Mac troubleshooting: What to do when your computer won't turn on
One of the scariest things that can happen to your Mac, short of actual flames and smoke billowing from the case, is a failure to turn on at all. You press the power button and nothing happens—no startup sound, no light, nothing. If this happens, you can check several things before hauling your Mac to the nearest Apple Store for repair—as often as not, this seemingly difficult problem might have a simple solution.
Electricity, e-lec-tricity
First, make sure that your Mac is getting juice. To do this, you may need to trace the entire flow of electricity to your Mac. Check your Mac’s power cord to ensure it is firmly seated where it connects to the computer as well as where it plugs into the wall. If it goes through an outlet strip or a UPS, make sure that’s also connected and turned on. Also check that any surge protectors are still working—a power surge might have knocked them off.
You can confirm that an outlet is good by plugging in something else, such as a light. (If it doesn’t work, check your fuses or circuit breakers.) If the outlet and all cable connections check out, make sure the power cord has no crimps, breaks, or other damage; a broken wire could be the culprit.
Faulty peripherals and broken buttons
Once you’ve established that your AC power path is good, it’s time to look at your Mac itself. Unplug everything you can—not the power cord, obviously, or your mouse and keyboard if they’re wired, and your monitor if it’s not built in, but disconnect everything else and try pressing the power button again. If your Mac turns on, you know that one of your peripherals was at fault.
To read this article in full or to leave a comment, please click here
http://www.macworld.com/article/2028143/mac-troubleshooting-what-to-do-when-your-computer-wont-turn-on.html
