iMac Troubleshooting Display Issues
Troubleshooting display and image issues
Troubleshooting camera or ambient light sensor issues
Troubleshooting display and image issues
Identify issues
Read this article if you notice any of the following issues:
Distorted, blurred, or illegible image
Inconsistent image clarity
Vertical lines of nonuniform brightness
Flickering or intermittent image
Video noise
Incorrect or missing colors
Nonuniform color, contrast, or brightness
Image that sticks or remains on screen
Light leakage around the display
Particles or debris under the glass
Pixel anomalies
Horizontal or vertical lines
Can't change resolution
Display not illuminated
Display backlight not uniform
Display backlight fails after warm-up
Display backlight fails at some brightness settings
About LCD display pixel anomalies for Apple products released in 2010 and later
If the issue wasn’t resolved by following a support article, continue to the next section.
Try quick troubleshooting steps
Remove any cases, covers, or screen protectors.
Clean the display with a soft, slightly damp, lint-free cloth.
Caution: Unplug all cables and turn off the computer first. Don't use aerosol sprays, solvents, abrasives, or cleaners containing hydrogen peroxide that might damage the finish. Avoid getting moisture in any openings, and don't spray liquid directly on the computer. Don't use compressed air.
Refer to steps and support resources in Troubleshooting Quick Checks.
Run manual and diagnostic tests
If the issue wasn’t resolved by following a support article or checking for potential causes, run these diagnostic and manual tests to help isolate the cause of the issue:
Open and inspect the computer
If your issue wasn’t resolved or isolated by following support articles or running diagnostics tests, refer to the computer's repair manual to open and inspect the computer. A damaged or out-of-place part may be causing one of the issues.
Note: This section requires ordering parts and tools. Replacing a part may not resolve the computer's issue. You can find other service options at support.apple.com/repair.
Replace the part
If the issue wasn’t resolved or isolated by following the previous steps, replace the following parts one at a time in the order shown. After you replace the first part, repeat the troubleshooting steps to determine whether replacing a part resolves the issue. If it still isn’t resolved, replace the next part.
If an image is clearly visible on a connected external display but no image appears on the internal display, replace the display.
If no image appears on a connected external display and no image appears on the internal display, replace the logic board.
Note: This section requires ordering parts and tools. Replacing a part may not resolve the computer's issue. You can find other service options at support.apple.com/repair.
Troubleshooting camera or ambient light sensor issues
Identify issues
Camera not functioning
No camera indicator light
Overexposed images
Poor white balance
Poor focus
Distorted or discolored images
Display or keyboard brightness unresponsive to changing ambient light conditions
Camera unresponsive to changing ambient light conditions
Try quick troubleshooting steps
Remove any cases, covers, or screen protectors.
Ensure that the ambient light sensor isn’t covered. It’s located at the top of the computer display near the camera.
Clean the display with a soft, slightly damp, lint-free cloth. Verify the camera lens area at the top of the display is clear of contaminants. Some cleaning solutions leave behind a film that could impact camera image quality. Thoroughly clean the top of the display surface using only a damp cloth, and try to reproduce the issue.
- Caution: Unplug all cables and turn off the computer first. Don't use aerosol sprays, solvents, abrasives, or cleaners containing hydrogen peroxide that might damage the finish. Avoid getting moisture in any openings, and don't spray liquid directly on the computer. Don't use compressed air.
Refer to steps and support resources in Troubleshooting Quick Checks.
Run manual and diagnostic tests
If the issue wasn’t resolved by following a support article or checking for potential causes, run these diagnostic and manual tests to help isolate the cause of the issue:
Open and inspect the computer
If the issue wasn’t resolved or isolated by following support articles or running diagnostics tests, refer to the computer's repair manual to open and inspect the computer. A damaged or out-of-place part may be causing one of the issues.
Note: This section requires ordering parts and tools. Replacing a part may not resolve the computer's issue. You can find other service options at support.apple.com/repair.
Replace the part
If the issue wasn’t resolved or isolated by following the previous steps, replace the display.
Note: This section requires ordering parts and tools. Replacing a part may not resolve the computer's issue. You can find other service options at support.apple.com/repair.