Symptoms
- Monitor shows 'No Signal' even though a device is connected and on
- Monitor automatically switches back to a different input
- Manually selecting the correct input doesn't stick
- Multiple devices connected but only one input is ever shown
Likely causes
- CommonAuto Input Select feature choosing the wrong sourceMany monitors automatically scan and switch to whichever input has an active signal, which can override your manual choice.
- PossibleMenu button stuck or registering repeated pressesA physically stuck button can cause the input to keep cycling or reverting.
- CommonConnected device not actually sending a signalIf the intended source device is off, asleep, or disconnected, the monitor may auto-switch away from it.
- Less commonFirmware quirk on certain monitor modelsSome monitors have known bugs with their auto-switching feature that manufacturers address in firmware updates.
What to do
- Open the monitor's on-screen menu and look for an 'Auto Input Select,' 'Auto Source,' or similar option, and turn it off if you want manual control.
- Confirm the device on your intended input is actually powered on and sending a signal (wake it or check cable connections).
- Manually select the desired input again after disabling auto-switching, and see if it now stays put.
- Check that the input select or menu buttons aren't visibly stuck or sticky, and clean around them if needed.
- Power cycle the monitor by unplugging it for 30 seconds if the input selection seems stuck in a glitchy state.
- Check the manufacturer's site for a firmware update if the monitor has a known issue with input switching.
Tools and parts
- None
When to call a pro
If disabling auto-switching and power cycling don't resolve a monitor that won't stay on the chosen input, the control board may need professional service.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.