Calvin Vai - Help please!

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Archaide
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Post by Archaide »

Hi all.

After some trouble with my build i found a small piece of wire (with help of a magnifying glass and some patience) which was connecting the leads of two resistors. I also found a lead where the isolation was defective and one could see the bare wire. But i'm pretty sure the wire was not touching anything.
So far so good.
It is still not working. The Problem i Have now is that as soon there is a plug in the output Jack, the tip connection goes to ground. Tested with the beeper from the multimeter. No power connected to the Pedal and nothing in the input Jack. Input Jack does not Have this behaviour. Looks like there something wrong with my ground, right?
I Have no idea where to look. Could it be the 3pdt switch?
Does someone Have an idea?
Thanks in advance.
Archaide
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mauman
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Post by mauman »

Try bending the sleeve lug of your Output jack (black wire) away from the path of the cable plug. The plug's tip may be touching it when you plug in the cable. It's OK if this sleeve lug touches a pot, they're both ground.

Make sure the green wire from the tip lug of your Output jack is not touching the DC jack lugs.

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Archaide
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Post by Archaide »

Thanks you very much. It was the tip lug wich was very close to the corner of the case and touched it when a plug was plugged in and bended it slightly outwards. :oops: :slap:
Unfortunately it is still not working. There is guitar sound hearable but burried deep in hisses and other noises. All pots are working. The eq section changes the noises as expected. Drive and presence change the noise as well and Volumen can make the Pedal completly silent.
Does anybody can provide a picture of a populated and working board that i can compare it with mine? I used SMD transistors. Might this be a Problem?
Best regards.
Archaide

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mauman
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Post by mauman »

I think the next step is to use an audio probe to trace the signal from the input jack through the PCB, and listen for where it stops sounding good. That will help you find the problem. There is information about making, and using, audio probes here: viewforum.php?f=91

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Archaide
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Post by Archaide »

Thank you.
Will read this and see if i can build one. Very helpful forum here.👏

In the meantime it would be helpful to have a picture from a working board.
Can anyone provide one please?
I'm New to all this and not sure if i done everything right.
Thanks,
Archaide

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Archaide
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Post by Archaide »

To whom it may concern:
Audio probe?
Check!
Probe.jpg
Now let's find the bug that keeps me from playing.
probe21.jpg

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mauman
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Post by mauman »

Great! Now work your way from the input jack, thru the switch and into the PCB, then left to right thru the schematic.

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