My Phantom FC40 dove into the pool (shame on me...), and after opening it up and drying everything thorougly, I started it again. The startup is OK (sound ABCDEF), but there is only yelow light blinking now, even when I turn to GPS mode in the trasmitter; the 2 front rotors work well, and respond to the transmitter, but the 2 rear rotors just "tremble". I tried lubricating it, with no change. What do I do? Do I need to replace the rear rotors or the problem could be in the rotors controllers? I think there must be some issua with GPS, because I suppose the yellow blinking is altitude mode functioning. Any help would be appreciated. In my country there is no authorized dealerships/ repair shops, so I must do everything by myseld. Thank you all.