Failure analysis
Switch ON the POWER, turn ON the main switch at the back of the machine, press the "POWER ON" button, the monitor and keyboard lights are off, the cooling fan is not turned, and the machine has no response.POWER ON cannot be activated when the UPS POWER supply and the main switch of the machine are restarted. The output voltage of UPS measured on field is 222V,which indicating that the POWER supply is normal.After turning on the main switch of the machine, the waiting light next to the transformer can be seen from the transformer cooling hole below the machine, showing that AC 220V has entered the machine.Press POWER ON at this time, still no response, suspected the machine internal POWER supply (APS) may be faulty.
Troubleshooting
Open the side cover of the machine, observe the APS panel indicator, only the LPS indicator flashes, and the other lights do not works.According to the working principle diagram of APS, LPS is the preparation indicator light of APS, which should be in the long and bright state.Flashing indicates that the machine is in a protected state.Test the voltage at each connection from the motherboard of the machine, and the voltage deviates from the normal value, so that the lock fault is caused by APS's failure to start vibration normally. Replace the APS, and the machine is in normal use.
