You can test your radio simply by connecting a battery to it and a RC servo (i.e. no controller attached).
If the servo moves, then the radio and battery are OK.
Then you could keep your radio connected to the battery. Connect ch1, ch2 to the controller and ch3 to the servo. If the servo still moves, then the radio is still ok and probably sending pulses to the controller.
If controller still doesnt respond, take the servo that has signal wire separated (per previous post) and touch the pin 3 or 4 on the controller connector. If the servo moves and the controller still says no ctrl, then it may be a fault with the controller.