Troubleshooting method of switching power supply
When it comes to switches, I believe everyone is very familiar with them. Since the switching power supply has entered our family life, it has quickly replaced the traditional linear power supply with its advantages of environmental protection, energy saving and high cost performance, and has been accepted by everyone. Today, we mainly come to understand the switching power supply fault maintenance method.
1. The fuse is blown
Under normal circumstances, a blown fuse indicates that there is a problem with the internal wiring of the power supply. Because the power supply works in the state of high voltage and high current, the fluctuation of power grid voltage and surge will cause the current in the power supply to increase instantaneously and blow the fuse. The focus should be on checking the power input rectifier diode, high-voltage filter electrolytic capacitor, inverter power switch tube, etc., to check whether this component has breakdown, open circuit, damage, etc. If the fuse is indeed blown, you should first look at the various components on the circuit board to see if the appearance of these components is burned, there is no electrolyte overflow, if the above situation is not found, then use a multimeter to measure whether the switch tube breakdown short circuit.
2, no DC voltage output or voltage output is unstable
If the fuse is intact, there is no output at all levels of DC voltage under load. This situation is mainly caused by the following reasons: open circuit, short circuit phenomenon in the power supply, overvoltage, overcurrent protection circuit failure, auxiliary power supply failure, oscillation circuit does not work, power load is too heavy, high-frequency rectifier filter circuit rectifier diode breakdown, filter capacitor leakage and so on. After measuring the secondary components with a multimeter and excluding the breakdown of the high-frequency rectifier diode and the load short circuit, if the output is zero at this time, it can be sure that the control circuit of the power supply is faulty. If some voltage output indicates that the front circuit is working normally, the fault is in the high-frequency rectifier filter circuit
