I have a DC44 Animal with the same problem. As an electrical engineer, I can tell you that if the power feed circuitry detects ***too much*** current (because of hair buildup etc) OR if there is ***no current*** (because of a broken wire or faulty motor), the voltage to the power head is disabled. That is why we see so many of these things starting and then stopping. In my case, I have a intermittent wire to the head motor that makes or breaks depending on the the position of the swivel head. Sadly, try as I might, I cannot open up the swivel unit that houses the slip rings which would give me access to the broken wire. Does anyone out there know how to do it? There must be a way, but it has defeated me and rather than spend more time on it, I have reluctantly ordered a new head unit.