happy sailor wrote:
Sorry, I can't help you out, I have a Canon 600 and a Yongnuo 600 so I just got them both out and checked the dials, the Canon one is definitely stiffer than the Yongnuo but both operate very well. I can only think dust or heavy humidity is causing it. I know your probably moving it back and forth to loosen it up and hopefully it will.
Good luck on getting to the bottom of this and please let us know.