I am trying to sort out one of these for a friend's son. Problem is that the servos go haywire and tail rotor runs constantly when battery is connected. Remove the Gyro Gain connection and the servos are stable and responding correctly to the Tx.
Tail rotor motor was faulty, has been replaced and is correctly wired. The 3 in 1 controller has also been replaced.
Any helpful comments will be greatly appreciated.