First: open the back cover of the LCD advertising machine, and use a multimeter to measure whether the power amplifier on the driver board is powered on normally;
Second: If the power amplifier is powered on normally, the next step is to check whether the speaker connection line is normal;
Third: If the power amplifier of the LCD advertising machine driver board is not normal, then replace the driver board; if the speaker is not normal, then replace the speaker.
Note: Generally, if the connection line of the LCD advertising machine speaker is not firmly connected, it is the easiest to fall off; if it falls off, then use a soldering iron to solder it. If the speaker makes a lot of noise, it means that the advertising machine driver board is damaged, and the driver board should be replaced immediately.
