Got a renault espace with

got a renault espace with blaupunkt rds rad cas , had flat battery , recharged it and reentered the radio code it works but have an annoying beep that goes up and down with the volume , thought it was the rds but no , tried taking battery off to re do code but after no battery for an hour put it on again and it didnt ask for code and still the annoying beep every 2 econds how can i get rid of it ??? plesase