A Macbook screen goes black randomly, sometimes completely black and sometimes near black (you can still see the GUI).
This happens in OS X Yosemite and also during USB (Mavericks) (Yosemite) install wizards. However the screen remains perfectly bright in the boot selection menu.
As mentioned in the video the model is Macbook mid 2009.
- F1 and F2 keys don't affect the brightness levels. However they appear to help to wake up the screen for short periods of time.
- Battery does not affect the screen state.
- The screen is always bright during the Boot selection menu.
- Screen rotation does not affect the display.
- Display brightness is set to 100% and Power options are set to max with or without battery.
- The problem started after upgrading Mac OS X Leopard to Yosemite.