Yamaha DTXpress/DTXplorer/DTXtreme

Hello all, has anyone had any problems with their kick pad??  

I have been having problems with mine.  Mine seems to go in and out.  I 
am not sure if there is a short or what.  I am using the KP60 kick pad 
that came with the set. 

If I end up purchasing a new one, do you have any sugestions on an 
upgraded or better model?

Thanks

Tim H.