casino en ligne courses:casino,ligne,courses,锘縶,Keywor:锘縶Keyword}#Title Split # 2) The fuse is blown but not blacked out. It is not a short circuit causing the fuse to blow. Tip: This situation is more complicated and difficult to judge, but it can be considered from the following aspects: 3
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2) The fuse is blown but not blacked out. It is not a short circuit causing the fuse to blow. Tip: This situation is more complicated and difficult to judge, but it can be considered from the following aspects: 3+5VSB has output, but the main power protection is also more such cases, due to manufacturing process or early failure of the device will cause This phenomenon.
The difference between this phenomenon and 2 is that the fan will shake when it is turned on, that is, the power supply has output, but it is protected due to malfunction or external factors.
In order to eliminate the short circuit or other factors caused by the power load (main board, etc.), the power supply can be removed from the host, and the green wire of the 20 cores is short-circuited to the ground. If the power output is normal, it may be: 2. Common computer Power failure analysis and maintenance (1) AC filter capacitors C3, C4 are short-circuited due to AC surge voltage breakdown. Some ATX power AC filter circuits are more complicated, and should check for short-circuit components.
2. The fault type power supply has an output, but the host does not display it.
1) The fuse is blown and blacked out, indicating a serious short circuit. The rectification filter and power inverter circuit should be checked.
4 The power supply is normal, but the motherboard does not give a power-on signal. In this case, the power supply has no output. You can measure whether the green-to-ground voltage of the 20-core is reduced to the following after the host is turned on by the multimeter. Not following the above, it may cause the power to fail to turn on. Well, how to solve this computer blue screen is here, if you have a blue screen in the process of using the computer in the future, you can solve it according to the above method. Of course, good computer usage habits are also very important. Only by paying attention to the use of computers can the problem of blue screen be completely eliminated. This type of fault is generally caused by insufficient battery voltage on the motherboard. This can be replaced, but some motherboards can not solve the problem after replacement. There are two possibilities: (2) One of the AC main circuit bridge rectifier circuits Diode breakdown. Cause of damage: Since the DC filter capacitors C5 and C6 are generally large-capacity electrolytic capacitors of 330渭F or 470渭F, the instantaneous charging current can reach more than 20A. Therefore, the instantaneous large-capacity surge current is likely to cause a slightly worse rectifier tube in the rectifier bridge to burn out. In addition, the AC surge voltage will also break through the rectifier diode and short circuit. [Computer power supply repair] How to repair the computer power failure How to repair the computer power supply How to repair the US-based computer power supply: US-based 1U350T 3, computer hardware fault diagnosis method 1. Direct detection method direct detection method refers to by eye, ear, nose, hand Touch and other means of sensing to determine the location of the computer fault and the cause of the fault. 1) See if the computer system can start normally; whether the chassis power indicator and the hard disk light are on; whether the surface of the board has focal color or cracks. Determine which parts have problems based on the phenomenon. This requires managers with a wealth of hardware knowledge and experience. For example, if the computer cannot be started frequently, it is necessary to first check whether the system has performed a self-test. If the self-test is normal, the computer can be regarded as basically normal, and the fault may be on the hard disk or software (operating system). If there is no self-test, the power can't be turned on. There are usually two reasons: one is that the power supply box is damaged, there is no power output; the other is that the CMOS battery of the motherboard is dead, causing the CPU frequency of the BIOS to be disabled and cannot be started. The CMOS battery needs to be replaced. , reset BI0S. 2) The sound that the earphones listen to during the startup process, and whether the working sounds of the hard disk, fan, display, power supply, etc. are normal during operation. The machine startup process is performed under the control of the system BI0S. The first is to perform POST (Power0nSeIfTest, power-on self-test). The main task of POST is to detect the presence and function of some key devices in the system, such as memory and display cards. Since the POST detection process starts before the display card is initialized, if the POST finds some fatal errors during the self-test, such as no memory is found, or the memory is loose, the memory is golden finger, the display card has a problem, etc., the detection information It can't be displayed on the screen, then the system POST will use the built-in speaker to report the error. Monitoring can detect some hidden dangers in time and help to take timely measures when the fault occurs. 3) Nasal sniffing and smelling the host, motherboard, card, monitor, etc., whether there is a burnt smell, easy to find the fault point and determine where the short circuit is. 4) Touch the hand or touch the CPU, monitor, hard disk, etc., and judge whether the device is running normally according to its temperature (the normal temperature of the hardware of the hardware component does not exceed 40 to 50 degrees Celsius). Touch some of the chip surface with your hand. If it is hot, the chip may have an internal circuit short circuit. 2. Removing dust The dust of the air string is a big killer of the computer. After using the computer for a period of time, it often causes a large amount of dust to accumulate due to the motherboard, the fan, etc., or malfunction due to the dust attracted by the static electricity of the microcomputer. If the computer is faulty, there is more dust in the mainframe. The first thing to do to eliminate the fault is to remove dust. The dust inside the main chassis can be gently brushed off with a brush and then cleaned with a vacuum cleaner. The dust in the component slot can be wiped with an alcohol-free (ethanol) cotton ball or sprayed with a special cleaner. 3. Resistance Test Method The resistance method is one of the more important methods for diagnosing computer hardware. Using the ohmic block of the multimeter, the suspicious points in the measuring circuit, the suspicious components, and the resistance values 鈥嬧€媜f the pins of the chip to the ground are compared with the normal values, and then the components can be quickly judged to be damaged. The resistance method is divided into two types: 'on-line' resistance measurement method and 'de-soldering' resistance measurement method. 'Online' resistance measurement is usually only effective for checking short-circuit faults and some open-circuit faults; 'de-soldering' resistance measurement is widely used, and most components can be qualitatively inspected by means of measuring resistance. 4. Isolation is a method of judging hardware or software that may interfere with fault diagnosis. It can also be used to isolate suspected conflicting hardware to determine if a fault has changed. In the device operation, disable or unload its driver, or simply remove the hardware from the system. 5. Plug-in detection method If the computer suddenly has problems and can not determine the cause, the plug-in detection method is an effective method. The premise of the plug-in detection method is that the software system is normal. The computer may not operate properly due to the failure of the motherboard itself, the failure of the IO bus components, or various board failures. The use of the plug-in detection method is a simple method to determine the failure of the motherboard or IO set saw. Turn off the computer first, open the chassis, pull out the suspected board, and reboot the machine. If the fault persists, pull the other boards and try again. Once the machine is up and running after pulling out a board, this indicates that the fault is on the board or the corresponding IO bus slot that was removed. 6. System Minimization Method The system minimization method refers to the most basic hardware and software environment that enables the computer to be powered on or running from the perspective of maintenance judgment. The minimum system has two forms. The hardware minimum system consists of a power supply, a motherboard, and a CPU. In this system, there is no connection of any signal lines, only the power supply to the motherboard. After the power is turned on, the sound from the internal speakers can be used to judge whether the core component is working properly. The software minimum system consists of power supply, motherboard, CPU, memory, display card and display, keyboard, mouse and hard disk with system. This minimum system is mainly used to determine whether the system can complete normal startup and operation. The minimum system method is mainly used to judge whether the system can work normally in the most basic software and hardware environment. If it does not work properly, it can be determined that the most basic software and hardware components are faulty, thus functioning as a fault isolation. If it works, plug in the other components one by one to determine which component the fault is on. 7. After tapping the vibration method, turn off the chassis casing or the display casing with the palm of your hand and turn it on again. If the fault is eliminated, this indicates that the fault is caused by poor contact, virtual welding or metal oxidation into holes. Then further check to find out where the fault point is excluded. However, if there is a malfunction inside the monitor or the main unit, the general computer maintenance personnel should not disassemble it for repair. These components have high voltage inside, which can easily cause personal injury, and the fault should be eliminated by professionals. In addition, the computer should not be tapped after the computer is turned on, especially the main chassis, otherwise the hard disk may be damaged. I. Power supply damage causes power supply protection, replaces damaged power supply load; [Example 4]: The temperature control of the main board is abnormal, resulting in no booting. The ASUS P3B-F motherboard can monitor the CPU temperature, using a 2Pin temperature monitoring line. Plug in the JTP pin next to the CPU socket. Later, during a game play, the machine suddenly blue screen, after restarting, after the CD-ROM drive and hard disk self-test, the display does not light up. The cause of the fault: The temperature control line connected to the motherboard falls off and falls on the motherboard, causing the motherboard to automatically enter the protection state and refuse to power up. Since the CPU is now very hot, many motherboards offer strict temperature monitoring and protection. Generally, if the CPU temperature is too high, or the temperature monitoring system on the motherboard fails, the motherboard will automatically enter the protection state. Refuse to power up, or alert you. Solution: Reconnect the temperature monitoring line and turn it on again. Note that when your motherboard does not start properly or alarm, you should first check if the temperature monitoring device of the motherboard is normal.
This fault is developed by removing the power supply from the main unit, connecting the mains power AC input line, and measuring the voltage of the purple line (+5VSB) in the 20-pin plug of the power supply output to the main board with a multimeter. The voltage indicates that the +5VSB line is damaged and the power supply needs to be replaced.
For some motherboards with a standby indicator, if there is no multimeter, you can also use the indicator light to judge whether +5VSB has output.
This type of fault indicates that there is a device damage inside the power supply and the fuse is likely to be blown.
2) No signal, that is, whether the gray line in the 20-core line is high. If it is low, the host will remain in the reset state and cannot be started.
1. Fault type: no output of power supply. This is the most common fault, mainly because the power supply does not work.
When the main unit confirms that the power cord is connected (some power supplies with an AC switch are to be turned on), the power is not responding and the display is not displayed (the display indicator flashes).
(4) The power switching transistors VT1, VT2 and the commutating diodes VD1, VD2 in the DC conversion circuit are broken by breakdown.
Cause of damage: Since the output voltage after rectification and filtering is generally up to 300V, the load of the inverter power switch tube is inductive load, and the voltage peak formed by the leakage inductance may be close to 600V, while the withstand voltage of VT1 and VT2 is Vceo. Only about 450V.
Therefore, when the input voltage is high, some of the low-voltage switch tubes will be broken down.
So you can choose a power switch with a higher withstand voltage.
1) One or more output voltages of the power supply are not normal, and can be tested with a multimeter. Although the computer fault check is not high-tech, it needs some experience to accurately and quickly judge the problem. Some people say that nothing is Replacement and exclusion methods, but at least you have to know which hardware to replace, and which place to exclude.
Computer problems are generally divided into two categories, system problems and hardware problems. The general solution to system problems is to reinstall the system, and hardware problems, then it is necessary to see what hardware is broken.
3) The rising edge or timing of the power supply is abnormal, or the compatibility with the motherboard is not good, and the host can not be displayed. However, this situation is more complicated and can be analyzed by means of a storage oscilloscope.
First, the computer power supply common fault 1+5VSB no output has been mentioned before +5VSB in the host power supply should be connected to the AC power should have a normal 5V output, and power supply for the motherboard startup circuit.
Therefore, +5VSB has no output, the motherboard startup circuit cannot be operated, and it will not boot.
The software cause of such a failure is generally caused by a CMOS setup error.
The power management bar of the CMOS settings has a modemuseIRQ project. Its options are 3, 4, 5, ..., NA. Generally, its default option is 3, which is set to an interrupt other than 3. Items can be.
8. At this time, be sure to restart the computer, this setting will be effective.
(2) Burning insurance during use, mostly due to excessive load.
1. A computer that can be used normally, a USB flash drive, a faulty hard disk (3) DC filter capacitors C5 and C6 in the rectifier filter circuit are broken down, and even bursting occurs.
Cause of damage: Since the large-capacity electrolytic capacitor has a withstand voltage of about 200V, the actual working voltage is about 150V, which is close to the rated value.
Therefore, when the input voltage fluctuates or some electrolytic capacitors are of poor quality, the breakdown capacitance is likely to occur.
In addition, when the electrolytic capacitor leaks, it will be severely heated and burst.
(1) When the power is turned on, the fuse is burned, and the large current is instantaneously interrupted, such as the charging current of the DC filter capacitor when the power is turned on.
II. The internal power supply is abnormal and the power supply needs to be replaced. III. The power supply and the load are matched, and the compatibility is not good, resulting in protection under a certain load. This situation needs further analysis.
1. No output of power supply When the power supply is under load, the DC voltage of each output terminal cannot be measured.
At this time, the power supply should be turned on to check the fuse, and the fuse range is analyzed to analyze the fault range.
No output faults are divided into the following types: 2+5VSB has output, but the main power supply has no output. In this case, the standby indicator lights up, but after the power button is pressed, there is no response, and the power supply fan does not move.
This phenomenon indicates that the fuse is not blown, but the main power supply does not work.
The fault determination method is: remove the power supply from the host, short-circuit the 20-core green line (PSON/OFF) to the ground or connect a small resistor to the ground to make the voltage below. At this time, the power supply still has no output. If the fan does not show signs of rotation, the main power supply is damaged and the power supply needs to be replaced.
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