1. The whole panel of the full-color led display unit board is not bright: check whether the power supply and signal line are connected; check whether the verification card can recognize the interface; if the red light of the verification card flashes, it cannot be recognized; check whether the light board is connected to the verification card Same; check whether the light board is the same as the verification card; check whether 74HC245 is suitable for virtual welding short circuit; check whether the corresponding ENable signal input/output pin on 245 is virtual welding or short circuit.

2. When scanning obliquely, the stacking rules are staggered and flashing images: check whether there is a disconnection, virtual soldering or short circuit between the signal input ports a, b, c, d and the signal input port 245; check the signals a, b, and 245 c. Whether the output terminal of d is disconnected or soldered; check whether signal 245 is disconnected or soldered; check whether signals a, b, c, and d are short-circuited or whether signal a and ground are short-circuited.

3. If one or more lines are completely lit, there is no brightness: check whether the lines between 138 and 4953 are disconnected, soldered or short-circuited.

4. When doing internal scanning, light up two or more lines at the same time (usually twice, rule): check whether the signals A, B, C, D are short-circuited; check whether the output 4953 is short-circuited.

5. When the full-color LED display is fully lit, check whether the control pin of the corresponding module is short-circuited, replace the module or a single light source, and single or multiple points do not light up (irregular).