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Archived - Mac notebooks: Troubleshooting power adapters with a barrel-type connector

This article has been archived and is no longer updated by Apple.

Symptoms

Is your notebook computer's power adapter not working correctly? This article will tell you what you can do if you experience one or more of the following issues:

  • Your power adapter won't charge the computer.
  • The LED on the adapter connector doesn't light up when attached to the computer.
  • The adapter only charges the computer intermittently.
  • A separation of the white insulation on the adapter (also known as strain relief)

Note: If you are attempting to troubleshoot a MagSafe or MagSafe 2 power adapter, please refer to Mac notebooks: Troubleshooting MagSafe adapters.

Barrel-type connector MagSafe connectors Magsafe 2 Connector

Resolution

Follow these steps to identify the cause of the issue and find out which solutions are available to you.

If you see a spark

Sometimes when you plug the power adapter into the wall, you may see a spark. This is usually normal and can occur when you plug any electrical appliance into a live outlet. If the spark comes from somewhere other than the blades of the plug, if you experience damage or discoloration of the adapter, or if you have other concerns about sparking, contact Apple.

Troubleshooting power adapter issues

1. Use a known good outlet.

Verify that the power outlet you're using is working correctly. Plug in a known-good appliance, such as a lamp, TV, or clock, and confirm it powers on properly.

2. Make sure to use the proper wattage adapter for your notebook computer.

Select the appropriate power adapter for your Mac notebook computer.

3. Identify line noise issues.

Unplug the power adapter from the wall, let it sit for 60 seconds, then plug the adapter back in.

    • If the adapter works after this 60-second "rest", you most likely have a line noise issue with your power source. You will need to reset the adapter periodically by repeating this moment of rest. This issue occurs when the AC adapter's "over voltage protection" feature senses ground noise and then turns off the adapter.
    • Some possible sources of line noise include lights with ballasts, refrigerators, or mini-refrigerators that are on the same electrical circuit as your computer. This behavior may not occur if you plug the power adapter into an uninterruptible power supply (UPS) or plug it into a different circuit.
    • Unless the adapter continues to exhibit this behavior on a known good outlet, it does not need to be replaced.

4. Be sure you are using the adapter in a well ventilated area.

The power adapter may become very warm during normal use. Always put the power adapter directly into a power outlet or place it on the floor in a well-ventilated location. If you are using your power adapter in a poorly ventilated area or if the power adapter is covered by a blanket or other form of insulation, it may turn itself off in order to prevent damage to the adapter.
You may notice the following:

    • Your power adapter may not charge the computer.
    • The LED on the adapter connector may not light up when attached to the computer.
    • The adapter may only charge the computer intermittently.

5. Check for possible AC plug (also known as a "duck head") or two- or three-pronged AC cord issues.

If you're using the AC plug (also known as a "duck head") with the power adapter, swap it out for the included two- or three-pronged AC cord.  If you are using the two- or three-pronged AC cord swap it out with the AC plug. Either connector can be easily connected the adapter as shown below.

    • If the adapter now charges the computer and the LEDs on the barrel connector are lit, the AC plug "duck head" or AC cord that was originally in use is no longer functioning.  You should stop using that connector until you obtain a replacement connector. Refer to the additional information section of this article for further assistance.
    • If the LEDs do not work or the power adapter does not charge the computer, you should continue troubleshooting using the steps in this article.

6. Inspect the DC barrel to see if it's bent or if it has pin damage.

With the adapter connected both to the wall outlet and to the computer, rotate the DC barrel that connects the adapter to the computer. Does the computer start to charge or do the LEDs turn on intermittently? If so, inspect the DC barrel to see if it's bent or if it has pin damage (such as a bent or missing pin). Here are some examples of what this damage can look like:

Bent barrel ring Bent pin Missing pin

If the barrel is not perfectly round or if the pin is bent or missing, contact AppleCare. You should not use power adapters where the barrel isn't perfectly round or if the pin is bent or missing. Please note that damage resulting from excessive force or improper use is not covered by Apple's one year limited warranty. Replacement power adapters may be purchased from the online Apple Store or from an Apple Authorized Reseller.

7. Check for strain relief issues.

Strain relief is defined as a condition where the DC cable (the thin cord attached to the power adapter) separates from the end of the adapter. Strain relief is typically identified visually by observing a separation of the white insulation on the adapter (see below). Under continued use the cable may discolor and the rubber molding may become deformed. Another indication of possible strain relief, which may or may not be visible, is intermittent connectivity. This condition can often be verified by wiggling the cable back and forth near the adapter and observing if the amber or green LED indicator flashes on or off on the barrel-type connector depending on the position of the cord.

8. See if the computer is charging and the LED is lit.

After following the steps above see if the computer is charging and the LED is lit. If not, please refer to the Additional Information section of this article.

Additional Information

Whether your product is in or out-of-warranty, you can take your adapter to an Apple-Authorized Service Provider or Apple Retail Store for evaluation and replacement if necessary. Replacement will be dependent on the evaluation and warranty status.

Although you are not required to bring in the computer used with the adapter please be sure to bring the serial number from the computer; it is required to process potential replacements. The location of your computer's serial number can be found in the following articles: PowerBook and iBook.

If you plan to visit an Apple Retail store please make a reservation at the Genius Bar using http://www.apple.com/retail/geniusbar/.

Last Modified: Dec 17, 2012
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  • Last Modified: Dec 17, 2012
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