PVX 15p Powered Speaker Stops Producing Sound

[orion2099]

I have a pair of Peavey PVX 15p powered speakers. I have only used them for solo acoustic gigs (one vocal + one acoustic guitar, running off of a small mixer). At a recent gig, one of them was working perfectly fine during soundcheck but once I started the set, there was no sound coming out of it. I tried swapping all of the cables out, powering it off and back on, switching channels and outputs on the mixer, etc. Nothing worked. A few days later I hooked it up to the same mixer at home, and played music off of my phone and it worked perfectly fine. Ran it for 30 minutes or more, at high volume, with no issues. Then I took it out to a gig today and it did the same thing as the last show. It worked perfectly during sound check but come showtime, no sound. What could be causing this??