Another thing to check ...
On my one, one of the wires that ran up to the moving assembly was broken internally.
I would say that would be pretty common, the thing is moving a lot ...
I replaced both the wires (from memory there are two, it was a while back) and it’s been faultless since.
Hard to find a break in a wire ... you can put a meter on it and wiggle it around. Or just replace them, only takes a few minutes.
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