A monitor that will not turn on, shows "no signal" or flickers is often a cable, a setting or the computer, not the monitor. Check the power light first. If the light is off, test the power cable or adapter. If the light is on but the screen is blank, check the input source and the video cable, then try the monitor with another computer. If it works there, the computer is the problem. If it fails everywhere, the monitor needs repair, and whether that is worth doing depends on its age and what failed.
People often replace a monitor that only needed a new cable, or repair one that was not worth fixing. This guide gives you a short test routine, explains the common faults and their typical causes and shows how to decide between repair and replacement. It covers desktop monitors, and the same logic applies to a display connected to a laptop. An all-in-one has no separate input to test, so it needs a technician to separate the panel from the board.
Test in this order
- Look at the power light. A light that is off means the monitor is not getting power or has failed. On many monitors a light that is on, or blinking amber, means it has power and is waiting for a signal.
- Check the power cable and the socket. Reseat both ends, try another socket and, if the monitor has an external power adapter, check it is plugged in and warm. Some monitors have a switch at the back.
- Press the power button and the menu button. If the on-screen menu appears but the picture does not, the monitor itself works and the signal is missing.
- Check the input source. Use the monitor's input button to select the port you are actually using, such as HDMI or DisplayPort.
- Reseat or change the video cable. Try another cable of the same type. Bent pins on a VGA or DVI plug and worn HDMI cables are common.
- Test with another computer or a laptop. This separates the monitor from the computer.
- Test the computer with another screen or a TV, if you have one.
What each symptom usually means
| Symptom | Likely causes |
|---|---|
| No light, nothing happens | Power cable, adapter, power switch, or a failed power board inside the monitor |
| Light on, "No signal" message | Wrong input, loose or faulty video cable, or the computer is not sending a picture |
| Light on, a faint picture you can see with a torch | Backlight failure |
| Monitor turns on, then switches itself off | Failing power board or capacitors, or overheating |
| Flickering or flashing | Cable, refresh rate setting, graphics driver, or a failing backlight or power board |
| Vertical or horizontal lines | Panel or its ribbon cable, sometimes the video cable or the graphics card |
| Lines or odd colours that also appear on a second monitor | The computer's graphics output, not the monitor |
| Patches, cracks or ink-like marks | Physical damage to the panel |
| Dead or stuck pixels | Panel defect: dead pixels are usually permanent, stuck pixels sometimes recover |
The torch test for a dim screen
If the monitor is on but you see nothing, dim the room and shine a torch at an angle at the screen. If you can make out icons or text, the panel works and the backlight has failed. That can be repaired on many monitors, and it is a different case from a dead panel.
Settings that cause flicker
- Refresh rate. In Advanced display settings, set the monitor to the rate it supports, usually 60 Hz, and try a lower one if the flicker continues.
- Resolution. Use the monitor's native resolution.
- Graphics driver. Update or reinstall the driver. Press the Windows key, Ctrl, Shift and B to restart it.
- Power saving. Some monitors flicker when a power or eco mode is on. Check the on-screen menu.
- Interference. Move other electronics and cables away from the video cable.
- Variable refresh and overdrive. FreeSync, G-Sync, Adaptive Sync and overdrive options in the monitor menu can cause flicker or odd colours on some setups. Turn them off to test.
When the computer, not the monitor, is at fault
If the monitor works with another computer but shows nothing with yours, the problem is on the computer side: the cable port, the graphics card, memory that is not seated or a fault that stops the computer from starting properly. A common mistake on a desktop with a separate graphics card is plugging the cable into the board's port, which is usually switched off. Plug it into the graphics card. Our guide to fixing a PC with no display goes through those causes, and the desktop symptom guide maps other symptoms to parts.
Repair or replace?
Whether a repair makes sense depends on the fault and the monitor.
- Often worth getting a quote for: a failed power board or bad capacitors, a backlight fault on a good monitor, and a loose or damaged connector. These are common faults, and a skilled technician can fix them. A bad cable is simply replaced.
- Often not worth it: a cracked or damaged panel, and dead pixels or large patches, because the panel is the most expensive part.
- The age and value test: if the quote is close to half the price of a comparable new monitor, think about replacing it, especially for an old, small or low-resolution model. A large, high-refresh or colour-accurate monitor is more likely to repay a repair.
The written quote should say what failed and what part is needed, so that you can weigh it against a new monitor.
How we can help
We repair monitors, and you can see what is covered on the monitor repair page, or for a desktop on the desktop monitor repair page. The inspection costs ₹350 and is credited to the bill if you go ahead, and you get a written quote before any work. Book by call or WhatsApp and we collect the monitor within 2 hours. Repairs carry a 90-day warranty. For the nearest branch, see computer repair near me.
Frequently asked questions
Why does my monitor say "no signal" when the computer is on?
The input may be wrong, the cable loose or faulty, or the computer is not sending a picture. Test the monitor with another device to find out which.
Can a monitor be repaired if the screen is cracked?
A new panel is usually the most expensive part, so for most monitors the repair costs close to the price of a new one. It is rarely worth it.
Why does my monitor flicker only sometimes?
A loose cable, a refresh rate setting, a driver issue or a failing power board or backlight can all cause intermittent flicker. Check the cable and settings first.
Is a monitor that turns off by itself dangerous?
It is usually a sign of a failing power board or overheating. Do not leave a monitor that clicks, smells or turns itself off running unattended, and do not open it yourself, because the power board can hold a charge after it is unplugged.
