Every laptop screen has a built-in backlight lamp. The backlight lamp is a tiny light bulb inside the LCD screen that lights up the screen. Without a properly functioning backlight, your screen will appear dim, or completely black. Repairing the backlight means replacing it. Since the backlight is located inside the LCD screen, replacing it requires dismantling the display panel and LCD screen. If you're not careful, you can damage the screen during this procedure.
Shut down your Sony laptop using its current operating system. Disconnect the AC power adaptor from the laptop. Disconnect and remove any external storage, data or networking devices. Remove the battery pack from its compartment on the bottom side of the laptop. Make sure all potential power sources are disconnected from the laptop. It is never a good idea to work on your laptop with any type of power connected to it.
Open your display panel as far as possible. Use a small, flathead screwdriver to remove the rubber screw covers from the front display assembly's front cover. Remove the Phillips-head screws revealed by the rubber covers. Separate the front cover from the display panel with your fingertips. You may have to use a guitar pick, or flathead screwdriver, to pry the front cover from the laptop.
Remove any screws from either side of the LCD screen that secure the screen to the display panel casing.
Locate the inverter board inside the bottom edge of the display panel just below the LCD screen. Disconnect the cables from each end of the inverter. Peel away the sticky tape securing the inverter in place. Remove the inverter from the LCD screen.
Grasp the top edge of the LCD screen. Tilt it forward until you can access the back side of the screen. Disconnect all ribbon cables from the connectors on the back side of the screen. Lift the LCD screen out of the display panel assembly. Place it face down on a clean, flat work surface.
Peel away the large strip of foil tape along the lower edge on the screen's back side. This tape reveals the backlight lamp. Locate the plastic, Phillips-head screw in the lower right or left corner of the screen's back panel. This screw secures the backlight in place. Remove the screw from the screen, and pull the bad backlight lamp out of its slot on the bottom of the screen.
Reverse this procedure to install your new backlight lamp, and reassemble your Sony VAIO laptop.