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Ping debug help

Started by don72129, October 30, 2016, 02:42:22 AM

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don72129

I've experienced a problem I haven't had before building pedals and need a little advice.
Building the Ping reverb. I have a good bypass signal and a good signal with the pedal turned on but no effect.
Using an audio probe I found that I have signal to C1 but not through C1. No signal anywhere else on the board. I replaced C1 but still same results. I have good voltage through the board (5.06vdc pin 1 on BTDR-3)
I can send pics of board if needed. 

I have it on my test board now. Here's the debugging steps I've taken:
Voltage- almost exactly the same as Brian's on the .pdf
Flowed all solder points- no bridges (continuity check)
Swapped opamp (TL072) three times also swapped transistor (2n5088)
Doubled checked all values of components
Used audio probe
I also built the Mimik and Glam the same day and tested them with the same test board- works great
Any help would be appreciated
Thanks

m-Kresol

It sounds to me as if the left pin of C1 is connected to ground. Use a multimeter to check that. If it is indeed connected to ground use a magnifier to see if you can find a jumper or solder bridge of some sorts. Could also be at the left pin of R2 as it is connected with C1.

There is a small chance that there is a manufacturing error from the etching process leaving a very fine trace to the gnd layer. If you have excluded everything else you could use a scalpel to scratch around the two pads trying to find and cut it. obviously you need to be careful not to cut any of the traces that are supposed to be there.
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

don72129

Ok so I check the left pin of C1 and R2 to make sure it wasn't connected to ground. Everything shows to be good. I also used a razor blade and carefully scraped around the suspect pins. No positive results. I've lifted the left pins of C1 and R2 off the board and connected them leaving right side pins connect. That didn't work either. I'm going to walk away for a few days and come back to it. Thanks m-Kresol it was good advise


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