It is most likely either the board that controls the tray or the ribbon cable that attaches to the tray. Over time, the ribbon cable wears and eventually breaks. One of mine has the opposite problem, sometimes it won't open all the way or it will pause for like 30 seconds before it closes. There is good and bad news. The good news is it can be repaired and the cable is only like $20, if that is all it is. The bad news is, if you take it to a service center, it will likely be a minimum of $100 just to look at it and then in labor to fix it, at which point you could practically buy another player.
