NAD T550 ....make sure disc tray is open, go to "set-up" menu,go to "password" press enter. input the numbers 5978, press enter, a block will appear then enter the numbers 92 then press the audio button then the resume button then press enter. the block will now show "region change code 0000", enter the numbers 550* , the * being the region code. e.g 5501,5502. press enter and the player will close the tray and shut itself down. re-start the player and its ready to rock.