The monitor writes No signal, No signal detected, Check signal cable, what does this mean and what should I do?

A common question from users is what to do if the monitor writes "No signal" but the computer works, as well as what the following messages mean: No signal detected, Check signal cable, No input signal, "Check cabin »,« No signal detected »and the like. The problem can occur with any type of connection: HDMI, VGA, Display Port, and DVI.

This manual details why there is no signal or "No signal detected" on the monitor when you turn on the computer, the possible causes of the problem, and ways to remedy the situation. First the simple options, then the more complex ones, but also activated in many cases. Similar problem: The monitor writes Out of Range, Input Not Supported (or Out of Range and Input Not Supported).

What it means Check signal cable, No signal detected and "No signal" on the monitor

All the messages that appear on the monitor screen have the same meaning: no video signal compatible with that input is being received. The cause is the same, but the messages vary depending on your particular monitor.

• Consult cable means "Check signal cable" (the one connecting the monitor to the computer). It may also appear as "Check signal cable."
• No means "Signal not detected".
• No entry He says it translates to "No entry sign."

Simple reasons why there is no signal on the monitor and how to fix them

First of all, about the simple and fairly common causes of the problem and the corresponding solution methods. I recommend not skipping any item, even if you are sure there is nothing wrong with it.

1. Cable really disconnected or not well connected to the monitor or video card side of the computer: it may be accidentally touched, someone may have moved the monitor. Definitely check it out, it's not such a rare case.
2. If you have upgraded the monitor or video card and then connected the monitor using any adapter or cable with different interfaces (for example, Display Port - HDMI, HDMI - VGA / DVI and the like), please remember that this cable or adapter itself It may itself be the source of the problem: some of them are unidirectional, some work only on certain hardware (for example, only on those video cards that support analog output via HDMI, and such are not produced lately). Solutions in this case - try to use the connection with the same type of ports or at least connect the digital output to the digital input, you can also buy active signal converter. Ideally, use an original monitor cable without adapters.
3. If you have connected your computer to a second monitor, projector or television (How to connect a laptop or computer to a television), turn off your computer, disconnect the cable that goes to the television from the video card (even if it is disconnected from the television itself or second monitor), turn the computer back on and check if the No signal detected or Check signal cable problem has disappeared.
4. If the monitor menu itself has an input source selection option (Input Item, Input), open that menu and try manually selecting the input used.
5. If possible, connect your monitor to another computer or laptop to rule out a malfunction of the monitor itself or its ports: if the other computer does not have a signal either, the problem should be found at the monitor itself.
6. If your computer previously had a discrete video card, but now you connect your monitor to a built-in one (motherboard output), resulting in "No Signal", the cause may be either the on-board video is disabled on BIOS, or PCI-E video card priority is set there as well, or a non-video integrated processor.
7. Some older graphics cards cannot output the signal to the Display Port (theoretically the same is possible with HDMI as well) before the drivers are loaded (at the beginning of the installed OS boot). What it means: If you just built a computer with such a video card or have decided to reinstall it from a USB stick and your monitor is connected via Display Port, there may be no signal from it.
8. If you bought a new monitor with a USB-C / Thunderbolt connection and you connect your laptop to it, study the specifications of your laptop: not all of them support display output via USB-C. I also recommend using "native" monitor cable, USB-C cables are different and some of them may not support video / audio output to the monitor.

On the other hand, on the second of the previous points: it is common today for a user to acquire a modern graphics card that only has Display Port and HDMI, but has an old and cheap monitor that only has VGA / DVI and that is when he finds there is no signal. This can be solved by buying an active converter from HDMI or DP to a standard monitor, but if there is a possibility, I would recommend changing the monitor.

Other Possible Causes of No Signal on the Monitor and Possible Solutions

If everything described above has not worked, let's move on to other possible variants, also reasonably common:

• If you have onboard video, try physically disconnecting the discrete graphics card, plugging the monitor into the onboard output, and see if that solves the problem. If it does, the possible options are: additional power is not connected to the discrete video card, hardware problems with the video card, lack of power supply (actual power may be dropping due to wear and tear), problems with the slot where the video card is plugged in.
• The problem in question is often described as "No signal on the monitor, but the computer is working." Actually, the noise of the fans and lights after pressing the power button does not always mean that the computer turns on and works: if there are problems with the video card, the power supply, the RAM memory, the absence of connecting some power lines to the motherboard (often during independent cleaning, assembly and disassembly, component replacement) can just turn on some power lines, but it does not start and there is also no signal on the monitor, if It had been before and now there is no OS loading sound. If other monitors of the same computer also do not appear, it is another argument in favor of this case. For more information, see the separate manual What to do if your computer won't turn on.
• If your computer starts up with a monitor displaying something (POST / BIOS screen, logo) and then you get a message that there is no signal, there is probably something wrong with the image output settings you set in your operating system. True, this is often reported as the Signal being out of range. A possible solution if you have Windows is to run safe mode and use the recovery points, or boot from a pendrive with the same version of the OS you have installed, select "System Restore" in the second screen from the bottom left and use the recovery points. With Windows 10, the recovery environment can be entered after two forced shutdowns (holding the power button down for a long time, although it is not the safest technique). As a last resort, you can also resort to reinstalling the operating system.

Video Tutorial

I hope some of the options have worked for you. If you still have to fix it, please describe the situation in the comments: video card model, monitor model, how exactly it was connected, after what the "No signal" problem occurred and what you tried. Perhaps, a solution can be found for your situation as well.