a friend brought me one with a rx85 I think it was and what he had done was put the hot wire to 8 volts on RX and when you went into TX mode the voltage dropped off, he had hooked it to the wrong location. after hooking it up for 8 volts on tx it worked just fine. I had talked to him on the phone trying to help trouble shoot it and he kept telling me it was hooked to 8 volts. for some reason he would not test it in TX mode.