2. What should I do if CLASS A is abnormal?

How do I restore CLASS A to factory settings?

1. With the unit powered off, long press the front-panel power button, then flip the rear rocker switch on. After power-up it will enter upgrade mode, and the system will restore factory settings in the background. Short press the volume knob to exit, or power off and restart.

What should I do after CLASS A triggers over-temperature or over-current protection?

Power off and restart, or wait until the temperature drops, then power on and use it as normal.