My Mac Pro Desk Top computer no longer can "see" my second display??

Question

My Mac Pro Desk Top computer no longer can "see" my second display??

I've tried reversing the connections on the back of the MacPro but it still doesn't "see" the second display. I've had these two displays hooked up for years with no problems. I recently upgraded to Mountain Lion and I just had the MacPro in the Apple Store for a "One To One" transfer of data to my new MacBook Pro laptop. When I brought it back home it still worked fine. I then was cleaning up some stuff and I know I went into my "Users and Groups" panel in System Preferences and I did remove some items from the "Login Items" list that open automatically so maybe that is the problem?? I know the second display is getting power and recognizes it's connection to the compuiter because when I disconnect it, it says, "no signal" and when I reconnect it, it just goes to sleep. Advice appreciated.

Saratoga Lefty

Mac Pro, OS X Mountain Lion (10.8.2)

Posted on Dec 31, 2012 7:48 AM

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Answer 1

Dec 31, 2012 8:45 AM in response to saratoga lefty

What graphics card?

Two DVI displays? Any Mini DisplayPort ? Any adapters in use?

Is one (or both) wider that 1920 wide?

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Answer 2

Dec 31, 2012 10:01 AM in response to Grant Bennet-Alder

My main monitor is a Samsung SyncMaster 213T and my secondary display is a Samsung Syncmaster 173P. I have them both hooked up directly to my Mac Pro Desktop with DVI cables. I have a 2008 Mac Pro with 2x2.8GHz Quad Core Intel Xeon processor and NVidiaGEForce 8800GT 512MB graphics card. I have 22Gb of Ram. I will try to find Samsung Display drivers and download them and see what happens.

Saratoga Lefty

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Answer 3

Dec 31, 2012 10:15 AM in response to saratoga lefty

It doesn't appear there are drivers for Mac, only for Windows?? Not sure what to do next? The 213T is working fine but the 173P isn't detected. Tried holding down the opt key and clicking on "Detect Displays" but nothing. Really frustrated.

Saratoga Lefty

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Answer 4

Dec 31, 2012 1:10 PM in response to saratoga lefty

Thanks for providing additional information. Since you did not answer my specific, pointed questions about connection and the exact reolution of these displays, I will have to look them up ... later.

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Answer 5

Dec 31, 2012 6:17 PM in response to Grant Bennet-Alder

The Samsung 213T has a native resolution of 1600x1200 and this display is working fine. The 173P has a native resolution of 1280x1024 and it is the display that is not connecting with the Mac Pro Desktop. I tried switching the connections on the back of the computer for the two cables and same result. Then I tried unhooking the 213T and only leaving the 173P connected and still no image. If I disconnect the 173P I get the message "No Connection Check Signal Cable Digital" and the box moves around the screen. If I reconnect it I get the "Going To Sleep" message. So apparently the 173P display recognizes when it is connected to the computer but it no longer will show any image. In the past both screens worked well and I had a large image area which I could use. For example, I could put my CS6 panels on the smaller screen and just have my image working area on the larger screen. Same with Lightroom. Now I can't get anything on the smaller screen, even if it is the only one hooked up.

Saratoga Lefty

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Answer 6

Dec 31, 2012 6:57 PM in response to saratoga lefty

Some of the graphics cards that had two DVI connectors had one Dual-Link (suitable for all resolutions including wider than 1920 wide) and one Single-Link (suitable for resolutions up to 1920, but not wider). This does not appear to be your problem, since both are less than 1920 wide.

The "Drivers" business is a complete Red Herring (Not Applicable), as the Mac does not use Drivers for displays -- it uses a unified driver for the Display CARD, and customizes it based on the capabilities reported by the Display when connected. In order to get this to work, the display must correctly self-identify.

To verify that the display is correctly detected, look in:

About This Mac > ( More Info ) > Graphics and Displays ...

... a correctly self-identified display shows its Name and its maximum resolution. be skeptical, this information does not update when you plug/unplug the display, and you have to close and re-open this window (or possibly the entire program) to get the information to refresh after a change.

If either display provides a USB cord, it must be plugged in to complete the display connection and provide display ID and control (this is much more common with Apple displays that third-party displays).

Is there any evidence of trauma to the display connectors or cables? Any bent pins on the connectors?

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Answer 7

Dec 31, 2012 7:10 PM in response to Grant Bennet-Alder

Grant,

I really appreciate your help, especially on New Year's Eve. I looked at the pins on the cable and no visible damage of any kind. I unhooked the power cable and rehooked it up and no change. The 173P just flashes back and forth "analog" and "digital" and then goes to sleep. I went up under the "About This Mac" "Displays" tab and it just shows the one display, the 213T, which is the one that is working. I'm thinking maybe I should take the Mac Pro and the 173P over to the Apple Store and see what they can do. I was there earlier today and they didn't know of any reason why it should be acting this way. I recently installed Mountain Lion but it was working okay after that and I also took in the Mac Pro Desktop and my new MacBook Pro to have data transferred, but it was working okay after that (for a day or so) also. My wife is yelling at me as we have to head out to a party; Happy New Year to you and your family. I'll check back tomorrow to see if you have any further advice. Thanks again.

Saratoga Lefty

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