Emexar New v4 issues (solved)

[Anonymous]

I bought the Emexar PCB. It looked like it didn’t have as much components as other builds so I figured I might be able to pull it off.

I assembled it. Had a couple of issues that I fixed. Finally  it worked! …… for a couple of minutes.

When I put it in the enclosure it stopped working properly. When It’s clicked off the guitar can be heard in the amp clean tone. When I click the button on the pedal…… the guitar doesn’t make a sound and there is this tap…tap….tap….tap sound in the amp. It’s barely audible.

Any guess what this can be?

 

[Playsforfun]

I’ll take a gamble. It’s a ground issue. Something is backwards or touching where it ought not. Trace all the paths that you created carefully. And check that all op amp pins are seated and soldered properly.

[Anonymous]

Thanks for the reply. That gives me something to aim towards. I will crawl over it when I get home tonight.

 

 

[Barry]

There is no protection on the back of the pots and since you hand wired pots they can easily make contact with the solder side of the PCB.

 

I would also suggest re-flowing solder that is balled up. Even if it is working now it could cause an issue down the road.

 

Also with the Jack on the left, the Tip seems close to the enclosure so that when you insert a plug it might be too close and grounding? Hard to say for sure from the photo but you can simply rotate the Jack a little to avoid that. Additionally I am not seeing a good solder joint on the ground wire connection to the Sleeve lug. You will want to scan all of your off board wiring.

[Anonymous]

Thanks for the help. I got it working last night. I re-soldered the jacks and put electrical tape on the vol. pots.

I also replaced the dc jack. It seemed like it was faulting at times.

Now with this win under my belt I’m on to the zoso pedal! wish me luck.

 

[Brent]

Heck yea!  Congrats on the completed Emexar!  It’s such a good circuit to get your feet wet in pedal building, plus it sounds soooo good.

Running into problems during assembly can be REAL frustrating,  but the satisfaction of successfully troubleshooting an issue and then fixing it is a super satisfying feeling.   It’s a huge confidence builder.

You totally got the zoso pedal under control.  Im sure that you will have success with it.

[Playsforfun]

I knew you could do it. Congrats. And you learned some stuff. The problem could easily have been at the jacks. I fancy myself a decent solderer and like to think that I don’t make mistakes. But soldering mistakes are easy to make. Too much solder is probably worse than starving a joint. For cold solder joints (the ones where you think the component or wire is soldered but you can just pull it right out with a little tug.), my top three to pay extra attention to are jacks, pots and to the ground plane of the circuit board. Each takes a little longer to heat to melt the solder properly. Using flux on jacks and pots works wonders. I don’t know how many folks know that the ground points on the circuit board, including all components that go to ground, are mostly attached to a plane of copper sandwiched between the front and back of the board. If you hold the board up to light you can see them. It can take an extra second to heat up all that ground plane to get a good joint. Something to keep in mind. Each of these problems has got me more than just a few times. Again nice job.

ps. Try an Emexar into a second Emexar.

[mybud]

Yes, echoing these posts, seems like you’re on the right track as far as troubleshooting is concerned.

You might consider testing before boxing next time around. If the circuit works out of the box, it will probably work once boxed up and if not, you’ve eliminated the circuit itself as the potential problem. That means only having to check the offboard wiring (jacks, foot switches, and so on).

Best of luck with the Zoso.

[Author]

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