MBA cant drive monitor with out AC power?

Discussion in 'MacBook Air' started by alpha752, Mar 16, 2011.

  1. macrumors newbie

    Joined:
    Feb 25, 2011
    #1
    I have a 2010 13" Ultimate. I connect it via HDMI to my 21" Acer monitor and it works fine. Today I noticed that the AC power was disconnected, and it wouldnt connect to my monitor. It was wierd, because if I opened the lid, it would connect and power the external in dual monitor mode, but it would not drive the external monitor as a single screen (I do have resolution set to 1080p. Once I plugged in the Magsafe, it started up the monitor no problem.

    Is this a known thing? I didnt think driving a slightly bigger screen would cause an issue like that, I figured it would drain the battery faster.

    Its usually not a problem to leave the MBA plugged in when docked to the monitor, but I happened to need the plug for something else this time. Is this how it should be or what?
     
  2. macrumors 601

    alust2013

    Joined:
    Feb 6, 2010
    Location:
    On the fence
    #2
    That's normal. Apple notebooks will not use "clamshell" mode without being plugged in. They will dual screen fine, however. No idea why it's that way.
     
  3. hfg
    macrumors 68030

    hfg

    Joined:
    Dec 1, 2006
    Location:
    Cedar Rapids, IA. USA
    #3
    Here is the Apple support document on clamshell mode:

    http://support.apple.com/kb/HT3131


    If you are using a Bluetooth keyboard and mouse on a Bluetooth enabled Apple portable:

    Make sure the computer is plugged in to an outlet using the AC power adapter.
     
  4. thread starter macrumors newbie

    Joined:
    Feb 25, 2011

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