News:

Forum may be experiencing issues.

Main Menu

Dist+ DOA -- tested fine

Started by lincolnic, December 24, 2013, 09:11:48 PM

Previous topic - Next topic

lincolnic

So today I went to box up this Distortion+ I've had waiting around forever. I checked it on my test rig first, and everything was rockin'. I proceeded to wire it into the enclosure, and when I went to flip it on for the first proper time: nothing at all.

Even stranger, when the pedal is engaged, the LED lights up but then immediately fades to nothing. I'm using the same power supply as I did when I had it on the test rig. I checked continuity on my 3PDT, and that's all as it should be. I do have bypass signal. I didn't break any wires in the boxing (have continuity there too). The PCB's not touching anything (I mounted the pots via extra diode leads, so it's happily floating). There's no continuity between +9V and ground. The only thing that changed between testing and boxing is that I removed the metal can LM741 and shortened the leads -- I'd left them at full length in the socket to make sure it tested properly. As far as I can tell, it's properly seated in the socket. Could I have somehow killed the IC while trimming the leads? And if I did, why would this affect the LED behavior?

I need some more eyes and brains on this, it's endlessly frustrating. Here's a picture of the guts. (It may be hard to see, but there's a wire running from the sleeve of the DC jack to the sleeve of the input jack, and a second wire from the input sleeve to the 3PDT.) Any ideas would be greatly appreciated. Thanks, guys.


rullywowr

Quote from: lincolnic on December 24, 2013, 09:11:48 PM

It may be hard to see, but there's a wire running from the sleeve of the DC jack to the sleeve of the input jack, and a second wire from the input sleeve to the 3PDT.

What you just described sounds like a dead short.  Sleeve of the DC jack = positive... sleeve of the input jack = negative.  Connect the two together and....

:)



  DIY Guitar Pedal PCB projects!

lincolnic

Quote from: rullywowr on December 24, 2013, 10:36:47 PM
Quote from: lincolnic on December 24, 2013, 09:11:48 PM

It may be hard to see, but there's a wire running from the sleeve of the DC jack to the sleeve of the input jack, and a second wire from the input sleeve to the 3PDT.

What you just described sounds like a dead short.  Sleeve of the DC jack = positive... sleeve of the input jack = negative.  Connect the two together and....

:)

I may be using the wrong terminology here - I'm never sure what "sleeve" means in context of the DC jack. But I assure you that it's wired according to the standard MBP diagram.

rullywowr

Sleeve means the outside of the plug and tip means the pin.  The dc plugs used for pedals have the pin negative and the outside (sleeve) positive.

Just double check that this is how you have it. A dimming led means there is probably a short and the power supply is shutting down.



  DIY Guitar Pedal PCB projects!

lincolnic

Thanks for clearing that up. As I said, it is wired according to the standard MBP diagram. You can check the picture if you don't believe me!

I agree that the dimming LED means something's up with the power, but according to my DMM there's no continuity between power and ground. I'm not sure where else to look - I'm going to try reflowing the +9V joint on my DC jack since I'm out of other ideas!

pryde

I once had a similar build with this symptom (no effect signal, engage and LED lit for a second then faded out). I found it was a poor ground solder lug on the 3PDT. Maybe reflow ALL those again and feed a bit more solder in there for good measure. Worth a try.

lincolnic

Thanks for the suggestion, I'll give it a shot tomorrow when I take another swing at the DC jack.

m-Kresol

what kind of power source are you using? I have this crappy thing with a lot of output jack adapters. The point is that you can flip that thing around to give you -9V on the sleeve. Almost killed my first Overdrive with that.
Make sure that you have +9V using your multimeter (at the output jack and the pcb)
I build pedals to hide my lousy playing.

My projects are labeled Quantum Effects. My shared OSH park projects: https://oshpark.com/profiles/m-Kresol
My build docs and tutorials

lincolnic

Got it working! Turns out the culprit was a cold solder joint on the sleeve of the input jack. Thanks for all the suggestions, everyone! Build report to follow.

jimilee

Great tp hear, if it works on the test rig, but not in the box, you can almost always guarantee it's an issue with the off board wiring. I have, and probably always will continue to do this myself!
Pedal building is like the opposite of sex.  All the fun stuff happens before you get in the box.