Basic knowledge of computer maintenance, after reading this article you will repair the computer!
Most computer failures are software failures, so it is not necessary to move the entire machine before it is determined that it is a hardware failure. Even if it is a hardware failure, there is no need to move the entire machine, just take the failed part. Therefore, it is necessary for us to understand the diagnosis and test methods of hardware faults. In the future, if the computer fails, the entire machine will not be moved (of course, it is better not to fail!).
Failure and countermeasures
If you want to do a comprehensive analysis of computer problems, I am afraid to write a book, and that is not easy. The software failure has been introduced in various newspapers and periodicals, so only the symptoms, causes and solutions of hardware failures are introduced here.
First, the computer startup process
I, first come to understand the computer startup process
1. The Bootstrap Loader program and the self-diagnostic program stored in the ROM (Read Only Memory) are moved to the RAM (Random Access Memory).
2. As the Bootstrap Loader runs, the operating system stored in the auxiliary memory device sends the system files to the RAM.
3. Execute the system files Io.sys and Msdos.sys. At this time, the message "Starting Windowsn98..." appears on the screen.
4. Execute it if you have Config.sys.
5. Execute the Command.com file for the system files.
6. Execute it if you have Autoexec.bat.
7. Read the Windows initialization files "System.ini" and "Win.ini" and read the registry file.
8. At the end of the startup, the initial screen appears and the operating system is running.
In this process, the hardware of the motherboard is monitored in the ROM BIOS for abnormalities, including hardware failures, wiring, and installation of various types of cards. If an error occurs, nothing appears on the screen and the startup stops.
This is most likely a hardware failure.
II, system startup sequence
1. PC power ON - the display, keyboard, and lights on the chassis flash.
2. Detecting the graphics card - a short video card message appears on the screen.
3. Detect memory - The capacity information of the memory appears on the sound screen of the beep.
4. Execute BIOS - A brief BIOS message appears on the screen.
5. Detect other devices - information about other devices (CPU, HDD, MEM...).
6. Execute the OS (Operating System) initialization file - Starting Windows 98, etc.
III. A sound is emitted from the motherboard at startup, and this sound can be used to determine what kind of error
The representation of the sound varies depending on the form of the motherboard.
AMI BIOS:
1 short: memory refresh failed
2 short: memory check error
3 short: basic memory error
4 short: system clock error
5 short: CPU error
6 short: keyboard error
7 short: real mode error
8 short: memory display error
9 short: ROM BIOS check error
1 long 3 short: memory error
AWARD BIOS:
1 short: start normal
2 short: non-fatal error
1 long 1 short: display error
1 long 2 short: keyboard error
Other BIOS can check the "BIOS Error Prompt", which will not be described in detail here.
Second, confusing software failure
Hardware faults and software faults must be clearly distinguished. Otherwise, it takes a lot of effort to move the computer to the computer market. The store owner tells you what it is like when the software fails. In particular, startup failures may also be caused by software failures. Let's take a look at the startup exception caused by a software failure.
I, CMOS Setup error
If the hard disk setting in CMOS Setup is not correct, the computer cannot recognize the hard disk, so it cannot be started by the operating system (Windows) in the hard disk. The contents of the CMOS Setup should be checked when a screen appears but cannot be started. To correctly identify the hard disk, you can use the "IDE HDD Auto Detection" option in CMOS Setup.
II, system file error
Windows starts with Command.com, Io.sys, Msdos.sys, Drvspace.bin and four files. If these files are corrupted, they will not start even if the hard disk is recognized. You can then restore these files using the "Sys.com" file. After booting with the boot disk, type "Sys c:".
III, the error of the initialization file
Windows should read "Autoexec.bat", "Config.sys", "System.ini", "Win.ini", "User.dat", "System.dat" six files at startup. However, if there is an error message during the read, the startup will fail. These files are difficult to recover, so use Windows reset and other methods. But this is not a hardware failure, and it is not necessary to hold the computer to the computer market.
IV, Windows Errors Most of the failures after the Windows initial screen appears are software failures. Conflicts between programs or problems with drivers, etc. Such problems can be solved by flipping through books and other methods.
Third, not a faulty hardware failure
Although it is not a malfunction, it is often the case that the user is not assembled correctly or the socket is loose. At this time, you can turn on the computer to check the wiring, socket and other errors. When purchasing a new EIDE device such as a hard disk or a CD-ROM, be careful to set the device connected to the middle to “SlaveE†and the device connected to the side to “Masterâ€. If it is set incorrectly, it may not be able to start or An error occurred while using the corresponding device.
Fourth, the detection method of hardware failure
Let's take a look at the basic test methods for hardware failure. The following method can be used to test the failed part when no image appears on the display.
First, prepare a workbench first.
Second, pull the motherboard out of the chassis, then pull out all the components on the motherboard, leaving only the CPU and RAM. Then put the motherboard on the workbench.
Third, connect the regulated power supply to the motherboard.
4. Insert the graphics card into the AGP slot. Of course, if it is a PCI graphics card, it is inserted into the PCI slot. When inserting, be careful to insert the gold-plated part of the graphics card completely into the slot.
5. Connect the graphics card to the monitor after connecting the monitor's power jack.
6. Turn on the monitor and turn on the power switch of the chassis. Then use a metal rod to touch the power switch of the motherboard.
The power switch of the motherboard is the part that is connected to the power switch of the chassis and is generally labeled "PWRSW" or "POWER SE".
7. If the BIOS version information appears on the screen, the screen is not abnormal, indicating that the CPU, motherboard, RAM, graphics card, and power supply are all normal. Usually, the components that are often prone to failure are "graphics card", "board", "hard disk". order.
Eight, then connect the hard disk and soft area for testing. Then connect to the CD-ROM test, then the sound card. Modem and other one-to-one connections are detected. If the screen does not appear, the component that is connected later is faulty or has compatibility problems. Just deal with the faulty part.
Nine, the problem of the chassis
Sometimes a problem occurs when the motherboard is installed in the chassis, causing the startup to fail. Therefore, if there is no problem in the above component inspection, you can install the motherboard to the chassis for testing. If there are no errors in the test, it is a software problem such as CMOS Setup error, driver, etc.
An easy way to detect computer problems
If the "fake fault" is ruled out, then there is really a fault! If you check the appearance of each accessory, including opening the case to see the surface of the components inside the mainframe are not damaged by high voltage, or obvious scars, if any, the faulty parts will be clear. If you don't have one, try the following processing method first.
1. Remove dust
The dust floating in the air is a big killer of the computer. After using it for a while, it may fail due to too much dust on the key components such as the motherboard, even in a dedicated computer room. Therefore, for computers that have been used for a long time, they should be cleaned first, and the dust on the motherboard and peripherals should be gently brushed with a brush. If the dust has been cleaned, or there is no dust, the fault still exists, indicating that there is something else with the hardware.
In addition, because some cards or chips on the board are in the form of pins, vibration and dust often cause the pins to oxidize and the contact is poor. Use an eraser to wipe off the surface oxide layer, re-plug it and turn it on to check if the fault is eliminated.
By the way, if the keyboard is used for a long time, there will be faults such as electric leakage and button jam. This fault should be handled in time, otherwise some wrong characters will be typed when inputting the file. When handling, the keyboard should be lifted with a bracket, the button should be pressed down, the back cover of the keyboard should be opened, the contacts of the circuit board and the buttons should be cleaned with alcohol, and the shrapnel under the stuck button should be properly picked up to restore the original. Some flexibility.
Note: When a floppy disk is in use, a dirty or scratched floppy disk will scratch the head when it is inserted into the floppy disk drive and damage the floppy disk drive. Be careful when cleaning the magnetic head. If the floppy drive is not used for a long time, there may be rust on the magnetic head. At this time, the cleaning disk cannot be used. The specific method is to open the case and drop the cleaning agent on the magnetic head. After soaking for half an hour, use the grease. Wipe clean carefully. If the cleaning disk is used blindly, it will inevitably cause damage to the floppy disk read/write head, and the floppy drive will be scrapped.
2. Look, listen, smell, touch
“Look†means observing whether the plug and socket of the system board are skewed, whether the resistance and capacitance pins touch each other, whether there is burnt mark on the surface, whether the surface of the chip is cracked, and whether the copper foil on the main board is blown. Of course, it goes without saying that you also need to check if there is any foreign matter falling between the components of the motherboard (this will cause a short circuit), or you can see if there is any burnt-colored place on the board, the trace on the printed circuit board ( Whether the copper foil is broken or not.
“Listen†means that the working sound of the power supply fan, soft/hard disk motor or seek mechanism, display transformer, etc. is normal. In addition, when a short-circuit fault occurs in the system, it is often accompanied by an abnormal sound. The monitor can detect some hidden dangers in time and take immediate measures before the accident occurs.
“Smell†means that there is a burnt smell in the main unit and the board, which is convenient for finding faults and determining the location of the short circuit.
“Touch†means to press the movable chip of the socket to check whether the chip is loose or not in contact. In addition, when the system is running, the shell of the device, such as the CPU, the display, the hard disk, etc., can be judged to be normal according to its temperature; the surface of some chips is touched by hand, and if it is hot, the chip is damaged.
3. Plug and insert detection
As mentioned earlier, there are many reasons for a computer failure. The motherboard itself, I/O bus failure, and various card failures can cause the system to malfunction. The plug-and-play maintenance method is a simple way to determine if a fault has occurred on a motherboard or I/O device. The method is that after the shutdown, the plug-in board is pulled out one by one, and each board is pulled out to observe the running state of the machine. Once the board is operated normally after pulling out a certain block, the fault is caused by the fault of the board or the corresponding I/O bus. Slot and load circuit failure. If the system startup is still not normal after all the boards are removed, the fault is likely to be on the motherboard.
When plugging and unplugging detection, it can also eliminate computer faults from another aspect: some chips, boards and slots are in poor contact. After these chips and boards are pulled out, they can be correctly inserted again to solve the malfunction of the microcomputer components caused by improper installation contact. .
4. Exchange detection
The same type of plug-in board, the same bus type, the same function of the same board or the same type of chip exchange, according to the change of the fault phenomenon can also determine the fault. This method is often used in easy-to-plug maintenance environments. For example, memory self-test errors can be exchanged for the same memory chip or memory module to judge the fault location. The fault-free chips are exchanged. The fault phenomenon remains the same. If the fault phenomenon changes after the exchange, It means that one of the chips exchanged is bad, and the location can be further determined by block-by-block exchange. If you can find the same type of microcomputer components or peripherals, you can use the exchange method to quickly determine whether it is the quality of the component itself.
5. Comparative testing
Run two or more computers of the same or similar type, and determine the location of the fault according to the different performance of the normal computer and the faulty microcomputer when performing the same operation.
6. Vibration tap detection
Gently tap the chassis with your finger. If the fault is removed, the fault is caused by poor contact or solder joint. Then, the location of the fault point can be further checked and excluded, but it is difficult to detect the exact location of such fault.
7. Temperature rise and temperature detection
By artificially raising the temperature of the operating environment of the microcomputer, it is possible to check the high temperature resistance of various components, especially the CPU, so that accidents can be detected early. After reducing the temperature of the operating environment, if the failure rate is greatly reduced, it indicates that the fault is in a high temperature or high temperature resistant component, which can help narrow the fault diagnosis range.
This part of BBQ Tools Set is packing with aluminum case for showing the professional .The BBQ utensils set comes with a convenient and ultra-strong fitted case so you can take your tools go to everywhere. The storage case makes the barbeque tools perfect for camping trips and beach barbecues.This complete set of barbeque accessories is an ideal gift for any avid griller or cook. It is perfect for Father`s Day, birthdays, Christmas, wedding showers, as a housewarming present and more.Certainly ,customized is accepted that you can print your logo on it or manufacture your design. Our bbq tools of handle material have many different choice like hardwood ,beech,PP,PVC, bakelite , metal etc..
BBQ Set With Plastic Case,Plastic BBQ Set,Carving Set In Case, BBQ Tools Set
MEO DEMO CO., LTD. , https://www.meokitchenknives.com