Faulty Input...where to begin troubleshooting?

whitebread47 · Post by **whitebread47** » 01 Feb 2012, 07:34

Hi there, I am an utter noob. I have a couple of projects in the mail (byoc & madbean board + parts) but was hoping to get some help on a prebuilt pedal (not by me). I have a SHO clone and the input has gone finicky on me. It seems like something is slightly loose, as I can nudge it a little and the sound will come back or go away. Like I said, I'm a noob, but I opened her up to see if any of the input solder joints were loose and couldn't see any obvious issues. What do I need to begin looking for?

A little background: I have basic soldering skills and work on my own guitars and other stuff just not pedals thus far, but I know very little about circuits at the moment. As far as tools at my disposal I have a soldering iron and some rosin-core solder. Do I need to get a voltage tester of some sort?

Many thanks ahead of time!

Seiche · Post by **Seiche** » 01 Feb 2012, 10:38

whitebread47 wrote:Hi there, I am an utter noob. I have a couple of projects in the mail (byoc & madbean board + parts) but was hoping to get some help on a prebuilt pedal (not by me). I have a SHO clone and the input has gone finicky on me. It seems like something is slightly loose, as I can nudge it a little and the sound will come back or go away. Like I said, I'm a noob, but I opened her up to see if any of the input solder joints were loose and couldn't see any obvious issues. What do I need to begin looking for?

A little background: I have basic soldering skills and work on my own guitars and other stuff just not pedals thus far, but I know very little about circuits at the moment. As far as tools at my disposal I have a soldering iron and some rosin-core solder. Do I need to get a voltage tester of some sort?

Many thanks ahead of time!

hi, you're best bet would be to post some pictures of the guts, maybe we can spot something on them.

other than that, is the input jack loose? does it improve if you tighten the jack? because it could simply be the jack not getting a decent ground with the enclosure, thus disconnecting in and output jack from each other (the grounds have to be connected). Cold solder joints could also be a problem.

also what makes you assume the problem lies within the input jack? Could the pcb be shorting out on the enclosure when you nudge it? Try to look for possible shorts between components when their position changes (if the pcb is not securely attached to stand-offs or tape, etc.).

whitebread47 · Post by **whitebread47** » 01 Feb 2012, 20:23

Seiche wrote: hi, you're best bet would be to post some pictures of the guts, maybe we can spot something on them.

other than that, is the input jack loose? does it improve if you tighten the jack? because it could simply be the jack not getting a decent ground with the enclosure, thus disconnecting in and output jack from each other (the grounds have to be connected). Cold solder joints could also be a problem.

also what makes you assume the problem lies within the input jack? Could the pcb be shorting out on the enclosure when you nudge it? Try to look for possible shorts between components when their position changes (if the pcb is not securely attached to stand-offs or tape, etc.).

Okay, I have some gut shots ready.

The first thing I checked was the input jack, as I'm used to that issue with amps, guitars, etc. It's tight. I'm only assuming it is a problem with the input, as I have very little experience with effects circuits to go on, so I kind of approached it at the most basic or seemingly obvious level. As you can see in the picture, the pcb appears to be secure and I can see no obvious issues with any solder joints.

I'm making the assumption that a DMM would be a good thing to have in troubleshooting this and handy either way, so I've ordered one that should be here in a few days. Let me know if you see anything that is a problem in these pics.

Seiche · Post by **Seiche** » 01 Feb 2012, 20:40

could the input jack tip be touching the enclosure when you put in the plug? Like when the metal tip bends because of the plug?

is the pcb securely taped to the side or does it move when turning over the effect?

just for the heck of it you could try to reflow the solder joints of the in and output jacks just to be sure there are no cold solder joints or loose wires.

whitebread47 · Post by **whitebread47** » 01 Feb 2012, 22:36

Just checked and the input jack doesn't touch the enclosure when plugged in. The pcb is pretty secure and no loose wires.

By the way, how would one spot and what exactly is a cold solder joint?

Seiche · Post by **Seiche** » 01 Feb 2012, 22:40

whitebread47 wrote:Just checked and the input jack doesn't touch the enclosure when plugged in. The pcb is pretty secure and no loose wires.

By the way, how would one spot and what exactly is a cold solder joint?

cold solder joints are usually matte instead of shiny and don't conduct well or at all. They are prone to failing or don't work from the start. Just reheat the solder joints to reflow them.

whitebread47 · Post by **whitebread47** » 01 Feb 2012, 22:45

Ah, I see. I'm not seeing any non-shiny joints.

Come to think of it there's another clue that may help. Even with the pedal bypassed on my board (with other pedals of course) the sound will go in and out just as it does when the pedal is engaged.

DrNomis · Post by **DrNomis** » 09 Feb 2012, 15:23

If you don't have a multimeter, buy one and use it to check that you have continuity where you should, and that you don't have any short-circuits where you shouldn't have....

whitebread47 · Post by **whitebread47** » 09 Feb 2012, 21:23

DrNomis wrote:If you don't have a multimeter, buy one and use it to check that you have continuity where you should, and that you don't have any short-circuits where you shouldn't have....

Good timing. I just got a multimeter in today, so it'll get immediately put to good use. Thanks!