To repair a laptop backlight, the backlight will need to be replaced. In general, the screen is the most expensive part of a laptop to replace because it is made up of so many intricate components. Most people will replace the entire screen, because replacing the backlight (or CCFL: cold cathode florescent lamp) is a comprehensive and meticulous process.
Flip the laptop with the bottom side up and remove the battery. Flip the laptop screen side up.
Open the laptop and look on the front bezel in front of the keyboard. This bezel should gently pop off once the screws that hold it in place are removed.
Flip the computer back with the bottom side up. Remove the screws that lock the bezel down.
Flip the computer back with the top side up. Gently pop the bezel off. Place it aside.
Unscrew the two to three screws holding the LCD into place on the inside of the laptop.
Remove the LCD and gently pull up the LCD cabling that is attached to the laptop motherboard.
Remove the rubber bumpers and the screws underneath them to take the LCD out of the plastic casing.
Spray all the dust off of the LCD with the compressed air before starting.
Remove the sticky tape and foil from the back of the LCD and set them aside so it can be reused when reassembling the LCD.
Remove the sticky tape aside from the backlight cables.
Remove the circuit board carefully. Do not bend or tweak the circuit board. Any damage to it will make it useless.
Place the screen on its side and remove the metal frame latches that secure it to the LCD and the plastic frame. Every side of the frame will have latches; unlock them all gently with a small screwdriver.
Detach the metal frame and LCD away from the rest of the components.
Remove the clear layered screens on the inside.
Remove the metal cover from the CCFL backlight.
Remove the backlight cables from the screen.
Remove the backlight lamp and reflector from the screen.
Remove the reflector from the backlight.
Put on your latex or rubber gloves and detach the leads that connect to the CCFL backlight. CCFL backlights are considered mini florescent lights. Inside the lights contains mercury. Without the latex or rubber gloves, the mercury would absorb in through our skin.
Remove the insulating tape from both sides of the CCFL backlight. Use a soldering iron to detach the backlight from the leads.
Solder the leads to the replacement CCFL backlight.
Take the screen inverter and connect it to the cabling for the CCFL backlight to make sure the light successfully turns on.
Unplug the screen inverter and turn off the system. Reassemble the screen, plug the LCD in and test it.
Article Source: ehow.com