Apple MacBook Pro (17-inch, Early 2011) - Manual (Page 73)

73 Chapter 5 Last, but Not Least
Disconnect the power adapter and disconnect any other cables if any of the following
conditions exists:
 You want to add memory or upgrade the hard disk drive.
 You want to clean the case (use only the recommended procedure described on
page 76).
 The power cord or plug becomes frayed or otherwise damaged.
 Your MacBook Pro or power adapter is exposed to rain, excessive moisture, or liquid
spilled into the case.
 Your MacBook Pro or power adapter has been dropped, the case has been damaged,
or you suspect that service or repair is required.
The MagSafe power port contains a magnet that can erase data on a credit card, iPod,
or other device. To preserve your data, don’t place these or other magnetically sensitive
material or devices within 1 inch (25 mm) of this port.
If debris gets into the MagSafe power port, remove it gently with a dry cotton swab.
MagSafe power specifications:
 Frequency: 50 to 60 Hz, single phase
 Line Voltage: 100 to 240 V
 Output Voltage: 18.5 V DC, 4.6 A