Ron you old bugger, I have to give my very best attention for sure, when the $hit hits your fan.
First thought --- Does not appear too expensive as it closes, but does not reverse, but I gather does grunt/try in reverse. The previous post suggesting a balance spring problem makes good sense. Give it a helping hand when you give it the necessary, and observe all of the mechanical stuff involved.
Whatever you can fix it.
Don’t panic.
Follow your nose.
Do not use that big hammer.
Contemplate and open one or two.
Report your findings here for plan B, which may involve shocking electric stuff.
Meantime, howsat for now.
Thanks will be due only when the old girl can lift her skirt.
Old Fart.