cassatte adapter for radio not working?

It's because of the way your player protects itself and the cassettes.
Most players will shut off if the leading wheel that moves the tape doesn't turn.
Your adapter will have been designed to allow for this.

I guess that your player requires both leading and trailing wheels to turn as they would when a cassette was moving normally.

Sorry, there's not much you can do except perhaps have a new stereo fitted.

Colin
February 2007