Power adapter manufacturers: How to determine where the power adapter is damaged?

With the popularity of smart mobile devices, power adapters have become one of the essential necessities of life. In daily use, power adapters may be damaged. What are the common reasons for power adapter damage? The editor will take you to understand the following reasons;
 

The first: the output voltage is too high

The output voltage is too high generally comes from the voltage stabilization sampling and voltage stabilization control circuit. In the closed control loop composed of DC output, sampling resistor, error sampling amplifier such as TL431, optocoupler, power control chip and other circuits, any problem in any part will cause the output voltage to increase.
 

The second: the output voltage is too low

The main reasons for the low output voltage: the performance of the switch tube is reduced, resulting in the failure of the switch tube to conduct normally, increasing the internal resistance of the power supply and reducing the load capacity; the filter capacitor is poor, resulting in poor load capacity of the power supply, and the output voltage will drop once the load is connected; the switch transformer is poor, not only causing the output voltage to drop, but also causing insufficient excitation of the switch tube, thereby damaging the switch.
 

The third: the fuse is burned out or blown up

Mainly check the rectifier bridge, each diode, switch tube and the large filter capacitor on 300 volts. The fuse may burn out and turn black, or it may be caused by a problem with the anti-interference circuit. It is particularly noteworthy that the fuse burns out due to the breakdown of the switch tube, which usually burns out the power control chip and the current detection resistor. The thermistor can also be easily burned out together with the fuse.
 

The fourth type: line failure

Line failure includes power cord damage and poor contact due to oxidation of the contact port. Focus on checking whether the input and output lines are powered. If it is a line failure, it can be solved by replacing the power cord.