How can i fix my grundig ST 63-725/8?

All of the channels which i had stored have now de-tuned themselves, seems like the stereo mode has changed (on its own!). Everything on the remote works, except for the tuning button. It doesnt seem to be a problem with the remote, as the tuning button will still call up the text menu when pressed with text on.
Is there some sort of a manual reset on the tv i can try? I *think* i know how to fix the problem with the channels, but need to get into the tuning menu to start with!