What caused the screen crash/black, etc ?

1. Please ensure all are getting in power correctly; (+5V and GND, do not mix.)
2. Check and ensure the serial port is in stable connection;
3. The screen black when write parameters, it may be the communication line is loosed, so, please check it again and again;
4. Check the 50PIN row cable is not loosed, and not reverse;
5. Please check the interface definition is the same with HUB, or the screen cannot work normally;
6. When something wrong with the power supply, the LED screen will not work normally;
7. 5V power supply cannot support too many modules, will cause low power, then, the controllers cannot work normally(black screen,crash,or some lines lighten). Also the controller or HUB cannnot work stabely, screen will show “ please add programs ”. 
8. Please check the programs you edit, it has contents in it or not. If there is no content in, also will cause black screen;
9. The scan configuration is not correct.