On the first use of my Domino DF 500, after a dozen or so mortises it failed to start or, after many switching attempts, started but quit in the middle of a cut. I sent it back to Festool and they "fixed it"-- they checked boxes for alignment (nothing to do with the problem), calibration to specs (no idea which specs), and did an electrical safety test (tool got warm and had an electrical smell--if it passed this test, I don't know how.). They sent the tool back a couple of months ago and I had a chance to use it again today. I was feeling pretty happy with the first 12 mortises, then on the 13th it would not start, finally did, but quit 1/4" deep. The repair people apparently did not look at the switch or motor. Not impressed. I'm asking for a replacement and hope their quality control has figured this out.