By any chance do your 'new' old throttles have a different number of sections on the plug? I tried to use the newer [old] controller with the dynamic braking and 2 insulating rings on the plug with my older non braking power/control strip and the track had power with out depressing the throttle.As soon as I plugged in the correct throttle.[one insulating ring on the plug] everything was good again. Colt.45