Weird shorting problem

[iain]

I have a fun issue with my Pitch Witch build, where plugging in a cable to either input or output causes the whole circuit to cut out (based on the modulation LED turning off... and not back on). On investigation it seems like it also happens when the sockets are held at a particular angle against their holes in the case. It seems to me like a short with probably a very obvious cause but I haven't been able to find an answer so far, can anyone help to put me on the right track?

I've checked through the soldering and can't find any of the usual suspects. The case is a Tayda painted pre-drilled one.

 

[Nostradoomus]

Pics? Was there paint on the inside of the enclosure? If so sand it down to the bare metal around where the jacks are.

 

[iain]

Pics? Was there paint on the inside of the enclosure? If so sand it down to the bare metal around where the jacks are.

Attached some blurry photos, but it is indeed mostly painted inside so I am deploying the sandpaper as we speak, thanks!

EDIT: actually attached now

 

[Nostradoomus]

You may also want to try spinning your jacks a bit so the contacts aren’t close to the enclosure.

 

[iain]

So after a bit of sanding down I get a consistent connection which is good news, something to keep in mind with the painted enclosures in future.

Having been able to turn it on, it seems I've created some kind of a monster:

• No dry signal but a "beat" in time with modulation occurs when pedal turned off
• When turned on the external LED copies the behaviour of the modulation LED (but maybe this is deliberate? if so, I like it!)
• When turned on the guitar signal is intermittent with the modulation "sound" and is not audible in certain positions on the wave selector
• Extremely noisy!

However, I actually kind of love it! Both the modulation and delay sections create some great oscillation and really interesting, often deeply unmusical sounds come out. The only change I made was using a white LED in place of yellow so I'm sure I've wired something wrong elsewhere, but I may just keep it and build a more conventional delay pedal alongside.

Thanks for the troubleshooting Nostradoomus

 

[Nostradoomus]

If you have a TL062 try that in place of the 4558, got rid of the ticking in mine.

Did you clean the enclosure really well before installing the board back in, and the board clean too? Metal shavings are circuit board nightmare fuel haha

 

[iain]

Didn't do the best job cleaning up but now that sound comes out I'll go back and deploy the alcohol swabs.

Have now learned that there is a TL062 along with the usual 72, 84 etc ?

 

[iain]

Comedy update: after labeling the enclosure wrongly I noticed that pressure on the "depth" knob caused the signal to cut in and out, and once I unscrewed the nut all the above problems went away completely. Guess that pot isn't on super straight and the board was being warped when everything was tightened up ?