Sharkfin Build

[TheMilksteak]

Hey guys, I'm hoping someone might be able to help me here. I recently built the madbean sharkfin but and my wife spent hours handpainting an enclosure and i can't get anything out of the pedal but a huge squeal when plugged in.  I've tried different wall warts and all that, replaced IC's etc.  Still just a louda** squealing sound.  I've built about 20 other pedals (not from madbean) etched and tagboard yadda yadda.  I've done my fair share of debugging but I can't find much info on the squeal when power is connected.  I never put a battery clip in it so I can't test it with a battery but several wall warts have all had the same sound.  Any have any clues?  Bad transistors or bad batch of transistors?  I tried swapping most out and am pulling my hair.  Was going to go through with an audio probe tonight and hope that helps find the sulprit bt I figured I'd ask you experts first to get an idea... thanks in advance.

[Bret608]

Squealing makes me think it has to do with the charge pump. Which chip did you use there?

[Govmnt_Lacky]

1) Do you get the squeal when the pedal is BYPASSED, Input and Output jacks installed, and powered up?
2) Do you get the squeal when the pedal is BYPASSED, Just the Output jack installed, and powered up?
3) Do you get the squeal when the pedal is BYPASSED, Just the Output jack installed, and not powered up?

Now... follow the above steps with the circuit in the loop.

This will eliminate your Input and Output jacks, their wiring to the switch, etc.

[darrenw6000]

im with bret on this

[TheMilksteak]

Thanks guys. I checked the charge pump too.  It was real hot.  Every solder point was like perfect but I just decided to buy a new board. I pulled a trace trying to desolder for the hundredth time.  I should've just tagboarded it but now I'm just annoyed with myself and wanna finish. Plus the enclosure already done for it so I figured what the hell.  I was switching between the max1044 and tc1044. Both seemed to have the same effect. Maybe it was ground loop.  To me this was a fairly easy build so I don't know what the hell happened I just hope it doesn't happen again.  Argh.  Thanks for all the help fellas

[Bret608]

No problem, and I hope your next build of this goes better! I've got a board but haven't built it up yet; otherwise I may have been more help. I do wonder if the 12v zener was screwed and just overloading the charge pump or something.