How to fix my footswitch?

[Guitarfreak]

I hooked up my footswitch the other day and sometimes it fades over to the other channel intermittently.  I'll be playing some clean chords with some chorus and all of a sudden my amp goes nuts and wants to tear my face off!  Is this a problem with the footswitch circuitry itself or with the amp?

I opened up the footswitch and everything seems fine.  Inside there is a switch with three lugs.  A red wire is connected to the middle lug and a white wire to one of the other lugs, the third lug is unused.  The LED cathode is soldered to the side lug with the anode soldered to the center lug through a series resistor.  Everything checks out although the switch itself may be in fact be bad?  Or the amp's footswitch channel is shot.

[GibsonGM]

Seems like maybe the jack or circuitry that does the switching, inside the amp. 
You'd wanna make sure of the footswitch first, though!  See if you can tell if the switch is making reliable contacts by testing it with a DMM....if the cord were bad, or contacts intermittent, maybe that would give you a "1/2 on, 1/2 off" sort of thing as they made and broke contact.  Hopefully you don't have to crack the amp open...

[panterafanatic]

If your amp uses a relay, perhaps that is the issue. I'd check the footswitch first as well, although even an analog meter should work, I'd unplug the footswitch and hook up the resistance setting. Thats the nice thing about analog meters, you get to see the pretty meter move.

[petemoore]

 Everything checks out although the switch itself may be in fact be bad?
  Map it with the DMM, create drawing for both or all switch states.
  Wiggle the lugs while testing between any two lugs that seem to connect.
  However, "Fades over" doesn't fit with what mechanical switches usually fail-to [instant drop out, scritching intermittencies, partial dropout till whapped etc.].

[Guitarfreak]

I think scratchy intermittences about fits it.  I don't have a DMM, but for all the work I do and the fact that I'm an engineering major... I probably should?  Hah, anyway, if I did have one, what would I be looking for?

[theehman]

Could be broken solder joints on the footswitch jack.

[GibsonGM]

As simple as testing between the tip and barrel of the plug that goes in the amp....hook the DMM to those points, note reading, operate switch, note the different reading.   If it's in the "off" position, and then there is some 'bounce' going on, it means the cable is shot, or the switch needs to be replaced, etc....Don't forget to plug the switchbox in, and take voltage readings across those red/white wires and post them.   Watch the voltages for change when you're wiggling on the cable and lightly tapping the switch.

If there is no discernable problem with the switchbox/cable, then the issue is in the amp. I'd say 8 out of 10 times, it would be bad connecting cable or switch, but relay problems can and do happen.

[Guitarfreak]

Thank you!