1, the humidifier power adapter line is faulty Line failure, including damage to the power cord is not power, contact bad oxidation and so on. Focus on the input line, the output line is powered. If the power adapter is a line fault, you can replace the power cord, etc. to solve. 2, the output voltage is too low Switching power supply load short-circuit fault, the output voltage side of the filter capacitor or rectifier diode failure, the performance of the switch tube, resulting in the switch can not be properly turned on, so that the power supply resistance increases, load capacity decreased.
3, the output voltage is too high Power output voltage is too high generally from the regulator sampling and regulator control circuit.
4, the fuse is normal, no output voltage The power supply is normal and no output voltage indicates that the switching power supply is not working or is in a protected state.
5, insurance burned or blown up To check the rectifier bridge, the diode, switch and 300 volts on the large filter capacitor and other parts.