I've been turning on my A/C for a few months now with no probs. The other day, a burning smell started coming out of the vents and next thing you know, smoke is coming out as well. I immediately turned off the A/C unit (we have central air). Anyone know the potential cause of this? We're having someone come check it out in a few days but just thought I'd see if anyone had any clues as to the source of the problem.