BleepingComputer.com: Inverter or backlight?

I have a IBM Thinkpad 600E.
The LCD screen goes black after a min it boots into windows.
Of course if I take flashlight to it, I can see the screen.
I took the screen casing off and I heard the buzzing noise coming from the upper right side of the SCREEN not the INVERTER.
So I am wondering is it the inverter that is bad or the Screen?
cause I thought the inverter buzzed when they were bad not the LCD screen its self.
also Where I hear the buzzing on the screen is not where the back lights are located the lights are on the bottom and left hand side of the LCD screen.