Specifications

iMac (Early 2006 17-inch) Troubleshooting — Symptom Charts 138
7. At this point in the Power On process, you should hear a boot chime and see the front LED on
the computer light up. When the main logic board and LCD panel communicate to deliver video,
the front LED should go out. Does the Front LED go o?
Yes: The LCD and main logic board have communicated. If there is no picture on the display,
follow No Video troubleshooting.
No: Your logic board is not communicating with LCD panel. Open the unit and re-seat the
TMDS cable and test again. If the issue persists, replace the main logic board.
Audible buzzing, whining, or ticking noise
The iMac (Early 2006) contains several mechanical devices such as motors and fans that may
make audible buzzing, ticking, or whining noises when they are operating in a normal manner.
The sounds will vary depending on how the system is used.
When troubleshooting abnormal noises try the following:
Verify that the computer is running a supported version of the Mac OS X operating system.
If an earlier version of the operating system has been installed then the fans may run at
excessive speeds.
Determine that this noise is related to the computer by removing and shutting down all
other devices in the vicinity of the computer that could be causing a sound.
Eject any media inserted into the optical drive. The optical drive will make a variety of normal
sounds when accessing the optical media.
Quit all applications and test the computer again. Processor intensive applications may cause
the fans to run at a higher RPM and therefore be more audible.
Boot to Apple Service Diagnostic v. 3S100 or later and select the EFI test suite by holding
down the D key during startup. The diagnostic tests fan speeds and thermal sensor
functionality. Should tests fail, replace any parts indicated by the diagnostic.
Reboot the computer and check the computer again. If the noise persists and is unusually
loud, contact Apple Technical Support.
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