LCD ( Liquid Crystal Display), now is one of the devices that can be seen everywhere, and the use of industry has increased with technology! Now, the industrial industry has begun to use industrial control LCD, although clear but there will always be a white screen. So, how to solve the white screen failure? LCD industrial control LCD boot black screen, blue screen failure is a very common phenomenon, black screen, blue screen is the system or hardware problems, while the display boot white screen failure - generally is the LCD industrial control LCD own fault.
Fault Causes:
LCD industrial white screen failure may be caused by three aspects: the LCD panel driver circuit problems, LCD panel power supply circuit problems, poor contact with the screen line, the main board control circuit problems. IPC LCD can be normal boot, indicating that the backlight and high-voltage generation circuit is working properly, indicating that the LCD panel does not get the drive signal; if the screen disappears after shutdown, followed by a white screen, it may be a power board problem.
This means that whether the power is on or off, as long as the power is plugged in, the high-voltage generation circuit is in working condition, and the backlight is always lit. That is to say, the high-voltage generation circuit has not been controlled by the switch, that is, the motherboard to the high-voltage generation circuit issued by the switch signal lost control. As the motherboard microprocessor issued by the switch signal generally go through several transistors to control, so the fault may be the control of the switch signal transistor damage.
Fault Repair:
1. Disassemble the shell, and then check whether the screen line interface is loose or not connected.
2. Then the power switch, and then use a multimeter to measure the screen line interface power supply voltage is normal. If the supply voltage is normal, check the timing signal in the LCD panel driver circuit, the drive signal is normal; if not, then check whether the insurance resistor or insurance inductor near the output of the screen line is open or damaged. If damaged, then replace the damaged components.
3. If the insurance resistor or insurance inductor near the output of the screen line is normal, then check whether the voltage at the output of the DC-DC voltage conversion circuit supplying power to the LCD industrial control LCD is normal. If the output voltage is not normal, check the insurance resistor, PWM controller, switching tubes, inductor coils, filter capacitors and other components in this power supply circuit, and then replace the damaged components.
4. If the DC-DC voltage conversion circuit output voltage is normal, the DC-DC voltage conversion circuit output to the screen line interface between the damaged capacitors and other components, check and replace the damaged components can be.
5. If the screen line interface supply voltage is normal, then check the LCD panel driver circuit timing signal, drive signal is normal. If not normal, check the output signal, input signal and power supply voltage of the chip that generates this signal respectively, so as to determine whether the driver chip is damaged. If damaged, then replace it.
