Yamaha DTXpress/DTXplorer/DTXtreme

HI....my first post...It feels good to have you all out there...but I 
am hoping someone has an answer to a problem I am having....It seems 
that as of late, my dual zone snare pad has the flu....What I mean 
is, the rim sensor? is not triggering at times....the center trigger 
seems fine...I've messed around a litte with sensitivity on the 
pad,and swapped stereo cords, but no real difference......any 
ideas? ...and again thanks for any and all help....just getting 
started,so I want to say HI from down east Maine...