?

    On 2nd sheet, you still have "minutes" spelled "minuets" in the lower right corner.

    Same on 3rd sheet; left center.

    Sheet 5, upper left - I don't like it that you have two gas tubes sharing the same current limiting resistor. That could cause just one of them to glow, leaving the other dark. Do yourself a favor and use 1 current limiter per tube.

    I'm not keen on the idea of neither P3 nor P5 having fixed current limiting resistors, to protect the pots in case you happen to turn them all the way down accidentally.
     
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  6. magnet18

    Thread Starter Senior Member

    Dec 22, 2010
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    Thanks Wookie!
    Yea, D10&11 were typos, I'll make the modifications you suggested to page 5
     
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