How to repair a broken power adapter

　　How to repair a broken power adapter

　　1. Tool preparation

　　In fact, the notebook power adapter is not a high-tech product. In fact, the principle is basically the same as that of power adapters such as mobile phones and digital cameras. Anyone who knows some electronic knowledge can repair it. Therefore, we only need a multimeter, screwdriver, welding tools, etc. (Figure 1).

　　2. Disassembly process

　　If the external power supply does not supply power, you can plug in the battery and try. If the machine can start normally, there may be a problem with the power cord or the adapter. Then check with a multimeter to find out whether there is a problem with the power cord to simplify maintenance. Don't try to open the adapter shell at the beginning.

　　First unplug the octa-shaped cable and the connection line of the power adapter (as shown in Figure 2), first use a multimeter to check whether the octa-shaped cable of the power adapter is short-circuited; if so, you must replace an octa-shaped cable. Of course, if the fault persists after replacement, then the power adapter must be disassembled.

　　There are 4 plastic caps on the power adapter. First buckle them down, then use a screwdriver to remove the screws (as shown in Figure 3), and then open the adapter shell. Please note: When removing the adapter, do not damage the shell as much as possible. After the damage, there will be problems such as enhanced electromagnetic radiation, which will affect the stability of the machine. If the shell is damaged, try to repair it.

　　Open the shell, the first thing we see is the shielding layer (Figure 4), carefully remove the shielding layer. Then we can see the internal circuit boards and capacitors and other components. The power adapter, in fact, is nothing mysterious, and there is no principle difference from ordinary switching and voltage regulator circuits. That is, some capacitors, resistors, inductors, switching diodes, power core chips, etc. (Figure 5).

　　3. Find the fault

　　First, check the solder feet with naked eyes, and then check the circuit with a multimeter. If the circuit is intermittent, it is usually a bad contact. Check the capacitor, resistance, and inductance for any problems. If the capacitor is bulging, it is best to replace it in time to avoid hidden dangers. Use a multimeter to check the protection circuit and rectifier circuit. Figure 6 shows the protection circuit. The rectifier circuit is a filter circuit composed of inductors and capacitors, and then enters the switch tube circuit composed of transistors (Figure 7).

　　During the test, the author found that the resistance pin was soldered (as shown in Figure 8), and then repaired it with a welding tool, installed the power adapter again, and started the test, and the problem was solved.

　　It should be noted that if you encounter a problem with a certain capacitor during the testing process, you can buy a capacitor with the same model and capacity (the price is about 5 yuan), and then solder down the problematic capacitor and solder the new capacitor on. That's it.

　　If you find that there is a problem with the IC power chip, you can solve it in the same way. Of course, since the IC chip is definitely one of the most important electronic components in the power adapter, the circuit is too complicated, so I found a circuit diagram inside the power adapter (Figure 9), and look for the fault according to the circuit diagram, which can easily solve the problem. .

　　When in use, because the current notebook power adapter power is about 65 W, the internal heat is mainly dissipated through the conduction of the plastic shell. The surface temperature of the power adapter is still quite high. It is estimated that the temperature is generally around 80°C. Therefore, when you use a laptop, try not to pile things on it, especially flammable materials, otherwise there will be amazing results.

　　4. Finally

　　In addition to the usual maintenance, when buying a laptop or purchasing a power adapter separately, you need to pay attention to the quality of the power adapter. Do not buy shoddy products. Strong quality and good treatment of yourself will be a very good thing. The ending. As for the maintenance of the power adapter, you can usually read more of these information. If your electronic level is limited, especially when welding circuits, you may as well ask a knowledgeable friend to help. Of course, it is best to send it for repair during the early warranty period. s Choice.

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