This is the power amplifier protection mechanism activated, there is a flashing light at the same time the power amplifier output is turned off. The power amplifier will start the protection mechanism when the following situations occur, including but not limited to: overload caused by short circuit of the output (short circuit of the line or speaker);
The output impedance is set incorrectly and should be set to the position corresponding to the impedance of the speaker;
Working at high volume for a long time causes the power amplifier to overheat; The power supply voltage is too low; A circuit component is damaged resulting in midpoint voltage deviation.