Help Debugging Woolly "Mastadon" Build - ITS GETTING WEIRDER !!!

[Giglawyer]

I built the "Mastadon Fuzz" guitarpcb.com project.  On the board, it just rocks.  When I boxed it up...silence (but the LED works), including no bypass tone.  

So I started experimenting, and here is what I found.  The pedal works fine with evertyhing boxed up EXCEPT the input jack.  If I leave that unscrewed, the Pedal rocks, and I get clean tone when bypassed.  Like below:  



But, if I screw in the input jack - no sound, period:





Any thoughts?  I tried a different jack, with the same result.  I verified that it is wired into the PCB correctly as well.  

EDIT:  Although it should, the back wire on the jack does not correspond with "ground."  It is wired correctly.  I even tried reversing the wiring on the jack just to see, and it wouldn't work at all.

[AS74]

Assuming the black wire is ground on both input and output jacks, you have the input jack wired opposite, grounding the tip.  Try swapping those wires.

[armdnrdy]

Assuming the black wire is ground on both input and output jacks, you have the input jack wired opposite, grounding the tip.  Try swapping those wires.

+1

That's what I see as well.

[Giglawyer]

Yeah, you would think that it might be this easy, but its not.  Black does not correspond to ground. And, I checked this already, thinking that it was a grounding issue, but it is wired according to the diagram.  And, just to be certain, I switched them anyway, and tried it, and it still didn't work. 

Thanks for your thoughts though.  Anyone else???

[JFace]

Check if there is continuity between the jack bushing and the tip contact. You may need a different jack.

[Giglawyer]

I have tried different jacks with the same result.  Thanks, though...

[Giglawyer]

AIGH!   OK, in continuing to tinker with this, I installed the input jack in the hole where the output jack was, and vice versa.  Now the input jack is FINE, and the output jack won't work when installed.  Of course, when not installed, it work great!  WTF!?!   

Any thoughts?!?

[duck_arse]

take both sockets outta the box. measure continuity sleeve to sleeve, then tip to tip. what results? work the bypass switch. what results?

[nocentelli]

I suggest that particular hole is drilled a little too low: When you insrt the jack into the tightened socket, the tip contact bends enough to short out against the box.

[Giglawyer]

Thanks for the ideas.  I fixed the problem, although I did not find the answer.

I used some heat shrink tube around the base of the threads of the jack, and segregated the jack from the box with a rubber washer.  SUCCESS!

I still don't know what the problem was, other than the hole was a little too big.  But it all works, so I am glad for that.

Ugh...on to the next project!  Thanks again to everyone for the help!

[Giglawyer]

take both sockets outta the box. measure continuity sleeve to sleeve, then tip to tip. what results? work the bypass switch. what results?

I may do this out of a sense of scientific exploration.  What would this tell you? 

[AS74]

Isolating the jack still sounds like a grounding issue..

[duck_arse]

it would tell you, for 100% sure and certain, that you had wired tip to tip and sleeve to sleeve, not a combination of both that were fluking some signal through. then you could move on to blaming other things.

[yvarg]

As others have stated, the black and white wires are swapped between the two jacks (assuming both black wires to and from the PCB are either ground or hot). duck_arse's continuity test would confirm whether this is true or not. I feel like the effect wouldn't work at all if that were the case though. Hmm . . .

[Giglawyer]

I really do appreciate the thoughts on this.  I will see what I can find and report back.