Please help! Maestro Boomerang suddenly out of order...

[soulboogaloo]

Hey guys,

I'm the happy owner of a Maestro Boomerang BG2. I use it extensively for 3 years now, and last day, during a rehearsal, it just didn't work anymore 
A few minutes before, it was ok, then I played again, and it was wrong. I mean, I can still hear the sound, but it doesn't make "wah wah" anymore. It's more like it's stuck in a frequency.
I opened it and had a look inside, chasing bad soldering or something, but didn't notice anything suspect 
I have a digital multimeter, but honnestly, I don't even know what to test, and how to test it!
Any advice would be really appreciated!

Btw, I found a site called Banzai Music which sells 50k pots and 500mh inductors, just in case I had to swap those parts...

Thanks guys!

[soulboogaloo]

  Oops... I'm going to reply to myself, because I found what happened! Actually the plastic gear (with the teeth) around the pot shaft was not tightened anymore, so the pot didn't turn!
I tightened it again and it's ok!
I just worry a bit about the robustness of the plastic gear, I hope it will not loose again!