How to solve the problem of the air pump in the cup printing machine?

How to solve the problem of the air pump in the cup printing machine? The air pump in the cup printing machine cannot start normally. There are several inspection methods:
1. Check if the start button and stop button (normally closed point) of the air pump are functioning properly.
2. Check if the paper counter of the cup printer has reached the preset number. If it has reached the set number of papers, the counter will flash. Press the reset button to reset the counter before starting the air pump.
3. Check if the AC fuse in the control box is blown (located on the left side of the AC contactor).
4. Press the start button of the air pump and check if the D8 indicator light on the circuit board is on. If the indicator light is on, use a multimeter to measure terminals 54 and 51 of the circuit board in AC mode, and check if the meter displays 220V. If there is 220V, check the AC contactor; If there is no 220V; Check if the screw fuse of the circuit board is blown.