Display goes black on Log in screen

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Level 1

96 points

Display goes black on Log in screen

Hi everybody.

Sometimes, not always, when i switch on my Mac Pro, it starts up as normal until the log in screen should appear. At this moment the screen goes black.

I checked the connection and the display settings. Nothing. I then spot that setting the Mac Pro to sleep and waking up again solves the problem. The log in screen appears, everything is ok from then on.
So i think the display is not the problem. It is not in standby mode! I think the Mac or the OS sometimes doesn't recognize the display correctly and then send a black signal. But it must send a signal because otherwise the display would show this message that no input signal is present.

The display is from DELL, the connection is DVI. It is a Mid2010 Mac Pro Quad with AMD 5870 GPU.
Any ideas?

Mac OS X (10.6.5), Allways got the latest updates installed.

Posted on Nov 19, 2010 8:34 AM

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Answer 1

Nov 22, 2010 12:51 PM in response to Tohu

You might take a look at this : "http://macperformanceguide.com/blog/2010/20100916_MacProVideo--macpro-bugs.htm l".

I have very similar problems with an equal machine and also a DELL monitor also with DVI, just that the screen goes black BEFORE the login screen appears and not after. I prefer to login blindly and then move the mouse cursor blindly to a screen corner as described in the link above.

If you have a chance to tell Apple, please do it!

BTW: doubleyouseven works fine...

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Answer 2

Tohu Author

Level 1

96 points

Nov 23, 2010 7:35 AM in response to Andi-0815

Hey thanks for your comment. So i'm not the only one with that problem.

The hot corner workaround may work but i don't use hot corners because it would disturb me on regular work.
Apple has to fix that. Especially if it is true for Apple Displays as well, as they said on the website.

What is meant by "doubleyouseven"?

Regards
Alexander

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Answer 3

Dec 12, 2010 8:25 PM in response to Tohu

Wow! I have a similar issue, started out with a 24" Dell monitor herringbone & flashing on and off at start up. I thought it was the monitor since it happened once in awhile, so I purchased a new 27" Samsung monitor everything seemed ok until tonight, black screen as described above. Now I know am not alone. My video card is the ATI HD 5770.

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Answer 4

jbphil1

Level 1

44 points

Dec 13, 2010 12:56 AM in response to My White Dog

Same thing with my Mac Pro 2010 ATI 5770 and CinemaView 24A monitor (I posted on this last week).

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Answer 5

Dec 13, 2010 12:44 PM in response to Tohu

What also might be interesting:

If you start doubleyouseven, everything works fine. It's a great system. 🙂

If you then directly reboot to MacOS without switching the computer off, you get a horrible screen with terrible noise that is so ugly you think your monitor will soon explode. Note that you get that terrible picture AFTER the boot screen (which is fine), you get it during login.

When you manage to shutdown the Mac and switch it completely off, then reboot to MacOS, everything is (hopefully) fine again.

This proves that Apple's graphics card initialisation in MacOS is insufficient.

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Answer 6

Dec 13, 2010 1:22 PM in response to Tohu

What is meant by "doubleyouseven"?

= W7 = Windows Seven

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Answer 7

Dec 13, 2010 1:28 PM in response to Grant Bennet-Alder

God save me from such cuteness.

Almost enough to gag you that one.

___________________

Allan

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Message was edited by: Allan Eckert

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