wah pedal shorting out?

[stump_jumper]

I'll preface this in saying I am very new to this so apologize if what I am explaining doent make sense :oops:

I completed a "vocal mod" to my gcb-95 wah pedal. I first tried changing the resistor to a higher value, and once that work proceeded to replace the resistor with a 100K linear trimpot. Everything worked as expected, until I tried to mount the trimpot in the steel casing of the pedal. What I did specifically, was a drill a hole in the casing, and mount the trimput from the inside so that the adjustment knob protruded through the drilled hole and was exposed on the outside of the case. (The idea being that it would allow me to easily make adjustments).

Once I did this, the wah stopped working when the switch was engaged (i.e., when the wah circutry and trimpot were put in play). What happens is the guitar chord cable ends (the metal part) touch the casing and i hear a popping and the guitar sound disappears. If i wiggle teh guitar cable and wafer board around, or pull the entiire wafer board out and use it that way, all is well.

So it would appear that the metal case of the pedal is becoming a conductor for the trimpot and the guitar chord then createas a short? Does that make sense? And how can i remedy the problem? Is there some way I could insulate the trimpot perhaps?

Any info would be helpful!

Thanks.

[niftydog]

you obviously used a metal trimpot, yes? what you are describing certainly makes sense.

Go and get a plastic one, or somehow insulate the metal one.

[markr04]

The shaft of the pot should be isolated from the legs by design. But you might have one of the pot's legs touching the chassis on the inside.

1) You can bend the legs away from the chassis.

2) You can also use something to isolate them, such as a layer of electrical tape on the inside wall of the chassis. Put a strip over the hole (2 strips if you have a big pot) and push the pot back through the tape, to the way you had it before. You might need to help the pot along by making a little cut in the tape. The area of the chassis now under the pot's legs should be isolated. Screw the nut back on it and you should be set.

If I were you, I'd do both of those things.

P.S. I did the same mod last year. It was the first DIY I did and now I can't stop building and modding. Welcome to the board. I bet we see a lot more of you around here.