Drive/Tray will not open

For DP-558/VR-558/DP-500/DP-508/DP-450/DP-470:

To open the CD tray on the player please follow the three steps below.
1) Press "Eject" on the player, and hold it down!
2) Press the "POWER" (off) button on the players left side 
3) Press the "POWER" (ON) button on the players left side 
Keep the Eject button pressed down until the CD tray opens!

For DP-1000/DP-1500/DP-1504/DP-1100:

To open the CD tray on the player please follow the three steps below.
1) Press "Eject" on the player, and hold it down!
2) Unplug the power of the player, wait 5 sec.
3) Plug the power again of the player.
Keep the Eject button pressed down until the CD tray opens!

For DP-600:

-After the main POWER ON( Red LED is then active) 
-press and hold the default button on the   back panel of the player 
-simultaneously press the stand-by button on the remote 
-(or the STOP button on the front panel on the player). 
-While “Please wait” is shown on in the front panel display
-keep holding the default button  until the player ejects the tray. (Usually around 10-15 secs)