I assume you mean 4024, not 4040.
It depends on how old your PCB is. I believe there was an issue with
layout that had to do with the clock for this circuit. I think the
diode might have been in the wrong place. Search the messages. I
think Richard Brewster wrote about it.
I had the same problem with non-clocking, but at very low
frequencies. Basically the 100N capacitor forms a high pass filter
and stops clocking the 4024. I suppose the transistor change, wrong
parts values, or even the PCB error could all be contributing to this.
I changed mine to a level shifter and eliminated the transistor. I
don't know if you problems are similar but the details are at:
http://modularsynthesis.com/cgs/bi-n-tic/bi-n-tic.htm
Dave
--- In cgs_synth@yahoogroups.com, Anthony Rolando <goldenechos@...>
wrote:
It depends on how old your PCB is. I believe there was an issue with
layout that had to do with the clock for this circuit. I think the
diode might have been in the wrong place. Search the messages. I
think Richard Brewster wrote about it.
I had the same problem with non-clocking, but at very low
frequencies. Basically the 100N capacitor forms a high pass filter
and stops clocking the 4024. I suppose the transistor change, wrong
parts values, or even the PCB error could all be contributing to this.
I changed mine to a level shifter and eliminated the transistor. I
don't know if you problems are similar but the details are at:
http://modularsynthesis.com/cgs/bi-n-tic/bi-n-tic.htm
Dave
--- In cgs_synth@yahoogroups.com, Anthony Rolando <goldenechos@...>
wrote:
> On my scope I can see that after a certain point it stops getting
> any lower in frequency and when turned up to a certain point I lose
> pulses at the input of the 4040. The pulses die at around 3.9khz
>
> I used a BC550 instead of the BC547, but those are pretty similar
> transistors.
>
> Any tips, or tricks to calibrating this circuit? Is this just
> typical behavoir?