SOLVED Part of PT2399 delay circuit responsible for repeats (Madbean Degenerator)

[sticky1138]

Is there a typical spot in a PT2399 delay circuit responsible for the number of repeats?

I built a Madbean Degenerator and everything works perfectly, except the feedback pot is unresponsive, only producing one repeat regardless of position.

I tried replacing the pot, the PT2399 chip and reflowed some of the joints that looked weak, even though there really weren’t any. I adjusted the internal feedback trim, which is used to find the sweet spot without any oscillation, but it also does nothing.

This is my second Degenerator (cool pedal, by the way). The other worked fine on the first try, and I've never encountered this problem with a PT2399 before.

Here are some pics and the schematic:

https://imgur.com/a/0b0AC9w

https://www.madbeanpedals.com/projects/_folders/Delay/pdf/Degenerator.pdf

 

[Bio77]

Not 100% sure, but seems to me that without feedback default would be one repeat. Makes me think there is something wrong in the feedback path. I'd audio probe everything around Q1.

 

[bean]

Yup, Q1 is your suspect. Audio probe the gate and source pins (gate for input, source for output).

 

[sticky1138]

Wow, thanks for the fast replies. It was indeed Q1. I used an SMD adapter as you can see, and I must have had shoddy connections on the pin headers I used to connect it to the PCB. I replaced it with a fresh one and it's good to go!