Internal leakage → check whether the seal is damaged and the spring is not well assembled
External leakage → Loose connection or broken seal → Tighten screws or replace seal
There is noise when power is on → The solid parts on the head are loose and tightened. The voltage fluctuation is not within the allowable range. Adjust the voltage. Impurities or unevenness on the iron core suction surface, clean or replace in time.