Tray Won't Open

[Gregavi]

Hi. New to this forum. I have a Pioneer Elite and a Denon Blu Ray Player that are having a very similay issue. The tray will not open unless there is a disc in the tray. Kinda strange behavior. I have taken the cover off of each and find that if I push down a little on the top of the tray while it is trying to open, they both open. I then put a disc in, and they open and close with no issues. Any ideas as to what causes this and what a fix might be? I'm thinking it's the gears that open the tray that need greasing but not sure.
Thanks in advance.

[johns0]

Take off the cover and see if the rubber belt is stretched if it has one.