Audioengine Speakers Screaming At Me

Came into my office this morning to find the powered speaker (L) of my A5's buzzing louder than a stadium megaphone. cabinet is very hot where the amp is housed.  Woofer was moving like a tidal wave/tweeter seems fine.   Power switch works normally and fuse is intact.   Any ideas?
I should add that these are approx. 3 yrs old, always left on, and have never been overdriven.  
Hmm ... I use the +A2's for my bedroom computer system. They have worked fine for almost two years. I leave them powered on all the time too.  I think I'll start turning them off after use. I don't like the overheating problem you alluded to, that's for sure.s

Why not contact Audioengine via their website and see if they will make it good for you? 

Good luck. 
Thanks, Oregonpapa.  I'm definitely in contact with Audioengine, and hoping to get a response soon.