The phenomenon of white screen indicates that the backlight board can work normally. First, determine whether the main board can work normally. You can press the power switch to check whether the indicator light has a response. If the indicator light can change color, it indicates that the main board is working properly.
1, check the main board signal output to the screen connection cable is bad (you can replace the cable or screen);
2. Check whether the voltage of each working point of the main board is normal, especially the power supply voltage of the screen.
3. Check the line field signal and clock signal (from input to output) with an oscilloscope;
4. Replace with a general-purpose board tester that writes programs. If the light does not respond or is off, it indicates that the board is not working properly.