What to do if the LED screen goes black

First of all, it is necessary to determine whether it is the motherboard problem of the LED screen or the backlight problem, and check whether the indicator light responds. If the light is off, check the power section of the motherboard.

Use a multimeter to measure the working point of the main power supply of the LED screen and whether the fuse is blown. If the fuse blows, disconnect the power. Use resistance gear to measure the absence of short circuits at each mains operating point. If there is a short circuit, carefully check the wiring (whether the copper foil of the circuit board is short-circuited) and various related parts (whether it is damaged or even tinned). If there is no short-circuit phenomenon, you can refer to the white screen phenomenon to repair to ensure that the voltage and signal input and output of each operating point are in normal working condition.

If the LED screen motherboard is in normal working condition, please check the backlight board:
1. Check the connection between the main board and the backlight board for poor contact.
2. Measure the backlight voltage with a multimeter. There should be 12V power supply voltage, 3.3V-5V switching voltage, and 0-5V backlight adjustment voltage. The switching voltage of the backlight is the most important. If there is no voltage or the voltage is too low, check whether the output level of the single-chip microcomputer and the working state of the triode are normal, pay attention to no short-circuit phenomenon, and replace all parts if necessary.
1) Check if there is no short-circuit soldering between the main chip and the connector (pay attention to the chip pins, chip resistance and connector, especially the flat socket).
2) Check for poor contact between connecting wires such as flat cables from the screen to the motherboard.
3) If necessary, replace the motherboard, cables and even the screen to find out the problem.

Measure the ground voltage of each LED screen key. If the voltage is too low or 0, check that there is no short circuit in some lines from the keyboard to the microcontroller, whether the open circuit and pull-up resistors have wrong values and soldering, and whether there is poor contact between the seat and the connecting line. Watch out for damage to the key itself. Enbon