Microcomputer is a high-precision equipment, in addition to correct use, daily maintenance is also very important. I found that in the long-term maintenance work, many failures are due to the lack of daily maintenance or improper maintenance methods. We launch this set of articles, which comprehensively introduce the disassembly and general maintenance methods of various parts of the computer system, with the aim of helping computer users personally protect their computers and nip in the bud. This is the first article, which introduces common maintenance tools, maintenance precautions, daily maintenance methods of main box connection and disassembly, dust in the box and circuit board.

Maintenance tools:

Computer maintenance does not need complicated tools and general maintenance dust, but only a cross screwdriver, a flat screwdriver and a paint brush (or a paint brush, which is easy to shed and should not be used). If you want a clean floppy drive, lens wipes, hair dryers, anhydrous ethanol (AR), absorbent cotton balls, clock screwdrivers (1), tweezers, balloon blowing (leather tiger), paper clips, clock oil (or sewing machine oil) and butter are also needed. If further maintenance is needed, prepare needle-nosed pliers, electric pen and multimeter.

Second, maintain the notes.

If users are not allowed to open some computers with original brands, for example, if they do, users may lose some special attention and have no warranty rights from manufacturers;

Handle each part gently, especially hard wrestling will want it;

Please pay attention to the wiring direction of each plug, such as hard disk cable, floppy drive cable, power cord, etc., so as to restore and disassemble it correctly;

For the repaired screw part, align the first part with the position of the component, and then tighten the screw. Especially for the motherboard, a slight position deviation may lead to poor contact card, and uneven installation of the motherboard may lead to poor contact between the memory card and the adapter card, which may even lead to short circuit or even failure and deformation for a long time;

Integrated circuit devices, computer boards and semiconductor devices are quite sensitive to the manufacture of electrostatic high-voltage MOS technology. When electrostatic people or things touch these devices, electrostatic discharge will occur, and the electrostatic high voltage of discharge will damage these devices. Static electricity is everywhere in our daily life. For example, when you turn off some synthetic clothes, you may hear sounds or see flashing lights. At this time, the damage of static electricity to computer parts is at least 5kV, so you should pay special attention to static protection when maintaining your computer. Therefore, before disassembling and maintaining the computer, the following tasks must be completed:

Disconnect all power supplies;

(2) In the case of opening, both hands should touch the ground or wall to release the static electricity of the body. For the motherboard and card, try to take the side card, and don't touch the integrated circuit board with your hands. If you must contact the internal wiring, it is best to ring the ground;

(3) Don't wear rubber shoes that are easy to generate static electricity, and walk on all kinds of carpets, floors and carpets. In the workplace where metal can release static electricity, good shoes with anti-static floor should be used;

(4) In order to maintain a certain humidity, air drying may also generate static electricity, and the ideal humidity should be 40%-60%;

(5) When using an electric iron, the electric fan should be connected to the primary electric ground wire.

The microcomputer mainframe is being dismantled.

Unplug the peripheral device.

The first step is to turn off the power switch and unplug the power cord, and then you can start to delete all the peripheral devices connected to the back of the chassis.

There are two main forms to disconnect the connection between the peripheral device and the computer. A person just needs to unplug the plug, such as keyboard cable, PS/2 mouse cable, power cable, USB cable and so on. The other plug-in first unscrews the screw handles on both sides of the plug, and then pulls out the printer signal line plug of the horizontal display signal line plug. Some early signal lines did not tighten the handle, so it was necessary to remove the screws on both sides of the plug with a screwdriver.

Open the case cover.

Unplug all peripherals and you can turn it on. No matter whether it is a horizontal or vertical chassis, the screws of the chassis cover are mostly on the back of the chassis. Remove the edges of several screw machine case covers with a cross screwdriver.

Take out the adapter card

The video card and sound card are inserted into the expansion slot on the motherboard and fixed in the back bar window of the chassis with screws. Delete the interface card. First, unscrew the screw with a screwdriver, and then use the upper edge of the crimped interface card to pull out the interface card straight with both hands.

Unplug the drive data cable.

Hard disk drive, floppy disk drive, insert the optical cable into the drive and the other end of the interface socket on the motherboard, and pull the two ends of the tightly held data cable plug horizontally and grind it flat.

Pay attention to two points when unplugging the driver's data cable. Do not unplug the data cable to avoid damaging it. Pay attention to the pull-out direction. Use the red line (1 line) to restore the edge of the data line driver. Corresponding to the pin of the driver interface 1 on the motherboard, there are interface sockets to identify most drivers and board drivers.

Unplug the power plug from the drive.

Hard disk floppy drive, optical drive power plug, advanced pin plug and power plug are a small four-pin plug, which can be pulled out horizontally. Please pay attention to the direction when restoring and installing. Generally, you can't insert it when twisting, and forcibly plugging the power back will damage the drive.

Remove the drive.

The hard disk drive, floppy disk drive and CD-ROM drive bracket are fixed on the chassis panel. You can move the drive when you unscrew the drive bracket screws (some screws on the panel) on both sides of the drive. Unscrew the last screw from the hard hand to the hard disk drive, and be careful to drop the hard disk, which will be damaged if you drop it lightly. Some chassis drives do not require screws and clamping springs. In this case, as long as the spring is released, the driver can be pulled out of the slide rail.

Unplug the power plug from the motherboard.

The power socket is on the motherboard, and the power plug ATX power plug is a double 20-pin plug with a small plastic card on it. You can disconnect it by pinching the power plug of ATX. At the power plugs P8 and P9, the upward pulling force is stabilized and two six-pin plugs are used. Please pay attention to the last reset direction of the power plug. The black line between the 6-pin plugs P8 and P9 should converge in the wrong direction, which will lead to a short circuit of the power supply.

Other plug-ins

The plug may need to be unplugged from the power plug of CPU fan, optical drive and sound card, motherboard and chassis, panel plug, and SB-LINK plug between sound card and motherboard. Such plugging and unplugging should be recorded, such as the color of plug connection and the position in the socket, which can reduce the arrangement of socket pins.

Fourth, clean the dust on the surface of the chassis.

For large areas? Dust on the inner surface of the chassis can be wiped with a wringing wet cloth. Dry the wet cloth and soak the hair dryer with water after wiping. All kinds of plugs and sockets, expansion slots, memory sticks and cards are generally not wiped with water.

Clean slots, plugs and sockets.

Slots to be cleaned, including various bus (ISA, PCI, AGP) expansion slots, memory slots, drive interface plugs and sockets. Generally, all kinds of grooves in the dust are brushed first, and then the dust is blown out by blowing balloons or hair dryers.

In the groove of the metal needle, if there is oil leakage, it can be removed with a cotton ball dipped in special computer cleaner or ethanol. The computer cleaner is mostly carbon tetrachloride plus activator, and the volatiles of the decontamination cleaner are applied. First of all, volatile detergent is available. Of course, it is unstable. The sooner the better. Neutral PH test paper is required to check its acidity, such as acid corrosion, on the blackboard.

Sixth, clean the CPU fan

The CPU of PII and Celeron is still relatively new, and the fans generally don't delete or brush the paint. Dust on older CPU fans generally needs to be removed and cleaned. Let's take the CPU of Socket 7 as an example to introduce the CPU fan dust.

Fix the card of the large-capacity CPU fan on both sides of the CPU socket, and gently press it to remove the CPU fan buckle. Remove the dust from the gap of CPU fan radiator, and pay attention to the dust removal of many fans.

The original CPU fan and CPU are connected into one. Socket 7 socket is gently assigned to the handle and the external handle and the handle positioning card, then pushed up 90 degrees to the vertical position, and then the new CPU is deleted. Clean the CPU fan, and be careful not to dirty the heat-conducting silica gel of the heat sink on the CPU and the joint surface.

Seven, clean the memory and adapter card.

Memory and adapter cleaning, including dust removal and circuit board cleaning. Brush away the dust. The gold finger is the connection point between the circuit board and the socket. If there is dust, oil pollution or oxidation, it will cause poor contact. Outdated computers have caused many failures. High-grade plate gold finger is plated with gold, which is not easy to oxidize. In order to reduce the cost, the gold fingers of adapter cards and memory sticks are not gold plated, but a layer of copper foil, which will oxidize over time. You can wipe the dust, grease or oxide layer on the surface of the golden finger with an eraser, but you can't wipe the golden finger with sandpaper, otherwise it will destroy the thin coating.

Removal and maintenance of the driver-cleaning the focusing lens, laser head and laser power adjustment

In the initial failure, more drives, the basic configuration of CD-ROM multimedia computer, in actual use, the drive failure, choose the disk, because it is more and more serious, until the disk can not be read. This failure is usually caused by the aging of the focusing lens, dusty laser head or laser tube. Therefore, when the unreadable disk fails, the cleaning process of the first optical head includes general dust removal and cleaning of the focusing lens and the laser head. If the fault still cannot be eliminated, the laser current adjusting potentiometer is broken or the laser diode is aging, you can try to solve it by adjusting the potentiometer. The failure of the CD-ROM drive can be mainly repaired by the above methods. Taking Sony CDU3 1 1 eight-speed optical drive as an example, this paper explains how to disassemble the optical drive, clean the focusing lens and laser head, and adjust the laser power.

CD-ROM drive is a kind of high-precision optoelectronic equipment. Disassembly and cleaning should follow certain steps, so it is easy to be damaged. Removing a CD-ROM drive usually follows the following steps.

1, remove the bottom plate.

A flat-bottomed optical drive is installed. Unscrew the screw mounting base with a Phillips screwdriver and remove the circuit board at the bottom of the optical drive from the metal floor. The bayonet got stuck in the backboard. The backplane must be gently pushed to the back of the CD-ROM drive to get rid of its bayonet, and then enter the CD-ROM drive on the floor to unload the backplane of the corresponding buckle of the drive housing (concave metal upper cover).

2. Pull out the CD tray

The button is on the disk on the left side of the CD-ROM drive with a diameter of 1.0? Insert the 1.5mm paper clip straightened from the forced ejection hole into the emergency ejection hole, push it about 2.5cm, eject the tray, and then pull the tray out by hand. Some optical drives don't eject the hole forcibly, the power tray bracket slides out, the "tray" button is completed, and then the power supply is turned off. If the CD-ROM is inserted into the chuck and deleted, check the lubricant sliding on the disc tray. If it is dirty or solidified, a few drops of watch oil or high-grade butter will wipe off the movement. Of course, the chuck may be caused by mechanical failure, so check the mechanical part.

Remove the front panel of the optical drive.

In the front panel at the side and top, everyone gently moves the buckle inward and pulls the front panel forward away from the metal groove where the buckle is stuck on the metal shell (cover).

4. Take out the movement

Sony CDU3 1 1 drives the movement (including the circuit board) to pull out the front panel, and then it can be taken out of the housing.

As shown in fig. 5, clean the focus lens.

Moving face up, the optical disc tray, the glass spherical focusing lens at the top of the optical head assembly can already be seen, transparent body-sized soybeans. You can clean the focusing lens with a cotton swab dipped in a little alcohol. Before cleaning, take a closer look at the surface of the focusing lens. Dust or fog can be seen with a magnifying glass. Gently wipe the dust on the lens surface with absorbent cotton or lens paper, which is a little more than wiping a few times, so that you can get a clear and transparent lens. When the focusing lens is mounted on the elastic body, a slight wiping force is applied, but excessive displacement or deflection will affect the reading disk of the ambassador lens. Do not use tweezers to avoid scratching the lens surface. Hit the focusing coil on one side of the unfocused lens.

Cleaning solution is needed, and what kind of cleaning solution is controversial in the industry. I believe it is usually unnecessary to use cleaning solution. If dirt cannot be removed by drying, consider using a cleaning solution. Never rinse with clean water. Whether the laser head can be cleaned with alcohol is also controversial. I believe it is with high-purity anhydrous ethanol. Alcohol usually refers to an ethanol solution containing water and impurities. Therefore, alcohol is not suitable for cleaning laser heads. Anhydrous ethanol is a weak organic solvent close to neutrality, and its purity can be divided into industrial purity, chemical purity, analytical purity and spectral purity from low to high. The higher the purity, the less moisture and impurities in laser generators, photodetectors, focusing lenses, laser beam splitters, servo motors, etc. The focusing lens of the optical disc located below is most easily contaminated by dust, and the surface of the lens is cleaned by the cleaning device under normal conditions. The surface of the lens is coated with a film, that is, an anti-reflection film, which is called magnesium fluoride. The function of antireflection film is to reduce refraction and increase transparency. Magnesium fluoride is insoluble in ethanol and easy to absorb water and deform.

Absolute ethanol above AR level contains water and impurities with low content and high volatility, which can dissolve organic impurities without causing harm. Anti-reflection coating. So I think we should use high-purity anhydrous ethanol to clean the optical head of the lens. Actual maintenance work, such as focus plane appearance without damage. Cleaning with water is not advisable, because magnesium fluoride can easily absorb water and impurities in water may damage the anti-reflective coating and make the optical drive work abnormally. Similarly, laser heads containing impurities and alcohol in water are not suitable for cleaning.

6. Remove the laser head assembly.

If cleaning the focusing lens can't eliminate the fault, further disassemble the laser head assembly for further processing. One side of the laser head assembly is provided with a cylindrical metal rod, and the metal rod converges and slides with the other side of the stepping motor driving mechanism.

Sony CDU3 1 1 driver can remove the laser head assembly by unscrewing at most one screw. The suggestion of the front cord is to unplug the cord and draw a straight line with pen and ink, and make a good mark to determine whether it is in the right rear position for easy recovery. Don't fold, gently pull the plug and insert the cord, which is difficult to repair after damage.

7. Clean the laser head

The laser head (laser emitting tube and photoelectric receiving tube) is mounted on a small circuit board, usually an 8-pin flexible cable lead. The circuit board of the laser head is installed on the side of the laser head assembly. The laser emitted by the laser emitting tube is separated from the optical path by the prism formed by Descartes, reflected by the back focusing lens and the optical disk, and received by the photoelectric cell. The circuit board fixes the optical head assembly of the laser head. You can take out the circuit board, then clean the laser transmitter and photoelectric receiver tube, or wipe the hole prism off the cotton of the corresponding hole circuit board.

The optical head Sony CDU3 1 1 of the driver cancels the reflective prism, and the laser beam used for transceiving directly passes through the focusing lens. This method can be used for cleaning without removing the circuit board.

To clean the dust cover of the focusing lens of Sony CDU3 1 1 optical drive laser head, the black plastic cover must be taken out first. Two snap buttons and two metal casting holes on both sides of the plastic dust cover are stuck at the bottom of the optical head assembly, and the bottom of the laser head with glue faces upwards. Remove the plastic end clip fixed at the front end of the tweezers dust cover 2 and loosen the dust cover upwards.

After opening the dust cover and focusing the lens, you can see that there is a circular hole in the lower part of the laser head just below the circular hole. L-shaped reel cotton made of fine copper wire carefully wipes the photoelectric device of the laser head, and cotton is inserted in the hole at the bottom. Be careful not to scratch the surface of photoelectric device by laser, and don't hang the elastic line of focusing lens that is broken due to bumping, only from its hanging effect and the lead wire of focusing coil, otherwise the loop of focusing coil will be damaged. It should be noted that the sealed cavity of most drivers' laser heads is not easy to enter dust, and it is not easy to disassemble and clean, and careless operation may lead to the waste of drivers. It is strongly recommended that ordinary users do not implement the topping operation.

8. Adjust the working current of the laser tube.

If it still doesn't work, the driving during cleaning shows that the laser tube is aging to some extent. You can try to adjust the current to increase the output power of the laser tube.

Sony CDU3 1 1 The working current of the driving laser is on the side of the laser head assembly, and the fine-tuning potentiometer is the size of mung bean. Many early laser power fine-tuning potentiometers are on the side of the laser head assembly, and the laser head assembly you need to delete can be adjusted more conveniently.

Before adjustment, make a mark with the potential of colored pen, and pay attention to the initial position; The screwdriver potentiometer rotates by a small angle in a certain direction. According to the author's experience, one of the reasons for the poor contact caused by the failure of the fine-tuning potentiometer is that sometimes the potential problem can be solved with a little movement. We strongly recommend that each adjustment should not exceed 10 degrees, which will provide users with the condition that the resistance of direction adjustment measured by multimeter decreases. Adjust the installation each time, and then try again until you can read the disk correctly. The overall adjustment range should not be too large to prevent the laser tube from being burned by excessive current.

After reading this article, you may want to clean your CD-ROM. However, a little carelessness may lead to the scrapping of the hard disk. Since the current CD-ROM drive is not cheap, I think you should explain the following precautions.

Do not turn on the CD-ROM drive without fault. The optical drive is a precision device, but it will not disassemble the damage of the frequency converter. Many CDs are irretrievably disassembled and improperly maintained, which means: as long as your drive works normally, don't toss it.

Some CD-ROMs that CD-ROMs can't read may be due to poor quality of CD-ROMs, circuit failure, mechanical failure or software factors. It is suggested to rule out other factors first.

When removing the optical drive, please pay attention to save all the removed parts. The loss of any small part may lead to an unrecoverable CD-ROM drive.

During operation, because many optical drive parts are made of plastic, the force should be moderate, otherwise the plastic parts will be damaged. In addition, do not use hair dryer, hot air not only causes plastic deformation, but also may affect the normal performance of other parts.

5. Different types of optical drives have slightly different structures. Introduce Sony series optical drives. How do you drive? Disassembly and cleaning mainly depend on your own exploration.

Cleaning, maintenance and repair of floppy disk drive

Floppy disk is an external device that needs to be maintained in the microcomputer system of 1. Too much dust is the most common cause of floppy disk drive failure, and dust head, photoelectric detector and stepping motor drive screw are the key points of floppy disk drive cleaning. When cleaning dust, be careful not to damage the head or head deviation, otherwise the head deviation caused by man-made craniocerebral injury will be difficult to deal with. If the magnetic head is not dirty, it can be used to clean the disk without disassembling and cleaning the floppy drive. Invalid cleaning and cleaning disk, manual cleaning floppy disk drive must be removed. The process is carried out in the following order.

Eight-head cleaning disc

Frequent contact with floppy disks, pollution on CDs, and excessive dirt and dust lead to floppy disks.

Reading and writing floppy drive is the most common fault. Cleaning the floppy disk is very simple. Spray detergent or ethanol (analytical grade) evenly to clean the disk and the power supply of the computer. After the system is successfully started, insert the cleaning disk into the floppy disk and the floppy disk will rotate by itself, and the dirt and dust around the disk will be adsorbed on the magnetic head.

X. take out and clean the floppy disk.

1, remove the cover.

Screw down the next screw or two screws on the concave thin metal cover of the floppy disk (this step can omit some floppy disk drives that cannot be tightened). The cover pulls the upper structure slightly to both sides and fixes it on the cast aluminum base with a Phillips screwdriver and screws. The protruding button is manually cleaned, and the aluminum base is cast. You can remove the floppy drive from the cover.

Cleaning head

The number 0, 1 of the floppy drive is fixed at the bottom of the car, and the plastic-headed car connected with the fixed arm under the head cannot move, making it easier to clean. The magnetic head is fixed on the top of the movable arm of the plastic head trolley through an elastic piece, and the upper part of the other end of the movable arm is a spring piece of the screw. It is possible to clean the print head with a little force, but it should be noted that excessive force may lead to the deviation of the print head and the urgent attention to the adjustment of the deviation fault of the print head, which is very difficult to clean.

Absorb water to clean, dip in alcohol or special head cleaner, gently scrub the head and wipe it more. You can wipe off stubborn attachments. Press your hand down gently to avoid head deviation. Alcohol dissolves in the dirt on your head. Clean your head and gently wipe off the dirt.

3. Clean the stepper motor shaft screw.

If it is dirty or floppy disk reading, if the system often gives the wrong file reading or the department can't find the prompt, and the most important stepping motor shaft and the print head car are not connected well, please check whether the spindle screw lubricating oil of the stepping motor is solidified. You can clean it with alcohol and add a little Jason Chung oil or advanced butter. You can rotate the screw by hand to move the headstock to clean the whole screw.

4. Cleaning and photodetector

In the old floppy drive, the disk density detection and disk replacement detection are completed by photoelectric detectors, and the photoelectric surfaces of photoelectric emission tubes and receiving tubes are wiped with cotton swabs dipped with a small amount of anhydrous ethanol. There is no need to deal with a new floppy disk drive whose detector is a microswitch.

Cleaning, Maintenance and Repair of Mouse

The mouse is an input device and the computer is indispensable. Dust should be when you find the mouse, the mouse pointer moves on the screen and can't work normally. The cleaning and maintenance of rats can be carried out according to the following steps.

As shown in figure 1

Contact with the mouse and the bottom of the table for a long time is the most vulnerable to pollution. Especially mechanical and optical mechanical mice are easily affected by dust, hair and fine fibers. Optical mouse, the following example illustrates the method of disassembly and dust prevention.

At the bottom of the mouse ball in the outer ring is a round plastic cover. Gently press the plastic cover and turn it counterclockwise. You can take off the plastic cover and take out the ball. Remove the dirt on the fingers of two shafts and a wheel inside the mouse, and remove the ball falling into the mouse. You can use neutral detergent to avoid dirt.

2, open the lid to dust

If the pointer moves or the problems mentioned above, especially if it doesn't work in a certain direction, and most photoelectric detectors cause dirt on the files, then remove the screws on the mouse bottom cover and scrub the photoelectric detectors and the dirt in the middle with a cross screwdriver.

3 button troubleshooting

Wear of mouse buttons is a common failure that leads to button failure. The worn part is generally the contact of the small button on the spot. Main mechanical switch or small button with plastic cover can be connected with self-adhesive paper or brush to solve dry glue in case of emergency. A better way is the key to change. Mouse buttons are sold by General Electric Accessories Company, and left communication is also a common practice.

Hodge's poor quality mouse buttons can't be broken, and small copper replaces the existing micro-switch of waste electronic lighters. Bad soldering components of mouse circuit board may also fail. The most common fault is that the mechanical switch at the bottom of the solder joint is damaged or desoldering.

Cleaning and maintenance of keyboard

Keyboard is one of the most commonly used input devices, and it is very convenient to use even if the keys fail. Keyboard belongs to electromechanical equipment, which is used frequently. There is a big gap between the keyboard base and the keys, which is easy to invade dust. It is very important to clean and maintain the keyboard regularly.

One of the simplest maintenance is to tap the keyboard to let the dust drip out of the school gate. Two. Clean the keyboard surface with a damp cloth, but pay attention to wring it out to prevent water from entering the internal keyboard.

Longer keyboards need to be disassembled for maintenance. Dismantling the keyboard is relatively simple. Unplug the cable plug connecting the keyboard and the host, then put the keyboard on the workbench and unscrew the screws on the floor. You can remove the keyboard cover. The following respectively introduces the disassembly and maintenance of mechanical key keyboard and electric touch key keyboard.

Mechanical key keyboard

After deleting the keyboard backboard of the mechanical key, you will see a circuit board. Several screws of the circuit board are fixed on the front panel of the keyboard. Unscrew the screws and remove the circuit board.

Connect the plug, unplug the cable and circuit board, and clean the dust on the circuit board and keyboard keys with a paint brush or oil painting pen. Under normal circumstances, do not clean with a wet cloth. The key switch welded on the circuit board is stuck, and the key switch on the key cap. If you want to pull out the key cap of the key switch, you can gently pry it up with a flat screwdriver to loosen the key cap. Generally speaking, there is no key cap that needs to be removed, and some keyboards are difficult to recover after deleting the key cap.

One of the key faults is that the key switch can be welded, which is convenient for maintenance, disassembly and maintenance. However, the components of the key switch are very small. Due to mechanical failure, in most cases, the best way to repair short-lived keys is that the keys on the same type of keyboard or the keys (F 12) fail to exchange welding positions.

Secondly, electrically contact the key keyboard.

When the electric contacts of the keyboard are opened behind the bottom plate and the cover plate, you will be able to see three films embedded in the bottom plate, the lower contact layer, the middle spacer layer and the upper contact layer. The upper and lower contact layers inhibit the connection of metal circuits, and the keys of the corresponding circular metal contacts have a circular hole, corresponding to the upper and lower contact layers and the middle spacer layer. A front panel embedded in the electrical contacts of all keys of the keyboard, three layers of thin films and keys on the front panel have rubber pads between them, and the convex parts of the rubber pads embedded in the keys corresponding to the keys on the front panel press down the downward concave parts on the convex parts corresponding to the rubber pads, so that the films contact with the circular metal contacts through the lower contact layer of the circular hole on the intermediate isolation layer and send key signals.