George aka Machintec is your best hope First check power supply voltages I think that the 3 is series 1 iron and the 4 is 2 the controls are simaler to my BTC 7.2 I'v looked at some and I think they have the same servos and the control is much the same but to be sure try to p.m. George he post's in the BPT fourm regulary Kevin |