Common problems and solutions of power adapter

The common faults of the power adapter are generally the following: circuit problems, low output voltage, high output voltage, normal but no output voltage of the fuse tube, burning or blowing up of the fuse. Let's analyze them carefully below.

1、 Line problem

Line problems, including power line damage, no power supply, poor contact of DC head, etc. Check whether the input line and output line can be powered on normally. In case of line fault, it can be solved by replacing DC line or AC line.

2、 Output voltage too low

The following are the main causes of low output voltage:

1. Power adapter load short circuit fault (especially DC / DC converter short circuit or poor performance, etc.), first disconnect all loads of the power circuit and check whether the switching power circuit fault or the load circuit fault. If the load circuit is disconnected and the voltage output is normal, it indicates that the load is too heavy; Or it is still abnormal, indicating that there is a fault in the switching power supply circuit.

2. The failure of the filter capacitor or rectifier diode at the output voltage end can be judged by the replacement method.

3. The performance of the switch tube decreases, resulting in the failure of the switch tube to conduct normally, increasing the internal resistance of the power supply and reducing the load capacity.

4. The poor switching transformer not only causes the output voltage to drop, but also causes insufficient excitation of the switch tube, thus damaging the switch tube.

5. The 300V filter capacitor is poor, resulting in poor load capacity of the power supply, and the output voltage will drop as soon as it is connected to the load.