Kaoss pad dead channel. Repair ideas?

[autotel]

The left input channel on my kaoss pad 3 has gone mute. I checked for continuity between the connectors and the board, and they are all well placed. The worst part, is that I find the same with the mic line. It looks like something more complicated than just a loose wire.

This unit has traveled many times by airplane and it might've been mistreated; but the nature of this problem looks a lot like a component failure.

I hope somebody out there have some ideas, because I love it, and I'd like to have it back. I appreciate suggestions, heuristics for checking the defect, schematics of how it is wired, etc.