If one of the Apple LCD displays detects an error condition, the power LED will flash in a certain pattern to indicate the issue.
| Pattern | Meaning |
| short, short, short | The display is detecting wrong video format or an unsupported resolution. Verify that your equipment is compatible and restart the computer. If the issue continues, reset the PRAM. |
| short, long, short | Make sure you are using the correct power adapter with the display. This alert will only appear on displays built in 2004 or later which require an external power adapter. |
| short, short, long | The display is detecting a backlight error. Check your display's power connections and restart the computer. If the problem continues, contact Apple or an Apple Authorized Service Provider. |