Faulty Sync button...

My sync button started behaving strangely last night.
It is the one on the left hand side (by deck A/C)... for some reason it wont stop triggering!

It's exactly as if I were to continually jab at it randomly, which has the upshot of constantly enabling the SYNC function on that deck, which in turn makes the track jump around out of time and the whole thing generally unplayable. :(

I've had to disable the SYNC on that side and beatmatch manually for now.

Any ideas what could of caused this?
:confused:
Anyone got an idea how I can FIX it?!

Thanks..