Well, the indicator to me was I think I heard a thump or something, and then I started seeing smoke. The smoke ended up being because the belt had slipped off and was rubbing (burning) against the crank screw. Otherwise, no, there were no warning signs prior to that. Fed great, never burned the wood, never bogged down, never louder than usual. I love the thing, really, compared to my jet 10" jointer/planer.