Analogman POT clone Trouble Shooting :: Haaalp!!!

[modernage]

A buddy of mine has a pedal I built a while back, and has started to act up and make noise. He said it didn't happen all the time, but the noise was loud enough to where the the pedal wasn't usable at all when it did happen. When he came down to Nashville from Cincinnati he brought the pedal with him so I could check it out and fix it. Well we hooked it up and nothing, it was dead quiet and work just like it should. We were both puzzled that we couldn't get it to reproduce the noise. He left the pedal with me and I played with it for the next week or two. Never could get it to act up. Opened up the pedal and nothing seemed odd.

Sent the pedal back to him because he wanted to use it for a gig he had coming up. Plus I didn't really know what else to do since there didn't seem like there was anything to fix. When he got it back he said it was worse than before. It got to the point where now it is making noise every time he plugged it in. I gave him a list of things to check to narrow down whether it is the pedal or something in his rig (guitar cables, patch cables, power supply, weird interaction with other pedals, etc) since it only acts up with his setup. The pedal is definitely the problem.

He made some videos which I will post below. I'm pretty sure it's a grounding issue. It sounds pretty bad. I think I'm going to have him mail it back to me so I can check it out in person, but want to have a game plan before it gets here. What do you guys think, and what should I look for when it arrives? Maybe it's something he can fix? If soldering is involved than I'm going to have to be the one to fix it though. This is the first pedal I've built that has started actin a fool, so I don't have a lot of experience with troubleshooting. It'd be good to get some of you champs involved, and get your opinions.


[youtube]http://www.youtube.com/watch?v=T6LLOyDxODE[/youtube] [youtube]http://www.youtube.com/watch?v=txQoI8mVilQ[/youtube]

Thanks bros!

[mysteriousj]

The good news is that at least there's probably nothing wrong with the actual PCB. (Since it makes basically even the same sound when powered off and in bypass). So I'd say it's probably one of two,

1) Faulty GND. For some reason Ground isn't ground, could be a loose wire or bad connection. Did you solder a GND wire between the two jacks? - Sometimes it's hard to rely on GND through the enclosure with some jacks. A

2) Stuffed 3pdt? Might also explain why it was working.. and then not. They get a little like that when they're temperamental. If you've got a multimeter check each pole connects and then disconnects.

[crazynoises]

I don't know if your buddy has tried this, but have him loosen the input and output jacks and maybe give each a slight turn. Sometimes they spin around a little with all the constant plugging and unplugging and the inside part of the jack ends up touching something or a wire gets twisted in such a way that it ends up touching something.

I mean, it's at least worth a shot.

[eatyourguitar]

I could almost bet money that it is the 3PDT. when they start to break or if something gets in there, you can have intermittent problems. a better test would be for him to ground the tip to the sleeve of the cable that is plugged into the amp. it should be dead quiet. then touch the side of the sleeve to the metal on the outside of the jack while the tip is still grounded to the sleeve. you can do it with a ring on your hand or anything metal. then do it again with the power not connected to the pedal. when he touched the tip to the ground on the pedal in the video, he did have his hand on the sleeve. skin conducts electricity. in theory, one conductor will not ever have any electrical potential to another conductor that is floating (open circuit). the fact that he can just touch tip to pedal ground and get more hum suggests that the amp is mains earth referenced AND the power supply is passing an AC signal.