Schematic diagram of computer power supply
 The power supply of the computer is broken. If you have professional tools and some experience, you can try to repair it yourself. The methods are as follows:
 1. Detect faults. First, check whether the power supply is burnt. If so, replace the power supply. If not, use a multimeter to measure the power supply connector of the power supply and the voltage. If the connector supplies power normally, go to the next step.
 2. There is a fuse inside the power supply, which can fuse to form self-protection in case of overpressure. At this time, just remove the fuse from the spring bracket and replace it with a new one. This process only needs a screwdriver, and the operation is very simple without any technical content.
 3. Capacitance is a relatively fragile part of the hardware. There are many phenomena that the hardware cannot work due to the damage of capacitance. It is easy to identify the damage of capacitance from the appearance: bulge, bleeding, burst, which is very intuitive. It is only necessary to buy and replace by model. The required tools are also very simple. A screwdriver is used to open the power supply housing and remove the circuit board; A soldering iron and a section of solder wire are used to remove and weld capacitors. Only simple welding technology is required, without professional training.
 4. As long as the warranty period is exceeded, the computer maintenance company will not repair the hardware when it is damaged. It will only sell you a new one and install it for you. Although there are certain risks in self repair, there is still a glimmer of hope. It doesn't matter if it can't be repaired properly. It needs to be replaced anyway. So, don't worry, especially this simple and easy maintenance.
 Computer power supply illustration
 Red: represents+5V power cable (chip working voltage on mainboard, hard disk, optical drive and other hardware).
 Yellow:+12V power cable (working voltage on hard disk, optical drive, fan and other hardware, and - 12V supply EIA power to the serial port at the same time).
 Orange: represents+3.3V power cord (directly supplying power to DIMM and AGP sockets).
 Grey: represents P G
 Signal line (power status information line, which is the result of calculation of other power lines through a certain circuit. When the computer start key is pressed, this signal indicates that the power supply is good and can be turned on. No signal indicates that there is automatic monitoring of the faulty motherboard).
 Blue: represents the - 12V power cable (providing EIA power to the serial port).
 White: - 5V power cord (floppy disk lock-in data separation circuit).
 Purple: it represents the+5V StandBy power cord (it powers a small part of the circuit on the motherboard after shutdown to detect various startup commands).
 Green: represents the PS-ON signal line (the signal line of the main board power on/off has a certain voltage when it is not connected, which can be directly connected to the black line to connect a switch for testing, or can be regarded as the power on key when starting).
 Black: Ground wire of system circuit.
 How to draw the schematic diagram of computer power supply
 Fan: red - positive black - negative yellow - speed control pole~mainboard, optical drive, hard disk: yellow+12V blue - 12V red+5V white - 5V orange+3.3V purple+5VSB (+5V standby power supply)
 Green P-ON (power on/off terminal)
 Grey P-OK (power signal line) Computer power line color definition table and corresponding main resistance value Red represents+5V power line (chip working voltage on mainboard, hard disk, optical drive and other hardware)
 Yellow represents+12V power cable (working voltage on hard disk, optical drive, fan and other hardware, and - 12V supply EIA power to the serial port at the same time)
 Orange represents+3.3V power cord (directly supplying power to DIMM and AGP sockets)
 Grey represents P G signal line (power status information line, which is the result of calculation of other power lines through a certain circuit. When the computer start key is pressed, this signal indicates that the power supply is good and can be turned on. If there is no signal, it indicates that there is automatic detection of faulty motherboard)
 Blue represents - 12V power cable (providing EIA power to the serial port)
 White represents - 5V power cord (floppy drive phase-locked data separation circuit)
 Purple represents+5V StandBy power cord (it powers a small part of the circuit on the motherboard after shutdown to detect various startup commands)
 Computer power definition diagram
 The power cord is divided into nine colors, namely red, yellow, orange, purple, black, green, gray, blue, and white. Their respective meanings are as follows:
 1. Yellow mainboard power cord:+12V. The yellow mainboard power cord should be one of the many in the power supply. The yellow power cord outputs+12V voltage. With the addition of CPU and PCI-E graphics card power supply components,+12V plays an important role in the power supply+ 12V power supply provides power for the spindle motor and seek motor of hard disk, optical disk drive and floppy disk drive in the computer, as well as working voltage and logic signal level of circuit such as serial port device for ISA slot.
 2. Red mainboard power cord:+5V. The red mainboard power line outputs+5V voltage. The number of red power lines is equivalent to that of yellow power lines. The+5V power supply voltage mainly provides working voltage for integrated circuits such as CPU, PCI, AGP, ISA, and is the main working power supply in computers. Since the+5V power supply mainly supplies power to CPU and other major equipment, its power supply stability is directly related to the stability of the computer system.
 3. Orange mainboard power cord:+3.3V. The orange mainboard power cord outputs a voltage of+3.3V, which is a voltage specially set by AT power supply and mainly supplies power to the memory. In the latest 24pin main interface power supply, the+3.3V power supply is strengthened. The voltage is strict, the output is stable, the ripple coefficient is small, and the output current is more than 20A. If there is a problem with the+3.3V power supply voltage, it will directly cause the failure of the memory power supply circuit, which will lead to the instability of the memory operation, a crash or failure to start.
 4. Purple mainboard power cord:+5VSB (+5V standby voltage). The output voltage of the purple mainboard power line is+5V, and the output voltage of the purple mainboard power line is+5V SB standby voltage, that is, the AT power supply supplies the mainboard with a voltage of+5V and a current of 720MA through the ninth pin of the power mainboard interface. This power supply voltage is mainly used for the network wake-up and power on circuits and USB interface circuits. If there is a problem with the purple power supply, there will be a failure to start the machine.
 5. Blue mainboard power cord: - 12V. The blue mainboard power cord outputs - 12V power supply voltage- The 12V power supply voltage mainly provides logic judgment level for the serial port, and the required current is small, generally below 1A. Even if the voltage deviation is too large, it will not cause a fault. The current mainboard hardly uses this output, but obtains the required current through+12VDC conversion.
 6. White mainboard power cord: － 5V. The white mainboard power cord outputs - 5V power supply voltage. At present, the mainstream AT power supply has canceled the white power cord. The - 5V power supply voltage output by the white power line is mainly used to provide judgment level for the logic circuit, and the required current is very small, which generally does not affect the normal operation of the system.
 7. Green mainboard power cord: P － ON (power on/off end). The green mainboard power cord is the power on/off terminal, and the power is turned on by the level of the power cord. When the signal level of this pin is greater than 1.8V, the main power supply is off; When the signal level is lower than 1.8V, the main power supply is on. Use a multimeter to test the output signal level of this pin, which is generally about 4V. Because the output voltage of this pin is the signal level.
 8. Grey mainboard power cable: POWER － GOOD (power signal cable). The power line of the gray mainboard is the power signal line. Generally, if the output voltage of the gray power line is above 2V, the power supply can be used normally; If the output voltage of the gray power line is below 1V, the power supply cannot guarantee the normal operation of the system and must be replaced. This is also one of the main means to judge the service life of power supply and whether it is qualified.
 9. Black mainboard power cord: ground wire. The black motherboard power cord is the ground wire. Power cords of other colors need to work with the black power cord to provide power for the computer. There are black ground wires in various output interfaces of AT power supply, and there are 8 black power cables in the AT motherboard power interface.
 Detailed explanation of computer power supply schematic diagram
 DC socket is a socket matched with the special power supply for computer monitor. It is composed of a horizontal socket, a longitudinal socket, an insulated base, a fork shaped contact spring and a directional keyway. Two fork shaped contact spring are positioned in the center of the base and are arranged in a vertical and horizontal manner and are not connected with each other.
 One end of the fork contact spring is a wiring port, which is exposed on the top surface of the base cylinder for connecting the input power cord or flexible cable.
 Computer power indication
 Charge and power are car anti-theft alarm indicators.
 The red light in the car after locking the car is the anti-theft alarm indicator, which flashes to indicate that the anti-theft system is starting.
 The car anti-theft indicator flashes regularly and intermittently, indicating that the car anti-theft system is working and playing the role of indicating that the car anti-theft equipment has been turned on. The car anti-theft indicator is an integral part of the anti-theft system. As long as the car is parked and the door is locked, the car anti-theft indicator will always flash no matter in the day or at night, but it will not be noticed that the anti-theft indicator flashes when there is light in the day. If the anti-theft indicator no longer flashes on a certain day, it indicates that the car anti-theft system has failed.
 Computer Power Schematic HD
 Green line and black line. The computer is started by the pwon pin on the motherboard. After the computer is connected, it can be started by short circuit
 The computer power supply is a device that converts 220v AC power into DC power to power CPU, motherboard, hard disk, memory stick, graphics card, optical disk drive and other computer accessories.
 The power supply of the computer mainly consists of the following parts:
 1. Filter: The main function of the circuit is to filter out external burst pulse and high-frequency interference. On the other hand, it can also reduce the electromagnetic interference of the switching power supply itself to the outside world.
 2. According to the electromagnetic principle, the conversion ratio of the transformer is mainly determined by the number of turns of the coil, so the size of a larger switching transformer can usually provide more energy, which is a solution to the poor quality or power supply of the observation point. To some extent, the size of the transformer directly affects the actual output and quality of the power supply.
 3. Protection circuit: the protection circuit inside the power supply monitors every action of the power supply and is the brain of the power supply. Be responsible for starting the power supply, monitoring and regulating the voltage/current, and providing automatic protection in case of short circuit, open circuit, overvoltage, overcurrent, undervoltage, undercurrent, etc.
 Schematic diagram of computer power switch
 The power under the computer monitor generally refers to the power key, which is the key to turn on the computer monitor. Generally, there is a row of buttons below the computer monitor. This is to adjust the brightness, switch, screen display size, etc. of the computer monitor. These buttons can be adjusted. But some of them are touch buttons, that is, you can press them to display a row of buttons.
 What about the schematic diagram of computer power supply
 Step 1: Check the basic information of the power supply. When buying a power supply, the basic information of the power supply, voltage and current input and output brands and models are written on the power supply.
 Step 2: Check the rated power of the power supply. In one case, the rated power is marked directly on the power supply, indicating the rated output power of 300W. Some only indicate the maximum power, which is not equal to the rated power.
 The third step is to calculate the rated power. Some power supplies do not directly indicate the rated power, but only give a bunch of data. At this time, we need to calculate the actual rated power of this power supply by ourselves. Let's calculate. The current of 5v is 22 22 * 10=220, and the rated power of this power supply is about 220w. If it is marked with 400A, it does not mean that this power supply is 400w