Quote Originally Posted by RidingWaves View Post
It's one of the four DC motors that the F4 uses, the one that charges the aperture lever AND one cycle of set of shutter blades.

I've had this happen twice to one body, fixed once, and once to another body. Still awaiting diversion of repair budget on that one.

Funny enough, my former shooting partner with two F4 with nearly same amount of wear (5-7 years of hard wedding use) it has not happened.

I attribute this to my use of Continuous High motor setting *every time* and her use of Single *every time*.

As I know it and you can search it, the stepping of the motors is different in S, Cs, CL and Ch.

I'm certain that my constant use of Ch has led to this.
I didn't know that the motor does the stop down of the lens. I thought although the motor would charge the shutter mechanism but then after that it's spring operated. I love the high speed motor drive in both my F3 and F5 but I never use the continuous mode. I always have them on S mode.