What causes the power adapter to be damaged?

With the popularity of personal smart mobile devices, power adapters have become one of the essential necessities of life. In everyday use, the power adapter may be damaged. What causes the power adapter to be damaged?

First: The output voltage is too high

The output voltage is too high generally from the regulator control circuit. In a closed control circuit formed by a circuit such as a DC output, a TL431, an optocoupler, a power supply control chip, etc., any problem with any of the parts will cause the output voltage to increase.

Second: Line failure

Line failure, including damage to the power cord, poor contact, etc. Focus on checking whether the input line and output line are powered. If the line is faulty, it can be solved by replacing the power cable.

Third: Insurance burns or blows up

Mainly check rectifier bridges, diodes, switches, and large filter capacitors on 300 volts. Causes insurance burnout and blackening, and may also be caused by problems with the anti-interference circuit. In particular, it is worth noting that if the switch causes the insurance to burn out, the power control chip and the current detection resistor will usually be burned. The thermistor is also easily burned together with the fuse.

Fourth: The output voltage is too low

The following are the main causes of low output voltage:

4.1. The performance of the switch tube is reduced, resulting in that the switch tube cannot be normally conducted and the internal resistance of the power supply increases.

4.2, 300V filter capacitor is bad, resulting in poor power supply load, the load output voltage will drop.

4.3, switching power supply load short-circuit fault, this time, first off all the switching power supply circuit load, check whether the switching power supply circuit failure or load circuit failure. If the load circuit is disconnected and the voltage output is normal, it means that the load is too heavy;