Radio frozen on Code input

[The Devils Bravo]

Hi Guys,

Dunno if any one can help me here.. a mate of mine has a Renault Scenic
and his radio in it has thrown a wobbly.. basically he removed the fuse and it de-powered the radio on repowering it asked for the code which he input. but didnt accept he has done this numerouse times and it kept comming back invalid. Now the radio allows him to inout the code but wont accept it just goes back to the first number!!?? any ideas would be greatly appriciated.