Maintenance of Common Computer Faults

The cause of computer failure is confusing and elusive. Moreover, because the components of the Windows operating system are relatively complex, it is almost impossible for ordinary users to accurately find out the cause of the failure once the computer fails. So does it mean that if there is a computer failure, we are completely helpless? The following is what I collected and arranged for you. I hope I can help you with the maintenance of common computer faults!

0 1 boot without display:

The computer does not display when it is turned on. The first thing we need to check is the BIOS. Important hardware data is stored in the BIOS of the motherboard. At the same time, BIOS is also a fragile part of the motherboard, which is easy to be damaged. Once damaged, the system will not work. This failure is generally caused by the CIH virus destroying the BIOS of the motherboard (of course, it is not excluded that the failure of the motherboard itself causes the system to fail to run. )。 Generally, after the BIOS is destroyed by virus, all the data in the hard disk will be lost, so we can judge whether the BIOS is destroyed by detecting whether the hard disk data is intact. If the data on the hard disk is in good condition, there are three other reasons why it will not be displayed when it is turned on:

1. Because there is something wrong with the motherboard expansion slot or expansion card, the motherboard does not respond after inserting expansion cards such as sound cards and does not display.

2. The CPU frequency of the jumper-free motherboard set in CMOS is wrong, which may also lead to the failure of not displaying, which can be solved by clearing CMOS. The jumper for clearing CMOS is generally near the lithium battery on the motherboard, and the default position is generally 1 2 short circuit. As long as it is changed to 2, 3 short circuit for a few seconds, the problem can be solved. For the old motherboard, if the user can't find the jumper, just take out the battery, wait until the boot display enters the CMOS setting, then shut down and put the battery on it to achieve the purpose of CMOS discharge.

3. The motherboard can't recognize the memory, and the memory is damaged or mismatched, which will also lead to the failure of not displaying when booting. Some old motherboards are very picky about memory. Once the memory that the motherboard can't recognize is plugged in, the motherboard can't start, and even some motherboards don't give you any fault tips (chirp). Of course, sometimes in order to expand memory and improve system performance, plugging in different brands and types of memory will also lead to such failures, so pay more attention to maintenance.

For the failure of motherboard BIOS damage, we can plug in ISA graphics card to see if it is displayed (if prompted, you can follow the prompt steps). ), if there is no boot screen, you can make a floppy disk that automatically updates the BIOS and refresh the BIOS, but after the BIOS of some motherboards is destroyed, the floppy drive doesn't work at all. At this time, you can try to solve it by hot plug (I tried, as long as the BIOS is the same, it can burn successfully on the same level motherboard. )。 However, in addition to using the same BIOS, hot plug may also damage some components of the motherboard, so a more reliable method is to write the BIOS update file into the BIOS with a code writer (it is safer to find a computer manufacturer with this service).

02 Unable to save MOS settings:

This kind of fault is generally caused by insufficient voltage of the motherboard battery, which can be replaced, but some motherboard batteries can not solve the problem after replacement. At this time, there are two possibilities:

1. The motherboard circuit problem needs professional maintenance;

2. The problem of the motherboard CMOS jumper, sometimes because the CMOS jumper on the motherboard is mistakenly set to the reset option, or set to the external battery, resulting in CMOS data can not be saved.

03 When installing or starting Windows, the mouse is not available:

The software cause of this fault is generally caused by CMOS setting error. There is a modem use IRQ item in the power management bar of CMOS settings, and the options are 3, 4, 5 ... and NA. Generally, its default option is 3, so you can set it as an interrupt other than 3.

04 computers often crash, and setting CMOS will also crash:

In CMOS, there is a crash phenomenon, usually there is something wrong with the motherboard or CPU. If the failure cannot be solved by pressing the button, the motherboard or CPU must be replaced.

This kind of fault is generally caused by the problem of motherboard cache or poor heat dissipation in motherboard design. The author once found that the motherboard on 8 15EP failed due to poor heat dissipation. Touch the motherboard parts around the CPU after the crash and find that its temperature is very hot. After replacing the high-power fan, the crash fault was solved. For the fault with cache problem, you can enter CMOS settings, and the problem can be solved smoothly after disabling cache. Of course, the speed will definitely be affected after caching is prohibited.

05 motherboard COM port or parallel port, IDE port failure:

This kind of fault is generally caused by users plugging and unplugging related hardware. At this time, the user can replace it with a multi-function card, but before replacing it, the COM port and parallel port on the motherboard must be disabled (some motherboards even disable the IDE port to work normally).

display card

Common fault one: no display when starting the machine

This kind of failure is generally caused by poor contact between the graphics card and the motherboard or problems with the motherboard slot. For some motherboards with integrated graphics cards, if the main memory is used for video memory, it is necessary to pay attention to the location of the memory bar. Usually, the memory module should be inserted into the first memory module slot. Because of the graphics card, the computer did not show the fault when it was turned on. Generally, there will be a long beep and a short beep after the computer is turned on (for the BIOS graphics card).

Common fault 2: display the flower screen, and you can't see the handwriting clearly.

This failure is usually caused by the monitor or graphics card not supporting high resolution. When the screen is displayed, you can switch the startup mode to the safe mode, then enter the display settings under Windows 98, and click the "Apply" and "OK" buttons in the color state of 16. Restart, delete the graphics card driver in the normal mode of Windows 98 system, and restart the computer. You can also edit the system. INI file in pure DOS environment, change display.drv = pnpdrver to display.drv=vga.drv, save and exit, and then update the driver in Windows.

Common fault 3: The color display is abnormal, and such faults generally have the following reasons:

1. The graphics card has poor contact with the display signal line.

2. The monitor itself is out of order

3. Some softwares have abnormal colors when running, which are common in old machines. There is an option to check the color in the BIOS, so just turn it on.

4. The graphics card is damaged;

5. The display screen is magnetized, generally because it is too close to a magnetic object, and it may also cause the display screen to deflect after magnetization.

Common Fault 4: Crash

This kind of fault is generally seen in the incompatibility or poor contact between the motherboard and the graphics card; Incompatibility between graphics cards and other expansion cards can also lead to crashes.

Common fault 5: Abnormal spots or patterns appear on the screen.

This kind of fault is generally caused by a problem with the video memory of the graphics card or a poor contact between the graphics card and the motherboard. Need to clean up the gold finger of the graphics card or replace the graphics card.

Common Fault 6: Missing Video Card Driver

The graphics card driver is loaded and automatically lost after running for a period of time. This kind of fault is generally due to the poor quality of the graphics card or the incompatibility between the graphics card and the motherboard, which makes the temperature of the graphics card too high, leading to unstable operation or crash of the system. At this time, you can only replace the graphics card.

There is also a special case, that is, you can load the graphics card driver before, but it crashes when you enter Windows after loading the graphics card driver. Other models of replaceable graphics cards can be solved by loading their drivers and inserting the old graphics cards. If this failure cannot be solved, it means that the registry is faulty, and you can restore the registry or reinstall the operating system.

06 sound card

Common faults 1: There is no sound on the sound card. The common causes of this fault are:

The default output of the 1. driver is Mute. Click the small sound icon (small beep) in the lower right corner of the screen, and the volume adjustment slider will appear with the option of "Mute" below. Click the check box in front, clear the check mark in the box, and you can pronounce it normally.

2. The sound card conflicts with other cards. The solution is to adjust the system resources used by PnP cards so that these cards will not interfere with each other. Sometimes when you open Device Management, although there is no yellow exclamation mark (conflict sign), the sound card just doesn't sound. In fact, there is a conflict, but the system did not find it.

3. After installing Direct X, the sound card cannot make sound. This means that this sound card is not compatible with Direct X, and the driver needs to be updated.

4. A channel is silent. Check whether the audio cable from the sound card to the speaker is damaged.

Common fault 2: The sound card makes too much noise. Common causes of this failure are:

1. Card is not inserted correctly. Because the manufacturing accuracy of the chassis is not high enough, the external baffle of the sound card is not well manufactured or installed, and the sound card cannot be closely combined with the expansion slot of the motherboard. Visually, the "golden finger" on the sound card is misplaced with the expansion slot reed. This phenomenon is very common in both ISA cards and PCI cards. Generally, it can be corrected with pliers.

2. The input of the active speaker is connected to the speaker output of the sound card. For an active speaker, it should be connected to the line output of the sound card and the signal it outputs.

When there is no power amplifier on the sound card, the noise is much less. Some sound cards have only one output. Whether it is line output or speaker depends on the jumper on the card. The default mode of the manufacturer is often the speaker, so unplug the sound card and adjust the jumper.

3.Windows comes with a bad driver. When installing a sound card driver, you should choose "driver provided by the manufacturer" instead of "driver provided by the manufacturer".

If the Windows default driver was installed through Add New Hardware, select Have Disk instead of from the list box. If you have installed the drivers that came with Windows, you can select Control Panel → System → Device Management → Sound, Video and Game Controller, click each device, and then select Properties → Drivers → Change Drivers → Install from Disk. At this time, insert the disk or CD attached to the sound card and load the driver provided by the manufacturer.

Common fault 3: the sound card can't be "plug and play"

1. Try using a new driver or a replacement program. I used to have a sound card, but I couldn't install the driver with the original drive disk under Windows 98, so I had to use the creative SB 16 driver instead, and everything was fine. Later, I upgraded to Windows Me, but it didn't work properly. Then I switched to Windows 2000 (full version) and the sound card driver came with it worked normally.

2. The biggest headache is that Windows 9X detects the plug-and-play device but helps you install the driver without permission. This driver is not available. In the future, you will repeat this problem every time you delete and reinstall, and it cannot be solved by adding new hardware. Here, the author reveals a trick: enter the Win9xinfother directory and delete all the *. About the inf file of the sound card, restart and install it manually. This trick 100% is effective, saving countless sound cards ... Of course, modifying the registry can also achieve the same goal.

3. Installing a PnP sound card is not supported (also applicable to PnP sound cards that cannot be installed by the above PnP method): Enter the control panel/Add new hardware/Next, and prompt "Do you need Windows to search for new hardware?" , select "No", and then select "Sound, Video and Game Controller" from the list to install with the drive disk or directly select the sound card type.

Common fault 4: playing CD silently

1. Completely silent. Windows 98 CD player plays CD silently, but the CD player works normally, indicating that the audio cable of the CD drive is not connected properly. Just use a 4-core audio cable to connect the analog audio output of the optical drive with the CD-In on the sound card. This cable comes with the purchase of CD-ROM.

2. There is only one channel. The output port of CD-ROM drive generally has two lines of signals, and the middle two lines are ground wires. Because the colors of the four audio signal lines are generally different, one-to-one interfaces can be found from the colors of the lines. If there is only one interface on the sound card or each interface does not match the audio cable, we have to change the wiring order of the audio cable, usually only two can be interchanged.

Common breakdowns The PCI sound card has a sonic boom.

The background noise is amplified when the general PCI graphics card uses the bus master control technology, which leads to the hard disk hanging on the PCI bus reading and writing, and the mouse moving.

Solution: Turn off the bus master control function of PCI graphics card, switch to AGP graphics card, and switch PCI sound card to slot.

Common fault 6: unable to record normally.

First, check whether the microphone is inserted into other jacks by mistake. Second, double-click the speaker and select "Properties → Recording" on the menu to see if the settings are correct. Next, adjust "Mixer Equipment" and "Line Input Equipment" in "Control Panel → Multimedia → Equipment" and set them to "Use" status. It would be too bad if the "Record" option in "Multimedia → Audio" is grayed out. Of course, there is no room for redemption. You can try to add "ISA Plug-and-Play Bus" to "Add New Hardware → System Equipment", simply install the sound card with the card tool software and restart it.

Common fault 7: Wav music and Midi music cannot be played.

Few Wav music can't be played. It is often because there is more than one audio device under Multimedia → Devices, so just disable one. If the MIDI file cannot be played, there are three possibilities:

1. The early ISA sound card may be caused by the incompatibility between 16 bit mode and 32 bit mode, which can be solved by installing a software wave table.

2. Most popular PCI sound cards now use wave table synthesis technology. If the MIDI part can't be played, it's probably because you haven't loaded the appropriate wave table sound library.

3. MIDI channel in 3.Windows volume control is set to mute mode.

07 mouse

Common failure 1: mouse not found.

1. The mouse is completely damaged and needs to be replaced with a new mouse.

2. The mouse has poor contact with the host serial port or PS/2 port. After carefully connecting the cable, restart.

3. The serial port or PS/2 port on the motherboard is damaged, which is rare. If this is the case, we must replace the motherboard or use the serial port on the multi-function card.

4. Poor mouse line contact is the most common situation. Poor contact points are mostly at the connection between the wires inside the mouse and the circuit board. As long as the fault is not at the PS/2 connector, it is generally not difficult to repair. Usually because the line is short or messy, the mouse line is pulled hard. The solution is to turn on the mouse and then weld the solder joint with an electric soldering iron. There is also a situation that the mouse cable is caused by poor internal contact and long-term aging. This kind of fault is usually difficult to find, and replacing the mouse is the fastest solution.

Common fault 2: the mouse can display, but it can't move.

The flexibility of the mouse is reduced, and the mouse pointer is not as arbitrary as before, but slow in response, inaccurate in positioning, or simply unable to move. This situation is mainly due to the accumulation of too much dirt on the mechanical positioning roller in the mouse, which leads to transmission failure and inflexible rolling. Maintenance focuses on the X-axis and Y-axis transmission mechanisms inside the mouse. The solution is to open the rubber ball lock plate, take out the mouse ball, wash the rubber ball with clean cloth dipped in neutral detergent, and scrub the friction shaft with alcohol. It is best to drop a few drops of sewing machine oil on the shaft, but be careful not to flow to the grating gap between the friction surface and the code wheel. After all the dirt is removed, the flexibility of the mouse is restored.

Common fault 3: mouse button failure

1. The mouse button does not move, which may be because the distance between the mouse button and the microswitch on the circuit board is too far or the resilience of the click switch decreases after a period of use. Disassemble the mouse and stick a plastic sheet with moderate thickness under the mouse button. The thickness should be determined according to the actual needs, and it can be used after processing.

Wireless mouse how to use wireless mouse tutorial

2. The mouse button can't bounce normally, which may be caused by the fracture of the bowl-shaped contact piece in the microswitch below the button, especially the plastic reed is easy to break after long-term use. If it is a pc mouse, you can remove the middle key for emergency. If it is an original brand-name mouse with good quality, you can weld it, disassemble the microswitch, carefully clean the contacts, apply some grease and install it.

08 keyboard

In the process of using the keyboard, there are various manifestations and reasons for the failure. There are bad contact faults, mechanical faults of keys themselves, logic circuit faults, virtual welding, virtual welding, desoldering, metal hole oxidation, etc. In the process of maintenance, we should analyze and judge according to different fault phenomena, find out the cause of the fault and carry out corresponding maintenance.

How to clean the surface of computer keyboard?

Common fault 1: Some keys on the keyboard, such as space bar and enter key, don't work. Sometimes, you need to press them countless times to enter a character or two. Some keys, such as cursor keys, can't get up after being pressed, and the cursor keeps moving on the screen. At this time, other characters on the keyboard can't be input, so they need to be pressed again to pop up.

What should I do if the computer keyboard fails? The solution of computer keyboard not working.

This kind of failure is the "stuck key" failure of the keyboard, not only the old keyboard that has been used for a long time, but also some new keyboards that have not been used for a long time. Keyboard jamming is mainly caused by the following two reasons: one reason is that the position of the lower insertion column of the key cap is offset, which makes the key cap stuck with the shell of the key body after being pressed and unable to bounce up, resulting in key jamming, which mostly occurs on new keyboards or keyboards that have not been used for a long time. Another reason is that the button is used for a long time, the elasticity of the return spring becomes worse, and the friction between the elastic sheet and the push rod becomes larger, which can not make the button bounce up, resulting in the button being stuck. This reason mostly occurs on keyboards that have been used for a long time. When the keyboard is stuck, you can take off the key cap and press the button. If the pressure bar is not elastic or weak, it is caused by the second reason, otherwise it is caused by the first reason. If the keycap is stuck to the shell of the key body, a washer can be placed between the keycap and the key body. The washer can be made of slightly hard plastic (such as discarded floppy disk sleeve), and its size is equal to or slightly larger than that of the key body. A square hole can be opened at the position where the push rod passes, so that the ammonium rod can pass freely. After being sleeved on the push rod, the key cap can be inserted. Using this gasket to prevent the key cap from sticking to the key body, the faulty key can be repaired; If the spring is tired and the resistance of the elastic sheet becomes greater, you can open the key body and slightly stretch the return spring to restore its elasticity. Remove the elastic sheet to restore the key body. By removing the elastic piece, the resistance of pressing the lever is reduced, so that the faulty key can be restored.

Common fault 2: Some characters cannot be entered.

If only one key character cannot be entered, it may be that the key is invalid or the solder joint is empty. When checking, open the keyboard according to the above method, and measure the on-off state of the contact with a multimeter resistance file. If the button is always non-conductive when pressed, it means that the button reed is tired or has poor contact and needs to be repaired or replaced; If the contacts are normally on and off when pressing the key, it may be caused by virtual welding, desoldering or oxidation of the gold chip hole. You can measure it section by section along the printed circuit to find out the fault and solder it again. If the metal hole fails due to oxidation, the oxide layer can be cleaned and welded again; If the metal hole falls off completely, resulting in an open circuit, additional welding leads can be added for connection.

Common fault 3: If there are multiple keys that are neither in the same column nor in the same row, you cannot enter them.

Maybe the column line or row line is broken somewhere, or maybe there is something wrong with the logic gate circuit. At this time, 100MHz high-frequency oscilloscope can be used to detect, find out the virtual solder joint of the faulty device, and then repair it.

Common fault 4: The keyboard input is inconsistent with the characters displayed on the screen.

This fault may be caused by a short circuit in the circuit board, which shows that pressing this key displays other characters in the same column. At this time, a multimeter or oscilloscope can be used to measure and repair the fault point.

Pressing a key will produce a string of multiple characters, or the characters will jump when pressing the key.

This phenomenon is caused by the failure of logic circuit. First, select a list of characters. If there is a row and a column without the enter key, there may be multiple other characters. If it is a column with enter key, the characters will jump around and eventually cannot enter the system. Check the logic circuit chip with oscilloscope, find out the fault chip, replace the new chip with the same model, and eliminate the fault.

The modem cannot dial or connect:

If the modem is not installed correctly, the communication function will not work properly. The following steps list the incompatible driver files installed in the communication program between the modem and Windows, which may cause the COM port and modem to work abnormally, so you should first check whether the correct Windows98 files are loaded.

1. Check the existing communication file.

(1) Compare communication DRV and serial. Compare the VXD file in the system directory with the original file in Windows95 floppy disk or CD-ROM, and check whether the file size and date are the same.

(2) Confirm that there are the following lines in the System.ini file: [boot] comm.drv = comm.drv [386enh] device = * VCD.

(3) Run the "Add New Hardware" wizard in the Control Panel to detect and install the Windows98 driver. Note: Windows98 does not load serial. VXD driver, but use the registration command to load it. In addition, there are no files related to *VCD in System.ini, and these files are built into VMM32. VXD

2. Verify the configuration of the modem

In the control panel, double-click the modem icon. Verify the manufacturer and model of the modem, run the Install New Modem wizard to detect the modem, and confirm that the current configuration is correct. If your modem does not appear in the list of installed modems, click Add, and then select the appropriate modem. If the manufacturer and type are incorrect, and your device manufacturer and type are not in the list, try to set the maximum baud rate supported by the modem using Hayes compatible option in Universal Modem, and then click OK. Delete all modem entries in the conflict exclusion list.

3. Check whether the modem is available.

Double-click the System icon in Control Panel, then click the Device Management tab, select your modem in the list, and then click Properties to confirm whether the device already exists, please use it.

4. Check the correctness of the port

Double-click the Modem icon in Control Panel, select your modem, and then click Properties. On the General tab, verify that the ports listed are correct. If it is not correct, select the correct port, and then click OK.

5. Confirm whether the I/O address and IRQ settings of the serial port are correct.

Double-click the System icon in Control Panel, click the Device Management tab, then click Ports, select a port, and then click the Properties tab to display the current resource settings for that port. Please refer to the modem manual to find the correct settings. In the Resources dialog box, check the Conflicting Device List to see the devices used by the modem.

Note: If there is a mouse or other device on COM 1, please do not use a modem on COM3. Generally speaking, COM 1 and COM3 ports use the same IRQ, which cannot be used at the same time on most computers. COM2 and COM4 have the same problem. If possible, please change the IRQ settings of COM3 and COM4 ports so that they no longer conflict. In addition, the addresses of some graphics cards also conflict with COM4 ports. If a conflict is found, please use another port or replace the graphics adapter.

6. Check the port settings

Double-click the Modem icon in Control Panel, click Modem, and then click Properties. In the menu that appears, click the Connection tab to check the current port settings, such as baud rate, data bits, stop bits and check.

7. Check the baud rate of the modem

Double-click Modem in Control Panel, select a modem, click Properties, click the General tab, and then set the baud rate to the correct rate.

Matters needing attention

Don't turn it on 24 hours a day, you will occasionally encounter thunderstorm weather.

Will damage the computer.