Help! Unable to connect new rMBP to external monitor

Discussion in 'MacBook Pro' started by Mesonoxian, Mar 16, 2014.

  1. Mesonoxian macrumors newbie

    Mar 16, 2014
    Hey guys, longtime lurker here. Had to register to post this because I need some help desperately.

    So 1 week ago I bought a new Haswell rMBP 13 (2.4GHz i5, 8GB, 256GB), and today I tried to connect it to my external monitor (Acer P235H - from an old PC) through HDMI.

    When I plugged the HDMI cable into my rMBP, the screen flickered as if it detected the monitor, but the monitor kept saying "Cable not connected". Tried going into System Prefs>Displays>Detect Display, but when I pressed Detect Display, nothing showed up. Unplugged and replugged the HDMI cable and toggled the power for the external monitor, but still no luck.

    Then I tried googling the issue, and found a 24 page(!!!) thread over at apple discussion forums full of ppl having the same issue. Tried some of the fixes described there, including resetting PRAM and SRAM, toggling the external monitor power supply on and off, sleeping the rMBP then connecting the HDMI cable, full shut down and connect the monitor only after startup etcetc. Did not try the gfxstatus one as this rMBP only has intel iGPU.

    The monitor and HDMI cable are both working, plugged them into a windows laptop and a nexus 10 (with an adaptor) to check. For both the windows laptop and the nexus 10, the display was mirrored just seconds after plugging the HDMI cable in.

    I currently do not have any HDMI to thunderbolt adaptors, so I cannot check whether its a problem with the HDMI port or not, but I am certain the rMBP detects the monitor (but it does not show up in the displays section in system prefs) because every time I plug the HDMI cable in, the rMBP screen flickers, and when I toggle the external monitor on and off, the screen flickers twice. I also do not have any other external displays to test.

    I will be going down to the store that I bought to from sometime this week to see whether they can help, but in the meantime any suggestions?
  2. Fishrrman macrumors G5


    Feb 20, 2009
    I checked and the Acer P235H has the following inputs:
    - HDMI
    - DVI
    - VGA

    I would suggest you get a "minidisplayport-to-DVI" connecting cable and try that.

    If that doesn't work, try a "minidisplayport-to-VGA" cable.

    Looks like you may have to experiment to find what works for you...
  3. Mesonoxian thread starter macrumors newbie

    Mar 16, 2014
    Well yeah, I would've thought that any of the inputs would be a plug-n-play kind of thing. So basically I need to get a bunch of cables and adaptors to try and fix this, when HDMI should have worked out of the box? Meh...

    I'm surprised that a windows laptop and a nexus 10 can connect without any problems to the external monitor but my new rMBP cannot.
  4. porthole2 macrumors member

    Feb 26, 2014
    Know very little about Mac's.
    But, what I just found out and hour or so ago with my new rMBP and a Thunderbolt display was that it will not work correctly unless the power cord is attached.

    Just a thought.
  5. Mesonoxian thread starter macrumors newbie

    Mar 16, 2014
    Well thanks for the suggestion, but my rMBP was plugged in to the MagSafe the whole time when I was trying to connect it to the external monitor. Anybody has any ideas?
  6. DeltaMac macrumors G3


    Jul 30, 2003
    Did you try a different HDMI cable?

    Better choice will be a Mini DisplayPort to DVI cable.
  7. Mesonoxian thread starter macrumors newbie

    Mar 16, 2014
    Yes I have tried it with another HDMI cable. No luck there. I don't have a Mini DisplayPort to DVI cable, but I'll definitely check it out when I go back to the store.

    Mind explaining why a Mini DisplayPort to DVI cable will be a better choice? Just curious
  8. Merode macrumors 6502


    Nov 5, 2013
    Warszawa, Poland
    I've tried plugging my LG 21.5 display this weekend and it worked well. I have exact same rMBP.

    Maybe it's the display that is broken? Have you tried plugging different device to it via HDMI? Have you tried plugging rMBP to other display? Have you tried other HDMI cables?
  9. Mesonoxian thread starter macrumors newbie

    Mar 16, 2014
    Update: I just went down to the apple service centre and tested out my rmbp. HDMI ports and thunderbolt ports verified to be working as per normal on several of their monitors.

    I just find it puzzling that my external monitor and HDMI cable works with my windows laptop and nexus 10 but not with my rmbp. Maybe MacBooks are more particular about cables and connections. Oh well. Time to get a new monitor/cable :)

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