1. Maintenance tools:

Computer maintenance does not require very complicated tools. For general dust removal maintenance, you only need to prepare a Phillips screwdriver, a flat-blade screwdriver, and a paint brush (or oil paint brush or ordinary brush) It is easy to remove hair and should not be used). If you want to clean the inside of the floppy drive or optical drive, you also need to prepare lens wipes, hair dryer, absolute ethanol (analytical grade), absorbent cotton balls, clock screwdriver (set), tweezers, blower (pipe tiger), paper clips, clock oil ( Or sewing machine oil), butter will do. If further repairs are needed, prepare a pair of needle-nose pliers, a test pen and a multimeter.

2. Maintenance Precautions

Some original and brand computers do not allow users to open the case by themselves. If you open the case without authorization, you may lose some warranty rights provided by the manufacturer. Please pay special attention to Attention;

Each component should be handled with care, especially the hard disk, as a drop will kill it;

When disassembling, pay attention to the orientation of each plug cable, such as the hard disk cable , floppy drive cable, power cord, etc. for correct restoration;

When restoring and fixing each component with screws, you should first align the position of the components, and then tighten the screws. Especially for the motherboard, a slight positional deviation may lead to poor contact of the plug-in card; uneven installation of the motherboard may cause poor contact of the memory module and adapter card or even cause a short circuit, which may even deform over time and cause malfunction;

< p>Since the integrated circuit devices on computer boards are mostly manufactured using MOS technology, this type of semiconductor device is quite sensitive to electrostatic high voltage. When people or objects with static electricity touch these devices, electrostatic discharge will occur, and the released electrostatic high voltage will damage these devices. Static electricity is ubiquitous in daily life. For example, when you take off some chemical fiber clothes, you may hear a sound or see a flash of light. The static electricity at this time is at least 5kV, which is enough to damage the components of the computer. Therefore, it is necessary to maintain the computer. Pay special attention to electrostatic protection. Therefore, the following points must be done before disassembling and maintaining the computer:

(1) Disconnect all power supplies;

(2) Before opening the case, both hands should touch the ground or wall , release the static electricity on your body. When holding the motherboard and plug-in card, try to hold the edge of the card and do not touch the integrated circuit of the card with your hands. If you must come into contact with internal circuits, it is best to wear a grounding ring;

(3) Please do not wear rubber shoes that are prone to friction with floors and carpets to generate static electricity when walking on various types of carpets. Wearing metal shoes can effectively release static electricity from the human body, and anti-static floors should be used in workplaces where conditions permit;

(4) Maintain a certain humidity. Dry air can also easily generate static electricity. The ideal humidity should be 40%-60%;

(5) When using electrical appliances such as electric soldering irons and electric fans, the grounding wire should be connected.

3. Disassembly of the microcomputer host

Unplug the peripheral connections

Turn off the power switch and unplug the power cord, then you can start to disassemble the host. The first step in disassembling the console is to unplug all peripheral cables from the back of the case.

There are two main ways to unplug the connection between the peripheral and the computer. One is to pull the plug directly outward, such as keyboard cable, PS/2 mouse cable, power cable, USB cable, etc. ; For another kind of plug, you need to loosen the screw fixing handles on both sides of the plug first, and then pull it flat outward, such as the monitor signal cable plug and the printer signal cable plug. Some early signal cables did not have screw fixing handles, so you need to use a screwdriver to unscrew both sides of the plug. of screws.

Open the chassis cover

After unplugging all peripheral connections, you can open the chassis. Whether it is a horizontal or vertical chassis, most of the fixing screws of the chassis cover are on the rear side of the chassis. On the edge, use a Phillips screwdriver to unscrew a few screws to remove the chassis cover.

Remove the adapter card

Insert the display card and sound card into the expansion slot of the motherboard and fix them on the strip window on the back of the chassis with screws. When removing the interface card, First use a screwdriver to unscrew the screws fixing the card on the upper edge of the strip window, then pinch the upper edge of the interface card with both hands, and pull the interface card straight upwards.

Unplug the drive data cable

Plug one end of the hard disk, floppy drive, and optical drive data cable into the drive, and the other end into the interface socket on the motherboard, and pinch both ends of the data cable plug. , pull it out smoothly in the horizontal direction.

When unplugging the drive data cable, pay attention to two points. First, do not pull the data cable downward to avoid damaging the data cable; second, pay attention to the direction of unplugging for restoration. There is a stripe on the edge of the drive data cable. Red line (line 1), this line corresponds to pin 1 on the driver and motherboard driver interface. There is a 1 mark next to the driver and motherboard driver interface sockets.

Unplug the power plug of the drive

The power plug of the hard disk and optical drive is a large four-pin plug, and the power plug of the floppy drive is a small four-pin plug. Just pull it out in the horizontal direction and install it. Please pay attention to the direction when restoring. Generally, it cannot be inserted in the reverse direction. Forcibly inserting it in the reverse direction will damage the drive after turning on the power.

Remove the drive

The hard disk, floppy drive, and optical drive are all fixed on the drive bracket inside the chassis panel. When removing the drive, please first unscrew the screws on both sides of the drive bracket that fix the drive (some set screws on the panel) and the drive can be pulled forward. When unscrewing the last screw of the hard drive, please hold the hard drive with your hands. Be careful if the hard drive falls. The hard drive will be damaged if it is dropped lightly. Some drives in the chassis are not fixed with screws but are clamped with spring sheets. In this case, just loosen the spring sheets and the drive can be pulled out from the slide rail.

Unplug the motherboard power plug

Plug the power plug into the motherboard power socket. The ATX power plug is a double-row 20-pin plug. There is a small plastic card on the plug. Pinch it. The ATX power plug can be unplugged. The AT power plugs are two six-pin plugs P8 and P9, just pull them out smoothly. When restoring the AT power plug, please pay attention to the direction. The black wires in the middle of the six-pin plug P8 and P9 should be close together and inserted downward. Wrong direction will cause a short circuit in the power supply.

Other plugs

The plugs that need to be unplugged may include the CPU fan power plug, the audio cable plug between the optical drive and the sound card, the plug between the motherboard and the chassis panel, and the plug between the sound card and the motherboard. SB-LINK plugs, etc., when unplugging these plugs, you should make a record, such as the color of the plug wire, the position of the socket, the arrangement of the socket pins, etc., to facilitate restoration.

4. Clean the dust on the inner surface of the chassis

For large areas of dust on the inner surface of the chassis, you can wipe it with a wrung-out damp cloth. The wet cloth should be as dry as possible, and after wiping, use a hair dryer to dry the water stains. Generally, various plugs and sockets, expansion slots, memory slots and boards should not be wiped with water.

5. Clean slots, plugs and sockets

Slots that need to be cleaned include various bus (ISA, PCI, AGP) expansion slots, memory slots, various Driver interface plug socket, etc. The dust in various slots is generally cleaned with an oil paint brush first, and then blown away with a blower or hair dryer.

If there is any oil on the metal pins in the slot, you can use absorbent cotton balls dipped in computer-specific cleaner or absolute ethanol to remove it. Computer-specific cleaners are mostly composed of carbon tetrachloride and activators. Apply the decontamination and then clean. The agent can evaporate automatically. When purchasing a cleaning agent, firstly, check its volatility. Of course, the faster it evaporates, the better; secondly, use PH test paper to check its acidity and alkalinity. It must be neutral. If it is acidic, it will corrode the board.

6. Clean the CPU fan

PII and Celeron CPUs are still relatively new. Generally, the fan does not need to be removed, just clean it with a paint brush or oil paint brush. Older CPU fans have a lot of dust on them and generally need to be removed and cleaned. The following uses a Socket 7 CPU as an example to introduce dust removal from the CPU fan.

The loose CPU fan is stuck on the buckles on both sides of the CPU socket. Press the fan buckle slightly to remove the CPU fan. After removing the CPU fan, you can remove dust from the fan. Note that there is a lot of dust in the gaps of the heat sink.

The original CPU fan is integrated with the CPU. You need to gently pull the handle next to the Socket 7 socket out a little to disengage the handle from the handle positioning card, then push it up to a vertical 90-degree position, and then Lift the CPU upwards. When cleaning the CPU fan, be careful not to dirty the thermal silica gel between the CPU and the heat sink.

7. Cleaning memory modules and adapter cards

Cleaning memory modules and various adapter cards includes dust removal and cleaning the gold fingers on the circuit board. Just use a paintbrush to remove dust. The golden finger is the connection point between the circuit board and the slot. If there is dust, oil or oxidation, it will cause poor contact. This resulted in a large number of failures in old microcomputers. The gold fingers of high-end circuit boards are gold-plated and are not easily oxidized.

In order to reduce costs, the gold fingers of adapter cards and memory modules are generally not gold-plated, but only a layer of copper foil, which will oxidize over time. You can use an eraser to wipe away dust, oil or oxide layer on the surface of the gold finger. Do not use sandpaper to wipe the gold finger, otherwise the extremely thin coating will be damaged.

Disassembly and maintenance of the optical drive - cleaning the focusing lens, laser head and laser power adjustment

The optical drive is an indispensable basic configuration of a multimedia computer. In actual use, the optical drive fails Most of the time, when the optical drive fails initially, it usually picks the disk, and then it becomes more and more serious until it cannot read the disk. This failure is usually caused by excessive dust accumulation on the focusing lens, laser head, or aging of the laser tube. Therefore, after the failure of disk reading occurs, the optical head can be cleaned first, including general dust removal and cleaning of the focusing lens and laser head. If the fault still cannot be eliminated, it may be caused by poor contact of the laser current adjustment potentiometer or aging of the laser diode. You can try to solve the problem by adjusting the potentiometer. Most of the faulty optical drives that the author dealt with were repaired through the above methods. This article mainly takes the SONY CDU311 eight-speed optical drive as an example to introduce the methods of disassembling the optical drive, cleaning the focusing lens, laser head and adjusting the laser power.

The optical drive is a high-precision device that integrates optical, electrical and mechanical components. Disassembly and cleaning should be carried out according to certain steps, otherwise it will be easily damaged. Disassembly of the optical drive can usually be carried out according to the following steps.

1. Remove the bottom plate

Put the bottom of the optical drive flat upwards, use a cross screwdriver to remove the screws fixing the bottom plate, and remove the metal bottom plate upwards. At this time, you can see the circuit at the bottom of the optical drive. plate. Some optical drive base plates have bayonet pins that are stuck on the corresponding buckles of the casing (concave metal upper cover). To remove such optical drive base plates, you must push the base plate slightly toward the back of the optical drive to disengage it from the bayonet pins, and then lift it upwards. Lower base plate.

2. Pull out the disc tray

On the left side of the disc drive button, there is a forced ejection hole with a diameter of 1.0~1.5mm. Straighten a paper clip and insert it into the emergency disc tray. Push it into the disc ejection hole and push it in for about 2.5cm. The disc tray will pop forward, and then pull out the disc tray by hand. Some optical drives do not have a forced ejection hole. You can turn on the power, press the disk ejection button to slide out the disk tray, and then turn off the power. If there is a jam when the disc is inserted, check the lubricating oil on the disc carriage slide after taking out the movement. If it is too dirty or solidified, wipe it off and add a little clock oil or high-grade butter. Of course, the chuck may also be caused by mechanical failure, and the mechanical part should be checked at this time.

3. Remove the front panel of the optical drive

On both sides and the top of the front panel, there is a buckle stuck in the hole of the metal shell (concave metal upper cover) , gently push the buckle inward to disengage it, and pull the front panel forward.

4. Take out the movement

The movement of the SONY CDU311 optical drive (including the circuit board) can be taken out of the casing after pulling out the front panel.

5. Clean the focusing lens

Put the movement face up and pull out the disc tray. You can already see the optical head assembly. The soybean-sized glass spherical transparent body on the top is the focusing lens. Now you You can now use a cotton swab dipped in a little absolute ethanol to clean the focusing lens. Before cleaning the focusing lens, you can use a magnifying glass to carefully observe the surface of the focusing lens. You may see dust or fog. Use absorbent cotton or lens paper to gently wipe away the dust on the surface of the lens. Just wipe it a few more times and it will return it to you. A clear and translucent mirror. The focusing lens is mounted on an elastomer. You can apply a little force when wiping, but excessive force will cause the lens to shift or deflect, which will affect disk reading. Do not use tweezers to avoid scratching the lens surface. Also do not damage the focusing coil on the side of the focusing lens.

There has been debate in the industry about whether cleaning fluid is needed to clean the optical head and what cleaning fluid should be used. The author believes that under normal circumstances there is no need to use cleaning fluid. If dry scrubbing doesn't remove the dirt, consider using a cleaning solution. Cleaning with water is an absolute no-no. There is also debate on whether alcohol can be used to clean the laser head. The author believes that it is completely acceptable to use high-purity absolute ethanol. The so-called alcohol usually refers to an ethanol solution containing moisture and impurities. Therefore, alcohol is indeed not suitable for cleaning laser heads. Anhydrous ethanol is a nearly neutral weak organic solvent. Its purity can be divided from low to high: industrial purity, chemical purity, analytical purity, and spectral purity. The higher the purity, the less moisture and impurities it contains.

The optical head of the optical drive is composed of a laser generator, a photodetector, a focusing lens, a laser beam splitter, and a servo motor. The focus lens located under the optical disc is most likely to collect dust. Generally, cleaning refers to cleaning the surface of this lens. The surface of the lens is coated with a thin film called an antireflection coating, which is made of magnesium fluoride. The main function of antireflection coating is to reduce refraction and increase transparency. Magnesium fluoride is not soluble in ethanol, but magnesium fluoride easily absorbs moisture and deforms.

Because absolute ethanol of analytical grade or above has very low moisture and impurity content, it is highly volatile and can dissolve organic impurities without causing damage to the antireflection coating. Therefore, the author believes that it is okay to use high-purity absolute ethanol to clean the optical head lens. In actual maintenance work, this did not cause damage to the film on the surface of the lens. It is not advisable to clean with clean water, because magnesium fluoride is easy to deform after absorbing moisture, and there are many impurities in the water, which may cause damage to the anti-reflection coating and prevent the optical drive from working properly. Similarly, alcohol containing a lot of moisture and impurities is not suitable for cleaning the laser head.

6. Disassemble the laser head assembly

If cleaning the focusing lens cannot eliminate the fault, you can further disassemble the laser head assembly for further processing. One side of the laser head assembly is mounted on a cylindrical metal sliding rod, and the other side is connected to the stepper motor transmission mechanism.

SONY CDU311 optical drive laser head assembly is fixed on the upper part of the optical drive. You only need to unscrew a screw and unplug the flexible cable to remove the laser head assembly upwards. Before unplugging the flexible cable, it is recommended to use a pen to draw a straight line at the interface between the cable and the socket and make a mark to facilitate the judgment of whether it has been restored correctly during restoration. When unplugging or plugging in flexible cables, do not disassemble them. Pull them out and plug them in gently. It is extremely difficult to repair if damaged.

7. Clean the laser head

The laser head (laser transmitter tube and photoelectric receiving tube) is installed on a small circuit board. There are generally eight lead wires, led out by flexible cables. . The laser head circuit board is mostly installed on the side of the laser head assembly. The laser emitted by the laser transmitting tube passes through the right-angle split light path formed by the prism. After being reflected by the focusing lens and the optical disc, it returns from the original path and is then received by the photoelectric receiving tube. The laser head circuit board is fixed on the optical head assembly. You can remove the circuit board to clean the laser transmitter tube and photoelectric receiving tube. You can also insert cotton from the corresponding hole of the circuit board to wipe the prism in the hole.

The optical head of the SONY CDU311 optical drive eliminates the reflective prism and emits and receives laser beams directly through the focusing lens. It can be cleaned without removing the circuit board.

To clean the laser head of the SONY CDU311 optical drive, you must first remove the black plastic dust cover covering the focusing lens. There are two buckles on both sides of the plastic dust cover. Use the two holes on the metal casting to snap on the bottom of the optical head assembly and stick it with adhesive. Turn the bottom of the laser head upward and use the tips of tweezers to pull the two ends of the dust cover off. Remove the glue on the buckle, loosen the buckle, and pull out the dust cover upwards.

After pulling out the dust cover, you can see a hole directly under the focusing lens. The lower part of the hole is facing the laser head. Use a piece of thin copper wire to make an L shape, wrap it with cotton, and carefully stretch the cotton. Enter the bottom of the small hole to wipe the optical and electronic components of the laser head. When wiping, be careful not to scratch the surface of the optoelectronic device with the laser, nor to damage or break the elastic metal wire that hangs the focusing lens. It not only plays a suspension role but also serves as the lead wire of the focusing coil. Otherwise, the focusing coil circuit will be damaged. It should be noted that the laser head of most optical drives has a sealed cavity, which makes it difficult for dust to enter and is inconvenient to disassemble and clean. Careless operation may very well lead to the scrapping of the optical drive. It is strongly recommended that ordinary users do not perform this operation.

8. Adjust the operating current of the laser tube.

If the optical drive still cannot work after cleaning, it means that the laser tube has aged to a certain extent. You can try adjusting the operating current of the laser tube to increase the output power.

The fine-tuning potentiometer for the operating current of the SONY CDU311 optical drive laser is located on the side of the laser head assembly and is only the size of a mung bean. Many early laser power trimmer potentiometers are on the side of the laser head assembly, and the laser head assembly needs to be removed for more convenient adjustment.

Before adjusting, use a colored pen to make a mark on the potentiometer and note the initial position; use a clock screwdriver to rotate the potentiometer by a small angle in a certain direction. According to the author's experience, poor contact of the trimmer potentiometer itself is also one of the causes of failure. Sometimes the problem can be solved by simply moving the potentiometer slightly.

Therefore, it is strongly recommended that each adjustment should not exceed 10 degrees. Users who have the conditions can use a multimeter to measure it and adjust it in the direction of decreasing resistance. After each adjustment, install and try again until the disk can be read correctly. The total adjustment range should not be too large to prevent excessive current from burning the laser tube.

After reading this article, you may want to clean your optical drive. But a little carelessness can cause the optical drive to become scrapped. Since the current price of optical drives is not cheap, I think the following precautions should also be stated.

1. Do not open a non-faulty optical drive. The optical drive is a precision device. Disassembling it at will will cause damage to the optical drive. Many irreparable optical drive failures are caused by improper disassembly and maintenance. The implication is: as long as your optical drive can work normally, don't bother with it.

2. The failure of some optical drives to read discs normally may be caused by poor disc quality, circuit failure, mechanical failure or even software factors. It is recommended to eliminate other factors first.

3. When disassembling the optical drive, be careful to save all the disassembled parts. The loss of any small part may cause the optical drive to be unable to be restored.

4. Since many parts of the optical drive are made of plastic, you should use moderate force during operation, otherwise the plastic parts will be damaged. In addition, do not use a hair dryer. Hot air may not only cause plastic parts to deform, but may also affect the normal performance of other components.

5. Different models of optical drives have slightly different structures. This article mainly introduces the SONY series optical drives. How to disassemble and clean your optical drive mainly depends on yourself.

Cleaning, maintenance and repair of floppy drives

Floppy drives are one of the external devices that require key maintenance in microcomputer systems. Excessive dust accumulation is the most common cause of floppy drive failure. The focus of cleaning and dust removal on floppy drives is the magnetic head, photodetector, and stepper motor drive screw. When cleaning and dusting, be careful not to damage the magnetic head or cause the magnetic head to shift. Otherwise, human-induced damage to the magnetic head and head displacement failure will be extremely difficult to deal with. If the magnetic head is not too dirty, it can be cleaned with a cleaning disk without disassembling the floppy drive. If the cleaning effect is not good with the cleaning disk, you must disassemble the floppy drive and clean it manually. The processing procedures are introduced in order below.

8. Clean the magnetic head with a cleaning disk

Since the magnetic head is in constant contact with the floppy disk, various dirt on the disk will contaminate the magnetic head, and excessive dust accumulation will cause the floppy drive

The most common floppy drive failure is that the magnetic head cannot read or write normally. It is very simple to clean the floppy drive head with a floppy drive cleaning disk. Spray detergent or absolute ethanol (required analytical grade) evenly on the cleaning disk. After the computer is powered on and the system starts successfully, insert the cleaning disk into the floppy drive and the floppy drive will rotate on its own. , the cleaning disk will absorb dirt on the magnetic head and surrounding dust.

10. Disassemble and clean the floppy drive

1. Remove the upper cover

The concave thin iron cover of the floppy drive is fixed on the cast aluminum base with screws Yes, when cleaning manually, first use a Phillips screwdriver to unscrew one or two screws fixing the upper cover (some floppy drives do not have screws, so you can omit this step), and pull the upper cover slightly outward on both sides to separate the upper cover from the cast aluminum. The upper cover of the floppy drive can be removed by using the protruding buckle on the base.

2. Clean the magnetic heads

The magnetic heads 0 and 1 of the floppy drive are fixed on and below the seek car respectively. The lower magnetic head is attached to the lower fixed arm of the plastic magnetic head car and cannot move. Easier to clean. The upper magnetic head is attached to the movable arm of the plastic magnetic head carriage through an elastic piece, and the other end of the upper movable arm is a spring piece fixed by screws. You can use a little force when cleaning the magnetic head, but you should be aware that excessive force will cause the magnetic head to shift, and it is extremely difficult to adjust the magnetic head deviation caused by human factors, so be careful when cleaning.

When cleaning the magnetic head, use a medical absorbent cotton swab dipped in anhydrous ethanol or a special magnetic head cleaner, and gently scrub the magnetic head. If you wipe it several times, you can wipe off the stubborn attachments. When cleaning the magnetic head, you can use your hands to press the magnetic head down slightly to prevent the magnetic head from shifting. After the alcohol dissolves the dirt on the magnetic head, gently wipe off the dirt.

3. Clean the screw rod of the stepper motor shaft

If the system often gives a prompt that the file is read incorrectly or the sector cannot be found during the floppy drive reading process, it is probably the stepper motor. There is a poor connection between the motor shaft and the magnetic head carriage. Please check the lubricating oil on the stepper motor shaft screw. If it is too dirty or has solidification, wipe it clean with alcohol and add a little clock oil or high-grade butter. You can also turn the screw by hand to move the head carriage to clean the entire screw.

4. Clean the photoelectric detector

The write protection detection, disk density detection, disk replacement detection, and 0-channel detection of the old-fashioned floppy drive are completed by the photoelectric detector, which can be wiped with a cotton swab. Wipe the surface of the photoelectric emitting tube and photoelectric receiving tube with a little absolute ethanol. The detectors of new floppy drives are all micro switches and do not need to be processed.

Cleaning, maintenance and repair of the mouse

The mouse is an essential input device for today’s computers. When you find that the mouse pointer is not moving properly on the screen, you should dust the mouse. To clean and maintain your mouse, follow the steps below.

1. Basic dust removal

The bottom of the mouse is in contact with the table for a long time and is most likely to be contaminated. In particular, the rolling balls of mechanical and optical-mechanical mice can easily bring dust, hair, and fine fibers into the mouse. The following uses an optical-mechanical mouse as an example to illustrate the disassembly and dust removal methods.

There is a round plastic cover on the outer ring of the rolling ball at the bottom of the mouse. Press the plastic cover lightly and rotate it counterclockwise to remove the plastic cover and take out the rolling ball. Use your fingers to clean the dirt on the two rotating shafts and one wheel inside the mouse. When cleaning, avoid dirt falling into the inside of the mouse. The rolling ball can be cleaned with neutral detergent.

2. Open the cover and remove dust

If the pointer still fails to move after the above treatment, especially when the mouse pointer in a certain direction fails to move, it is mostly because the photoelectric detector is blocked by dirt. In this case, please use a Phillips screwdriver to remove the screws on the bottom cover of the mouse, remove the upper cover of the mouse, and use a cotton swab to clean the dirt in the middle of the photodetector.

3. Troubleshooting button failure

Mouse button wear is a common fault that causes button failure. The worn part is usually the small button on the mechanical key switch or the contact area with the small button. For emergency treatment, you can attach a piece of self-adhesive paper or apply a layer of quick-drying glue to the plastic upper cover. A better solution is to replace a button. Mouse buttons are generally available at electrical parts stores. Swapping the infrequently used middle button with the left button is also a common solution.

Most of the button failures of inferior brands and inferior mice are caused by broken reeds, which can be replaced by small copper pieces from discarded electronic lighter micro switches. Failures may also occur due to poor soldering of components on the mouse circuit board. The most common failure is that the solder joint at the bottom of the mechanical switch is broken or desoldered.

Keyboard cleaning and maintenance

The keyboard is one of the most commonly used input devices. Even if one key fails, it is very inconvenient to use. Since the keyboard is an electromechanical device that is used frequently, and there is a large gap between the keyboard base and the keys, dust can easily invade. Therefore, regular cleaning and maintenance of the keyboard is also very necessary.

The simplest maintenance is to turn the keyboard over and tap it gently to let the dust inside fall out; second, clean the surface of the keyboard with a damp cloth, but be sure to wring out the wet cloth to prevent water from entering the inside of the keyboard.

Keyboards that have been used for a long time need to be disassembled for maintenance. Disassembling the keyboard is relatively simple. Unplug the cable connecting the keyboard to the host, then place the keyboard face down on the workbench, unscrew the screws on the base plate, and then remove the keyboard back cover. The following introduces the disassembly and maintenance methods of mechanical key keyboard and electrical contact key keyboard respectively.

1. Mechanical key keyboard

After removing the bottom plate of the mechanical key keyboard, you will see a circuit board, which is fixed to the front panel of the keyboard by several screws. Remove the screws to remove the circuit board.

Unplug the cable from the circuit board, and then use a paint brush or oil paint brush to remove dust from the circuit board and keyboard keys. It is generally not necessary to clean with a damp cloth. The key switch is welded to the circuit board, and the key cap is stuck on the key switch. If you want to remove the keycap from the key switch, use a flat-blade screwdriver to gently pry the keycap upwards and then pull it off. It is generally not necessary to remove the keycaps, and some keyboard keycaps are difficult to restore after being removed.

If a key fails, you can weld the key switch for repair. However, since the parts that make up the key switch are extremely small, it is very inconvenient to disassemble and repair. Since it is a mechanical failure, in most cases The service life of the repaired keys is extremely short. The best way is to use the same type of keyboard keys or unusual keys (such as F12) to solder them and exchange the positions of the failed keys.

2. Electric Contact Keyboard

After opening the base plate and cover of the electric contact keyboard, you can see the three layers of film embedded in the base plate. The three layers of film are respectively It is the lower contact layer, the middle isolation layer and the upper contact layer. The upper and lower contact layers are pressed with metal circuit connections and circular metal contacts corresponding to the buttons. The middle isolation layer has upper and lower contacts. layer corresponding to the circular hole. All keys of the electrical contact keyboard are embedded in the front panel. There is a layer of rubber pad between the three layers of film on the base plate and the front panel keys. The protruding parts on the rubber pad correspond to the keys embedded in the front panel. After pressing the key The corresponding protruding parts on the rubber pad are concave downwards, so that the circular metal contacts on the upper and lower contact layers of the film come into contact through the round holes in the middle isolation layer to send out key signals. There is also a small circuit board in the upper corner of the base plate, the main components of which are the keyboard socket, keyboard CPU and indicator light.

Since the electric contact keyboard sends key signals through the circular metal contacts on the upper and lower contact layers, the oxidation of the circular metal contacts on the film needs to be wiped clean with an eraser; in addition, If there is oxidation at the output interface socket, use an eraser to clean the oxide layer on the interface.

There is generally no dust between the three layers of film embedded on the base plate. You only need to use a paint brush to clean the surface of the film.

The rubber pad, front panel, and buttons embedded in the front panel can be cleaned with water. If the keyboard is dirty, you can use detergent. Some keyboards have all the keys embedded on the front panel that can be removed, but since it is troublesome to restore more than a hundred keys after removal, it is recommended not to remove them.

Clean all buttons, front panel, and rubber pads before installation and restoration can be carried out. When installing and restoring, pay attention to the first thing: wait until the keys, front panel, and rubber pads are all dry before restoring the keyboard. Otherwise, the contacts inside the keyboard will rust. The second thing is to pay attention to the accurate alignment of the three layers of film, otherwise the keys will be damaged. Unable to get through.

Dust removal and maintenance of power supply

The switching power supply is the power of the entire host. Although the power of the power supply is only 200-350W, due to the low output voltage and large output current, the power switching transistor generates a lot of heat. In addition to adding heat sinks to the power transistors, fans also need to be used to extract the heat from the power box. When the fan draws air outward, a negative pressure is formed in the power box, causing various parts of the power box to absorb a large amount of dust, especially the blades of the fan, which are prone to accumulation of dust. The accumulation of dust on the power transistors and heat sinks will affect heat dissipation. The accumulation of dust on the fan blades will increase the load of the fan and reduce the fan speed, which will also affect the heat dissipation effect. When the room temperature is high, if the power supply cannot dissipate heat in time, the power transistor will be burned. Therefore, dust removal and maintenance of the power supply is very necessary.

In addition to dust removal, the fan should also be lubricated when maintaining the power supply. The specific operation method is as follows.

1. Disassemble the power supply box

The power supply box is usually fixed on the metal plate on the back side of the chassis with screws. When disassembling the power supply, unscrew the fixing screws from the back side of the chassis and it can be removed. power supply. Some cases also have power supply fixing screws inside, which should also be removed. The power cord that supplies power to various parts of the host should also be removed, as has been introduced in "Chassis Dust Removal and Board Maintenance".

2. Open the power box

The power box is made of thin iron sheet. Its concave upper cover is buckled on the concave bottom cover and fixed with screws. Remove the fixing screws and remove the upper cover. Push inward slightly from both sides to lift up and take out the upper cover.

3. Dust removal from the circuit board and heat sink

After removing the upper cover of the power supply, you can use a paint brush (or oil brush) to remove dust from the power supply and fix it on the concave bottom cover of the power supply. There is often a lot of dust under the circuit board. You can unscrew the fixing screws at the four corners of the circuit board and remove the circuit board to remove dust.

4. Fan dust removal

The four corners of the power supply fan are fixed on the metal shell of the power supply with screws. When removing dust from the fan, first remove these four screws, and then remove the fan. You can use a paint brush to remove dust from the fan. The fan can also be wiped with a dry damp cloth, but be careful not to let water enter the fan shaft or coil.

5. Fan refueling

After one or two years of use, the sound of the fan's rotation will increase significantly, mostly due to poor bearing lubrication.

When refueling the fan, first use a knife to peel off the self-adhesive label on the front of the fan. You can see the front bearing of the fan (domestic ones also have a rubber cover that needs to be pried off to see); there is a snap ring on the top of the shaft, use a pair of tweezers to Separate the snap ring mouth, then remove it, and then remove the metal washer and plastic washer respectively; use your fingers to hold the fan blade and pull it out, and pull out the motor fan blade and rotor. At this time, the front and rear bearings are clearly visible. Put two to three drops of clock oil between the inner and outer rings of the front and rear bearings (the oil should be immersed in the bearings), re-insert the shaft into the bearings, install plastic washers, metal washers, snap rings, and affix a self-adhesive label , and then install the fan back into the machine. The rotation sound of bearings that have not been lubricated for a long time is significantly reduced after refueling. Is it specific enough?