Finished the Egghead baby build and having a bypass issue.

[Diocide]

So I've built 5 1590A builds and this is the first one I'm having an issue with.

I've done due diligence and in stumped. The effect bypasses fine, but when engaged, the led lights up, but there is no sound. At all. Like not even static or anything as the volume and gain are turned up.

I've done all the normal checks and the only thing I can find that's strange is that the "out" pad on the effect has continuity to ground. This seems strange and would explain why there is total silence when engaged.

I had a similar issue on another build, which ended up being explained by the fact I had mixed up the tip and sleeve of the output jack. I've checked, and that is. It the case here.

I've technically mounted the switch upside down from the normal wiring (to make the Led easier to mount), but besides that there's nothing done outside the norm. I've cheek the switch wiring a dozen times and everything is right.

Not sure what my voltages should be at the 4558, but they seem right. Since there are none listed in the build document, I can't be positive. Maybe I've tried the IC when soldering.

Anything else I should look at right off the bat?

[Diocide]

Here's my voltage readings on the IC.

1-4.7
2-4.7
3-2.3
4-0
5-4.6
6-4.7
7-4.7
8-9.3

I also notice that the vol pot has continuity to ground on all three terminals. Maybe the pot is not good?

[darrenw6000]

Did it work outside the box?

[Diocide]

Did it work outside the box?

I only test prototype PCBs outside of box. I know it's a bad habit, but if it's verified, I don't bother.

[jimilee]

Sounds like a sold bridge honestly.

[Diocide]

Sounds like a sold bridge honestly.

It shouldn't be a big deal to undo the pots and flip up the PCB to check it out. I'll probably dot that next.

[wgc]

You won't get any sound if all your volume pot connections are grounded.

Jimi is right, check your solder joints and wiring.

[Diocide]

It ended up being that when I tightened down the nut on the pot, it would twist the body of the pot just enough to cause it to ground out. I held it in place while tightening and the issue seems to be resolved.

[gordo]

Gotta love the easy stuff.  That avatar is going to give me nightmares :-)

[Diocide]

Gotta love the easy stuff.  That avatar is going to give me nightmares :-)

Yeah. It's kinda weird because I couldn't see any of the lugs touching each other, but as soon as I tightened the pot, it would cut out.

My avatar is from an album from a band called Black Pyramid. Awesome band.