4017 outputs going low

Discussion in 'General Electronics Chat' started by magnet18, Jul 16, 2011.

  1. magnet18

    Thread Starter Senior Member

    Dec 22, 2010
    1,232
    124
    Alright, I'm back and working on my clock, and I got another digit working (almost), but when the digit before it goes to a 5 or higher, it goes blank.
    Example-
    10
    11
    12
    13
    14
    _5
    _6
    _7
    _8
    _9
    20
    21
    etc...

    My first thought was that the clock in line was shorting to the inhibit, but I can't find any shorts or anything... ideas?
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    Lets see your current schematics. It could be a simple wiring error, or loading on the CMOS outputs (they can't take much). It may even be zapped chips, but at the moment that is bottom of the troubleshooting list.

    During the count monitor your DC power supply, make sure it is stable.
     
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  3. bertus

    Administrator

    Apr 5, 2008
    15,647
    2,346
    Hello,

    It could have something to do with the carry out signal.
    But as Bill also stated, what is the current schematic you are working on.

    Bertus
     
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  4. magnet18

    Thread Starter Senior Member

    Dec 22, 2010
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    124
  5. magnet18

    Thread Starter Senior Member

    Dec 22, 2010
    1,232
    124
    OK... funny thing happened...
    I connected the scope leads to the power supply, both at the pin of the chip and at the rail, (both of which are flatter than western kansas, so they probably weren't the problem), and the problem just disappeared...
    I have no idea why, I just looked at again and plugged it in... :confused:
    whatever I guess. :p
     
  6. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    I don't see how the seconds button and the minutes tag relate. There isn't a gate to combine signals. But this shouldn't have anything to do with your problem, it is just a observation.

    You probably have a bad connection somewhere, the scope leads only wiggled things a bit.
     
  7. magnet18

    Thread Starter Senior Member

    Dec 22, 2010
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    124
    Oh, I need to update that, I was originally going to use the seconds to set the time, but decided to use the unused half of the 4013 to prevent interference issues and to make a fast set option better.

    As for the connection, you're probably right, and either it shows back up and I track it down, or it doesn't and I don't worry about it.
    meh.
     
  8. tom66

    Senior Member

    May 9, 2009
    2,613
    214
    Scope connection tells me a ground loop, you probably haven't grounded a pin somewhere...
     
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