https://support.apple.com/en-us/HT204267　

1. 到底有没有电？那个电源线上有黄／绿灯吗？（没灯的话换电源线换插座）

（1有灯）2.　Hold down the power button for ten seconds. Then, press the power button again to see if the computer turns on.

（2不行）3. Reset SMC　

a. Press Shift-Control-Option on the left side of the keyboard, then press the power button at the same time

b. Release all keys, then press the power button again to turn on your Mac (https://support.apple.com/en-us/HT201295)

(都不行）http://www.stuff.tv/sg/features/where-repair-your-iphone-or-ipad