Intel-based iMac: What to do if your computer won't turn on

Symptoms

There are some simple troubleshooting steps you should try if your iMac (Early 2006) and later—the Intel-based iMacs—won't turn on. Use these steps if:

  • Your Intel-based iMac computer's display has no picture after you turn it on.
  • You don't hear any fan or hard disk activity sounds after you turn the computer on.
  • The computer doesn't seem to have any power when you try to turn it on.

Resolution

  1. Verify that the power outlet you're using is good and your power cable is firmly connected to the wall outlet—if using a surge protector, be sure that it's firmly plugged into the wall outlet. Also, try temporarily plugging directly into the wall outlet to eliminate any issue with the surge protector; plug a different electronic device into the same wall socket to make sure the socket works, and also try the iMac's power cable in a different wall outlet.
  2. Make sure the computer's power cable is firmly connected to the computer.
  3. If any external devices are connected to your iMac, disconnect them and try to turn the computer on again. If the iMac will power up when those devices are removed, but not when they are connected, contact the manufacturer of those devices for assistance.
  4. Try resetting the iMac's System Management Controller (SMC).
  5. Remove and reinstall the SO-DIMM memory modules, located in the bottom of the computer.

Additional Information

If your iMac still will not power on, make an appointment with a local Apple Retail Store or Apple Authorized Service Provider to have your Mac diagnosed.

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