Symptoms
- Monitor connected via HDMI shows 'No Signal'
- Cable was recently moved, replaced, or unplugged
- Signal drops out intermittently, not just once
- Other monitors or TVs work fine on the same computer
Likely causes
- CommonLoose HDMI connectionHDMI connectors can work partway loose without falling out completely.
- CommonMonitor set to wrong inputIf the monitor has multiple HDMI ports, it may be listening to the wrong one.
- PossibleDamaged HDMI cable or portBent pins or cable wear can interrupt the signal entirely.
- PossibleHDMI version mismatch limiting resolution/refresh rateAn older HDMI cable may not support the resolution or refresh rate the PC is trying to send.
- Less commonGraphics card not outputting signalA crashed driver or failing GPU can stop sending video over HDMI.
What to do
- Unplug and firmly reconnect the HDMI cable at both ends, listening or feeling for it clicking fully into place.
- Use the monitor's Input/Source button to confirm it's set to the correct HDMI port, especially if it has more than one.
- Try a different HDMI cable, ideally a newer high-speed one if the current cable is old or unmarked.
- Test the same HDMI cable and port with a different device, like a laptop, to isolate whether the monitor or computer is at fault.
- In Display Settings, lower the resolution and refresh rate temporarily to rule out the cable being unable to handle a high setting.
- Restart the computer with the HDMI cable already connected, since some systems only detect displays during boot.
Tools and parts
- None
High-speed HDMI cableSearch: “HDMI 2.1 cable 6ft”
When to call a pro
If a known-good cable and port combination still shows no signal on multiple devices, the monitor's HDMI input board may have failed and should be evaluated by a repair technician.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.