The computer has been like this since it was turned on, and nothing has been done when the keys are

How to troubleshoot the failure of the computer without display when it is turned on (check whether there is a bulging capacitor).

Step 1: First of all, check whether the external wiring of the computer is connected, and plug in each cable again to see if the fault is eliminated.

Step 2: If the fault persists, then open the main chassis to check whether there is any excess metal in the chassis, or a short circuit caused by the deformation of the motherboard, and smell whether there is a burning paste in the chassis, whether there are burned chips on the motherboard, and whether the capacitors around the CPU are damaged.

Step 3: If not, then clean the dust off the motherboard and check if the computer is in good condition.

Step 4: If the fault persists, unplug the reset cable on the motherboard and connect it with other switches and indicator lights, and then use the change cone short-circuit switch to see if it can turn on.

Step 5: If you can't turn on the computer, then use the minimum system method, unplug the data cable of the hard disk, floppy drive, and optical drive, and then check whether the computer can be turned on. Then connect the above devices to the computer one by one, when connecting a certain device, the fault will recur, indicating that the fault is caused by this device, and finally focus on checking this device.

Step 6: If the fault persists, the fault may be caused by devices such as memory, graphics card, CPU, motherboard, etc. Then, use the plug-in method, swap method and other methods to check whether the memory, graphics card, CPU and other devices are normal, and replace the damaged devices if there are damaged devices.

Step 7: If the memory, graphics card, CPU and other devices are normal, then discharge the BIOS, use the isolation method, place the motherboard outside the chassis, connect the memory, graphics card, CPU, etc. for testing, if the computer can be displayed, then install the motherboard into the chassis for testing until the cause of the fault is found. If the fault persists, you need to return the motherboard to the manufacturer for repair.

Step 8: When the computer is turned on without display but there is an alarm sound, when the computer is booted up, the system BIOS starts to POST (power-on self-test), when it detects a fatal error in a device in the computer, it will control the speaker to send out a sound to report the error. Therefore, there may be a fault that the power is turned on without displaying an alarm sound.

If the computer is turned on and there is no alarm sound, the fault can be checked according to the meaning of the BIOS alarm sound to check the faulty device to eliminate the fault.

If the system has not responded after starting, you should consider whether there is a problem with the system, you can restart the boot and press F8, select the correct configuration of the last time, see if you can enter the system, if you can't enter the system, choose the safe mode and try again.

Judging from the above description, there is no response when you press the on/off button, and the following reasons can be considered:

1) The first reason: first look at whether the power cord is not plugged in properly, resulting in no power input to the computer. Solution: Re-plug the socket of the power cord or replace the socket.

2) The second reason: the power cord of the host is burned out, and it cannot be turned on without power input. Test the voltage with a multimeter (or electric pen), if it is not at the normal voltage of 170 240V, too low or too high, it means an open circuit or a short circuit.

Solution: Replace the power cord.

3) The third reason: is the problem of the power supply, due to the fuse of the power supply burned out, the rectifier diode is damaged, the switch triode breakdown, the main transformer is damaged, the filter capacitor is exploded, and so on, it may lead to failure to boot, boot no response, detection and treatment method: open the host, find the plug-in of the motherboard and chassis panel, remove the motherboard power switch pin wire (power sw), and the pins on the motherboard are:

PWR SW or PS On, two small square-ended steel needles (as shown below), and then use a slotted screwdriver to short these two pins, if the host power supply will turn, this means that the power supply is normal, if it will not turn, it means that the power supply is broken, and it can be replaced.

Common fault diagnosis methods for motherboards:

The structure of the computer motherboard is relatively complex, the failure rate is relatively high, and the fault distribution is also scattered. According to the source of the fault, motherboard faults can be divided into power supply faults, bus faults, component faults, etc. The main causes of motherboard failure are as follows:

1. Component reasons: The quality of chips and other components on the motherboard is not good, resulting in aging and damage to the motherboard, resulting in motherboard failure.

2. Human reasons: When using the computer, hot-swap the hardware at will or touch various connectors with metal objects indiscriminately, resulting in the failure of the motherboard.

3. Dust and static electricity causes: due to dust or static electricity, the motherboard is in poor contact, short circuit or burns the chips on the motherboard, resulting in the failure of the motherboard.

Causes of poor contact: Poor contact of various chips, sockets, and interfaces in the motherboard due to rust, oxidation, weakened elasticity, pin desoldering, breakage, etc., resulting in motherboard failure.

There is a problem with the switching power supply, the computer presses the boot button and does not respond, it should be the switching power supply is damaged, and the switching power supply can be replaced directly, so that the computer can consume it.

If the computer boot button does not respond, it may be that your computer's power button is out of order or the computer has no power, or the computer power supply is not in good contact.

machine, pressed the power switch and nothing happened, out.