Internal troubleshooting method: 1. No power (black screen): It may be the built-in power supply or the internal drive board of the machine is bad; troubleshooting method: check whether the power output is normal, if there is no power output, you can confirm the power is bad, if the power output is normal, it may be the drive board bad. 2. Fuzzy screen: A certain area of the LCD screen has not been displayed or displayed abnormally is called a fuzzy screen; troubleshooting method: check whether the signal transmission line inserted on the LCD screen is loose and other phenomena that cause poor contact, if this happens Insert the signal cable tightly and fix it, and check whether the problem is solved; if this is not the case, the LCD screen may be defective. 3. Dark screen (no display on the screen, splash screen): The LCD screen is always in a black screen when the advertisement is played. The dark screen or the splash screen is called a dark screen. Solution: Check whether the power output is normal. If the output voltage of the power supply is unstable (the voltage value does not reach 11~12V), you can confirm that the power supply is bad. If the power output is normal, you need to replace the drive board and inverter one by one until the fault is eliminated. 4. If the card is not read, if the cause of the external failure does not exist, the decoder board (integrated board) needs to be replaced. 5. No signal: When the power is on, the words “no signal” appearing on the screen are called no signal. Solution: Check whether the internal video cable and the 5V power cable input to the decoder board are loose. If there is no such phenomenon, you need to replace the decoder board or drive board. After replacement, check whether the fault disappears. 6. After the power is turned on, the screen will automatically play red, green, blue and other pictures in a loop. The troubleshooting method: the signal line is loose or the driver board is bad.