Crashed my P4P, got my P4 out, which I have not flown in a few months. Last time I flew it, it flew great! I only can get 1500 feet and signal loss! RC and Video signals jump all over the place. From 100% to 27 back to 80%, then 0. Then from 0 to 100%. Tried different antennas (have TITAN antennas), no fix. Seems like loose connection in the RC. Without taking it apart, how could I check the antenna connections?