Setting up for a big gig coming into town and our mixer (Allen&Heath 14x) has developed a right channel main fader intermittent issue. I can get it to work, but seems like I should be able to pull it apart and clean it or something to keep it alive one more time. Our old back-up (cheap ass Behringer) doesn't have enough channels for this group. We used the back-up for a preliminary sound check (very complex set-up) using some splitters and we are not sure if we can get a new one in soon enough. Any help would be very appreciative.