i'm buy new adapter (miniDisplayPort - DVI F Unitek) last week, first connect and everything works great :).
unfortunately next day I can't connect external monitor. I don't know why :(
Any ideas? Thanks :)
In order to track the problem, please provide the output of these commands when you connect your external monitor (the external monitor must be powered on, and ready to receive DVI signal - Also make sure your external monitor is still functional):