Hi

Servos make a humming noise when there stalled or when the polarity is reversed usually followed by smoke as i said in my last post, but hopfully this is clearer are the 3 wires to each plug the right way round?

Particuarly the switch, are you connecting it through the switch when trying it outside the plane?

If you are using the switch both times are you connecting the charge lead to the rx when it dosn't work and the other lead when it does?

Simon