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Precautions for AC DC switching power supply

June 04, 2022

Power adapter is different from switching power supply. Their specifications, shape, size, precision density, performance and other parameters are different, and their applications are also different. The power adapter is mainly suitable for small electrical appliances and electronics, and the switching power supply is the conversion current equipment that controls the whole switch, which is suitable for all electronic equipment.



In the information age of science and technology, life and work are closely related to electronic products. AC DC switching power supply is also widely used. We often use power adapter. However, there are many misunderstandings. There are certain potential safety hazards in incorrect use.


1. Do not use supply with insufficient voltage and current


This is similar to the taboo on the use of battery packs, but here is from the perspective of the whole machine. Nowadays, the configuration of notebook computers, various medical equipment, LED light strips and other equipment is getting higher and higher, and the power consumption is also rising. Especially the high frequency P4-M machine consumes amazing power. Once the voltage and current of the switching power supply Insufficient, it is easy to cause problems such as A series of problems caused by insufficient power supply, such as frequent non operation of equipment, failure of normal use of equipment, etc


If you are used to removing the battery and plugging it directly into the power supply, it is more likely to cause damage (the battery can play a buffer role here). The worst thing about these problems is that these problems do not appear immediately, but only after a period of time.


In addition, when the current and voltage of the switching power supply are insufficient, it may cause the line load to increase, and the heat of the machine is inversely larger than usual, which is detrimental to the life of the equipment.


2. Do not fall or drown


The internal structure of the power supply is very compact and easy to carry. Although it is not as fragile as the battery, it should also avoid collision and falling. Once, the switching power supply of closed-circuit television fell from a height, resulting in a direct power failure in our home. Later, during maintenance, it was found that there was a short circuit inside.


As for flooding, because most of the power supply is placed on the ground, it is often found after flooding. Therefore, we should form the good habit of using the power supply first and then inserting the plug into the equipment. Try not to put the power supply directly on the ground or exposed, but in a visible place.


3. Avoid poor heat dissipation


Many people attach great importance to the heat dissipation of the device itself, but few people care about switching power supplies. In fact, the power adapter of many machines is not inferior to the heat of the device itself, so be careful not to cover it with clothes and newspapers, and place it in a well-ventilated place. In this regard, we have personal experience, that is, when a device used in the early years was medical power supply, because the power adapter itself generated a lot of heat, it was fully sealed with tape and adhered to the wall. As a result, the heat could not be discharged, resulting in local melting of the surface.


4.Purchase from powerful power adapter factory


Electricity is often inseparable from safety, and for many countries, the standards for power supply equipment are also different. When purchasing power adapter or switching power supply, in addition to the temptation of price, we often need to pay attention to whether the manufacturer provides after-sales service and guidance for you.


The fault of switching power supply is found through self inspection


1. When charging, the power indicator is on, and the charging indicator is orange.


First check that the supply output plug and battery box charging plug are not plugged in. If there is no problem, check that the fuse on the battery compartment is open or making contact with the fuse holder. Also, some models require the battery lock to be unlocked before charging. If all the above faults are eliminated, please consider whether the charger output line is turned on, and use the multimeter voltage stopper (200V shift) to measure the no-load output voltage of the power supply unit, which should be 41-44v 24v 2a power adapter 36v according to the supply and different, if not, it may be that the supply output line is open, and open the charger, replace the output line, and the fault can be eliminated.


Note: When replacing the output cable of the charger, it must be noted that the positive and negative poles of the original machine are not connected.



2. The power indicator does not turn on, and the charging indicator does not light up.


Check whether the input power plug of the power supply is well connected to the power supply, and try to insert the input plug of the charger into a normal power socket. If the condition persists, open the charger case and observe if the fuse in the machine is broken, if not, check if the input wire is good. After eliminating the input line fault, check whether the components near the high-voltage area of the circuit board have virtual welding and whether the fuse holder is in poor contact. The focus is on whether the virtual welding phenomenon exists in the transformer T1, transistors V1 and V2. Also, if R5 or R6 is open, it will also cause a malfunction. If the internal fuse is blown, do not replace the high amp fuse (usually a 2A charger). Emphasis should be placed on D1-D4, V1, V2, R4, R7, D15, D21, if damaged, the same type can be replaced. Please note that when the above parts are damaged, one or both may be damaged at the same time, and sometimes several may be damaged at the same time. During an overhaul, they need to be inspected and replaced one by one before they can be powered up.

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