I do not know your TT but it may be the motor capacitor gone bad. That is the only reason I know for a single phase motor to change direction on its own. On the VPI mk4 I owned the regular motor had a yellow run cap. You could see it if you pulled the motor and bracket out.
Most times if a run cap go's bad your motor is going bad also but not always. A cap cost a lot less to replace than the motor so try it.