The UK smart device adapter, as an accessory for electrical equipment, needs to be dealt with promptly when it malfunctions. So, how to troubleshoot UK smart device adapter failures? Let's take a brief look together!

How to troubleshoot the failure of the UK smart device adapter?

1. Line malfunctions

There are issues with the wiring, such as damaged power lines that fail to supply power, oxidized contact points causing poor contact, and so on. The key points to check are whether the input and output lines can be powered.

If it's a wiring problem, it can be resolved by changing the power cord or other methods.

2. Output voltage is too low

The following are the main reasons causing the low output voltage:

2.1 Short circuit problem of the switching power supply (especially for DC/DC converters that are short-circuited or have poor performance, etc.). At this point, first disconnect all the loads of the switching power supply circuit. Check whether the problem lies in the switching power supply circuit or the load circuit. If disconnecting the load circuit results in normal voltage output, it indicates that the load is too heavy; or if the voltage output remains abnormal, it indicates that there is a problem with the switching power supply circuit.

2.2 If the filter capacitor at the output voltage terminal or the rectifier diode fails, the determination can be stopped through the swapping method.

2.3 The performance of the switching tube deteriorates, causing the tube to fail to conduct normally, resulting in an increase in the internal resistance of the power supply and a decrease in the load capacity. 2.4 The switching transformer is defective, not only causing a drop in the output voltage, but also resulting in a lack of excitation for the switching tube, thereby damaging the tube. 2.5 The 300V filter capacitor is faulty, causing the power supply to have poor performance under load, and the output voltage will drop as soon as it is connected to the load.

III. Excessive Output Voltage

The excessive output voltage is usually caused by the voltage stabilization sampling and stabilization control circuits. In the closed control loop formed by the DC output, sampling resistor, error sampling amplifier (such as TL431), optocoupler, power control chip and other circuits, any malfunction of any component will result in an increase in the output voltage.

4. The fuse is in good condition and there is no output voltage.

The fuse is normal and there is no output voltage indicating that the switching power supply is not working or has entered maintenance mode. The first step is to check the startup voltage value of the startup pin of the power control chip. If there is no startup voltage or the startup voltage is too low, then check whether the external components and startup resistor connected to the startup pin are leaking electricity.

If the power control chip is functioning properly, the problem can be quickly identified through the above monitoring. If there is a startup voltage, measure whether there is a high or low level transition at the output terminal of the control chip immediately after power-on. If there is no transition, it indicates that the control chip is damaged, the peripheral oscillation circuit components are damaged, or there is a problem with the protection circuit. Replace the control chip and check the peripheral components one by one to conduct the inspection; if there is a transition, in most cases, it is due to poor or damaged switching tubes.

V. Insurance Burned or Exploded

The main inspection focuses on the rectifier bridge, each diode, the switching tube, as well as the large filter capacitors at 300 volts. This can lead to fuse burning and discoloration, or it might be caused by problems with the anti-interference circuit. It is particularly important to note that when the switching tube breaks down, it usually causes the power control chip and current detection resistor to burn out. The thermistor is also prone to being burned along with the fuse.

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