What are some tips on computer hardware maintenance?

Daily maintenance of computers

How to care for and maintain a computer and maximize its service life is a problem we are very concerned about and often face. In this article, we introduce to you the most basic computer maintenance methods and things you should pay attention to, so that your computer can always be kept in a relatively stable state, just like new.

1. Environment

The impact of the environment on the life of the computer cannot be ignored. The ideal working temperature of the computer should be 10℃-35℃. Too high or too low will affect the life of the accessories. If conditions permit, air conditioning must be installed. The relative humidity should be 30%-80%. Too high will affect the performance of the accessories. play, and even cause short circuits in some accessories. For example, when the weather is humid, it is best to use the computer every day or keep the computer powered on for a period of time. Some people think that using a computer less often or for a shorter period of time can extend the life of a computer. This is a one-sided view. On the contrary, if the computer is not used for a long time, the accessories may be damaged due to moisture or dust. Of course, if the weather is extremely humid, for example, if there is water vapor on the surface of the monitor or chassis, the machine must not be powered on at this time. Too low humidity can easily generate static electricity, which is also detrimental to the use of accessories. In addition, the dust content in the air also has a greater impact on computers. The dust is large and will corrode the circuit boards of various accessories over time. Therefore, dust the computer frequently.

Computers also have requirements for power supplies. The normal range of AC power should be 220V±10%, the frequency range should be 50Hz±5%, and there should be a good grounding system. If possible, a UPS should be used to protect the computer so that it can continue to run for a period of time if the mains power is interrupted.

2. Usage Habits

Personal usage habits also have a great impact on the computer. The first thing to do is to turn on and off the computer normally. The order of turning on the computer is to first turn on the peripherals (such as printers, scanners, etc.) If the monitor power supply is not connected to the host power supply, you must first turn on the monitor power supply, and then turn on the host power supply. The shutdown sequence is reversed, first turn off the power of the host, and then turn off the power of the peripherals. The rationale is to minimize damage to the host, because when the host is powered on, the moment the peripherals are turned off will have a greater impact on the host. For a period of time after shutting down, do not turn on and off frequently, because this will have a great impact on various accessories, especially the hard disk. Generally, the time between shutdown and next startup should be at least 10 seconds. Pay special attention to avoid shutting down the computer when it is working. If the machine is suddenly shut down while reading and writing data, the drive (hard disk, floppy drive, etc.) is likely to be damaged; the machine cannot be moved while the machine is working. Of course, even if the machine is not working, you should try to avoid moving the machine, because excessive vibration will cause damage to accessories such as hard drives. In addition, when shutting down, you must first close all programs and then exit in the normal order, otherwise the applications may be damaged.

3. Hardware faults

After installing a computer, it is inevitable that faults of one kind or another will occur. These faults may be hardware faults or software faults. Generally speaking, the machine that has just been installed is more likely to have hardware failures. After the machine has been running for a period of time, its failure rate will be relatively reduced. For hardware faults, as long as we understand the characteristics of various accessories and the occurrence of common faults, we can eliminate each fault one by one.

1. Poor contact failure

Poor contact is generally reflected in the poor contact between various plug-in cards, memory, CPU, etc. and the motherboard, or the power cord, data cable, audio cable, etc. The connection is poor. Among them, poor contact between various interface cards, memory and the motherboard is relatively common. Usually, the fault can be eliminated by simply changing the corresponding slot position or wiping the golden finger with an elephant leather.

2. Parameters are not set correctly

The settings of CMOS parameters mainly include the type of hard disk, floppy drive, memory, password, machine startup sequence, virus warning switch, etc. Because the parameters are not set or are not set correctly, the system will prompt an error. If the virus warning switch is turned on, Windows 95 may not be installed successfully.

3. Hardware failure

Hardware failure, in addition to its own quality problems, may also be caused by excessive load or other reasons, such as insufficient power of the power supply or CPU overclocking Use, etc. may cause machine failure.

4. Software failure

Software failure is usually caused by improper installation of hardware drivers or virus damage.

If the driver is not installed or there is a conflict between drivers, some marks can be found in the resource management under Windows 95/98. Among them, "?" indicates an unknown device, usually the device is not installed correctly. , "!" means there is a conflict between devices, "×" means the installed device driver is incorrect.

The harm of viruses to computers is well known, ranging from affecting the speed of the machine to damaging files or causing a crash. In order to facilitate the care and maintenance of your computer at any time, you must prepare tools such as a clean DOS boot disk or Windows 98 boot disk, as well as anti-virus software and disk utility software, etc. to cope with situations such as the system being infected with viruses or the hard disk failing to start. In addition, drivers for various accessories should be prepared, such as optical drives, sound cards, display cards, MODEMs, etc.

Cleaning disks and cleaning fluid for floppy drives and optical drives should also be kept on hand. (Bobo)

The "look, smell, listen, and feel" method for computer troubleshooting

In traditional Chinese medicine, "look, smell, ask, and feel" is a traditional method Today, I apply the four diagnostic methods of "looking, smelling, listening and feeling" to the troubleshooting of computer faults, and have achieved good results.

"Watch" means to observe whether the plugs and sockets of the system board are skewed, whether the resistor and capacitor pins are touching, whether the surface is burnt, whether the chip surface is cracked, and whether the copper foil on the motherboard is burned out. Also check to see if any foreign matter has fallen between the components of the motherboard (causing a short circuit), you can also check to see if there are burnt and discolored areas on the board, whether the traces (copper foil) on the printed circuit board are broken, etc.

"Smell" means to identify whether there is a burning smell in the host or board, which is convenient for finding faults and determining the location of short circuits.

"Listen" means to monitor whether the working sounds of power supply fans, soft/hard disk motors or seek mechanisms, monitor transformers and other equipment are normal. In addition, when a short circuit fault occurs in the system, it is often accompanied by abnormal sounds. Monitoring can promptly detect some accident hazards and help take immediate measures when an accident occurs.

"Cut" means pressing the movable chip of the tube holder with your hand to see if the chip is loose or has poor contact. In addition, when the system is running, touch or be close to the shells of CPU, monitor, hard disk and other equipment with your hands to judge whether the equipment is running normally based on its temperature; touch the surface of some chips with your hands. If it is hot, the chip is damaged.

Let me briefly describe my personal experience:

This morning, when I turned on the computer and pressed the Power switch, the computer went silent like death. I couldn't help but be shocked. My intuition told me that something was wrong with the computer. The only phenomenon after turning it on was that only the monitor's power indicator light was on and the host's power indicator light was off. Since my computer is a 6X86 assembly machine, the monitor power cord is directly plugged into the power output socket of the host computer. Therefore, it can be concluded that it is normal for the power cord to go from the mains socket to the host power socket. The problem lies in in the components after the host power supply.

After removing all external connections, open the vertical chassis, and then remove all DC power output lines and switches from the power supply unit above the chassis. What needs to be pointed out here is that special attention should be paid to the correct position of the two sets of motherboard power cords, because among the two sets of motherboard power cords, one of the power cords has a public ground wire, +5V and +12V output lines, and another - 5V output line. In addition to the public ground wire, +5V and +12V power lines, the other group also has two -12V output lines and PG lines. If the positions of these two sets of power cords are reversed during restoration, it will be a big mistake. But the installation of these two sets of power cords is very simple and unique, that is, the black ground wires of both sets of power cords are in the middle.

After opening the casing of the power supply component, the author found that the structure of the power supply component is not complicated and is mainly composed of transformers, rectifiers, filtering and voltage stabilizing components. Since the output power of the host computer is generally tens of watts, and after the mains power is introduced, it is divided and rectified first and then transformed by the inverter circuit. This makes the rectification, filtering and voltage stabilizing currents larger, so most of these components are large. Capacity electrolytic capacitors, high-power transistor components, and most of them have larger heat sinks for heat dissipation. Through the analysis of the circuit board, it is clear that the basic direction of the current is socket → fuse → voltage dividing power resistor → filter rectifier power capacitor → power three-level transistor → transformer → voltage stabilizing system of the rear pole, generally high voltage and high current power components Most are in front of the transformer.

According to past experience, the most vulnerable to damage in the power system are the fuse and power components. Especially when there is no current output, either the fuse is damaged or the front-end power components are damaged, resulting in The power system is locked up. As usual, check the fuse first. After careful inspection, test it again with a multimeter. The fuse is good. It can only be the downstream part, that is, in all likelihood, the power component is damaged. Check the power type voltage divider resistor. The voltage divider resistor is directly responsible for dividing the 220V AC power into about 180V AC power. It is more likely to be broken or broken down. The method of testing its resistance is simple and convenient, and it is intact after the test. Lossless.

Let’s check the filter rectifier capacitor. This capacitor is a large-capacity electrolytic capacitor with a rated voltage of 200V and a capacity of 220μF. Obviously, in order to obtain a relatively flat rectified DC power with an appropriate filter coefficient, a larger-capacity electrolytic capacitor is used. Since it is full wave rectification, there are two large capacitors. Large capacitors must be removed for testing. If it is a soft breakdown, it is difficult to test in a non-charged state. To be on the safe side, I did not solder the capacitor first, but carefully observed whether there was any abnormality in the capacitor, smelled whether there was any peculiar smell in the capacitor, and compared the two capacitors, because under normal circumstances, it is impossible for two capacitors to be damaged at the same time. Upon closer inspection, I noticed that the top of one of the capacitors was slightly higher than the top of the other capacitor. Since there is a large amount of electrolyte inside the electrolytic capacitor, if it works in a filtered state for a long time, it will easily cause the electrolyte to heat up, which in turn will accelerate the leakage of the capacitor. When this vicious cycle develops to a certain extent, the capacitor will either be completely damaged. Wear, or the current is too high and the capacitor is broken. But there is the same phenomenon, that is, the capacitor is damaged due to the heating and expansion of the electrolyte, and the shell bulges or even explodes.

To be sure, there is something wrong with this capacitor. Hurry up and buy an electrolytic capacitor with the same rated voltage and capacity to replace it. Aha! The problem lies here. Of course, you must pay attention to the positive and negative levels of the electrolytic capacitor during installation, and do not reverse them. Generally speaking, the positive and negative poles of electrolytic capacitors are marked on the power supply circuit board in a regular chassis. If they are not marked, the user should use a pen to mark the positive and negative poles when soldering the original capacitor.

Summary: Computer faults include both complex faults and simple faults. Practice has proved that whether they are complex faults or simple faults, most of them have certain clues, even some very obvious ones. Appearance manifestations, such as capacitor volume expansion and bursting, resistors being burned or blackened, transistors exploding or cracking, transformers having a burning smell, etc., as well as serious heating on the surface of non-power integrated blocks without heat sinks. phenomenon, etc. (Note: When checking the integrated block, you can only turn it off after a period of time, and then touch the surface of the integrated block with your fingers. Do not touch the integrated block when it is charged, because it will be broken down by high-voltage static electricity on your hands. Integrated blocks create new fault points. Human hands generally have tens of thousands of volts of high-voltage static electricity, but the electricity is so small that it is difficult for people to feel it, but it is more than enough to penetrate the integrated blocks.) As long as you can "look, smell, listen, and feel" and analyze carefully, you can successfully solve most of the faults using simple methods.

Common driver installation and precautions

Perhaps driver installation is a piece of cake for most friends, but there are still many friends who are new to computers because they cannot Having trouble installing the driver correctly. Today I will briefly introduce my experience in installing computer hardware drivers. I hope it will be helpful to everyone in installing drivers.

Installation of motherboard drivers

Currently, all motherboards provide "foolproof" installation of drivers. Just use the mouse to select the installation bar. The author recommends installing the motherboard driver first when installing the driver. Many motherboards, especially those using INTEL chipsets, require the motherboard driver to be installed before other drivers can be installed. Therefore, it is better to install the motherboard driver first. INTEL motherboard drivers are divided into two files, and there are different installation orders. The author has tried many times and needs to install INF first and then IAA. After installing INF, it is best to restart the computer, otherwise it will prompt that the installation cannot be performed. The VIA and NF motherboard drivers are much more convenient, and you only need to execute one program to complete everything. During installation, directly execute the installation program, and then click "Next" until the system prompts to restart. The author will say one more thing here, sometimes the CPU (mainly AMD processor) needs to install the driver. The author found that the system performance has been improved to a certain extent after installing the AMD processor driver under WIN XP. Therefore, friends who use AMD processors should carefully check your driver disk to see if there are any CPU driver instructions on it.

Installation of graphics card driver

The driver disk that comes with the graphics card generally comes with multiple versions of drivers, but the latest driver is not necessarily the most suitable. Friends who install operating systems above WIN2000 are best to install drivers certified by Microsoft. There is nothing particular about installing the WIN98 or WINME operating system. If you find that the graphics card crashes after installing the graphics card driver, it is recommended to replace the driver with another version.

Installation of sound card driver

Many friends may not know what sound card is integrated into their motherboard, and they do not know how to choose among the numerous drivers during installation. The author suggests that before installing the driver, it is best to check the sound card chip model on the motherboard, or read the sound card model label on the motherboard manual, and then install the corresponding driver. The author has encountered many friends who have installed inappropriate sound card drivers that caused computer abnormalities. The worst thing is that some drivers do not have a prompt such as "cannot be installed" when installing, so many friends do not know that they have been installed correctly. or not.

Installation of network card driver

At present, most motherboards have integrated network cards, and driver installation for such products is relatively easy. Unfortunately, some integrated VIA network cards are prone to problems that cannot be correctly recognized during installation. At this time, be sure to study the instructions carefully and then install it. The author has encountered many problems where the VIA network card cannot be installed normally under the WIN98 system. Everyone must pay attention to it.

Installation of USB interface driver

WIN98 cannot reach the transmission speed of USB2.0 at all, so only the USB1.X driver can be installed under WIN98. In systems above WIN2000, you also need to install a patch to achieve normal USB2.0 speed. So everyone should pay attention when installing the USB driver.

Installation of printer and scanner drivers

There are many peripheral products that need to execute the driver installation file first, and then connect according to the installation prompts, otherwise there will be problems that cannot be installed. For example, some Founder models of printers. In this case, the author also recommends carefully studying the instructions and then installing according to the instructions. If you find an installation error, it is recommended to delete the incorrectly installed device in Device Manager and then reinstall the correct driver.

Installation of RAID driver

Some friends mentioned before that installing the RAID driver under WIN XP needs to be done when installing the operating system. Here is a reminder for friends who install RAID. When RAID needs to be installed in the INTEL 865 chipset, a floppy disk must be used for installation.

In addition, the author would like to say that the WIN XP operating system is the most convenient among all operating systems for installing drivers. If you are afraid of trouble, it is best to install WIN XP. But even WIN XP does not support all hardware, and there are still many devices that require manual installation of drivers. What should you do if you find that the driver is installed incorrectly and it cannot be installed correctly after deleting the device (this situation occurs more in WIN98)? You only need to find the corresponding file in the INF in the WINDOWS directory and delete it. What I want to remind everyone here is that friends with little basic computer knowledge and poor English must not try it easily, otherwise they may need to reinstall the system.

Computer troubleshooting: "eight first and eight last"

Compared with other electrical products, computers are prone to malfunctions of one kind or another. Computer failure is a headache for many computer enthusiasts. How should we deal with and solve the computer failures we encounter? Here I summarize and write an article on the "eight first and eight last" rules in computer maintenance to provide readers with some ideas -

1. Investigate first, then become familiar with

Whether it is When repairing your own computer or someone else's computer, you must first find out the usage status of the computer when the fault occurred and the previous maintenance status, so that you can prescribe the right medicine. In addition, before repairing your computer, you should also understand the computer's software and hardware configuration, age, etc., so as to be targeted.

Example analysis--

For example, a computer with the first version of PWIN98 operating system frequently experiences system crashes and an increase in "illegal operation" prompts during use, which is very annoying. The user is ready to Reformat the disk and reinstall the operating system. The author doesn’t think it’s so troublesome. I carefully looked at the configuration and software and hardware installation of his computer and used anti-virus software to check for viruses... After the author asked, the user said that he had recently installed a new version of the IE6 browser. Could it be the IE6 browser? What about poor compatibility with its system? The author tried to uninstall the new version of IE6 browser in the "Add/Remove Programs" column. After restarting the computer, the fault no longer occurred frequently. Therefore, for this kind of failure, you cannot bear to remove the newly installed software or hardware or drivers/DirectX, etc. If the problem cannot be solved, then do extensive maintenance work.

2. First, look outside the computer, then inside the computer

For computers with problems such as the host or monitor not lighting up, you should first check the chassis and the external components of the display, especially the external components. Whether some switches and knobs adjust the external leads, whether the sockets are open or short-circuited, etc. Don't think that these are insignificant details. Practice has proved that many users' computer failures are caused by this. After confirming that the external components are normal, open the chassis or display for inspection.

Example analysis--

After a computer was moved, the host did not light up (the host fan did not spin). The user believed that the host power supply was in disrepair and was damaged. , open the chassis and prepare to remove the power supply and replace it. The author observed that the host computer and the monitor were connected with a power cord from the power socket, and the monitor displayed normally. Based on the principle of simple first and then easier, first try changing the power plug of the host to another power socket. If it doesn't work, then remove the power cord of the normally used monitor and connect it to the host, and the host returns to normal. When the problem line is connected to the monitor, it doesn't turn on, which proves that the problem comes from this seemingly inconspicuous power line (internal open circuit).

3. Mechanical first, electrical second in principle. For example, if the CD drive does not read the disk, you should first determine whether it is caused by mechanical reasons (such as a problem with the optical head) or by electrical problems. Only when it is confirmed that the rotating mechanism of each part and the bald head are fault-free, conduct electrical inspection.

Example analysis--

I bought a 40-speed optical drive more than a year ago, but the problem is that the disk cannot be read. After taking over, the author disassembled the optical drive and observed the internal structure of the optical drive. This optical drive is an all-steel structure, and generally there should be no serious mechanical problems. The author is not in a hurry to increase the power of the optical head or the laser head. to further "destroy" it. After putting in a disc, the author carefully observed the rotation of the disc and the movement of the optical head, and the advancement and retreat of the motor. I found that the rotation of the disc was basically normal, and the advancement and retreat of the motor was not a big problem. On the contrary, It is very difficult for the optical head assembly to slide on the sliding rod when it is unloaded or with a disc added. Turn off the power and gently push the optical head assembly a few times with your hand to make it slide on the rod. There is an obvious sense of lag. At this time, the author focused on observing the sliding rod of this optical drive, and saw that the originally white lubricating oil on it had turned into light black, and even dense dust and impurities could be seen in a place with strong light. No wonder the sliding rod was not flexible. First use pure alcohol to clean the impurity-containing lubricating oil on the sliding components, then add new lubricating oil, and then retest the machine, and the disk reading returns to normal.

4. Software first, then hardware

Troubleshoot software problems first and then hardware problems. This is an important principle in computer maintenance. For example, damage or loss of WINDOWS system software may cause a crash, because system startup is a step-by-step process, and no errors can occur in any link. If there are damaged execution files or drivers, the system will freeze. here. However, there are problems with the computer components themselves, poor interface contact of the plug-in connectors, hardware device settings such as BIOS, driver integrity, compatibility with the system, stability of the hardware power supply equipment, and compatibility between components. Poor resistance to external interference, etc. may also cause computer hardware crashes. When repairing, we should start with the soft aspects before considering the hard ones.

Example analysis--

After a computer starts the self-test, it displays the message "No ROMBasic, System Halted" on the screen and then crashes, and the hard disk light stays on. After ruling out the cause of bad sectors on the hard disk, it is obvious that the cause of this failure is that the boot program of the hard disk is damaged, causing the system to fail to find the hard disk and crash. There are many ways to fix this glitch. For example, you can use KV300, which can easily solve the problem of the hard disk boot sector being damaged. Its use is very simple. You can refer to the documentation of KV300. I won’t go into details here, but if you don’t have it, you can also use it. After starting the computer from the floppy disk, in pure DOS state, execute the special "FDISK/MBR" command. It can also force the correct main boot program and end flag to be overwritten on the main boot area of ??the hard disk, but everyone should pay attention to this command. There is a certain risk.

5. Clean first, then repair

When checking the internal accessories of the chassis, you should first check whether the inside of the machine is clean. If you find that the components, leads, wiring and If there is dust, dirt, cobwebs or excess solder, soldering oil, etc. between the gold fingers, they should be removed first before maintenance. This can not only reduce natural failures, but also achieve twice the result with half the effort. Practice shows that many faults are caused by dirt and will disappear automatically once cleaned.

Example analysis--

After a computer opened the case and installed a new graphics card, the display went black after restarting, and the speaker inside the computer emitted a continuous long beep. Sound the alarm. Fault analysis: The speaker inside the chassis beeps continuously, which is a typical memory error. Although you may not have touched the memory stick when disassembling or moving the computer, memory is a delicate thing, and its biggest enemy is dust. After using your computer for a period of time, the inside of the case is likely to be covered with dust. There is a thin layer of residual dust, and the memory that is close to the CPU is the biggest "victim". The dust blown by the CPU fan is likely to cover your memory with a thick layer of dust that vibrates slightly. It may fall into the memory slot, causing a local short circuit or poor contact, resulting in a black screen on the monitor and an error message on the speaker in the chassis when starting the computer. In this case, you should definitely check the installation of the memory first. You can press the memory a few times with your hands before turning on the computer to see if the contact has improved. If it still doesn't work, then you can remove the memory and clean the dust on the surface of the memory first. Clean it, then use a small fine-bristle brush to carefully clean the memory slot, and then re-insert the memory, and the fault can usually be eliminated.

6. Power supply first, then machine

Power supply is the heart of the machine and accessories. If the power supply is abnormal, it is impossible to ensure the normal operation of other parts, and there is no way to check other parts. Fault. According to experience, the failure rate of the power supply part accounts for the highest proportion in the machine. Many faults are often caused by the power supply, so repairing the power supply first can often get twice the result with half the effort.

Example analysis -

A 15-inch monitor has a display failure with no raster and no image, and an obvious "squeaking" sound can be heard from the power supply. Fault analysis: From the fault phenomenon analysis, it can be seen that faults in the power supply circuit, line scanning circuit, and main load circuit are the causes of this type of problem. Since the "squeaking" sound from the power supply indicates that the switching power supply is working, it indicates that there is basically no problem with the previous circuit of the switching transformer. First, use a multimeter to check whether the voltages at the five output terminals are normal. It is found that the positive terminal of the power supply filter capacitor C117 is 0V, while the normal value should be about 5V. This is obviously abnormal, which indicates that there is a short circuit or open circuit in the peripheral circuit components. Using the method of measuring current, we found that the current of L105 was very small. We further suspected that there was a problem with the rectifier diode VD106 in front of it. We replaced it with the replacement method and the fault was eliminated.

7. First common faults, then special ones

According to the unique characteristics of computer faults, first eliminate common faults with universality and regularity, and then check for special ones. Failure, in order to gradually narrow the scope of the failure, from surface to point, and shorten the repair time.

Example analysis - A computer experienced a problem where the power light came on but the system did not self-check and the display went black after the motherboard was replaced and the computer was restarted. Open the case, observe carefully, and find that the CPU fan is running normally. After turning off the power, carefully check the installation of the board. Focus on reinstalling the memory module and graphics card, and check the relevant jumpers on the motherboard. After confirming that everything is correct, the "minimum system method" is adopted. After troubleshooting, remove the connecting cables of the hard disk, optical drive, etc., and keep only the motherboard, CPU, memory, and graphics card as a minimal system. After booting, the system starts smoothly.

I focused on checking the connection between the optical drive and the hard disk. After the optical drive was installed, the above fault reappeared. Could it be that the optical drive was not installed properly? The optical drive was separately connected to the IDE2 bus interface. The author checked and found that the IDE cable connector used to connect the optical drive There is no anti-reverse insertion bump. Could it be that the connection is reversed? After a closer look, it turned out that the system started normally after being installed correctly.

8. Peripheral first, internal second Circuit, after confirming that the peripheral circuit is normal, consider replacing accessories or important components. If you ignore everything and blindly replace accessories or important components, you will only cause unnecessary losses. It can be seen from maintenance practice that the faults of peripheral circuits or machinery of accessories or important components are much higher than those of their internal circuits.

Example analysis--

The hard disk of a PC in a unit was in normal use, but after restarting the computer, the hard disk could not be found. According to the operator of the computer He said that the hard drive had this problem two days ago, but he could find it again after a while. When I went to work today, I just restarted the computer under normal use, and the system could no longer find the hard drive. . When I opened the case, I saw that the hard drive was a Western Digital 3.2G hard drive purchased three years ago. It looked very old because it was frequently disassembled to copy data. For this kind of failure, you can first check the IDE hard disk cable. After replacing it with a new one, it will not work. Try changing the power plug and plugging it in again. After turning on the computer, the hard disk will "shudder" and return to normal. Fix it! After installing the accessories, closing the chassis cover, and then restarting, the strange thing is that the hard drive is gone again... After repeating this for several times, the hard drive cannot be used normally, but as long as the author plugs and unplugs the hard drive power cord a few times, it can return to normal. Could it be that the terminals in the hard drive power interface have poor contact? Remove them and observe, and there is no rust or halogenation. Use a multimeter to check the continuity between the terminals and the terminal solder joints on the hard disk circuit board. The author found that there is a column (5V) that requires a test lead to be pressed tightly to achieve continuity. This rules out the possibility of oxidation of the surface of the terminal or virtual soldering of the solder joints. In other cases, the author spent 3 yuan to buy a power cord adapter, cut off the connector and stripped out the copper wires, and soldered them one by one to the corresponding solder points on the circuit board of the power socket terminal of the hard drive power supply part in order. , plug the male end of the power adapter cable into a female end of the host power cord, restart the computer, and the PC returns to normal.