One of my Epic 6500 power nozzles had no power when I got it.
I'm not sure if it's the same as yours. I know the part that attaches to the wand is different, but maybe they work the same way internally?
Anyway, on mine, there was a wire that had come loose because of the elbow (or neck?) moving.
I opened up the power nozzle, reconnected the wire, and it worked like new.
It would be great if yours is the same!
Barry