Troubleshooting: My computer won't turn on
If your Macintosh computer won't turn on, here's how to troubleshoot it. Please keep in mind that although your computer may display similar symptoms that prevent it from showing video, this article discusses what to do if the computer won't turn on, meaning that when you press the power button:
- You don't hear a startup chime.
- You don't hear any fan or drive noise.
- The power button or power indicator doesn't light up at all.
If your computer doesn't display any video, it may display one or more of these similar symptoms when you press the power button:
- You may hear a startup chime.
- You may hear fan or drive noise.
- You may see the power button or power indicator light up.
If any of these conditions occurs, see Troubleshooting: My computer has no video instead.
If your computer won't turn on, try each of these steps:
- Make sure that the power cord is plugged into a working wall outlet, and that it's properly connected to the power adapter. (To check if the wall socket is working, plug in a lamp or other electrical device.)
- Make sure that the power adapter is properly connected to the power port on the side or back of the computer.
- Disconnect all accessories that are plugged into the computer, such as a printer, hub, or other mobile device.
- Reset the computer's PMU, SMC, or PRAM. Refer to the instructions for your model:
- Try plugging a different power cord into the computer (if you have a working one available). If the computer starts up, replace the old power cord.
- If the computer uses a power adapter, try connecting a different power adapter to the computer (if you have a working one available). If the computer starts up, replace the old power adapter. (Computers that use a power adapter include MacBook, MacBook Pro, iBooks, PowerBooks, Power Mac G4 Cube, and Mac mini.)
- If you tried all of the steps above and the computer still won't turn on, contact Apple technical support (1-800-APL-CARE in the U.S.) or take your computer to the nearest Apple Store or Apple Authorized Service Provider (AASP) for diagnosis. If you plan to visit an Apple Retail store, make a reservation at the Genius Bar using http://www.apple.com/retail/geniusbar/ (available in some countries only).
Note: Diagnostic fees may apply for issues not covered under warranty or the AppleCare Protection Plan (APP).