[HomeBrew] Strange anomaly of a 74LS90

[Philip Atchley]

Steve,
It's built on one of those little RadioShack "universal" PC boards.  I've
built a lot of things on those boards, from RF to audio and never really had
a noise problem before (though of course some things needed to be shielded
from external sources).

I could actually hear the 625KHz on a portable radio placed next to the unit
and it sounded clean (I have no scope).  So I suspect the unit was truly
dividing by 8.

73 from the "Beaconeers Lair".
Phil, KO6BB



> >Has anyone here seen a decade divider (consists of a divide/5 and a
divide/2
> >divider) that divided by 8?
>
> A little bit of noise on one of the clock inputs could make it look like
> it's dividing by 8, when in reality it is dividing by 10. Problems like
> that can drive ya to drink, hi.
>
> Probably one chip is less sensitive to the noise than the other. How is
the
> circuit built? PCB or point to point wiring? That can make a big impact on
> how it works.
>
> 72,
> Steve, KD1JV
> "Melt Solder"
> White Mountains of New Hampshire
> http://www.qsl.net/kd1jv/
>