Yamaha DTXpress/DTXplorer/DTXtreme

Hello,

I'm looking for help with a problem I just started having about a week
ago.  I have the dtx II's and use the dual cymbal for my ride/2nd
crash.  Lately, the ride will work fine for a couple minutes, but then
get real quiet or not respond at all.  As I play it, it play at the
right volume on some hits, quiet on some, and not respond at all on
others...there's no way to know what sound I'll get.  Obviously this
is a pretty big problem, as I need to be able to rely on my pads when
I hit them.  Any feedback would be much appreciated.

Thanks