Yamaha DTXpress/DTXplorer/DTXtreme

Now then,

just recently bought a dtxpress II and have now discovered what 
appears to be either some sort of brain-glitch or a parameter that I 
need to change.
When playing the closed hat and snare together the snare does not 
trigger.  As you might imagine this can be mildly infuriating.

Please share your thoughts if you have encountered anything like this 
before.

Cheers