If the power indicator light is illuminated, potential causes for the keyboard display issue may include:
1. Damage or short circuit in the power supply board;
2. Poor connectivity of the keyboard cable;
3. Damage to the main control board.
If the power indicator light is not illuminated, possible reasons for this failure could be:
1. Absence of input power;
2. A broken fuse;
3. Damaged rectifier bridge.
