Trearjerker Wah cutting out in toe down position

[lalaka]

I've got a Tearjerker Wah , every time that I hit the toe down (full treble) position, it cuts out.

Does anyone know what could cause this ?

 

[mkstewartesq]

Sounds like a switch issue if the treadle/pad is contacting the foot switch when you go toe-down. Perhaps the soldering is a little off such that lightly tapping the switch causes a short (i.e., wires so close that they only make improper contact when the switch is lightly bumped), or the switch is just a bit too high such that you are momentarily switching it off/breaking the connection (although not depressing the switch enough to actually "click" the switch into the closed position).

I'd suspect the former (wires making temporary improper contact and shorting) - my Tearjerker treadle contacts the switch a lot when I go toe-down, just not enough to switch it off, and I don't get any signal cut-out unless I choose to push down extra hard to engage the switch to turn the effect off.

Or maybe the switch itself is just defective (i.e., the internals are "switching over" momentarily even when the switch is not fully depressed) and needs to be replaced. But maybe someone else has a better thought.

Mike

 

[lalaka]

Sounds like a switch issue if the treadle/pad is contacting the foot switch when you go toe-down. Perhaps the soldering is a little off such that lightly tapping the switch causes a short (i.e., wires so close that they only make improper contact when the switch is lightly bumped), or the switch is just a bit too high such that you are momentarily switching it off/breaking the connection (although not depressing the switch enough to actually "click" the switch into the closed position).

I'd suspect the former (wires making temporary improper contact and shorting) - my Tearjerker treadle contacts the switch a lot when I go toe-down, just not enough to switch it off, and I don't get any signal cut-out unless I choose to push down extra hard to engage the switch to turn the effect off.

Or maybe the switch itself is just defective (i.e., the internals are "switching over" momentarily even when the switch is not fully depressed) and needs to be replaced. But maybe someone else has a better thought.

Mike

Hey, thank you for reaching out !

I know that the problem is not the switch because when I move the potentiometre by hand, the same thing happens.

 

[mkstewartesq]

Then the issue would seem to be the pot. I can't imagine anything on the board that would cause a dropout only when the pot is at an extreme end of its turn/ But, fair warning, I'm also not the most imaginative person either, and I don't have a keen understanding of how the pot may interact with the other components on the board such as the transistors.

 

[Big Monk]

There is such a thing as setting the gear shaft too tight in toe down such that you are causing intense overtravel, i.e. causing the wah pot to physically push past its max travel.

That could be doing it.

Do you feel noticeable friction or “bounce back” in toe down?

 

[lalaka]

Do you feel noticeable friction or “bounce back” in toe down?

No, I don't feel any friction in thoe down.

 

[Big Monk]

Sounds like a bad/damaged pot.

I’d remove it and take some measurements and see if it goes open at the far end of the travel.

 

[Stickman393]

Hey there!

SO: some things to know about wah pedals.

They generally do not make use of the full rotation of a potentiometer. The crybaby shell itself isn't really designed to go through the entirety of the potentiometer's range. Thats why they tended to use S/Z taper pots where most of the change in resistance occurs in the middle of the sweep.

If there's a portion at the toe town position of your wah pot that cuts out, I recommend loosening up the rack gear tensioner and adjusting your wah pot's gear back counter-clockwise by a tooth at a time until it doesn't cut out any more in the toe-down position.

I've seen this same thing happen with certain wah pots. Generally, it seems the ones that drop down to close to 0 ohms between each ends terminal and the center common tend to be the offenders. Still looking into it and trying to wrap my head around how that works, but there's nothing wrong with adjusting the pot gear back a touch.