Hello, I'm having a problem with my phantom. A friend was using it some unfortunately I'm not sure what occurred to make this happen. 3 motors work great and respond to both joystick controls 1 receives power and seems to respond to the throttle and yaw but not to the pitch and roll. I've tried holding onto the phantom and giving it power and the motor will sometimes stutter and the red High Intensity LED Light below it will flash. Any suggestions? Thanks!