Problems Modifying Behringer VB300 Vibrato Pedal with External Footswitch

[Jimmy J]

Hi! I am trying to add an external momentary foot pedal switch to a Behringer UV300 Vibrato Pedal.


I want to be able to put my foot down on the external foot switch and the pedal will momentarily engage the circuit until I lift my foot.


This is what the built-in pedal switch does (it’s a momentary switch), but I want to be able to engage it from a simple emote footswitch on the pedalboard.


The pedal (like the Boss VB-2) has three switch modes; Unlatch, Bypass and Latch, with the first and last working as monetary switches to engage the vibrato when the foot is on it.


I soldered two wires from the switch wire-points on the back of the PCB to a 1/4” TS jack.


I then plugged a momentary foot switch in (I have a bunch, this one is an old Ensoniq).


The problem is that the pedal works fine without the foot switch plugged in using the pedal's own switch, but not with the external
footswitch plugged in.


I can’t figure out what I am doing wrong?


Thank you!

 

[Bio77]

Looks like the momentary switch in the pedal has 4 terminals? You should use your DMM to figure out what is not-connected/connected in both states of the switch. You might need to move your added wires or add a second set.

 

[Bio77]

Also check that your external momentary switch is the correct type, i.e., normally open versus normally closed.

 

[Jimmy J]

Hey thank you so much! I did check the foot-switch, and it is correct, but (forgive me for asking) what do you mean by "You should use your DMM to figure out what is not-connected/connected in both states of the switch. You might need to move your added wires or add a second set."? My knowledge of electronics is pretty limited. I do have a multimeter somewhere here. I figured (probably wrongly!) that the monetary switch was like the momentary SPST switches that I see in Arduinos and such (like the ones below). They have four terminals, but only two are functional, and the third and fourth terminals just do the same thing as the first two. They just seem to make them with four terminals so they can be mounted on the PCB? Thanks again!

 

[Jimmy J]

Also on this particular pedal (thank you Behringer) the LED on it doesn't seem to work like a normal pedal LED. I can't tell what it does, but it certainly doesn't seem to let you know when the pedal is on or off for some bizarre reason???!!!

 

[Bio77]

Hey thank you so much! I did check the foot-switch, and it is correct, but (forgive me for asking) what do you mean by "You should use your DMM to figure out what is not-connected/connected in both states of the switch. You might need to move your added wires or add a second set."? My knowledge of electronics is pretty limited. I do have a multimeter somewhere here. I figured (probably wrongly!) that the monetary switch was like the momentary SPST switches that I see in Arduinos and such (like the ones below). They have four terminals, but only two are functional, and the third and fourth terminals just do the same thing as the first two. They just seem to make them with four terminals so they can be mounted on the PCB? Thanks again!

View attachment 78260

You would use the continuity setting on your DMM to see which posts on the switch are connected/not-connected when pressed/not-pressed.

 

[Jimmy J]

Hey thank you!

I'll try that.