Common faults and maintenance of chargers and power adapters!Chargers and power adapters are must-haves in modern life,but what are the common faults of chargers and power adapters?How to repair them?The manufacturer of juyuanhai power adapters will take you to find out together,which is convenient for life!
1.Line failure
Line faults,including damage to the power line,no power supply,oxidation of the contact port,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 cord.
2.The output voltage is too high
Too high output voltage generally comes from the voltage regulation sampling and voltage regulation 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 with any part of it will cause the output voltage to rise.
3.The output voltage is too low
The following are the main causes of low output voltage:
1 Switching power supply load short circuit fault(especially DC/DC converter short circuit or poor performance,etc.),at this time,first disconnect all loads of the switching power supply circuit,and check whether the switching power supply circuit is faulty or the load circuit is faulty.If the load circuit is disconnected and the voltage output is normal,it means that the load is too heavy;or if it is still abnormal,it means that the switching power supply circuit is faulty.
2 The failure of the filter capacitor or rectifier diode at the output voltage terminal can be judged by the replacement method.
3.The performance of the switching tube is degraded,which leads to the failure of the switching tube to conduct normally,which increases the internal resistance of the power supply and reduces the load capacity.
4.The switching transformer is not good,which not only causes the output voltage to drop,but also causes insufficient excitation of the switch tube and damages the switch tube.
The 5300V filter capacitor is bad,resulting in poor load capacity of the power supply,and the output voltage will drop when the load is connected.
4.Insurance burned or blown up
Mainly check the rectifier bridge,various diodes,switch tubes,and large filter capacitors on 300 volts.It may cause the fuse to burn and turn black,or it may be caused by a problem with the anti-jamming circuit.
In particular,it should be noted that the fuse is burned due to the breakdown of the switch tube,which usually burns out the power control chip and the current detection resistor.The thermistor is also easily burned out along with the fuse.
The common faults and maintenance of the charger/power adapter are here.In addition,we should pay attention to the daily maintenance and maintenance of the charger/power adapter,which can reduce the occurrence of faults and effectively prolong the service life.
5.The fuse is normal and there is no output voltage
The fuse is normal,and no output voltage indicates that the switching power supply is not working or has entered a protection state.The first step is to check the starting voltage value of the starting pin of the power control chip.If there is no starting voltage or the starting voltage is too low,check whether the external components connected to the starting pin and the starting resistor are leaking.
If the power control chip is normal,the fault can be quickly found through the above monitoring.If there is a starting voltage,measure whether there is a high or low level jump at the output terminal of the control chip at the moment of starting up.If there is no jump,it means that the control chip is damaged,the peripheral oscillating circuit components are damaged or the protection circuit is faulty.Check the chip,check the peripheral components,and check them one by one;if they are jumping,most of the cases are due to bad or damaged switch tubes.
