HDMI to Mini Display port monitor won't work...

Question

HDMI to Mini Display port monitor won't work...

Hi all. I've been using an older Mac Cinema Display for a while... with a big Hanns-G as my secondary monitor (D-Sub) and a USB monitor for the third. Now I don't have as much space and want only 2 monitors. The Cinema Display is small, so I want to use the Hanns (with HDMI because the quality of the D-Sub is terrible). I bought an HDMI to Mini Display Port adapter and it works... until the computer sleeps or restarts or anything. Once the computer goes to sleep, I can't get the monitor to wake up. I have to force restart from the power button... Then, this morning, I wake up and turn the computer on and the monitor never works. It's pretty annoying and I feel like Apple has forced me into using their less than desirable peripherals once again. Anyone have any tips on getting around this? I'd really like to be able to clearly see the screen that I sit in front of all day... It would help me out tremendously.

Mac Pro (Early 2009), OS X Mountain Lion (10.8.2)

Posted on Feb 5, 2013 10:31 AM

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Answer 1

Feb 5, 2013 11:55 AM in response to BrandonScrushy

The Mac depends on getting ID and capabilities information from the display, and sometimes HDMI devices do not provide it readily. "Detect Displays" button may force the device to send ID and capabilities again.

It is also often the case that HDMI devices need an extra configuration step in the HDMI device, to tell it that they are talking to a computer.

The Voltage levels on the Mini Displayport converted to run DVI are sort of marginal. This shows itself as serious problems when trying to run three displays with more than one conversion.

It is possible your display is especially sensitive to the Voltage levels being a bit low. An ACTIVE adapter to DVI may be the solution for you.

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Answer 2

Feb 7, 2013 9:41 PM in response to Grant Bennet-Alder

Well, the same issues happen with only the one monitor running, so I don't think it's too much conversion going on. I do think you're right about there basically being some missing messages that are needed for the Mac to communicate with the monitor. I'm going to keep working on it. Thanks for your help. Also, I'm assuming by DVI you meant HDMI? If I had a DVI monitor, this would not be an issue at all, lol. DVI has always worked well, problem is I have an HDMI/D-Sub monitor that needs to be my one and only monitor (with possibility of the USB one)....

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Answer 3

Feb 8, 2013 6:32 AM in response to BrandonScrushy

DVI-D (the most common Digital implementation) converts directly to HDMI with only swapping the wires around. The Voltage levels and timing are identical.

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Answer 4

Feb 8, 2013 11:08 AM in response to Grant Bennet-Alder

Ah, gotcha. Thanks.

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