How to Check an LCD's Backlight

The backlight in your computer monitor is the bulb that powers the screen. This backlight sits on the back of the screen and connects to a rectangular circuit board on the front of the screen called an inverter. If you want to test the functionality of the backlight, do so through the inverter board.

Things You'll Need

• Phillips screwdriver

Instructions

1. Turn off your laptop and unplug the power cable. Unplug the battery pack from the bottom of the computer.

2. Remove all screws from the plastic frame that surrounds the LCD screen.

3. Pry the frame off of the LCD and set it aside. The rectangular inverter board will now be visible mounted below the screen. This is a circuit board that transfers power from the computer to the backlight. The backlight cable plugs into the port on the right side of the inverter board and runs to the back of the LCD screen, where the backlight itself is located.

4. Unplug the backlight cable from its port at the side of the inverter board.

5. Replace the laptop battery and turn the computer on. Plug the backlight cable back into its port on the inverter to reset the backlight. If the screen stays dark, regardless of the reset, the backlight has failed. If the screen works once you plug in the cable, the backlight is viable. Reverse the steps for reassembly of the laptop monitor.

References

• Screen Tek Inc: Laptop LCD Removal Instructions