Most like there is a small nylon gear that is either sticking thus not allowing the tray to open right awy even though you pressed the button. there could also be a bad circuit path in the unit. often times because of heat involved in the general operation of the unit the epoxy coating on the circuit board degrades allowing moisture to corrode the board and cause an intermittant short. depending on the age of the player depends on whether it's cost effective to either repair or replace it, however if your comfortable enough in doing the repair yourself then that weill atleast save you the shop rate in labor costs.