Rotel RX-402 receiver, faulty on/off switch

I have a Rotel RX-402 tuner and the on/off button does not work. It is a push button switch type and not a toggle switch. The push button goes in and gets stuck in the ON position. It won't come back out (turn OFF). So I guess it's a mechanical problem. Does anyone know if there are parts available or whether one can be made? Any help would be much appreciated.