The reason and overhaul of computer starting monitor black screen

Computer boot monitor black screen phenomenon is very common, the reason is also very many, the author has contacted a lot of display does not light the situation, here to share the solution for reference.

Computer power-on Monitor No response the most common problem is memory, graphics, hard disk and other hardware and the motherboard is good contact, as long as the one contact bad may cause the display black screen, so if it is used for a long time computer, it is likely that too much dust, resulting in poor contact or loose. Take a look at the specific steps of thinking it.

"Start black screen is a more common fault", mostly due to poor contact or hardware damage caused by the "minimum System method" and the replacement of inspection and maintenance. New installed and replacement hardware is more prone to black screen, if the failure of the replacement of hardware after the resulting, please check whether it is due to the following reasons:

* Hard disk or optical drive data cable reverse;

* System detects CPU error (easy to occur when overclocking);

* Short circuit and bad contact caused by oblique insertion of the board;

* The expanded memory strips do not meet the motherboard requirements.

Note: Some of the early 586 motherboards can only use the 5V 168-line Deo memory, newer 586 motherboards can only use 3.3V SDRAM, some use the Intel 440BX chipset motherboard requirements SDRAM must have SPD; some 486 motherboards do not recognize 72-line Edo memory. can only use ordinary FP memory, most of the original installed on the memory requirements, in the expansion of the original installed memory before the proposal to call the dealer advice. "Start black screen" can be divided into power supply system failure caused by black screen, not self-test black screen failure and self-test failure of three types of black screen failure, the following discussion of the phenomenon of black screen failure, cause and check the treatment methods.

　　One, the power supply failure caused by black screen

Symptom: After the boot, the host Panel host panel LED is not lit, the internal power of the host fan rotation and hard drive self-test sound, the entire system is silent. This is the phenomenon that the equipment in the host does not have normal power supply.

Inspection and Treatment methods: power supply failure can be caused by AC power line circuit breaker, AC power supply voltage abnormality, microcomputer power failure or short circuit phenomenon in the host. Power supply failure is not necessarily the main engine damage caused by AC power supply voltage anomalies (overpressure or undervoltage), the host power supply no-load and the machine has short circuit phenomenon, the host power supply inside the protection circuit to start, automatically cut off the power output to protect the equipment inside the host.

1. Power supply system failure, first check the AC power supply is connected to the host.

2. Confirm AC power supply access to the host, the ear close to the switching power supply, open the power switch for a short time and pay attention to listen, if you hear the power of the internal issue of "AIDS ...", indicating that the power supply in the "self-protection" working state, the reason is the AC power supply is not normal or the machine has short circuit phenomenon, Causes the protection circuitry inside the power supply to start. Use the following procedure to check the processing:

* First use a multimeter AC voltage file 250V Check the AC power supply voltage of the host power plug, if the AC voltage is more than 240V or less than 150V, the host power supply of overpressure and Undervoltage protection circuit will start, stop on the machine equipment power supply, please switch to the power supply and UPS power supply for the host.

* If the AC power supply voltage is normal, unplug the internal interface card and other equipment power cord, signal line, and then power test machine, such as unplug a device when the host power to restore work, it is just pulled out of the equipment damaged or improperly installed lead to short circuit, the power supply in the short-circuit protection circuit to start, stop on the machine equipment power.

* If the power cord is removed from all the devices, the power supply is still in no output state, which indicates a power failure, please repair the power supply.

Note: The overhaul of the power supply should be connected to at least one load (such as optical drive or hard disk), such as no-load connected to the microcomputer power supply, computer power no-load protection circuit will start, stop output.

3. If the host power supply does not work, please first check the chassis installed in the front panel of the host power switch is normal, such as power switch intact, is generally a power failure.

　　Second, do not self test black screen failure

Failure phenomenon: After the boot of the host panel LED light, fan normal rotation, but the monitor does not show. At startup, the three LEDs in the upper-right corner of the keyboard are not shiny, and the "click ..." Sound and PC speaker alarm sound are not heard from the self-test memory.

Check the processing method: By the phenomenon can be seen, the host power supply basic normal (do not exclude the host power failure), but failed to boot in the BIOS in the Self-Test program occurred a panic. The monitor, display card, memory, CPU, and motherboard should be checked primarily. Since there is no information about the failure of self-test black screen, the "Minimal system method" is usually used to check the processing.

"Minimum system method" means to retain only the motherboard, memory, CPU, display cards, monitors and power supplies and other basic equipment, the first power to check the minimum system composed of these basic equipment, after checking to confirm the retention of the minimum system can work, and then further check other equipment. When using the minimum system method, it is recommended that you check the display to see if the monitor works correctly before you open the chassis to remove other devices.

If only the minimum system is retained, the computer still does not work after powerup, generally use the replacement method to check the memory bar, display card and CPU in turn. Verify that the monitor, memory, display card and CPU can work, the source of the fault only the motherboard and power supply, to distinguish between the motherboard or power failure is the simplest way to switch to a good power to try.

　　Three, self-test failure black screen failure

Failure phenomenon: After the boot of the host panel indicator light, the machine fan normal rotation, can hear the hard disk disc rotating sound, self-test memory issued "Da da ..." Sound and PC speaker alarm sound. I see three LEDs flashing in the upper right corner of the keyboard at startup, but no display on the monitor.

Check the processing method: By the fault phenomenon that the main power supply basic normal, the motherboard most of the circuit is not faulty, and the memory of the first 64KB can be normal reading and writing, BIOS troubleshooting program began to run, and can be issued through the PC speaker alarm signal. This failure is primarily due to problems with hardware such as monitors, display cards, memory, motherboards, and power supplies. Most of these failures can be judged by the sound of the horn alarm to determine the approximate location of the fault. Due to different versions of the BIOS sound signal coding method, this article takes the MSI 5158 Motherboard (award BIOS) as an example, introduces its inspection processing method.

1. If you hear the "Toot toot ..." continuous short sound, indicating that there is a slight short-circuit phenomenon in the machine, please shut down immediately, open the chassis, one by one unplug the interface card and other equipment in the mainframe power cord, signal cable power test, such as the removal of certain equipment when the system back to normal, it is just removed equipment damage or improper installation caused by short circuit fault. such as only to keep the motherboard power cable on the test machine, can still hear is "du toot ..." continuous short sound, the failure of three reasons:

① motherboard and chassis short-circuit, can remove the motherboard power check;

② power supply overload ability, try to change the power supply;

③ Motherboard has short circuit fault, please repair the motherboard.

Warning: Plug the device, please turn off the power, live plug will damage the equipment.

2. If you hear a long, intermittent sound (some machines have a long break), it is a memory detection error, the user using ATX power supply with the chassis panel power switch is usually unable to shut down, only directly unplug the power cord. Unplug the memory strip and use the eraser as the "golden finger" of the memory bar to clean, keep only a 168-line memory bar or a set of 72-line memory (72-line memory on 586 motherboards is a group of 2), reinsert the installation to try, if not, please use the replacement method to check the memory bar.

3. If you hear the "Da Da da ..." from the self-test memory. Sound, see the keyboard in the upper right corner three lights flashing, PC speakers do not make other noises, and can feel the hard drive in the boot operation, the self-test passed, most likely a monitor failure, please check the monitor power is connected, the monitor power switch is open, If the brightness and contrast knob of the display is accidentally "shut down", it is best to try to connect the monitor to another computer after excluding the above possibilities.

4. If you hear a PC horn sound for a long three short (or a long two short), is a display system failure; Fast one long three short (or one long two short) is detects the card error, usually is the display card and the motherboard slot contact bad result (some 486 machine is one long eight short); The slow speed is one long three short is detects the display error, Please check whether the monitor and the display card signal line plug is in good contact with the display card plug pin whether there is a folding, broken phenomenon (some monitors plug pins only 12). Please use the eraser for the display card "gold fingers" clean after the insert or replace the slot to try, if still no display, change a good display card plug try.

5. If you hear other alarms, please note whether the PC horn beep changes when different BIOS detects hardware failure, and can help you to judge the source of the fault further.

There are also some such as hardware failures, data cable problems may also lead to the above problems, in general, there are many reasons for the problem, as long as we first soft after the hard, first observation and then start thinking to judge the problem, general computer problems can be solved, Not a very familiar friend. You can also use maintenance tools, such as the motherboard diagnostics card, to find the part of the computer that has failed, and then to repair it.