Computer hardware assembly and maintenance

How to maintain and maintain the computer and maximize its service life is a problem that we are very concerned about and often face. In this article, we introduce you to the most basic computer maintenance methods and precautions to keep your computer in a relatively stable state, just like a new one.

One. environment

The influence of environment on computer life can not be ignored. The ideal working temperature of the computer should be 10℃-35℃. Too high or too low will affect the life of accessories. If conditions permit, air conditioning must be installed, and the relative humidity should be 30%-80%. Too high will affect the performance of accessories and even cause some accessories to be short-circuited. For example, when the weather is wet, it is best to use the computer or turn it on for a period of time every day. Some people think that using computers less or for a short time can prolong the life of computers, which is a one-sided view. On the contrary, if you don't use the computer for a long time, the accessories will be damaged by moisture or dust. Of course, if the weather is extremely humid, for example, there is water vapor on the surface of the monitor or chassis, you must never power on the machine at this time. Too low humidity is easy to generate static electricity, which is not good for the use of accessories. In addition, the dust content in the air has a great influence on computers. A large amount of dust will corrode the circuit boards of various accessories for a long time. Therefore, it is necessary to dust the computer frequently.

Computers also have requirements for power supply. The normal range of alternating current shall be 220 V 10%, the frequency range shall be 50hz 5%, and a good grounding system shall be provided. If possible, you should use UPS to protect the computer so that it can continue to run for a period of time when the power is interrupted.

Second, the use habits

Personal habits have a great influence on computers. First of all, the computer should be turned on and off normally. The sequence of turning on the computer is to turn on the power of peripheral devices (such as printers and scanners) first. If the power supply of the monitor is not connected with the power supply of the host, the power supply of the monitor should be turned on first, and then the power supply of the host should be turned on. The shutdown sequence is reversed. First, power off the host, and then power off the peripherals. The reason is to minimize the damage to the host, because when the host is powered on, the peripheral has a greater impact on the host when it is turned off. After a period of time, you can't turn it on and off frequently, because it will have a great impact on all accessories, especially on the hard disk. Generally, there should be at least 10 second between shutdown and next startup. Pay special attention to avoid turning off the computer while it is working. If the machine shuts down suddenly when reading and writing data, it is likely to damage the drive (hard disk, floppy disk, etc.). ); Never move the machine when it is working. Of course, even when the machine is not working, you should try to avoid moving the machine, because excessive vibration will damage the hard disk and other accessories. In addition, when shutting down, you must first close all programs and then exit in normal order, otherwise the application may be damaged.

Third, hardware failure.

After installing the computer, it is inevitable that there will be some faults, which may be hardware faults or software faults. Generally speaking, newly installed machines are more prone to hardware failure, and the failure rate is relatively reduced after the machine runs for a period of time. For hardware faults, we can eliminate them one by one as long as we know the characteristics of various accessories and the occurrence of common faults.

1. Bad contact fault

Poor contact is generally reflected in poor contact between various cards, memory, CPU, etc. And the motherboard, or the power cable, data cable, audio cable, etc. are poorly connected. Among them, it is common that various interface cards and memories have poor contact with the motherboard. Usually, the fault can be eliminated by replacing the corresponding slot position or wiping the golden finger with image leather.

2. The parameter setting is incorrect

The setting of CMOS parameters mainly includes the types of hard disk, floppy disk and memory, as well as passwords, machine startup sequence, virus warning switches, etc. Because the parameters are not set or set incorrectly, the system will prompt an error. If the virus warning switch is turned on, Windows 95 may not be installed successfully.

3. The hardware itself is faulty

Hardware failure, in addition to its own quality problems, may also be caused by excessive load or other reasons, such as insufficient power supply or excessive use of CPU, which may lead to machine failure.

Fourth, software failure.

Software failures are usually caused by improper installation of hardware drivers or virus damage.

If there is no driver installed or there is a conflict between drivers, you can find some marks in resource management under Windows 95/98, including "?" Indicates an unknown device. Usually, the device is not installed correctly, which means there is a conflict between devices, and "×" means that the installed device driver is incorrect.

The harm of viruses to computers is well known, ranging from affecting the speed of machines to destroying files or causing crashes. In order to maintain the computer at any time, tools such as clean DOS startup disk or Windows98 startup disk, anti-virus software and disk tool software must be prepared to deal with the situation that the system is infected with virus or the hard disk cannot be started. In addition, drivers for various accessories, such as optical drive, sound card, video card and modem, should be prepared. Disks and cleaning solutions for floppy disks and CD-ROM drives should also be kept in stock. (bobo)

"Looking, Smelling, Listening and Cutting" Method for Computer Fault Diagnosis

In traditional Chinese medicine, "seeing, hearing and asking questions" is a traditional method to diagnose diseases. Today, I applied the four diagnostic methods of "looking, smelling, listening and cutting" to the maintenance of computer faults and achieved good results.

"Look" is to observe whether the plug and socket of the system board are skewed, whether the resistor and capacitor pins collide, whether the surface is burnt, whether the chip surface is cracked, and whether the copper foil on the motherboard is burnt out. Also check whether there are foreign objects falling between the components of the motherboard (causing short circuit), and check whether there are burnt and discolored places on the board, and whether the traces (copper foil) on the printed circuit board are broken.

"Smell" means to identify whether the main engine and the board have burning smell, which is convenient for finding faults and determining the short circuit position.

"Listening" refers to monitoring whether the working sound of power supply fan, soft/hard disk motor or seek mechanism, display transformer and other equipment is normal. In addition, the short-circuit fault of the system is often accompanied by abnormal sound. Monitoring can find some hidden dangers in time and help to take immediate measures when accidents happen.

"Cutting" refers to pressing the movable chip of the socket by hand to see if the chip is loose or has poor contact. In addition, when the system is running, touching or approaching the shell of CPU, monitor, hard disk and other equipment by hand can judge whether the equipment is running normally according to 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 the power switch of the computer was pressed, the computer was silent. I can't help being surprised. My intuition tells me that there is something wrong with the computer. The only phenomenon after booting is that only the boot indicator of the monitor is on, and the power indicator of the host is off. Because my computer is a 6X86 assembly machine, the power cord of the monitor is directly plugged into the power output socket of the host, so it can be concluded that it is normal to go from the power socket to the power cord and then to the power socket of the host, and the problem lies in the components powered by the host.

After removing all external cables, open the vertical chassis, and then remove all DC power output lines and switches of the power supply assembly above the chassis. It should be pointed out here that special attention should be paid to the correct positions of the two sets of power lines of the motherboard, because one of the two sets of power lines of the motherboard has a common ground, +5V and ++ 12V output lines and -5V output lines. In addition to the ground wire, +5V and+12V power wires, the other group has two output wires-12V and PG wires. It would be a big mistake if the positions of the two groups of power lines were reversed during the recycling process. However, the installation of these two groups of power cords is very simple and has its own characteristics, that is, the black ground wire of the two groups of power cords is in the middle.

After opening the shell of the power supply module, the author found that the structure of the power supply module is not complicated, mainly composed of transformer, rectifier, filter and voltage regulator. Because the output power of the host computer is generally tens of watts, and after the introduction of commercial power, it is rectified by voltage division and then transformed by inverter circuit, which makes the current of rectification, filtering and voltage stabilization larger, so most of these components are large-capacity electrolytic capacitors and high-power transistor components, and most of them have large heat sinks to dissipate heat. Through the analysis of the circuit board, it is clear that the basic trend of current is socket → fuse → voltage divider power resistor → filter rectifier power capacitor → power transistor → transformer → back-pole voltage stabilizing system. Generally speaking, most high-voltage and high-current power supply components are in front of the transformer.

According to past experience, fuses and power components in the power supply system are most likely to be damaged, especially when there is no current output, which often leads to the locking of the power supply system. As usual, check the safety tube first. After careful inspection, test it again with a 10 thousand meter. The safety tube is good. It can only be the latter part, that is, nine times out of ten, the power components are damaged. Check the power divider resistor. The voltage divider resistor directly undertakes the task of dividing 220V AC into about 180V AC, which is likely to be broken down or broken down. The method of testing its resistance is simple and convenient, and it is also intact after testing.

Then check the filter commutation capacitor, which is a large-capacity electrolytic capacitor with rated voltage of 200V and capacity of 220 μ F. Obviously, in order to obtain a relatively flat rectified DC with appropriate filter coefficient, a larger electrolytic capacitor is needed. Because it is full-wave rectification, there are two large capacitors. The test of large capacitors must be recorded. If it is a soft breakdown, it is still difficult to test in the uncharged state. To be on the safe side, I didn't weld the capacitor first, but carefully observed whether the capacitor was abnormal, smelled the capacitor and compared the two capacitors, because under normal circumstances, the two capacitors could not be damaged at the same time. Through careful observation, I found that the top of one capacitor is slightly higher than the top of the other capacitor. Because there is a large amount of electrolyte in the electrolytic capacitor, if it works in the filtering state for a long time, it is easy to raise the temperature of the electrolyte, thus accelerating the leakage of the capacitor. When this vicious circle develops to a certain extent, the capacitor is either completely broken down or disconnected due to excessive current. However, there is the same phenomenon, that is, due to the heating and expansion of electrolyte, the capacitor shell bulges or even breaks. To be sure, there is something wrong with this capacitor. Buy electrolytic capacitors with the same rated voltage and capacity to replace the installation. Aha! This is the problem. Of course, when installing, we must pay attention to the level of the anode and cathode of the electrolytic capacitor, and don't reverse it. Generally speaking, the positive and negative signs of electrolytic capacitors are on the power circuit board in the regular cabinet. If there is no mark, the user should mark the positive and negative poles with a pen when welding the original capacitor.

Summary: Computers have both complex faults and simple faults. Practice has proved that most of them have certain clues, even some very obvious appearances, such as the expansion and explosion of capacitors, the burning or blackening of resistors, the explosion or rupture of transistors, the burning smell of transformers and so on. And the surface of the non-power integrated block without heat sink is seriously heated (note: never touch the integrated block when charging, because it will break down the integrated block due to high-voltage static electricity in your hand, leading to new fault points. People's hands generally have tens of thousands of volts of high-voltage static electricity, but the amount of electricity is very small, which is difficult for people to feel, but it is more than enough to break through the integrated block. As long as you can "look, smell, listen and cut" and analyze carefully, most faults can be solved smoothly through simple methods.

Installation and Precautions of Common Drivers

Perhaps it is a piece of cake for most friends to install drivers, but there are still many friends who are new to computers who are distressed because they can't install drivers correctly. Today, the author briefly introduces his own experience in installing computer hardware drivers, hoping to help you install drivers.

Installation of motherboard driver

At present, all motherboards provide "fool" installation drivers, just use the mouse to select the installation bar in turn. I suggest installing the motherboard driver first when installing the driver. Many motherboards, especially products using Intel chipsets, require that motherboard drivers be installed before other drivers can be installed. Therefore, we'd better install the motherboard driver first. Intel motherboard drivers are two files, which are installed in different order. I have tried many times to install INF first and then IAA. It is best to restart the computer after installing INF, otherwise you will be prompted that it cannot be installed. VIA and NF motherboard drivers are much more convenient, and all operations can be completed by executing only one program. When installing, directly execute the installation program, and then click "Next" in turn until the system prompts you to restart. Here, I want to say that sometimes the CPU (mainly AMD's processor) needs to install drivers. I found that the system performance has been improved after installing AMD's processor drivers under WIN XP. Therefore, friends who use AMD processors should carefully check your drive disk to see if there is a description of the CPU driver on it.

Install the graphics card driver

Generally speaking, there are multiple versions of drivers in the driver disk attached to the graphics card, but not the latest driver is necessarily the most suitable. Friends who install operating systems above WIN2000 had better install drivers certified by Microsoft. However, people who install WIN98 or WINME operating systems are not picky about this. If it is found that there is a crash problem after installing the graphics card driver, it is recommended to replace other versions of the driver.

Installation of sound card driver

Many friends may not know what sound card is integrated into their motherboard, and they don't know how to choose among many drivers when installing. I suggest that before installing the driver, it is best to look at the model of the sound card chip on the motherboard, or look at the label on the sound card model in the motherboard manual, and then install the corresponding driver. I have met many friends who installed inappropriate sound card drivers before, which caused the computer to be abnormal. Unfortunately, some drivers don't have a prompt like "Unable to install" when they are installed, so many friends don't know if they are installed correctly.

Install the network card driver

At present, most motherboards are integrated with network cards, so it is relatively easy to install drivers for such products. Unfortunately, some integrated VIA network cards are prone to problems that cannot be correctly identified during installation. At this time, you must study the instructions carefully and then install them. The author has encountered many problems that VIA network cards can't be installed normally under WIN98 system, and everyone should pay attention to them.

Installation of USB interface driver

WIN98 can't reach the transmission speed of USB2.0 at all, just install USB 1 X driver under WIN98. In systems above WIN2000, patches need to be installed before reaching the normal speed of USB2.0. Therefore, everyone should pay attention when installing USB drivers.

Install printer and scanner drivers.

Many peripheral products need to execute the driver installation file first, and then connect according to the installation prompt, otherwise there will be the problem that they cannot be installed. For example, some models of printers are square. In view of this situation, the author also suggests that the instructions should be carefully studied first, and then the installation should be carried out according to the instructions. If an installation error is found, it is recommended to delete the incorrectly installed device in the device manager and then reinstall the correct driver.

Installation of RAID driver

Earlier, a friend mentioned that installing RAID drivers under WIN XP needs to be done when installing the operating system. Here, I want to remind my friends who installed RAID to pay attention. When RAID needs to be installed in Intel 865 chipset, it should be installed with floppy disk.

In addition, I want to say that WIN XP operating system is the most convenient of all operating systems for installing drivers. If you are afraid of trouble, you'd better choose to install WIN XP. But even WIN XP does not support all hardware, and many devices need to install drivers manually. What should I do if I find that the driver is not installed correctly, but I can't install it correctly after deleting the device (this situation is more common in WIN98)? You just need to find the corresponding file deletion in the INF of the WINDOWS directory. Here, I want to remind you that friends who don't have much basic computer knowledge and poor English should never try it easily, otherwise they may need to reinstall the system.

"Eight before Eight" in Computer Troubleshooting

Compared with other electrical products, the computer is a fault-prone thing. Computer failure is a headache for many computer enthusiasts. How to deal with and solve the computer failures we encounter? Here I summarize and write an article about the "eight before eight after" rules in computer maintenance, which will attract readers-

First, investigate, and then get familiar with it.

Whether you are repairing your own computer or someone else's computer, you must first find out the use state and previous maintenance state of the computer when it fails, so as to prescribe the right medicine. In addition, before repairing its computer, it is necessary to clearly understand the hardware and software configuration and service life of its computer, so as to be targeted.

Example analysis—

For example, a computer whose operating system is the first edition of PWIN98 frequently crashes and the number of "illegal operation" prompts increases, which is very annoying. The user is ready to reformat the disk and reinstall the operating system. I don't think it's necessary to go to such trouble. I carefully checked the computer configuration, software and hardware installation, and checked the virus with anti-virus software ... After the author asked, the user said that he had recently installed a new version of IE6 browser. Could it be that IE6 browser is not compatible with its system? I tried to uninstall the new version of IE6 browser in the Add/Remove Programs column. After restarting the computer, the failure phenomenon no longer occurs frequently. Therefore, for this kind of fault, we can't bear to remove the newly installed software or hardware or driver //DirectX, and carry out heavy maintenance work when the problem can't be solved.

Second, take the initiative, then take the initiative.

For computers with faults such as the host computer or the monitor not being on, we should first check whether the external components of the chassis and the monitor, especially some switches and knobs outside the machine, have adjusted the external wires and whether the sockets are open or short-circuited. Don't think these are trivial things. Practice has proved that many users' computer failures are caused by this. After confirming that the external components are normal, open the chassis or show it for inspection.

Example analysis—

After moving the computer, the host computer can't be turned on (the fan of the host computer doesn't turn). The user thought that the power supply of the host was damaged due to disrepair, so he opened the chassis and removed the power supply for replacement. The author observed that the host computer and the monitor are connected from the power socket with the power cord, but the display is normal. In line with the principle of easy before difficult, try to replace the power plug of the host with a power jack. If it fails, please unplug the normal monitor power cord and connect it to the host, and the host will return to normal. Connect the problem line to the monitor, it doesn't light up, which proves that the problem comes from this seemingly inconspicuous power line (internal open circuit).

Third, first, machinery, and then electricity.

For peripheral devices such as CD-ROM drives and printers, the general principle is to check whether there is a mechanical fault first, and then check whether there is an electrical fault. For example, if a CD drive cannot read a CD, it should be distinguished whether it is a mechanical problem (such as a bald head problem) or an electrical problem. Only when it is determined that there is no fault in the rotating mechanism and optical head of each part can the electrical inspection be carried out.

Example analysis—

After purchasing a 40-speed optical drive for more than a year, the failure phenomenon is that the CD cannot be read. After the author took over, I took apart the CD-ROM drive and observed its internal structure. This CD-ROM drive is made of all-steel structure, so there should be no serious mechanical situation on the whole. The author is in no hurry to further "destroy" it on its optical head and increase the power of the laser head. After inserting a CD, the author carefully observed the rotation of the CD, the movement of the feed parts of the optical head and the advance and retreat of the motor. It is found that the rotation of the disc is basically normal, and there is not much problem with the advance and retreat of the motor. On the contrary, when there is no load or an optical disc is added, it is difficult for the optical head assembly to slide on the slide bar. Turn off the power supply and gently push the optical head assembly several times by hand to make it slide on the rod, which has obvious hysteresis. At this time, the author focused his eyes on the slide bar of this CD-ROM drive, and saw that the lubricating oil that should have been white turned into light black, and even dense dust and impurities could be seen in places with strong light. No wonder sliding doesn't work. First, clean the lubricating oil containing impurities on the sliding assembly with pure alcohol, then add new lubricating oil again, and then try the machine again and read the disk to return to normal.

Fourth, the software first, then the hardware.

It is an important principle in computer maintenance to eliminate software faults first and then hardware problems. For example, the damage or loss of WINDOWS system software may lead to a crash, because system startup is a step-by-step process, and no mistakes can be made in any link. If there are damaged execution files or drivers, the system will die here. However, the problems of computer components, poor interface contact of connectors, and the settings of hardware devices (such as the perfection of BIOS and drivers, compatibility with the system, stability of hardware power supply devices, and compatibility between components against external interference) may also lead to computer hardware collapse. When maintaining, we should start with the soft aspects first, and then consider the hard aspects.

Example analysis—

After the computer starts self-checking, it displays the message "No ROMBasic, System Halted" on the screen and crashes, and the hard disk indicator light remains on. The cause of the bad track of the hard disk has been eliminated. Obviously, the cause of this failure is that the boot program of the hard disk was destroyed, which caused the system to crash because the hard disk could not be found. There are many ways to fix this fault. For example, you can use KV300, which can easily solve the failure of the hard disk boot area. Its use method is very simple. You can refer to the description file of KV300, so I won't say much here. If not, you can also use a floppy disk to start the computer and execute the special "FDISK/MBR" command in the pure DOS state. It can also forcibly overwrite the correct master boot program and end flag in the main boot area of the hard disk, but you should pay attention to this command.

Fifth, clean first, then repair.

When checking the accessories inside the chassis, we should first pay attention to whether the interior of the chassis is clean. If dust, dirt, cobwebs or redundant solder and welding oil are found between components, leads, wires and gold fingers in the chassis, they should be removed first, and then overhauled, which 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 they often disappear automatically after cleaning.

Example analysis—

After the computer opens the case and installs a new graphics card once, the display screen will be black after restarting, and the speaker in the computer will give out a continuous long beep alarm sound. Fault analysis: The horn in the chassis keeps beeping, which is a typical memory fault. Although everyone may not move the memory stick when disassembling or moving the computer, memory is a delicate thing, and its enemy is dust. After your computer is used for a period of time, it is likely to be covered with a thin layer of residual ash, and the memory near the CPU is the biggest "victim". The dust blown by the CPU fan is likely to spread a thick layer of dust on your memory, and the dust may fall into the memory slot with slight vibration, thus causing local problems. In this case, you should first check the installation of memory. You can press the memory several times before turning on the computer to see if the contact is getting better, if not; Then you can remove the memory, clean the dust on the surface of the memory first, then carefully clean the memory slot with a small fine brush, and then plug in the memory again, which can generally eliminate the fault.

Six, the first power supply, after the machine

Power supply is the heart of machines and accessories. If the power supply is abnormal, the normal operation of other components cannot be guaranteed, and other faults cannot be checked. According to experience, the failure rate of power supply is the highest in the machine, and many failures are often caused by power supply, so repairing power supply first can often get twice the result with half the effort.

Example analysis—

The 15-inch monitor has a display failure, and there is no grating or image, and an obvious "squeaking" sound can be heard from the power supply. Fault analysis: According to the fault phenomenon analysis, the faults of power supply circuit, line scanning circuit and main load circuit are the causes of this kind of problem. Because the "squeak" sound from the power supply indicates that the switching power supply has worked, it shows that there is basically no problem in the circuit before the switching transformer. First, use a multimeter to check whether the terminal voltages of the five outputs are normal. It is found that the positive terminal of the power supply filter capacitor C 1 17 is 0V, while the normal terminal should be about 5V, which is obviously abnormal, indicating that its peripheral circuit components are short-circuited or open-circuited. It is found that the current of L 105 is very small by measuring the current, and it is further suspected that there is something wrong with the rectifier diode VD 106 in front of it. After replacement, the fault is eliminated.

Seven, there are common faults first, and then there are special ones.

According to the * * * characteristics of computer faults, the common faults with universality and regularity should be eliminated first, and then the special faults should be checked, so as to gradually narrow the fault range and shorten the repair time.

Example analysis-the computer has a fault that the power light is on, but the system does not check the black screen of the display after replacing the motherboard and restarting the computer. Open the chassis and observe carefully, and find that the CPU fan is working normally. After turning off the power supply, carefully check the installation of the board card, reinstall the memory module and graphics card, and check the relevant jumpers of the motherboard to ensure that they are correct. Therefore, the "minimum system method" is used to troubleshoot, and the connecting cable of the hard disk drive is removed, only the minimum system of the motherboard, CPU, memory and graphics card is kept, and the system starts smoothly after booting. Mainly check the connection between CD-ROM drive and hard disk. After installing the optical drive, the above failure reappeared. Is it because the optical drive is not installed correctly? CD-ROM drive is connected to IDE2 bus interface separately. The author found that the IDE cable connector used to connect the CD-ROM drive has no anti-insertion protrusion. Is it connected in reverse? If you take a closer look, sure enough, the system will work normally after correct installation.

Eight, first peripheral, then internal.

When checking the important parts or accessories of the computer, don't rush to replace them or start work on their internal or important accessories first, but check their peripheral circuits, and then consider replacing the accessories or important parts when confirming that the peripheral circuits are normal. If you don't ask questions, just replace accessories or important parts, it will only cause unnecessary losses. From the maintenance practice, we can know that the fault of the peripheral circuit or machinery of accessories or important parts is much higher than its internal circuit.

Example analysis—

The PC hard disk of a company is working normally, but it can't be found after restarting the computer. According to the computer operator, this hard disk had such a problem two days ago, but it was discovered after a while. Today, when I went to work, I just restarted my computer after normal use, and the system couldn't find the hard disk anymore. When I opened the case, I saw that the hard disk was a Western Digital 3.2G hard disk I bought three years ago. Because it is often taken apart to copy data, it looks old. For this kind of fault, you can first check the IDE hard disk cable, which is invalid after replacing it with a new cable. Try to plug it in again with a new power plug, and the hard disk will return to normal after booting. It's done. Install accessories, close the box cover, and then restart. Strangely, the hard disk is gone again ... so many times the hard disk can't be used normally, but I can return to normal as long as I plug in the power cord of the hard disk several times and then unplug it several times. Could it be that the terminal in the hard disk power interface is in poor contact? Take it down for observation, and there is no rust or halogen phenomenon. The author uses a multimeter to detect the conduction between the terminals on the hard disk circuit board and the solder joints of the terminals. It is found that a column (5V) can only be conducted by pressing with an iron pen, which excludes the oxidation of the terminal surface or the virtual welding of solder joints. The author bought a power cord adapter from 3 yuan Money, cut off the connector, peeled off the copper wire, and welded it on the solder joint corresponding to the power socket terminal of the hard disk power supply part in turn, inserted the male terminal of the power cord into the female terminal of the host computer, and restarted the machine.