The backlight in a laptop's LCD screen may go bad, causing display problems.
The backlight in a laptop's LCD screen is a long, thin lamp that lights up the display as it forms images on screen. In most models, the backlight is mounted to a side of the screen and connected to an inverter board, which is its power source. In a laptop, images are initially generated by the video card attached to the motherboard (also known as the system board). Signals from the video card display the images, using the backlight to illuminate the screen. Common symptoms of backlight failure include dimness, flickering and colored tinges on screen. You will have to dismount the laptop's display assembly to access and replace the backlight lamp.
Instructions
1. Shut down the computer, unplug its AC power cable and remove the battery pack. Locate and remove small rubber seals from the screen bezel---the plastic border framing the LCD screen---to access concealed screws. Pry open the seals with a pointy implement, such as a box-cutter, and undo all screws. If you cannot locate all screws, refer to the product manual about your laptop's specific architecture.
2. Loosen the bezel from the laptop's back shell. Use a flat tool, such as a guitar pick or a plastic ruler, as a lever to loosen the bezel from the screen surface. Starting from the bottom center, insert the tool under the bezel and maneuver to loosen it from all four sides; you may have to undo locking mechanisms such as clips or latches. With all attachments disengaged, pull the bezel away to separate it completely.
3. Observe the orientation of the exposed LCD panel inside the laptop. The panel is usually attached to the back shell, held in place with a metal bracket. Locate and remove small screws from the metal frame to loosen the panel, while holding the top of the screen so it does not fall down. With all screws removed, gently tilt the screen toward you and place it on the keyboard, face down.
4. Detach the inverter board and disconnect its cable. Identify the flat, green board attached to the base of the panel, and dismount it by undoing a securing screw or adhesive. Pick the inverter up and disconnect cables from either end of the board. One of the cables is the power cable, connecting the inverter to the screen's backlight.
5. Unplug the video cable taped to the back of the LCD panel. The video cable is a broad, flat cable, resembling a ribbon, held in place with adhesive tape. Gently unplug the cable from the LCD panel by pulling the cable's plastic head away from its connector on the back of the screen. At this point, the panel is completely detached from the laptop.
6. Raise the LCD panel and locate the housing for the backlight lamp. In most models, the lamp is housed inside a protective casing and affixed to a side of the screen. Carefully dismount the housing from the panel, referring to documentation for any specific instructions. You may have to undo adhesive or other locking mechanisms to detach the housing.
7. Remove the backlight lamp. Once the housing is detached, pick or slide the lamp out and undo its cable connections from both leads. Remove small silicone caps from the ends of the lamp, then desolder the connections to detach the cables. Soldering is a process that forms a strong attachment between metallic components by using a melted metal as the bond, and desoldering is the process of undoing the bond by melting the metals.
8. Replace the backlight lamp by hooking up a new one. Connect cables to appropriate leads on the replacement lamp using a soldering iron, reattach the silicone caps and mount it back onto the housing. Reassemble the laptop's display assembly by attaching the housing to the panel, putting the inverter back, then replacing the panel inside the laptop. Make sure you reconnect all cables.
Tags: backlight lamp, back shell, backlight laptop, backlight laptop screen, bezel from, display assembly, from laptop