Fault phenomenon 1: Unit board does not light up. Fault reasons: 1. No +5v; 2. Data cable is broken. Fault analysis and handling: 1. Power supply is broken, replace the power supply; 2. Replace the data cable. Fault phenomenon 2: The entire screen does not light up. Fault reasons: 1. Main controller does not have +5v; 2. No AC power for the entire screen; 3. Computer settings are incorrect. Fault analysis and handling: 1. Power supply is broken, replace the power supply; 2. Check the power supply circuit; 3. Reset.

Fault phenomenon 3: A certain unit is constantly lit in red (or green). Fault causes: 1. There is a problem with the data cable connecting this unit; 2. There is a problem with the corresponding distribution board; 3. A certain unit board is faulty. Fault analysis and handling: 1. Re-insert the data cable, paying attention to the direction; 2. Replace the data cable; 3. Replace the distribution board; 4. Replace the unit board. Fault phenomenon 4: Communication is abnormal. Fault causes: 1. Whether the software settings are correct; 2. Whether the communication line is connected; 3. There is a problem with MAX323. Fault analysis and handling: 1. Restart the computer and turn the display screen on and off again. 2. Reset the settings. 3. Use a digital meter for measurement. 4. Replace this MAX232 chip.

Fault phenomenon five: The entire screen is bright in horizontal lines every few rows, and dark in others. Fault cause: The network cable is not plugged in properly. Fault analysis and handling: Plug in the network cable properly. Fault phenomenon six: The large screen displays normally, but the computer screen is black. Fault cause: The computer settings are incorrect. Fault analysis and handling: Reset the settings. Fault phenomenon seven: The information on the first few screens is normal, but the information on the later screens is abnormal. Fault causes: 1. The screen capacity is limited, and too much information is sent; 2. The storage device has not been erased. Fault analysis and handling: 1. Resend the information, reducing some unnecessary information; 2. Resend the information. Fault phenomenon eight: The information is correct, but the font lacks strokes. Fault cause: The size of the information made does not match the size of the screen. Fault analysis and handling: Remake the information, ensuring that the size is set to match the size of the screen.