Speaking of broken things...

When My brother moved out earlier this year, he gave me his cheap set of electronic drums. Since I had no place to put them in this shoebox I call home, I loaned them to my room mate's grandson. He's 14 and wants to play drums like his uncle Jon, and I thought I'd spare his parents some noise by letting him use them.
Anyhoo, one of the cymbal pads has stopped working. His step-dad checked what he could; no loose wires visible, and the cymbal doesn't work with a known good cable.
Does anyone have any experience opening these things up and what to look for? Is it even possible to open them for servicing?