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User profile for user: jourikupad
jourikupad Author
User level: Level 1
0 points

Mid 2008 Mac Pro is booting but screens are black

Hi!


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 intact...by 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?


Thanks!

Mac Pro, Mac OS X (10.7.5)

Posted on Dec 7, 2012 6:10 AM

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10 replies
User profile for user: Grant Bennet-Alder
Grant Bennet-Alder
User level: Level 10
127,387 points

Dec 9, 2012 8:11 AM in response to jourikupad

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.

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User profile for user: jourikupad
jourikupad Author
User level: Level 1
0 points

Dec 9, 2012 9:05 AM in response to Grant Bennet-Alder

Thanks for the reply!

ok I´ve read a lot negative comments about the 8800-card...maybe I should try to bake it.


But do you think this is a graphic card related issue only, or do you think this problem could be related to other hardware?

If this is an obvious graphic card related problem, maybe it´s worth investing in a 5770...the 8800 is quite bad

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User profile for user: Grant Bennet-Alder
Grant Bennet-Alder
User level: Level 10
127,387 points

Dec 9, 2012 9:57 AM in response to jourikupad

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.


.

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User profile for user: jourikupad
jourikupad Author
User level: Level 1
0 points

Feb 1, 2013 1:57 AM in response to jourikupad

Hi!


Yes the problem is solved!

I started by borrowing a friends graphics card and installed it in my Mac Pro, and both screens was working. I realized my 8800Gt was broken.

I baked the 8800GT in the oven, there is a lot of videos on youtube on how to do it, and it worked again!


But I was tired of my old 8800Gt which is slow and old, and I realized Nvidia has released drivers for Mac on almost every card. And the new OS 10.8 support by default almost all new Nvidia cards. So I bought a GTX670 card and installed, works perfectly!


Cheers!

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User profile for user: jourikupad
jourikupad Author
User level: Level 1
0 points

Feb 1, 2013 9:20 AM in response to jourikupad

I just bought a "off-the-shelf" standard model, Gigabyte GeForce GTX 670 OC 2GB RAM to be precise. Even though it requires one 6-pin and one 8-pin power cable (Mac Pro only support 6-pin) it´s not a problem, you can just use a 6-pin-to-8-pin adaptor. The power supply is well within limits, they put an 8-pin cable on the card if somebody wants to manually over clock the card, which is not a good idea if you got a Mac Pro, because then you´ll need to get an external power supply (the power from the Mac Pro is not sufficient).


I don´t get a startup screen, the displays remain black until the login screen. But that´s not a problem for me, if I want to boot on a different drive I just choose startup disk before restart.


So far, it works like a charm!

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User profile for user: The hatter
The hatter
User level: Level 9
60,990 points

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.

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Mid 2008 Mac Pro is booting but screens are black

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