Just took my babied Epi 310UL on a gig last night. Only one speaker is working. The other two move sympathetically but no sound coming out. Any troubleshooting ideas?? The box worked fine the last time I used it. Didn't push it very much. My AI Focus is fine, as are my cables and bass. I love this box and would like to use it for New Years. I guess I could still use an Epi 112UL/110UL combo, or the 210UL/112UL combo if I have to, I just like the 310UL lots.