Locked Disc Tray

The remote that I have is a Sony RM-Y909, and it does not have the "O Return" button that is required to unlock the disc tray. Somehow, someone in my family managed to lock the tray using this remote, but I cannot determine how to reverse this without knowing the equivalent to the "O return" button from the original remote for the Sony DVP-NS715P DVD Player. Looked for the original remote, no luck finding it, if we ever had one.


Tried unlocking with the O Return function off the face of the DVD player, but no luck. The manual states this must be done with the remote, but I tried it on the player anyway, just out of desperation and to rule out the possibility that it just might work.