If the hair dryer is not electrified, check whether the power supply is loose, it may also be the solder joint falling off, no power, the ability to disassemble and connect yourself, the general hair dryer is not electrified may be because the solder joint is falling off, check it first, if it is not possible to take it to the repair shop. If the hair dryer suddenly does not work during use, it may be because the temperature is too high, the temperature control device automatically cuts off the power supply, and so on, the temperature can be used, and the hair dryer failure can be seen according to the detection quartet 1. Check that the power supply is connected properly. 2. Check that the switch is on. 3. Smell for scorch. The hair dryer is composed of two parts, one is the heating part, the other is the fan part, the current fault is that the fan does not turn without wind. So we play the hair dryer to the cold air gear, so that the heating part is separated from the motor, in order to measure the circuit of the motor part, the multimeter to the resistance file, measure its resistance value, and find that the resistance is infinite, indicating that the line is blocked, the power is not sent to the motor and there is no wind. Open the hair dryer for internal inspection. Measurement line, switch, found that the resistance is zero, indicating that the line, switch is good, because the electric motor is a DC motor, its power is provided after the rectifier bridge, the table to the secondary tube measurement file, measurement of the rectifier bridge, which found two diode resistance is infinite, indicating that the secondary tube is broken. Replace the diode, measure the rectifier bridge, normal precautions: when measuring, pay attention to separate the heating part from the motor part, so as to accurately measure the fault point.