Symptoms
- Power LED blinks (often amber or a slow pulse) instead of staying solid
- Screen stays black with no image at all
- LED turns solid when a valid signal is detected
- Happens right after connecting a new cable or device
Likely causes
- CommonNo video signal being received (standby indicator)Most monitors blink or change LED color specifically to indicate standby due to no signal, which is different from a power fault.
- CommonCable not connected or wrong input selectedThe monitor may simply be waiting for a valid connection on its active input.
- CommonConnected device not powered on or asleepIf the computer is off or sleeping, the monitor correctly shows no-signal standby.
- PossibleFaulty cable or port preventing signal detectionA bad connection can look identical to 'no device connected' from the monitor's perspective.
What to do
- Confirm the connected computer or device is powered on and awake, not just plugged in.
- Check that the video cable is fully connected at both ends.
- Use the monitor's Source/Input button to cycle through inputs and confirm you're on the one that's actually connected.
- Try a different cable and port to rule out a bad connection.
- Consult the monitor's manual for what the specific blink pattern or LED color means, since this varies by brand and often indicates the exact standby reason.
- Test the monitor with a different device known to output video properly.
Tools and parts
- None
Replacement video cableSearch: “HDMI or DisplayPort cable”
When to call a pro
If a confirmed working device and cable still produce a blinking standby light with no image, the monitor's input board may be faulty and should be checked by a technician.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.