Hey
This happened on a vacuum i aquired for free. It was a Hoover wind tunnel anniversary edition. I believe the plastic royal is its sister machine. Anyways the person gave it away because it wouldn't shut off. I picked it up as a challenge.
I took a shop vac blew off excess dirt and used isopropyl alcohol wiping it down. I cleaned whole bag portion. I toik brush roller serviced it. Wiped evefything down. I don't know if there is a sensor in brush roll areacthat makes it not shut off. I basically cleaned up entire vacuum. It took maybe 15 minutes. I put a new bag and belt plugged in and it was fine. So i think sensor could be a isdue.. If cleaning doesn't fix.
I would unplug use rubber handled screw driver in case power has built up charge. Take off switch make sure no wires are loose. If no then check power cord. If not then use on a different outlet. That should narrow it down. I believe it's a sensor by brush or with hepa filter not sending to shut off.
Les
