Powerbook G4 17" Screen Flicker

I've searched all around and can't find any answers so I figured I'd post. My Powerbook's screen flickers on initial start up, when the apple logo and the white screen come up. If I move the screen during boot up it flickers slightly, but when it fully loads leopard it stops flickering but only on battery. When the laptop is plugged in, it flickers with the slightest movement. I'm very confused hopefully someone can help me