i have and arducopter 2.0 with 2.0.49 fw. 1 week ago all was fine, stable fly but today I cannot fly well. One motor spin more than others 3 motors and if i don't stop it with my hand it crash. I don't know why, i haven't change nothing and now it is't stable. I try to reinstall firmware but nothing, try to reset and erase to default but nothing, try to change the esc and redo esc manual calibration but nothing.
How can i resolve?