DVI out and ancient monitor

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DVI out and ancient monitor

I have a 2006 Mac Pro (8GB Version) Dual G5 with OS X 10.5.8 That I am experimenting with just for fun, it has a dual DVI out video card from AMD (ATI at the time), and I have two monitors attached to it.

a 1080p ASUS monitor as my prime monitor
a 640x480 monochrome monitor of an unbranded company

Now, as the experiment continues, I'm wanting to connect my 640x480 monochrome monitor as my secondary monitor to the DVI port. I purchased a DVI to VGA connector which works successfully on all other computers I have used as well as using the DVI to VGA connector on a more modern LCD screen on the Mac Pro (which worked). I have tried connecting the monochrome monitor to the DVI to VGA connector and to the Apple computer with no success what-so-ever.

I've gone into displays and selected 'Detect Displays', I see the monochrome monitor flash once and the Mac Pro does not recognize the monitor.

Is there ANY way that I can override or manually input the monitior into the OS X operating system or into the Kernel? As a software engineer I can work with the UNIX kernel, so any option is on the table at this point.

Suggestions or experiences?

Mac Pro, Mac OS X (10.5.8)

Posted on Oct 17, 2013 10:52 AM

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Answer 1

Oct 17, 2013 4:37 PM in response to RET80

On cards with two DVI ports, the two ports are not identical -- one has greater capability than the other. Try the other port.

VGA can be extracted from a DVI-I port by an adapter (no conversion required) that picks up the card-generated VGA signals presented by a DVI-I port. They are in the bar at the end of the connector and the four pins around it, plus the last pin in the top row of the grid. If the DVI port you are connecting to does not have these pins present, you will not get VGA out, because the adapters only re-wire what the card presents.

The VGA signals are shown in this diagram (courtesy Wikipedia) as salmon-pink.

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