Under normal circumstances, a blown fuse proves internal line supply problems. Since the power supply to operate at high voltage, high current, power grid voltage fluctuations, surges can cause momentary increase in the supply current, so that the fuse is blown. The focus should check the power input of the rectifier diodes, high-voltage electrolytic capacitors, the inverter power switches, etc., and check whether the breakdown which this component, open, damage. If the fuse blows, you should first review the various components on the board, look at these outer elements There are no burnt paste, there is no electrolyte leakage, if the above is not found, then the switch with a multimeter to measure whether the short-circuit breakdown. Special attention is required: must not be isolated when a component is damaged, replace direct boot, this is likely due to other high voltage components is faulty, for all high-voltage components must conduct a comprehensive inspection of the circuit after measurement, in order to completely exclude blown fuse failure.