So I bought an old 20" Cinema Display at a yard sale for dirt cheap. I didn't have any way to test it, but for the price I took their word that it worked great. Now I've got it connected with a Mini Displayport to DVI adapter, but all I'm getting on the monitor is a black screen. My laptop (newer Macbook Pro) recognizes it, but I don't get anything on the monitor. Does this mean the monitor is shot? Or do I need some other sort of connection? Thanks!