The solution is as follows:

Troubleshooting of computer failure to start and black screen

Many times, we will encounter the phenomenon that the computer can't start after pressing the computer's power-on button, and there is no post-test or entering the operating system, which often makes the user unable to handle it and affects the normal use. Here, we will make a simple analysis of common fault phenomena, analysis and solutions, hoping to help users who encounter such problems.

There is no response after pressing the power button.

Fault phenomenon: The screen does not display after startup, and the "drip" sound of the motherboard speaker cannot be heard.

Fault analysis: BIOS data inside the motherboard COMS chip is damaged by CIH virus or static electricity, so it can't be read, and the system can't complete self-check and start.

Known solution: contact the motherboard manufacturer to replace the new COMS chip or find the BIOS file provided by the motherboard manufacturer to write into the programming device.

Failure phenomenon: After the power-on key is pressed, the light of the CD-ROM drive flashes, the power indicator of the motherboard lights up, and the power supply is normal, but there is no display on the screen and no "click" sound.

Fault analysis: this phenomenon will occur after the cup is damaged. During the self-test, the BIOS first checks the CPU. If the CPU fails the self-test, the computer will not start.

Known solutions: check whether the CPU is installed correctly, check whether the CPU core is damaged, check whether the CPU is damaged by replacement, and replace the CPU if it is damaged.

Fault symptoms: no display and no prompt when starting the machine, the motherboard power supply is normal, the cup is normal, the fan is normal, and the screen is not displayed. "Didi" sound that failed the self-test.

Fault analysis: After the computer has been used for more than 3 years, the battery voltage that supplies power for BIOS settings gradually decreases, and data cannot be saved. Some motherboards using early chipsets can't complete the self-test, and there is nothing wrong with the motherboard hardware itself.

Known solution: buy a lithium battery of CR2032, replace the existing battery on the motherboard, then complete the self-test normally, and then reset the BIOS parameters.

Fault phenomenon: After pressing the power-on key, the computer will automatically shut down or have no response.

Fault analysis: In order to protect the CPU from being damaged by the heat sink, some motherboard manufacturers will not be able to turn on the CPU without installing a CPU fan or connecting the power cord of the CPU fan to the CFAN interface of the motherboard, or connecting the CPU fan to SFAN (the interface of the system fan).

Known solution: connect the CPU fan and the power interface of the motherboard correctly, and confirm that it is connected to the CFAN three-core dedicated CPU fan interface next to the CPU.

Symptoms: After the power-on key is pressed, the self-test fails, the display does not display, and the indicator light of the display is orange or flashing.

Fault analysis: During the self-checking, the self-checking of the graphics card failed, and the basic hardware could not be tested and started.

Known solutions: check whether the gold finger of the graphics card is oxidized or there is a lot of dust on the AGP interface to cause short circuit, rub the gold finger lightly with a rubber, and clean the dust on the AGP interface with a leather tiger. At the same time, the replacement method is adopted to eliminate the damage of the graphics card. If the graphics card is damaged, it can be replaced.

Failure phenomenon: the self-test is not completed after startup, and the "tick-tock" sound is not heard, and the sound is continuously "tick-tock ..." at the same time.

Fault analysis: According to the description of BIOS alarm tone provided by BIOS manufacturer, the problem is generally in memory, and the probability of memory damage is relatively small. Most of the problems are caused by memory oxidation or poor socket contact.

Known solution: First, check whether the gold finger, memory stick, chip and PCB are burnt out. If burnt out, it is recommended to replace the memory. If not, gently wipe the golden finger with an eraser, and then re-insert it into the memory slot.

Fault phenomenon: After starting the machine, the power supply is normal, but the NUM and other indicators on the keyboard do not flash. Unable to complete self-test.

Fault analysis: the motherboard keyboard controller or I/O chip is damaged, and the self-test cannot be completed.

Known solution: the manufacturer replaces the I/O chip and checks the keyboard interface circuit.

Symptoms: There is no response when the power button is pressed, and the power supply and hard disk indicators are not lit.

Fault analysis: By checking the output voltage of the power supply with a multimeter, it is found that 12V 5V 3.3V is abnormal, which is far from the standard voltage, and there is something wrong with the internal circuit of the power supply.

Known solution: After replacing the high-quality 300W power supply, the problem is solved.

Symptoms: The components in the chassis are removed and tested normally. It can't be turned on if it is installed in the chassis. Sometimes, the chassis can be turned on normally when it is upright, but it can't be turned on when it is flat.

Fault analysis: Some cases are not made standard, resulting in deformation of some motherboards or some boards after installation, and the bottom of the motherboard contacts with the case, resulting in short circuit and failure to start.

Known solution: replace the chassis with good quality, and install standard accessories for all components.

Symptoms: The power light flashes quickly after the power is turned on or the power button is pressed. It's not displayed on the screen.

Fault analysis: Sometimes the power supply and reset of some poor-quality chassis are easy to get stuck in it or short-circuit, resulting in the button being connected all the time, repeatedly starting or restarting, resulting in the illusion that it cannot be started.