Chosen Solution
If everything is plugged in and I boot with an external monitor the desktop / login screen appear on the external monitor despite the LCD screen being plugged in. Is it safe to say its likely the LCD then and not the Back Light board?
Press a flashlight against the display do you see the faint image of your desktop and its icons? If you do then its the backlight logic, otherwise you have either a mess-up display cable or the logic board connector, or the display is bad.
