iMac: fans run at full speed after computer turns on

  • Last Modified: April 22, 2008
  • Article: TS1433
  • Old Article: 304602

Symptoms

After plugging in the iMac and turning it on, the fans (blowers) may be noisy and appear to run at full speed. In this event, shutting the iMac off and turning it on again wouldn't fix the issue.

Products Affected

iMac (24-inch, Late 2006), iMac (Early 2006 17-inch), iMac (Early 2006 20-inch), iMac (24-inch Mid 2007), iMac (20-inch, Mid 2007), iMac (17-inch, Late 2006), iMac (17-inch, Late 2006 CD), iMac (20-inch Late 2006)

Resolution

If you press the iMac power button while you are inserting the power cord, the iMac will enter a mode in which the fans (blowers) run at full speed. In order to correct the issue, reset the SMC and then start the computer by pressing the power button AFTER the power cord has been fully inserted.

The iMac should now start up and operate as expected.

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