I'm setting up a new FT plane, using a Spektrum AR637 receiver, a Eflight 40 amp ESC, and several different 9G servos. The throttle and motor control is fine. Spektrum brand servos seem to behave normally when connected to any channel, aileron, elevator, or rudder. But I have tried two different FT branded servos and 3 different Arrows branded servos on the elevator and rudder channels, all of which make random rapid movements and only sporadically respond to transmitter input. I have tried factory reset of the receiver, re-binding, and switching which channels control which servos. Should FT and other brand brand servos work with a Spektrum receiver? Could I just have multiple bad servos? Is there a problem having different branded servos connected to the same receiver? These random movements are not AS3X "fluttering" they are very pronounced random movements with the plane stationary.