Jim:
There is another thread with the same question, but I will repeat the likely answer here:
When this happens again, and it will, just go up on the roof and manually lift the lid off of its gasket, then go back down and turn it on again. It should work again, until the next time tthe polycarbonate cover sticks to the rubber gasket. The newer models just shut down when the lid sticks closed. The older ones force the gear to run against the lift arm until something breaks. The replacement lift arms are cheap due to the large numbers sold. On the Fantastic Vent web site, the first of the FAQs is this very question.
In my 2007 Dynasty (Patriot Thunder clone) 2 of my 3 fans refused to turn on from the multiplex controls, so I went up on the roof and lifted the lids, tried again and now they all work.