Laptop LCD screen dark is described that you can only see vague image when adjust the maximum brightness, and the screen backlight does not shine, if not look closer, it would like a black screen. Indicator lights are lighting and flashing normal after boot, you can see the harddisk indicator is working, also can hear the voice into WINDOWS, if connect an external display to laptop. The images in external display is normal. This failure is called laptop screen dark failure, and it is the most common repair. Laptop screen turns red is also belongs to some class failures. Common causes and maintenance are as follows:

1: High voltage panel is damaged: High voltage panel is responsible for change DC voltage into 1000V high voltage which is light tube needs. Coil, the chip will be easier for aging or burning at high temperatures working for a long time. The solution is replacing, the effect of the original and alternate will be the same if not with the light.

2: The light tube problems. The light tube aging or short-circuit will cause the display dark, it is common for light aging. Generally because of the long-term use or collisions in the process of using(The light tube life is from 3-5 years if using normal). Sometimes the laptop LCD screen appears red when you booting, which is equivalent to warm, and it is not so obvious after into the new system. This process may continue for a long time before they are completely dark. Of course, there is no sign of screen become dark. Sometimes it is due to lamp connectors and cable short-circuit between the cold solder joint by ignition. You will see a small piece of black shadow in the screen corner after a good screen be held. The problems caused by light tube can be solved that only need to replace the lamp. That’s really a meticulous work requires a certain skill.

3: Screen cable problems. Screen cable break also a reason causes dark screen. Laptops are folding, the screen cable will wear when closing, and some design models used for a long time would give rise to breaking the screen.

4: Motherboard circuit failure. We talked about the the high voltage panel is responsible for power supply to screen backlight, and its supply is generated by the motherboard. Supply problems on the motherboard also caused dark screen failures. The reason is Lid switch damaged on the motherboard cause backlight are turned off. And there is a failure of opening the signal, it ia controlled by the graphics card, this is very rare.