Hello, i tried today to use my dji phantom 1 and i couldnt take off at all. Gps light was green indicating its locked to the satellites, then i gave throttle to it and full power (rotors was fully spinning) but it didnt do anything not even 1cm lift off. What might be the issue? is it a common issue that i might changed something by mistake or maybe the motors may have any issues? Please advice me on how to fix this Thank you!