Motherboard Fault Classification and Removal Method 
Motherboard is the most highly integrated PC computer accessory products, is also the most vulnerable parts of a failure. Maintenance of a high level of integration so that it is relatively cumbersome, maintainability getting lower and lower. However, many times computer failure caused by a motherboard is very easy to solve, as long as a good method at our disposal, is not difficult to repair them, then I will describe in detail the classification of board failures and elimination methods.
1, motherboard failure classification
Under normal circumstances, we can board failures divided into four categories: the first category is based on the impact of computer failures can be divided into non-lethal and lethal failures. Non-fatal failures also occurred on the system power-on self-test period, the general gives an error message; fatal failure occurred on the system power-on self-test period, the general cause the system to crash. Second category is based on the extent of the different faults can be divided into localized and global failures. Partial system failure refers to one or several features not working properly, such as the printing control chip on the motherboard is damaged, caused only online printing is not normal, does not affect other functions; overall failures often affect the normal operation of the whole system so that the loss of All features, such as clock generator damage will paralyze the entire system.
3 is based on failure phenomena can be divided into the stability of a fixed fault and fault instability. Stability of the fault is due to components function failure, circuit open circuit, short circuit caused the phenomenon of the stability of its repeated failures, rather than stability of the failure is often due to their connections and component performance, variation, so that chip logic function is normal from time to time, when instead of The critical state caused by the normal. Such as I / O slots deformation, resulting in display card with the slot being exposed, so that show was volatile error state. 4 is based on the independence of the impact can be divided into different levels of failures and related faults. Failure means the completion of the independence of single-function chips damage; related failure refers to a failure associated with some other fault, their fault phenomenon of multiple non-functional, and its failure to control the various functions in real terms in the common part of the failure cause (for example, the soft, hard disk subsystem not working properly, while the soft, hard disk controller on the control of its functions are more isolated, failure is often the peripherals on the motherboard data transfer control of the DMA control circuit).
2, causing the main board failure
1, man-made failures: Charged pluggable I / O cards, as well as when loading the card and plug the interface resulting from improper force, chips and other damage.
2, the environment bad: Static electricity often cause the motherboard chipset (especially CMOS chip) is the breakdown. In addition, the motherboard is damaged or experience a power line voltage transient spikes generated by pulse, they tend to damage the system board near the power plug chips. If the board covered with dust, can also cause signal short-circuit and so on.
3, device quality problems: Due to poor quality chips and other components leading to damage.
3, motherboard troubleshooting common method of repair
Motherboard failure is often manifested in the system failed to start, the screen no display and intuitive judgments are difficult to fault phenomena. Here are the repair methods have advantages and limitations, are often used in combination.
1, cleaning method: can be used to brush gently brush the dust on the motherboard In addition, a number of add-in cards on the motherboard, chip pin form, often because of poor contact pin-oxidation. Eraser can be used to the surface oxide layer, re-plug.
2, observation method: repeated view of the board and needed repairs to see if the plugs and sockets is skew, resistance, capacitance pin is touching the surface is scorched, the chip surface is cracking, copper on the motherboard is blown. Would also like to see if there is foreign matter falling into the motherboard between the components. Encountered in areas of doubt, you can look at the amount of help multimeter. Touch the surface of some chips, if the abnormal hot, try to change a chip.
3, resistance, voltage measurement: In order to prevent accidents, what should be measured before the power-board +5 V power supply and ground (GND) between the resistance value. The most simple way is to measure the power chip resistor between the pin and the ground. The power plug is not inserted, the resistance should normally be to 300Ω, the minimum should not be less than 100Ω. Test-retest about reverse resistance values, slightly different, but not too much difference. If the positive and negative or close to the resistance of a small turn-on, it shows a short circuit occurs, you should check the reasons for short. To generate such phenomena for the following reasons are several:
First, the system board has been the breakdown of the chip. In general more difficult to rule out such a failure. For example, TTL chips (LS series) +5 V connected together, can absorb +5 V pin on the solder, so that suspension, one by one measurement, in order to identify fault the film. If we adopt the secant method will certainly affect the life of the motherboard. Second, any damage to the board on the resistance and capacitance. Third, there are conductive debris on the board.
When excluding short-circuit fault, the plug in all the I / O cards, measuring +5 V, +12 V and ground is short-circuit. +12 V in particular, whether it collide with the surrounding signal. When there is a good hand the same type of motherboard, you can also use the method of measurement of resistance values measured on-board doubts, by contrast, you can quickly find chip failures.
When these steps were not bear fruit, you can plug in the power supply power-measurement. Generally measured power supply +5 V and +12 V. When they find out too much of a voltage deviation from the standard, you can cut through the separation or some wire or unplug some chips and then measuring voltage. When cut a certain wire or unplug a piece of silicon, if the voltage becomes normal, then this leads to the component lead or pull down the chip is the failures.
4, plug the exchange of law: the host system to produce failure for various reasons, such as the motherboard’s own fault or I / O bus failure can cause the system to a variety of plug-in card is not functioning properly. Using plug repair method is to determine the fault in the motherboard or I / O devices fast-track approach. The method is to shut down the plug-in board-by-block pull out, pull out a piece of board on the start of each observation of the machine running, once pulled out a piece of board, after operating normally, then the cause of the malfunction is that the plug-in board failure or the corresponding I / O bus slots and the load circuit fault. If the pull all the plug-in board to start after the system is still not normal, then the fault is likely on the motherboard. Exchange method is to use essentially the same type plug-in board, consistent with the way the bus, feature the same plug-in board or chip, each chip, the same model of mutual exchange, according to the changes in the phenomenon of failure to determine failures. This method is used for easy plug maintenance environment, such as memory, self-test error, exchangeable same memory chip or memory to determine the cause of troubles.
5, software diagnostic method: by random diagnostic procedures, special maintenance diagnostics card and based on various technical parameters (such as interface address), specific diagnostic procedures to aid in self-compiled hardware maintenance can achieve a multiplier effect. Principle of program testing method is to use the software to send data, commands, through reading the line status, and a chip (such as the register) state to identify the fault position. This method is often used to examine the various interface circuit faults and the various circuit parameters with the address. However, application of this method based on the premise that CPU and bus operating normally, be able to run the diagnostic software that can run the installation on the I / O bus slots on the diagnosis of cards. Prepared by the diagnostic procedures to be strict, comprehensive and focused, enabling emergence of certain key parts of a regular signal, able to carry out repeated tests and occasional failures can show an error of record
1, motherboard failure classification
Under normal circumstances, we can board failures divided into four categories: the first category is based on the impact of computer failures can be divided into non-lethal and lethal failures. Non-fatal failures also occurred on the system power-on self-test period, the general gives an error message; fatal failure occurred on the system power-on self-test period, the general cause the system to crash. Second category is based on the extent of the different faults can be divided into localized and global failures. Partial system failure refers to one or several features not working properly, such as the printing control chip on the motherboard is damaged, caused only online printing is not normal, does not affect other functions; overall failures often affect the normal operation of the whole system so that the loss of All features, such as clock generator damage will paralyze the entire system.
3 is based on failure phenomena can be divided into the stability of a fixed fault and fault instability. Stability of the fault is due to components function failure, circuit open circuit, short circuit caused the phenomenon of the stability of its repeated failures, rather than stability of the failure is often due to their connections and component performance, variation, so that chip logic function is normal from time to time, when instead of The critical state caused by the normal. Such as I / O slots deformation, resulting in display card with the slot being exposed, so that show was volatile error state. 4 is based on the independence of the impact can be divided into different levels of failures and related faults. Failure means the completion of the independence of single-function chips damage; related failure refers to a failure associated with some other fault, their fault phenomenon of multiple non-functional, and its failure to control the various functions in real terms in the common part of the failure cause (for example, the soft, hard disk subsystem not working properly, while the soft, hard disk controller on the control of its functions are more isolated, failure is often the peripherals on the motherboard data transfer control of the DMA control circuit).
2, causing the main board failure
1, man-made failures: Charged pluggable I / O cards, as well as when loading the card and plug the interface resulting from improper force, chips and other damage.
2, the environment bad: Static electricity often cause the motherboard chipset (especially CMOS chip) is the breakdown. In addition, the motherboard is damaged or experience a power line voltage transient spikes generated by pulse, they tend to damage the system board near the power plug chips. If the board covered with dust, can also cause signal short-circuit and so on.
3, device quality problems: Due to poor quality chips and other components leading to damage.
3, motherboard troubleshooting common method of repair
Motherboard failure is often manifested in the system failed to start, the screen no display and intuitive judgments are difficult to fault phenomena. Here are the repair methods have advantages and limitations, are often used in combination.
1, cleaning method: can be used to brush gently brush the dust on the motherboard In addition, a number of add-in cards on the motherboard, chip pin form, often because of poor contact pin-oxidation. Eraser can be used to the surface oxide layer, re-plug.
2, observation method: repeated view of the board and needed repairs to see if the plugs and sockets is skew, resistance, capacitance pin is touching the surface is scorched, the chip surface is cracking, copper on the motherboard is blown. Would also like to see if there is foreign matter falling into the motherboard between the components. Encountered in areas of doubt, you can look at the amount of help multimeter. Touch the surface of some chips, if the abnormal hot, try to change a chip.
3, resistance, voltage measurement: In order to prevent accidents, what should be measured before the power-board +5 V power supply and ground (GND) between the resistance value. The most simple way is to measure the power chip resistor between the pin and the ground. The power plug is not inserted, the resistance should normally be to 300Ω, the minimum should not be less than 100Ω. Test-retest about reverse resistance values, slightly different, but not too much difference. If the positive and negative or close to the resistance of a small turn-on, it shows a short circuit occurs, you should check the reasons for short. To generate such phenomena for the following reasons are several:
First, the system board has been the breakdown of the chip. In general more difficult to rule out such a failure. For example, TTL chips (LS series) +5 V connected together, can absorb +5 V pin on the solder, so that suspension, one by one measurement, in order to identify fault the film. If we adopt the secant method will certainly affect the life of the motherboard. Second, any damage to the board on the resistance and capacitance. Third, there are conductive debris on the board.
When excluding short-circuit fault, the plug in all the I / O cards, measuring +5 V, +12 V and ground is short-circuit. +12 V in particular, whether it collide with the surrounding signal. When there is a good hand the same type of motherboard, you can also use the method of measurement of resistance values measured on-board doubts, by contrast, you can quickly find chip failures.
When these steps were not bear fruit, you can plug in the power supply power-measurement. Generally measured power supply +5 V and +12 V. When they find out too much of a voltage deviation from the standard, you can cut through the separation or some wire or unplug some chips and then measuring voltage. When cut a certain wire or unplug a piece of silicon, if the voltage becomes normal, then this leads to the component lead or pull down the chip is the failures.
4, plug the exchange of law: the host system to produce failure for various reasons, such as the motherboard’s own fault or I / O bus failure can cause the system to a variety of plug-in card is not functioning properly. Using plug repair method is to determine the fault in the motherboard or I / O devices fast-track approach. The method is to shut down the plug-in board-by-block pull out, pull out a piece of board on the start of each observation of the machine running, once pulled out a piece of board, after operating normally, then the cause of the malfunction is that the plug-in board failure or the corresponding I / O bus slots and the load circuit fault. If the pull all the plug-in board to start after the system is still not normal, then the fault is likely on the motherboard. Exchange method is to use essentially the same type plug-in board, consistent with the way the bus, feature the same plug-in board or chip, each chip, the same model of mutual exchange, according to the changes in the phenomenon of failure to determine failures. This method is used for easy plug maintenance environment, such as memory, self-test error, exchangeable same memory chip or memory to determine the cause of troubles.
5, software diagnostic method: by random diagnostic procedures, special maintenance diagnostics card and based on various technical parameters (such as interface address), specific diagnostic procedures to aid in self-compiled hardware maintenance can achieve a multiplier effect. Principle of program testing method is to use the software to send data, commands, through reading the line status, and a chip (such as the register) state to identify the fault position. This method is often used to examine the various interface circuit faults and the various circuit parameters with the address. However, application of this method based on the premise that CPU and bus operating normally, be able to run the diagnostic software that can run the installation on the I / O bus slots on the diagnosis of cards. Prepared by the diagnostic procedures to be strict, comprehensive and focused, enabling emergence of certain key parts of a regular signal, able to carry out repeated tests and occasional failures can show an error of record
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