LCD Backlight failure is caused by:
- Inverter Failure - This is a small circuit board that sits under the lcd panel which charges up thousands of volts to power the backlight and the part itself usually costs around £25 excluding fitting.
- Broken Lid Switch - A small machanical switch that can jam with fluff and dust making the system think that the lid is permanently closed preventing the backlight from illuminating. Some laptops have magnetic reed switches which can also stick. We disable reed switches on our reconditioned laptops as these can fail. Resolving this fault often involves stripping the laptop down to get to the motherboard at a cost of £40
- LCD Cable broken - Often weakened by the opening and closing operation of the lid, small wires carrying 3 diiferent voltages (19v, 5v 3.3v) can break preventing backlight from illuminating. This failure will usually come with symptoms of lines and flickering bands on the LCD panel itself. LCD Cables usually cost £35 excluding fitting.
- Physically Cracked Backlight - caused by shock damage this is the most intricate and delicate repair which involves stripping down the LCD panel itself. Backlights are not designed to be changed and sit between 7 layers of liquid crystal glass, diffusers and plastic sheets. The cathode backlight tube itself is extremely delicate as it is made of glass only a few mm thick and spans the length of the screen.
Backlight repair starts at £60 for a standard 12.1" - 15.4" screen.