stanbenavides

Q: Does MacBook Pro require to be plugged in to use HDMI connected monitor

I have a MacBook Pro and use a 27 in monitor connected to the HDMI.  All is well unless I unplug the charging.  Even with 100% battery if I unplug the power and run on battery the HDMI doesn't drive the monitor.  I am pretty sure I had used the monitor on battery power before the upgrade to Yosemite.  MacBook is just a few months old.

MacBook Pro (Retina, 15-inch, Mid 2014), iOS 8.3

Posted on Jun 17, 2015 10:01 AM

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Q: Does MacBook Pro require to be plugged in to use HDMI connected monitor

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  • by jeremy_v,

    jeremy_v jeremy_v Jun 19, 2015 10:34 AM in response to stanbenavides
    Community Specialists
    Jun 19, 2015 10:34 AM in response to stanbenavides

    Hey stanbenavides,

     

    Thanks for visiting Apple Support Communities.

     

    It seems like you only see video on your external display when your MacBook Pro is connected to power.

     

    The MacBook Pro should not require being plugged in to use a HDMI connected display, and there are some troubleshooting steps that may help this situation.

     

    Try the steps in the "No video or no signal, image distortion, 'snow,' or flickering" section of Apple computers: Troubleshooting issues with video on internal or external displays, starting with these tips:

    You can reset the Mac's parameter RAM and SMC.

     

    Best Regards,

     

    Jeremy

  • by stanbenavides,

    stanbenavides stanbenavides Jun 19, 2015 11:02 AM in response to jeremy_v
    Level 1 (0 points)
    Jun 19, 2015 11:02 AM in response to jeremy_v

    Thanks Jeremy

     

    Yes and from all that I have read having the power attached to the MBP is required for external monitors.  That is and was my question.  I don't see anywhere in the documents that resetting the RAM or SMC would fix that.  It is pretty simple with an external monitor attached to the MBP, if I unplug the power the monitor goes off in clamshell or with the laptop monitor closed.  If I open the laptop the external monitor will come on.  So if the laptop is open and on battery the external HDMI monitor will work, if the laptop is closed then I have to have the laptop plugged in.

     

    So is that my answer?  the laptop can not be in clamshell (shut) and on battery and use an external monitor.  The laptop must be open to use an external monitor while on battery. 

  • by jeremy_v,Solvedanswer

    jeremy_v jeremy_v Jun 20, 2015 12:49 PM in response to stanbenavides
    Community Specialists
    Jun 20, 2015 12:49 PM in response to stanbenavides

    Hello stanbenavides,

     

    Thanks for replying with some additional detail.

     

    Yes, you're right. To use your MacBook Pro in closed clamshell mode with an external monitor, it must be connected to power.

     

    For more information, see How to use your Mac notebook computer in closed-clamshell (display closed) mode with an external display.

     

    Apologies for any confusion caused.

     

    Best Regards,

     

    Jeremy