No square signal [SOLVED]

I’m not getting a square signal on the pin marker H in the signal path image that’s in the assembly instructions. The sawtooth signal on G sounds fine. The sub-oscillator signals on I and J are also missing.

Any suggestions on what might be wrong here?

For the sub-oscillator:

Do you have a sawtooth signal on IC11 pin 1? Is the voltage on IC11 pin 14 equal to +5V and on IC11 pin 7 / 2 equal to -5V?

For the square:

What is the voltage on IC9 pin 7?

Do you have a scope?

I have a sawtooth signal on IC11 pin 1 which sounds identical to the signal on IC10 pin 1.

After pushing the ICs firmly down in their sockets once again I now also have square signals on H, I, and J. It still doesn’t end up in the final output when I turn then Mix pot to square or try to add the sub oscillators.

Voltages on IC11 check out.

Voltage on IC9 pin 7 is +3.3V.

Don’t have a scope; testing audio path with a wire attached to the signal input on the mixer.

After making sure all knobs are in a sensible position I seem to have solved the problem.

The problem was that I had both the PW and the PW Mod knobs open all the way clockwards resulting in no square in the output. Is that normal?

That’s right! Typically modular systems allow you to tune the PWM into cutoff-this gives you enough latitude to deal with the offsets that may be introduced by your mod sources (and in Anushri’s case is a clever way of turning off the internal VCO when you just want to use external audio or the DCO)-better than the Minibrute which will only let you manually set the PW down to 10%-not very pulse-y at all.

Awesome. Might be one for at the botton of the assembly instructions. :slight_smile:

Sory, I got carried away for 3 hours in a black hole created by a proto I’ve just managed to get working.

Anyway, I think what happened is also that the sync was enabled and the VCO frequency was below the DCO frequency. This prevented the VCO to do one full cycle ; and thus trigger the counter implementing the sub oscillator.

Heres a pic of Olivier on his way to fix the proto:

OOOO! New proto, can’t wait for news, did someone say testers, programmers, there will be a programming test, now I’m confused.

@pichenettes Seriously, don’t apologise for that!

It might help to add a short “first set your knobs like this before you start troubleshooting” section to the bottom of the build instructions for dumb guys like me. :slight_smile: