① Check whether the power cord and the positive and negative terminals are connected tightly, and whether there is any false connection or missing connection;
② Except for the power cord and grounding wire, remove all the wires, power off the host and restart it to see if it recovers. If it does not recover, it is judged that the module is damaged, replace the main controller;
③ If the main controller resumes work after restarting, it is judged to be a black screen caused by communication interference; then check that the communication line and the host "A, B" terminal and rail voltage terminal are incorrectly connected or missed; whether the communication shielding line is connected in series according to the requirements, and Single-point grounding was performed.
