원문 게시자: Dan ,
Could be software as well. What happens when you do a cold boot up and then put the lid down? Does it go into sleep mode? Also try using the Apple menu option. If it does then something that you are running is not allowing the system to go into sleep mode. In some cases you might have an OS process running (hung) which is causing the system not to go into sleep mode. Most of the time this is what I find is the cause. As far as hardware: The lid has a magnetic switch system which could have gone bad. I don't know where it is in this model (maybe someone else knows).