Experiences in computer maintenance

I have been engaged in computer management and maintenance for a long time. I need to check and maintain computers frequently to ensure normal teaching work. For school computers, due to frequent use by students, some problems often occur. I have observed that there are not many hardware faults, even if most of the contact problems are caused by oxidation of gold fingers of dust or components, the problem can be solved by removing dust or oxide from accessories. This is a hardware soft fault; more is caused by software or system faults. This requires us to take the right medicine and conduct reasonable analysis based on the actual situation to solve machine problems. I share my experience in computer maintenance with you to help readers.

1. Battery fault

There are a group of Lenovo 3000 computers in the school Data Center daily, which are usually used normally. However, after a holiday, more than a dozen machines experienced the following faults: when the power switch is pressed, the power supply does not start. At the beginning, I thought that the power supply was broken. I changed the power supply and pressed the power switch again. The computer still didn't respond, and the fan didn't rotate at all. After carefully observing the connection between the motherboard and the power supply, no exception was found. Other accessories were immediately tightened, and the fault still exists. Considering that the failure of so many machines is the same, it is considered that the motherboard, memory, and power supply are very less likely to be bad. After checking the random data, we also think that the startup of the motherboard is related to CMOS, however, CMOS is supported by * battery. The CMOS battery is taken out and measured with a voltmeter. the voltage is only about 1.0v, which is significantly lower than the original voltage 3.0v. The CMOS discharge on the main board is initialized, turn on the host power, the machine can perform self-check, I put the original battery back, the machine has a fault. Replace the new battery and the computer starts normally. All problems have been solved. This type of fault is caused by a CMOS battery, because the battery on the computer motherboard generally uses a lithium battery. After the battery is turned off, it supplies power to the CMOs. After the battery is turned off, the power is replenished from the motherboard, but the shutdown takes a long, if the machine is not powered for a long time, the CMOS battery will inevitably run out and cannot replenish the energy, which will lead to a fault that cannot be started on the motherboard. Therefore, we must pay attention to the battery maintenance when maintaining the computer.

2. Fault Caused by hard disk Protection Card
In school computer management, hard disk protection cards are usually installed on the machine to protect the machine system from being damaged by students and maintain normal teaching. This also causes some faults. If a student reports that the machine cannot be started, the user finds that the machine self-check is normal. After the self-check, the machine stops starting. According to experience, it is considered that the accessories are not in good contact, the accessories are tight and restarted, and the fault persists. Later, we minimized the startup of the machine, and the machine was normal. Then we added accessories to the machine. When the protection card was inserted, the machine encountered another fault. So far, The Culprit found out that this was a fault caused by the protection card. Because the machine runs the protection card program after self-check, the machine cannot be started due to the bad protection card. If the new protection card is changed, the machine can be started normally.

3. Reset Key Issues

Students' hands-on internships often have some strange problems. For example, during an internship, the student reported that the machine could not be started. I used to check that the fault was: The display was not displayed, the host power supply and hard disk indicators were normal, and no alarms were reported on the motherboard. Ask the students to say they still use the program, but the program crashes during compilation and restarts. Move the machine back to the repair room, open the chassis, clean the machine, restart the machine, or do not start it. Then remove unnecessary accessories and observe the accessories carefully. No problems are found and the fault persists. Later, the motherboard was removed for testing. Everything was normal, indicating that there was no problem with the motherboard. The motherboard, power supply, and display are good. Why can't they work together? Re-installation, unplug unnecessary motherboard and panel connections (such as hard drive indicators and reset keys), turn on the power, host self-check start normal, and then plug in the connections in turn, when the reset connection is plugged in, the machine encountered the problem just now. It was determined that the reset key was the cause of the fault. It must have been the reset key that students just pressed when programming crashed, and the reset key was not reset, computer Fault. It is found that there is dust in the reset button. As a result, the reset button cannot be reset, so that the machine remains in the reset state. After the reset key is cleared, the machine can be reset normally and the fault is immediately eliminated.

4. Computer black screen caused by memory

One day, the students had an internship on the computer and suddenly reported a black screen on the computer. I rushed to watch it. The computer was powered, but there was no display. Test the monitor first. It is suspected that it is a problem with the video card. I open the machine, unplug the video card, observe it is normal, and then perform dust removal, and then use an eraser to wipe the Gold finger of the video card, remove some accessories (such as NIC, the computer still cannot start. Later, I unplugged the memory and restarted the machine. The machine reported an alarm and initially determined that the memory may be faulty. I unplugged the memory and observed it carefully. I found that the memory was in good condition. Then I observed the memory slot and found that there was some dust in it, handle it, install a memory stick, boot everything is normal. This is because we generally think that the memory is faulty when we repair the machine, and the machine will issue an alarm. However, in this case, the machine does not trigger an alarm because of poor memory access, but the computer is black when it is started up, we didn't think of the memory problem, so we had to make a detour in service, so we should also consider whether the memory stick is plugged in and whether it is in good contact with the slot when repairing the machine.

5. System Blue Screen caused by hardware conflicts

Due to the needs of students' practice, sometimes some application systems need to be installed to meet the teaching needs. A large number of installation cannot be performed on a single machine. Generally, a machine is installed first and used as the master machine, then, the software is used for launch to complete mass installation. Once after installing a batch of application systems for Lenovo benyue-1100, it was found that a batch of machines Windows started to work normally. After a while, blue screens appeared in the system, but the security mode could work normally. Because a batch of machines cannot normally enter the system, and considering that the security mode does not load related hardware drivers and some system services, it is certainly caused by hardware incompatibility. Check again and find that the motherboard models of the two machines are different. One batch is Lenovo's qdi motherboard, And the other batch is the gigabyte motherboard. The minimum system method is used for the blue screen machines, and the machines cannot start normally, later, the device starts in safe mode, enters the Device Manager of the control panel, uninstalls the sound card and NIC Driver, restarts, and the machine runs normally. Then, the sound card and NIC driver are re-installed, let the system re-default the Interrupt Interface and address, and restart the machine normally. This is because different boards have different default interruptions and addresses for sound cards and NICs. When installing machine systems in large quantities due to hardware conflicts, we need to re-set them correctly, to ensure the blue screen of the machine.

In short, there will always be one or more problems during machine maintenance, which requires our management and maintenance personnel to be bold and meticulous, without any clues, solve actual problems based on your experience and actual machine faults to ensure normal operation of the machine.

Author: Yang zhenhui

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