Why there is noise when adjusting the screen brightness?
As the screen brightness adjusting is achieved by changing the screen size of the coil current. It is a normal physical phenomena the coil current changes in electricity eventually lead to the coil make voice. Because of the sensitivity of the human ear and different coil quality [...]

How to restore the dark screen to bright?
Lamps have already gone out if you confirm that the screen is brightest and still evident dark than before when used in AC power supply. You must replace the corresponding models of lamp.

Why LCD will become yellow or red?
Using LCD certain period of time, especially always adjust to the maximum brightness, screen aging itself and the lamp will be yellow. Cold boot screen is mainly red lamp aging, you can replace it.