If the disc tray doesnt open then follow these tips

1)just open the player
2)remove the rubber belt connecting the dc motor
3)you can open the disc tray now
4)if there are any dust particles or obstacles in the door way just clear them up by using the cloth(dry cloth preferred)
5)if you have any greasy material like vaseline,oil,etc then just put that in the door for easy movement of the disc tray

6)if needed change the rubber belt which is connecting the dc motor
7) just reconnect the rubber belt again and then just fit all screws that s all

what s more your player s disc tray will start ejecting like the previous how you were using..

any doubts you can reply me
i am always here to assist you
thank you
bye