MOD 6 Countdown Timer

Discussion in 'The Projects Forum' started by Lijah Samarzia, Nov 5, 2014.

  1. Lijah Samarzia

    Thread Starter New Member

    Nov 5, 2014
    Hello, I am currently constructing a countdown timer to count down from 4 preset times (30 minutes, 15 minutes, 12, minutes, and 8 minutes). I have everything installed and correctly working (including my presets) EXCEPT my "tens of seconds". I have been racking my brain trying different things and I can not get a MOD 6 to countdown (properly). I'm using 3 JK flip-flops and have it counting down from 7-0 (MOD 8). When I add a logic gate to make it a MOD 6, for some reason it is making it a MOD 5. I can not figure out my error. Does anyone have any hints or tips for me? I'm using IC 74112's feeding a 7447 and then into a 7-segment display. Any help would be appreciated. Thanks.

    p.s. should I abandon this and attempt a MOD 60? I had a little trouble getting that to count down. I didn't spend too much time on it though.
    Last edited: Nov 5, 2014
  2. Sensacell

    Senior Member

    Jun 19, 2012
    Please post your schematics?
  3. alfacliff

    Well-Known Member

    Dec 13, 2013
    why not use a 7492 ttl chip?