One of the scariest things that your Mac can do, short of emitting actual flames and smoke, is refuse to turn on at all. you press the power button and nothing happens— no startup sound, no light, nothing. If this happens, take a few minutes to perform several straightforward checks before hauling your Mac to the nearest Apple Store for repair. This seemingly intractable problem often has a simple solution. BY JOE KISSELL
Make sure it’s plugged in
Your first troubleshooting move when presented with a completely unresponsive Mac should always be to ascertain the answer to the classic question: is it plugged in? (You should be aware that failure to ask this question in the critical situation where it would have solved a hardware problem is grounds for Apple Genius disbarment.)
To make sure that your Mac is getting the juice it needs, you may have to trace the entire flow of electricity to your Mac.
First check your system’s power cord to ensure that it is firmly seated at the points where it connects to the computer and where it plugs into the wall. If the flow of electricity goes through an outlet strip or a UPS, make sure that the additional piece is also connected and turned on. Also confirm that any surge protectors still work – a power surge might have knocked them off.
You can confirm that an outlet is good by plugging something else, such as a light or a fan, into it. (If the outlet doesn’t work, check your circuit breakers to see if they’ve been blown or tripped.) If the outlet and all cable connections are working properly, make sure that the power cord has no crimps, breaks or other damage; a snapped wire inside the cord can bring everything to a halt.
Once you’ve established that your AC power path is good, it’s time to shift your focus to your Mac. Unplug everything that you can aside from the power cord, the mouse and keyboard (if those input devices are wired) and the monitor (if it’s not built in); then try pressing the power button again. If your Mac turns on, you’ll know that one of your peripherals was at fault.
If your Mac doesn’t turn on, it’s worthwhile attempting to reset the machine’s SMC (System Management Controller), a chip that manages various hardware functions, including the operation of the power button. Directions for resetting the SMC vary from one Mac model
to another. Apple has posted instructions for specific models; they are available at support.apple.com/kb/HT3964.
Check your power adapter
If you have a Mac laptop, its battery should last through most power outages (from whatever cause), so you may not notice that you have a power-related problem until the battery runs out, at which point your Mac may simply appear to be dead.
So try all of the preceding tips, but also check your power adapter. If you have an AC cable attached to the adapter (as opposed to a plug that runs directly into the wall), make sure that the cable is securely connected. If you have access to another AC adapter, switch to it briefly; if the system works normally, you’ll know that the original adapter is bad; if not, the problem may be your Mac.
Get help from the pros
Still not having any luck? In that case, you need professional help. We’ve had Macs fail to turn on for reasons such as faulty logic-board components and blown power supplies, but difficulties of that sort require heavy-duty intervention. Take your Mac to an Apple Store or authorised repair centre – they should be able to diagnose and correct the problem.
Coming up soon: Mac Emergencies Part 2, which will include kernel panics, being unable to get online and trash refusing to empty.
by Joe Kissell