When a computer is turned on, the monitor writes no signal

What to do if there is no signal on the monitor when you turn on the computer?

On the display is the inscription “Check Video Cable” or “No Signal Detected”. If you press the Num Lock button on the keyboard, then its indicator will light up.

This shows that the system has launched, but there is no signal on the monitor and writes No Signal Detected.

  • Check the condition of the cable coming from the system unit to the screen:
      inspect the cable. If there is damage, then replace;
  • Disconnect and re.Connect;
  • Connect via an adapter/converter or via another connector;
  • Check the “legs” in the cable connectors;
  • Twist to the end the screws on the connectors;
  • Connect another cable.
  • Check the source of the video signal:
      go to the menu on the monitor panel (entrance or source);
  • Select the right port;
  • Check the settings of graphics (can be incompatible with the parameters set by the OS).

Checking the condition of the video cable

This method is used in the case when there is no video signal on the monitor, but the computer itself works. Therefore, you first need to make sure if the video cable is connected correctly. Most often, when the contacts depart and the corresponding message appears.

This is especially true in the case when the computer was going independently. Then it is worth making sure that all the components of the system are correctly connected.

The next step, if everything is correctly connected, will press the Numlock button several times (Capslock).

If the buttons are blinking after pressing, the problem is precisely in the wire or monitor. You can check this by connecting a computer through another cord. If it is not at hand, you can try to connect to the TV or another monitor.

May sound corny, but if there is no signal through the VGA, you should fix the output with two screws. The reason is so simple that not everyone will pay attention to it.

It will also not be superfluous to check whether the signal source is selected correctly. Ideally, of course, this must be done first.

Diagnosis of the video card

If, after previously conducted checks, the video signal is still absent, this indicates a serious PC malfunction. One of these problems may be a breakdown of a video card, which is checked in the following ways:

  • Install another working video adapter in PC and connect the monitor to it.
  • Launch a computer with integrated graphics, if any. Then the cord should not be stuck in a separate discrete video card, but in the video connector of the system board. Connectors are: ancient VGA (D-Sub), DVI-D, DVI-I, DVI-A, DisplayPort, HDMI or even Thunderbolt on boards more expensive.
  • Connect the monitor to another exit, for example, if DVI was used earlier for connection, in which case you can try to connect to HDMI or VGA output of the video card or display.
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Diagnosis of the video card

If, after previously conducted checks, the video signal is still absent, this indicates a serious PC malfunction. One of these problems may be a breakdown of a video card, which is checked in the following ways:

  • Install another working video adapter in PC and connect the monitor to it.
  • Launch a computer with integrated graphics, if any. Then the cord should not be stuck in a separate discrete video card, but in the video connector of the system board. Connectors are: ancient VGA (D-Sub), DVI-D, DVI-I, DVI-A, DisplayPort, HDMI or even Thunderbolt on boards more expensive.
  • Connect the monitor to another exit, for example, if DVI was used earlier for connection, in which case you can try to connect to HDMI or VGA output of the video card or display.

There is no signal on the monitor when you turn on the computer. Why and what to do?

Sometimes users are faced with a situation where, after the computer is turned on, the message “No signal” appears on the monitor.

Such a message on the monitor can be caused by various problems with the computer, so without proper experience it is unlikely to find the cause of the malfunction.

Display Port No Signal FIX !! [Step-by-Step in Description]

If you are faced with the same problem, we suggest you familiarize yourself with our list of the most likely reasons that can lead to this.

Problems with the connection of the monitor to the computer.

If when the computer is turned on on the monitor there is a message that there is no signal, then the first thing to check is the cable that is used to connect the monitor to the computer. There are usually two problems with the cable: the cable may lose contact at the place of connection to the computer or monitor or the cable is not working and it needs to be changed.

First of all, you need to check the contact in the places of connection of the cable. To do this, turn off the cable from the monitor and the computer and connect it again. If it is a DVI or VGA cable, then be sure to twist two screws with which the cable is fixed in the connector.

Cabel fixation screw in the connector.

Cable breakdown, which previously worked normally, the phenomenon is quite rare. But, if you have another cable at hand, or you can remove such a cable from another computer, you can check how the monitor will work with another cable. It is possible to solve the problem after replacing the cable.

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The wrong signal source on the monitor was selected.

On the monitors that have several video inputs there is a button for switching between signals from these videos of inputs. As a rule, this button is called “Source” or “Input”. If the buttons are not signed on your monitor, then read the instructions.

Source button on a computer monitor.

Try to press this button several times to switch to another video input. If an incorrect video entrance was selected on the monitor, then this should solve the problem and the message “No signal” will disappear.

Video card malfunction.

computer, turned, monitor, writes, signal

If you checked all the above, but there is still no signal on the monitor, then this may mean a serious computer malfunction. The first suspect video card. If the video card is out of order, then when the computer is turned on on the monitor, the message “No signal” may appear.

You can check the video card for a fault in two ways: install a knowingly working video card on the computer or remove the video card and start a computer with integrated graphics (if any).

computer, turned, monitor, writes, signal

In the case of a video card breakdown, a situation is also possible when there is no signal on only one of the video card outputs. Therefore, it makes sense to try to connect the monitor to another video exit.

computer, turned, monitor, writes, signal

Video outputs VGA, HDMI and DVI on the video card.

computer, turned, monitor, writes, signal

For example, if DVI was used earlier for connection, then you can try to connect the monitor to the HDMI or VGA release of the video card.

Monitor breakdown. Is less commonly found in the video card, however, it can also lead to the appearance of the “no signal” message when the computer is turned on. Therefore, it is also impossible to exclude this option. Fortunately, in order to check this option you will not even need another monitor. All that is needed is any modern TV. Watch what video inputs (DVI, VGA, HDMI) your TV has and determine the easiest way to connect to your computer.

VGA and HDMI Video on TV.

Connect the TV to the computer and change the signal source using the Source button on the remote control. If the TV displays the picture from the computer, then the problem is either in the monitor or in the cable that was used to connect the monitor to the computer.

Монитор пишет Нет сигнала, No Signal Detected, Check Signal Cable — как исправить

The signal source is incorrectly selected

Another common reason is an incorrectly selected source for transmitting a signal to the monitor. On some monitors (as well as on TVs that are often used instead of monitors), it is possible to choose where the signal is transmitted to it.

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If we are talking about TV, this is most often done through the remote control. When the option with the monitor is considered, the signal source is selected on it through the “Source” or “Input” button, located near the power button or on the back of the monitor. Click on this button several times and select as a signal source the one from which the signal should come.

Please note: if you do not see buttons on your monitor or they have no signatures, refer to the instructions.

Evaluate the reliability of contacts

RAM, video card and other components are installed in slots on the motherboard. If they recently changed them, did cleaning or took them out of the nests for any other reason. There is a chance that the components were not inserted until the end. Due to poor contact, the image on the monitor may well be absent.

To check, turn off the power cable from the computer, carefully remove the side cover by turning the screws at the end panel end. Inspect the video card and RAM planks. Make sure they are inserted without distortions and until the end. Labs on the sides of the RAM should be closed, and the video adapter. Fixed with a screw to the chassis of the case.

The screen is black, the system unit does not start. The signal is not supplied not only to the monitor, but also to the rest of the components of the computer.

You can diagnose a malfunction of the motherboard only by swollen capacitors and other visible damage. To check it, you need special equipment that is in service centers.

This article discusses the main reasons that there is no signal on the monitor when the computer is turned on. Only the most obvious (the screen button is turned off are not indicated, the cable from the mains is disconnected, etc. P.) and problems arising from the installation of new or incompatible components in the computer.

The user will be able to perform simple actions himself, but complex diagnostic procedures are best entrusted to the masters. And before opening the computer, it is important to make sure that it is not under warranty.

Warranty equipment has the right to open only an engineer of the service center authorized by the manufacturer.

In the article, we made out the problem, no signal detected there is no signal on the monitor when you turn on the computer.

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