This is not my picture
http://i.imgur.com/KvdbJ.jpg
See the 11 slits on the inside of the tray, slide them open for trays that have disks and closed for trays that don't have disks.
http://i.imgur.com/KvdbJ.jpg
See the 11 slits on the inside of the tray, slide them open for trays that have disks and closed for trays that don't have disks.