A month or so ago, the backlight randomly went out on our MacBook. If you look very closely you can see the screen, but it's like you've got the brightness on its lowest setting. The backlight comes on as normal when you turn on the computer, or wake it from sleep, but goes out after about 2 minutes. Other than not being able to see what's going on, the computer works fine. I took it to the Apple Store, who said they'd have to replace something at a cost of £75, which was fine. Just over a week later, they called and said that hadn't worked, and that it was actually the logic board that needed replacing, at a cost of £385, more than the value of the computer. We decided it wasn't worth it. Yesterday however, I took it to a friends and connected it to his monitor, and even though the screen was dark on the MacBook, it came up fine on the monitor. To me, it seems strange that it's a logic board issue when it works fine with an external display. Anyone have any thoughts?