LCD (Liquid Crystal Display) is now one of the devices that can be seen everywhere, and the amount of industrial use has increased with technology! Now, industrial industries have begun to use industrial control LCD screens, although clear, there will always be white screens. So, how to solve the white screen failure? LCD industrial control LCD screen boot black screen, blue screen failure is a very common phenomenon, black screen, blue screen are system or hardware problems, and the display boot white screen failure-usually LCD industrial control LCD Failure of the screen itself.
—: Cause of failure:
LCD industrial control LCD white screen failure may be caused by three aspects: LCD panel drive circuit problems, LCD panel power supply circuit problems, poor screen cable contact, motherboard control circuit problems, etc. The industrial LCD screen can be turned on normally, indicating that the backlight and the high-voltage generating circuit are working properly, indicating that the LCD panel has not received a driving signal; if the screen disappears after shutting down, and then a white screen occurs, it may be a problem with the power board.
This shows that, no matter whether it is turned on or off, as long as the power is plugged in, the high-voltage generating circuit is in working state, and the backlight is always lit. In other words, the high-voltage generating circuit is no longer controlled by the switch, that is, the switching signal sent by the main board to the high-voltage generating circuit is out of control. Since the switching signal sent by the microprocessor of the main board generally needs to be controlled by several transistors, the fault may be the damage of the transistor that controls the switching signal.
Two: fault repair:
1. Disassemble the shell, and then check whether the screen cable interface is loose or not connected properly.
2. Then switch on the power supply, and then use a multimeter to measure whether the power supply voltage of the screen line interface is normal. If the power supply voltage is normal, check whether the timing signal and driving signal in the LCD panel drive circuit are normal; if it is not normal, then check whether the fuse resistor or fuse inductance near the output terminal of the screen line is open or damaged. If it is damaged, just replace the damaged component.
3. If the fuse resistance or fuse inductance near the output terminal of the screen line is normal, then check whether the output terminal voltage of the DC-DC voltage conversion circuit that supplies power to the LCD industrial control LCD screen is normal. If the output voltage is abnormal, check the fuse resistor, PWM controller, switch tube, inductance coil, filter capacitor and other components in the power circuit, and then replace the damaged components.
4. If the voltage at the output terminal of the DC-DC voltage conversion circuit is normal, there are damaged capacitors and other components between the output terminal of the DC-DC voltage conversion circuit and the screen line interface. Check and replace the damaged components.
5. If the power supply voltage of the screen line interface is normal, then check whether the timing signal and drive signal in the LCD panel drive circuit are normal. If it is not normal, check the output signal, input signal and power supply voltage of the chip that generates this signal to determine whether the drive chip is damaged. If it is damaged, just replace it.
