Mac Pro Late 13 - 2. monitor problem

Discussion in 'Mac Pro' started by Suchtkrueppel, Jun 23, 2014.

  1. Suchtkrueppel macrumors newbie

    Jan 7, 2014
    Hi everyone,

    I have a problem with my second monitor but before here some specs if needed: (Mac Pro Late 13' 6core 12Gb RAM D700, 1x BenQ GL2450H on HDMI Port, 1x BenQ GL2450H on Thunderbolt-HDMI-Adapter)

    So the problem is when I start my Mac Pro the main monitor, connected with HDMI, starts up right away but the second monitor with the thunderboltadapter often times doesn't get recognize or can't sync.
    The only way to get it running is to pull out the main monitor HDMI cable and plug it back in until the second monitor makes a high frequenzy noise and comes to life. Sometimes I have to repeat this process over 10 times until it works.

    Anyone else had this problem :confused:
  2. Digitalclips macrumors 65816

    Mar 16, 2006
    Sarasota, Florida

    I have s different but an oddity never-the-less. No sync or sound issue rather monitor recognition. I have an Apple 27" Thunderbolt Monitor and a second older monitor running using an Apple adapter VGA to Thunderbolt. The smaller monitor always boots first and the Apple Monitor doesn't come on for quite some time. However, if I reverse the Thunderbolt cables in the Mac Pro and reboot this will behavior stop with the Apple monitor firing up first. At the next reboot it is back to the other way around and the long delay. Here is the weird thing, I am a dev and now running the second beta of Yosemite and this has not altered this behavior which also happened in Mavericks.

    The commonality I see is the use of a Thunderbolt adapter, albeit mine is VGA - TB yours is HDMI-TB.
  3. Suchtkrueppel thread starter macrumors newbie

    Jan 7, 2014
  4. Kryckter macrumors 6502


    Mar 12, 2009
    What OS are you guys on? I have seen some very crazy graphics things with 10.9.3
  5. Suchtkrueppel thread starter macrumors newbie

    Jan 7, 2014
  6. gusanchezc macrumors newbie

    Jun 25, 2014
    Same problem

    I'm having the same problem with my Mac Pro (Late 2013 3,5 GHz, 16 GB RAM, SAMSUNG S27C350H on HDMI port, and a SAMSUNG S24C300 on thunderbold to HDMI adaptor) it gets really frustrating I really don't know what to do... I'm running OS X 10.9.3.
  7. Suchtkrueppel thread starter macrumors newbie

    Jan 7, 2014
  8. lemonade-maker macrumors 6502


    Jun 20, 2009
    First, there is no such thing as a thunderbolt to hdmi adapter. It's a mini display port to hdmi adapter. Second, since 10.9.2 apple has borked these adapters. I gave up and bought new monitors that support display port
  9. koban4max macrumors 68000

    Aug 23, 2011
  10. pstrudl macrumors newbie

    Feb 24, 2014
    Connecting via display port doesn´t work properly in 10.9.3 with my LG34UM95 monitor on my nMP. When waking from sleep the monitor stays black whereas the EIZO monitor connected via mini display port to DVI Adapter always works. I have order a long thunderbolt cable for my LG because that connection worked flawlessly in my tests.

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