[sdiy] simple TTL programmable counter question (74LS163)

[Michael Buchstaller]

>So, try toss your 47121 out of the loop (I don't see why it should be needed)
>and simply replace it by a simple inverter.


Somewhere in the rest of the board i have an unused gate on an LS00 that i
could use for that purpose. But it did not work, thus i added the ´121 to get the
"falling-egde trigger" instead of a constant level.

Anyway, it seems that for some reason i cannot get the counters to load the programming
inputs, at least not reliably.
If i tie the "Set" input to +5V, the output (and all outputs of any counter) has a rock stable square
wave on it. If i use the "set" input as intended, the frequencies do not change, but the squarewaves
look somewhat "wiggly" on the scope, as if their frequency would wobble a little bit.
Could that be some kinf of a hint ?

TIA !



-Michael Buchstaller