This machine came in with a complaint that the brush was not turning. I’ve not done one of these before so first had to figure out how to get it apart. I now have it connected up with with the pcb for the DC motor hanging loose. If I push in the red button on the device under the board the brush motor comes on for a few seconds with lots of blue sparks then stops. Is the red button some kind of TOC reset or just a switch? If it’s just a switch does it need to be held in to stay short circuit?