Plug in the power cord and turn on the power switch. The machine is not powered on

A. Power cord problem

The power switch socket is normal, but there is no 220V AC power from the power cord to the AC socket of the all-in-one machine

B. Power switch problem

The 220V input of the power supply is normal. Use the multimeter to measure the AC gear. After the power switch is turned on, there is no 220V power to the power board. Check that the connection cable inserted on the boat switch is correct. In this case, the general boat switch problem

C. Power board problem

The 220V power supply to the power board is normal, turn on the power switch, the indicator light of the driver board is not on, the multimeter DC gear measures 12V, and the 5V output is abnormal and there is no voltage.