I have the receiver and tape deck but dont have the controller. When I plug it in it defaults to the am radio function. If i put a tape in it plays and everything works fine but I have no control over any of the functions loke volume and am not able to access fm stations. Is there a way to step thru these functions manually. I dont see any access door on the front that opens When I push the step button on the front it goes to the next preset am station. is there a work around without the controller ?  Thanks.