General digital meter LCD LCD display is directly driven by A\/D control chip, but the digital meter LCD LCD can not use DC voltage signal to detect, must add AC square wave signal detection, so if the use of DC regulated power supply, or the use of multimeter electric block detection LCD LCD screen is wrong, If the fault of your digital table is that the display is not complete, first eliminate the fault of the LCD screen, you can find the model of the A\/D chip, short connect the V pin and COM pin on the A\/D chip, so that the digital circuit part of the digital table all stops working, at this time all the values on the multimeter display will be displayed, if your screen has a problem, It will definitely display incomplete, but if there is no problem with the display, you can determine that it is A\/D damage.