I had an accident recently with my phantom 3 and luckily still fly , but the camera gimbal not stabilized horizontally. (in the video you can see how it behaves ) . I disarmed the yaw motor and in that moment fell like dust parts of the magnet, that was the reason why when one moved his with the hand a cratchy noise was heard . If the camera is tilted sounds and looks the motor unsuccessfully tries to straighten , but if I help him with my hand to straighten then is heard trying to stop. With these symptoms that you think is the problem? the magnet ? the motor? the motor controller? The other axes work well , I'm thinking to verify my diagnosis the roll motor exchanging in place of the yaw motor, but I'm not sure that can be done . I listen to suggestions, thanks and regards !!!! Excuse my bad English , I hope it is understood .