The faults of computer monitors can be divided into software faults and hardware faults. When our monitor fails to display properly, we should analyze the problem to determine whether it's a software configuration issue or a circuitry problem within the monitor. This will help us decide whether to send it for repairs and avoid unnecessary troubleshooting. Based on the classification of monitor faults, the following fault phenomena can occur:

1. Black screen:

   • Check if the power indicator on the monitor panel is lit when you turn on the computer. If it's not lit, check if the power plug of the monitor is properly connected. If the power plug is connected correctly (ensure the power outlet is functioning, try another socket if possible) and the power switch is turned on but the monitor indicator light does not turn on, it indicates a circuit fault within the monitor that requires specialized repair.
   • If the power indicator light on the monitor is on, restart the computer and observe if the host's indicator light flashes and if there are any beeping sounds. If these indications are present, it means the computer has started normally. In this case, check the signal cable connection between the monitor and the host, ensure the 15-pin D-shaped plug connecting to the host is not loose and that the pins inside the plug are not broken, bent, or short-circuited. If the connection is fine (if conditions allow, try using a different monitor or host, as it can quickly reveal the faulty component, including the graphics card), it indicates an internal fault within the monitor that requires repair. Modern monitors are energy-saving and automatically operate in corresponding states and modes based on the horizontal and vertical sync signals emitted by the host, with the indicator lights on the panel indicating the respective states. Typically, an orange blinking light indicates off or sleep mode, orange indicates pause, yellow indicates standby, and green indicates normal display. When your monitor is black, after carefully inspecting and ruling out a fault in the host, it's best not to continuously or excessively power the monitor to avoid exacerbating the fault.

2. Color distortion:

   • Often, this occurs when the monitor does not support the display mode sent by the host, which is higher than the supported mode of the monitor, resulting in a scrambled image that makes it difficult to see clearly. If the monitor has automatic mode recognition, it may be in a black screen state, but the indicator light below the panel will be green. In this case, you can restart the computer in safe mode, change the display mode to 640x480, and then restart the computer to restore normal display. If this method doesn't work, you can delete the graphics card driver in safe mode and reinstall it in normal mode. Additionally, color distortion can occur when there is a fault in the video memory of the graphics card, resulting in distorted images in specific areas while other areas display normally. Although rare, there are cases where a faulty graphics card causes color distortion.

3. Color deficiency:

   • Clearly, there is a lack of red, yellow, or blue color, or the colors are distorted, but the image details remain clear. In this case, if you look at the monitor for a slightly longer period, your eyes may feel uncomfortable or experience a stinging sensation. In such cases, after shutting down the computer, you can check the connection plugs between the monitor and the host, ensuring that the pins inside are not broken (not all pins are missing, only partially exposed), loose, or misaligned (bent towards one side or connected to other pins). (Note that monitors and hosts typically use a 15-pin D-shaped plug, but usually only 11 pins are used, with pins 9, 5, and 11 typically left empty. It's not surprising if some pins are missing, and it's not necessary to compensate for the missing pins with large-headed pins.) Also, check if the graphics card is loose. If these components are in good condition, you can send the monitor for repair. When the entire screen displays red (R), green (G), and blue (B), the internal circuitry of the monitor must be disconnected.

4. White screen:

   • A white screen indicates that the backlight is functioning properly. First, check if the motherboard responds when you press the power button and if the indicator lights change. If the indicator lights change, it indicates that the motherboard is working fine.
   • Check if the connection cable transmitting signals from the motherboard to the screen is properly connected (the cable or the screen can be replaced).
   • Check if the voltages at various working points on the motherboard are normal, especially the power supply voltage for the screen.
   • Use an oscilloscope to check the circuitry for field signals and clock signals (from input to output).
   • Use a universal board tester for writing programs if necessary.

If the indicator lights do not respond or do not light up, it indicates a malfunctioning motherboard:

• Check the voltages at various points on the motherboard, payingspecial attention to the power supply circuit and the power management circuit.
• Check if the power supply is working properly and if there are any blown capacitors or other visible signs of damage.
• Inspect the motherboard for any physical damage or loose connections.
• Test the motherboard with a known working power supply to see if the issue is with the power supply or the motherboard itself.

In general, if you encounter any faults with your LCD monitor, it's recommended to check the connections, cables, and settings first to rule out any software or configuration issues. If the problem persists, it's best to consult the manufacturer's documentation or contact their support for further assistance.