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Mid 2008 Mac Pro is booting but screens are black

489 Views 10 Replies Latest reply: Feb 1, 2013 11:15 AM by Grant Bennet-Alder RSS
jourikupad Calculating status...
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Dec 7, 2012 6:10 AM



I have a Mac Pro bought in august 2008. 2.8GHz Quad-Core Intel Xeo. Graphics Card NVIDIA GeForce 8800 GT 512MB. 10GB RAM. OS 10.7.5 Lion.

I use two external displays. One using DVI and one using VGA.


All of a sudden when I was using the computer both my monitors just went black, completely dead. The computer remained turned on. I was unable to get the video back to the screens so I forced shutdowned the computer by holding the power button pressed 10 seconds.


When I turn the computer back on, both my screens remain black, completely dead. The computer seems to be booting though, the fans start and the light is solid white. There is no start up chime sound (I think I heard it once though...but I´m not sure)


This happened yesterday so I have tried to boot the computer after a night with all power cables removed.


After some reading on the Internet I tried to change the CR2032 battery cell, with no success.


The graphic card seems to be the look of it. The fan is spinning.

I´ve tried both monitors with another computer and both monitors are working perfectly.


I´ve tried to boot from bootable usb and it didn´t work.  I then realised that it seems like the computer is unresponsive to any keybord inputs. I am unable to open the DVD and enter a bootable disc. If I press the Caps lock button on the keybord the light on the keybord doesn´t turn on, so maybe the computer has no contact with the keybord?


I would appreciate very much and be very happy if someone could help me with this problem.

Is is something wrong with my graphic card? what could be the problem?



Mac Pro, Mac OS X (10.7.5)
  • Grant Bennet-Alder Level 8 Level 8 (48,110 points)

    The 8800 cards have been trouble-prone. In particular, they get hot enough to cause the low temperature solder (used with surface-mount chips) problems. There are online procedures for baking them in your home oven to re-flow the low-temp solder. This sometimes buys you more time.


    Many users have walked away from these cards and replaced them with Apple-firmware 5770 for about US$250. It is a substantial upgrade for not a huge amount of money, but it certainly is a pain that you have to consider this solution at all -- that the 8800 cards are not more reliable.

    Mac Pro (Early 2009), Mac OS X (10.6.8), & Server, PPC, & AppleTalk Printers
  • Grant Bennet-Alder Level 8 Level 8 (48,110 points)

    The simplest test is to hold the Alt/Option key at Startup. This invokes the Startup Manager, whose code is all in ROM. it draws a blue or gray screen and then shows an Icon for each potentially-bootable Volume. If the screen stays black, you clearly have a graphics problem.


    Whether you also have additional problems is very difficult to tell.



    Mac Pro (Early 2009), Mac OS X (10.6.8), & Server, PPC, & AppleTalk Printers
  • desertwest Calculating status...
    Currently Being Moderated
    Jan 30, 2013 11:45 AM (in response to jourikupad)

    Soooo... did you ever figure this out?  I have the same issue and would love to hear your status!  Thanks!

  • Grant Bennet-Alder Level 8 Level 8 (48,110 points)



    Did you have to shop for a card with Apple firmware, or card that had been flashed to Apple firmware, or did you buy an "off-the-shelf" standard model?


    Do you get the startup screens, or does the screen stay dark until the login screen or desktop?

    Mac Pro (Early 2009), Mac OS X (10.6.8), & Server, PPC, & AppleTalk Printers
  • The hatter Level 9 Level 9 (58,545 points)
    Currently Being Moderated
    Feb 1, 2013 10:02 AM (in response to jourikupad)

    Not just OC'ing a card but some programs and games can push a card and force it to use more power.


    There are people using a splitter to take one 6-pin and connect the two 6-pin. EVGA and others do have 670's that  only require 2 x 6-pin while some cards use 1x6-pin and 1x8-pin connector. And some people want/need a card with more than 2GB for better performance, 2.5-4GB for CS6 and other programs.

  • Grant Bennet-Alder Level 8 Level 8 (48,110 points)
    Currently Being Moderated
    Feb 1, 2013 11:15 AM (in response to jourikupad)

    Thanks for making that perfectly clear. Now users who want to use that card will know exactly what to expect.

    Mac Pro (Early 2009), Mac OS X (10.6.8), & Server, PPC, & AppleTalk Printers


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