How to repair common failures of LED backlight?

How to repair common failures of LED backlight?

1) No light and no flicker at boot. In this case, first check whether the connection relationship between the LED backlight board and the screen is correct. If it is normal, check the backlight board circuit. The necessary conditions for the normal operation of the backlight board are the power supply (usually 24V or 12V), the enable terminal, and the brightness input terminal are normal; if the above tests are normal, check whether the fuse is damaged, the drive switch tube is damaged, and the energy storage inductor is short-circuited. According to maintenance experience, the wearing parts are mainly driving switch tubes, energy storage inductors, etc.

2) A dark block or regular indirect dark block appears in a certain area of the LCD screen. This situation is generally that the Caiyi light bar is not lit, and the light bar or backlight board is abnormal. During maintenance, it is generally necessary to check whether the circuit related to this light bar is normal. If it is normal, there may be an LED open circuit, short circuit or abnormality in the connection line or connection socket in the street light string.

3) It will be off as soon as it is turned on. In this case, the protection circuit may have been triggered, usually the LED light bar is open, short-circuited, driving switch tube leakage, etc., or it may be a malfunction of the protection circuit itself.