I'm not sure. It is 5 years old. It displays when I initially turn on the MacBook but after a minute or so, it dims and stays that way until I either wake up the MacBook after it sleeps for a period of time or after the computer has been off for a while. I'm sure a $50 replacement part and the patience to replace the suspected faulty part will fix it, but I need to just go ahead and get a new one. Like I said, it's five years old. In the meantime, it's connected via a VGA adaptor to an old LiquidVideo LCD display that I bought long ago when I was using Windows PCs. It's better than nothing....