I have on my desk a TZ30 (half height TK50 drive) and it has a tape inside of it. Powering it up and pressing unload starts a rewind and then it gives up (all lights flash). I'm guessing the tape presense sensor is dirty or otherwise disabled but to get to it I really would like to remove the existing tape. Unfortuately I cannot find how to manually "unlock" the drive. Clues anyone? --Chuck