Awesome, just killed my clock >:(

Discussion in 'The Projects Forum' started by magnet18, Jul 19, 2011.

  1. magnet18

    Thread Starter Senior Member

    Dec 22, 2010
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    Alright, so I got another tube on, flipped it on... nothing happens. Try again, nothing happens. Check all the chips to see if they're warm, all are cold. About now I notice the ground wire smoking where it's exposed between the two clock sections (AFAIK it's the only thing that got hot), so I quickly unplug everything and go to pick it up (by the nixie power supply, since it's big and sturdy), then I notice that it's really hot on the side, and I realize that it's only 12mA, not 18...

    My theory, I over currented the power supply (5 nixies and 2 neons), and it fried inside, and sent a bunch of power to the ground, which went backwards to the v+ line and killed everything, but I'm not sure. I'm going to remove it and see if the chips still work, because I really don't know why the ground line would have smoked like that.

    For now I'm going to try to remove the nixie power supply and see if the chips work, if not I'll replace them all and hope the transistors survived. If not I'm printing a PCB.

    In the mean time, if anyone has any ideas on what might have happened I'm open to all suggestions and ideas, because I would have thought they would at least light up for a second...
    (also, if anyone knows any power supply schematics that can put out a lot of current, I'd appreciate it)
     
  2. SgtWookie

    Expert

    Jul 17, 2007
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    Gee, that sucks. :-( Sorry about that.

    Anyway, I've been helping someone else in over in General Electronics Chat with a flyback switcher; they needed 450v @ 1mA and I got theirs working pretty well - so thought I'd see how it would do with your 160v @ 18mA requirement. I was somewhat surprised that it not only was capable of producing that output; it was also better than 95% efficient. That's mighty impressive for a flyback.

    Have a look at the attached.
     
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  3. magnet18

    Thread Starter Senior Member

    Dec 22, 2010
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    Thanks wookie, I think I'm going to see what I can do with 555's and what I have, but out of curiosity, what would it take to get 180V @20-25 mA?
    (if I built it I'd like some wiggle room, and my resistors are set for 180V)
    not to be a pain or anything though...
     
  4. magnet18

    Thread Starter Senior Member

    Dec 22, 2010
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    Yay, the 4060 still works, and it was closest to the power supply, hopefully the rest follow suit and the ground line was smoking from overcurrent from the short in the power supply(12Vin, 12Vout, much heat dissipated) (hopefully)
    Now I just hope the transistors held up...
    I really, really don't want to replace them...
     
  5. SgtWookie

    Expert

    Jul 17, 2007
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    Yes, it'll go to 180v @25mA with a change in R2 and the transformer.

    It would make more sense to change the resistors though, because the supply will use a couple Watts more power.
     
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  6. magnet18

    Thread Starter Senior Member

    Dec 22, 2010
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    Alright, Thank you, I'll consider it, but I think I'm going to try a 555 based supply first though, mainly because I can build it with what I have laying around.

    Also, in case anyone was following, I think I'm going to have to replace all the decade counters, and probably the 4011. woot.
    I lack the motivation to do it tonight though.
     
  7. magnet18

    Thread Starter Senior Member

    Dec 22, 2010
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    Hawt damz, the 4017's work :D
    (had to fiddle withe the scope a bit to get it to output in human :p)
    now I just have to build a power supply, and try it, and pray that the transistors work...
    and figure out why the ground line was smoking... :confused:
     
  8. JingleJoe

    Member

    Jul 23, 2011
    185
    10
    It may be obvious but my first thought is a short, a really tricky one that you don't notice like a tiny solder bridge or a dodgy cap.
     
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