When it comes to switches, I believe everyone is very familiar with them. Since switching power supplies entered our family life, they have quickly replaced the traditional linear power supplies with their advantages such as environmental protection, energy conservation and high cost performance, and have been accepted by everyone. Today, let's mainly learn about the troubleshooting methods for switching power supplies.

The fuse has blown

Under normal circumstances, a blown fuse indicates that there is a problem with the internal circuit of the power supply. As the power supply operates under high voltage and large current conditions, fluctuations and surges in the grid voltage can cause an instantaneous increase in the current within the power supply, leading to the fuse blowing. The key points to be inspected include the rectifier diodes at the power input end, high-voltage filter electrolytic capacitors, inverter power switch tubes, etc. Check whether these components have breakdown, open circuit, damage, etc. If it is indeed the fuse that has blown, first check the various components on the circuit board to see if their surfaces are charred and if there is any electrolyte overflow. If no such situations are found, use a multimeter to measure whether the switch tube has been short-circuited due to breakdown.

2. There is no DC voltage output or the voltage output is unstable

If the fuse is intact, there will be no output of each level of DC voltage under load conditions. This situation is mainly caused by the following reasons: open circuits and short circuits in the power supply, faults in the overvoltage and overcurrent protection circuits, auxiliary power supply failures, the oscillation circuit not working, excessive power supply load, breakdown of the rectifier diode in the high-frequency rectifier filter circuit, and leakage of the filter capacitor, etc. After measuring the secondary components with a multimeter and ruling out the situations of high-frequency rectifier diode breakdown and load short circuit, if the output is zero at this time, it can be confirmed that there is a fault in the power supply control circuit. If there is a partial voltage output, it indicates that the previous circuit is working properly, and the fault lies in the high-frequency rectifier filter circuit