Apple 2009 iMac - Page 23

iMac (21.5-inch, Late 2009) — General Troubleshooting 23
2010-11-18
Diagnostic LEDs
Depending on iMac model, there are either three or four built-in diagnostic LEDs on the logic
board that can help troubleshoot the computer. LEDs are located on bottom right edge of logic
board (under a piece of black mylar tape) and can only be seen when looking through lower
vents of rear housing.