Blaupunkt Ontario DJ 30?

Hi have a Blaupunkt Ontario DJ 30 which worked really well until my battery went flat. So I went to my user manual and tried to enter in the 4 digit code after the 1 hour wait.

Nothing..... waited another hour... nothing..

For some strange reason the CODE 0 0 0 0 display does not appear.

Does anybody have any advice on how I can get around this, so I can enter my 4 digit code?

Thank-you in advance

Codboy