Details of switching power supply in maintenance

　　When repairing the switching power supply, there are some details that need to be paid attention to, which can effectively reduce the difficulty of maintenance, and the problem will occur in a short time. As a maintenance personnel, first look at the shell of the power supply, and then smell the power supply If there is a smell of paste, ask the user again if there is any abnormal phenomenon in use, and finally use a universal test to check whether the voltage is normal. Finally, after passing the test, you can quickly find the problem. Repairs and may be able to accept the cost of repurchase. Check to see if the fuse is blown. Most of the power supply problems in the Chinese market are blown fuses. By opening the shell of the power supply, it can be seen that if the fuse is not found, it is necessary to check whether the PCB board is cracked or not, and whether there is any burnt on the board surface. In fact, the cracking of components is the second problem. After eliminating these two reasons, it is necessary to proceed to the next step.

　　Take a sniff to see if there is a mushy smell inside the power supply. The paste is because the power supply is working, the heat is serious, and the external heat dissipation is not done well. If the paste is damaged, the board surface may be damaged, and the problem of capacitor diodes is also frequent. For people , maintenance becomes easier.

　　Ask users questions in use. Consumers generally have a better understanding of the problems that will occur during use, because he is the party concerned, ask what symptoms were there before the problem occurred, and whether other maintenance operations were performed during use. The cause of the occurrence, and then repairing it is easier.

　　Use a multimeter to measure the capacitor voltage. The multimeter is an indispensable device in the maintenance of switching power supplies, because it can timely find out whether the voltage is stable through gas. It should be noted that even when the power supply is removed, there is still more than 300V of voltage inside the capacitor that has not been released. Once it is touched, it will still be dangerous, and the maintenance personnel need to pay attention. When testing with a multimeter, the resistance should not be very low. If it is very low, it is likely to be caused by a short circuit after the diode and capacitor are burned out. It is also appropriate to measure the resistance of each component to see if it is damaged. When the performance is normal, the general capacitor will have the pointer swing when measuring.

　　The next step is to measure the appliance. When measuring, first check whether there is a phenomenon of burning the insurance when charging, and whether the individual components emit smoke. If the above phenomenon occurs, you must immediately cut off the power supply. In fact, maintenance should be performed by professionals. For home users, it is quite dangerous to disassemble the charger at will and operate in a random operation room without clarifying the principle and experience.

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