Second Display (Same Model) Not Detected

Question

Second Display (Same Model) Not Detected

Mid 2012 3.33 6-Core with the 2 MDP and 1 DVI OS X 10.9.5

Very perplexed by this issue... For the time being I'd like an extended desktop across two Samsung Syncmaster S20B250 monitors. I'm also using a Vizio TV to test the system. After some trial and error I discovered both MDPs and both MDP>HDMI cables to be working. The kicker... Only the Vizio TV and one particular Samsung monitor are able to be detected. Take the same cable using the same port from the first Samsung display or the Vizio TV and OS X suddenly does not recognize the second display. Plug in any other HDMI device into the second, non-detected Samsung display (Bluray, Xbox) and voila, works without issue.

Is my Mac Pro somehow detecting this exact monitor or is the monitor somehow not communicating well with only one device (the Mac Pro)? My previous setup was with these same monitors through a MBP, a Matrox Dual Head2Go ME and an HDMI splitter to mirror my second monitor (the one that doesn't work) to the Vizio TV when needed. It also doesn't play nice with the HDMI splitter anymore. Plug the Vizio in by way of the HDMI splitter (with nothing else plugged in) and it no longer works. It's important to note that after upgrading to a Mac Pro, I hadn't yet bought MDP cables so I used the MBP setup briefly (Matrox + HDMI splitter) and had all three monitors running correctly.

I've searched high and low (I know Mavericks has it's share of display issues) but haven't found anyone experiencing an issue quite like this. Is there some plist file or something that I can trash that will help reset the display profiles in OS X? I've reset PRAM, SMC. I've uninstalled any Matrox software and the monitors have already been reset themselves but only by way of navigating through the menu options. Unfortunately, I can't upgrade to Yosemite due to some applications that I use. Anyone have a clue of what's happening?

Thanks in advance for any help. 🙂

Mac Pro, OS X Mavericks (10.9.5), null

Posted on Jun 19, 2015 10:55 AM

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Answer 1

Jun 19, 2015 11:45 AM in response to alienobserver

You description of the problem is a little hard to follow. But if your two identical monitors are not interchangeable, then one is defective.

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Answer 2

Jun 19, 2015 12:35 PM in response to Grant Bennet-Alder

Thanks for the response Grant. That was my initial reaction, but any other device I've plugged in works fine with the non-detected display (a BD player and an Xbox). Also my HDMI splitter no longer works with the setup. Both devices (the second display and the HDMI splitter) suddenly became defective at the same time? Is it possible this is related to a Mavericks display bug I've read about? It seems likely to the me that somethings gone awry due to the Dual Head2Go (maybe dealing with resolution since Matrox's whole thing is splitting single monitor resolution across two separate displays). This happened as a result of my dropping the MBP/Matrox setup for the Mac Pro 2 MDP setup. I'm confident that if I were to reinstall Matrox software and wire my displays through the Dual Head2Go again, everything would come back to life.

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Answer 3

Jun 22, 2015 9:37 AM in response to Grant Bennet-Alder

Update:

The display also doesn't work with an old Macbook. However as I expected, when I plug everything back in using a Matrox Dual Head2Go, the display flicks on without a hitch. And in addition to the previously confirmed 1080p - 480p, 720p, 1080i, and 1024 x 768 resolutions are displayed using an Xbox. These Samsung displays have an optimal resolution of 1600 x 900... Is it possible for only specific input resolutions to become defective? Maybe the optimal resolution no longer works?

In sum:

Vizio TV: Works with all Xbox resolutions, a Sony BDP, a Mac Pro, and a Mac Pro/Matrox setup

Primary Samsung display: Works with all Xbox resolutions, a Sony BDP, a Mac Pro, and a Mac Pro/Matrox setup

Seconday Samsung display: Works with all Xbox resolutions, a Sony BDP, and a Mac Pro/Matrox setup

I'd hate to buy another display without ruling out that this isn't an Apple issue. Anyone have a clue as to what might have happened here? 😎

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