Does anyone have any idea as to why the servos on my Electrafun Xp (similar to Aerobird Challenger) move back and forth by themselves?

I tried a fully charged batt as well as a partial charged batt in the plane and this is what happens. With the batt in and the Tx turned off the servos will move back and forth continuously as well as the motor turning the propeller intermittently. As soon as you turn the Tx on, the servos and prop stop moving.

Everything was ok 5 minutes before this happened. Yes I did have a heavy landing before this happened , but it has had heavy landings before as well. It has always seemed like the range is not very far about 50-60m before I lose control of the plane.

Could it be the Tx batteries even though they are fairly new, the receiver, interferance from wires internally in the plane? Has this happened to anyone else, and if so, how did they fix it?

Thanks for any suggestions.