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User profile for user: desertwest
desertwest Author
User level: Level 1
10 points

Mac Pro now won't boot... had been acting strange

I recently bought this machine (second hand) and all seemed well until yesterday. I have searched and read MANY MANY similar problems on the net but no resolutions (why do so many people stop posting when they solve their problem and leave us hanging?) Thanks in advance for any ideas!


What I have:

2008 Apple Mac Pro "Quad Core" 3.0GHz dual Xeon (A1186-EMC2113)

8GB of Ram (4x: Samsung 2gb 2Rx4 PC2 -5300f-555-11-EO)

Graphic: Radeon X1900XT (512 VRAM) running 2 AOC 24" monitors DVI

250 HDD 7200PRM (and 500gig secondary drive)

OS: Lion 10.7 (recent clean install - 10.0.7 no updates yet)


What it is doing (or not doing):

First thing wrong was it dropped the Internet (ethernet wired) It thought it was not connected yet I tried same ethernet connection on my other computer and it was fine. Self diagnostic just said cable not connected. Connection would come and go so I decided to re-start machine. Upon restart, no boot. Fans kicked in full force and front power light was blinking (as well as blinking red led on memory tray), no monitors or beeps. Internet search said memory. Re-seated memory...seemed to have fixed that issue, maybe I had bumped a tray loose while checking for loose internet connection? Powering up now has fans full force and solid power light. Back to the internet! Seems like it could be any number of things but hardly anyone has posted a resolution. (Side note... when I say "fans full force", I think it's really the video card's built in fan making all the fuss because when I removed the card and powered up... still wouldn't boot but tower fans weren't that loud).


What I have tried so far: Removed and reinstalled memory in different combinations, removed and reinstalled video card (in case of loose connection), pushed reset button on logic board (after unplugging and replugging a/c), tried holding power button while plugging in a/c) btw video card fan spins continuously when I power up, replaced PRAM battery, tried booting in safe mode (same results), while it was stalled I powered off the monitors and powered them back up... they said "No Signal". Probably tried more stuff too... whatever I read that seemed like a good idea. Anyway, nothing has made a difference. Don't have start up discs or anything... like I said, I bought it used (please don't leave comments like "you get what you pay for", I understand that... but I would like to have this machine work if I can.) I will take it to the shop if I have to but would like to hear your advice first.


Have read it could be video card, mother board, bad RAM, etc. Seems like this happens to a lot of people but I can't seem to find an answer besides start swapping out all the guts. Is that really how to solve something like this? I really don't know much about repairing these things.


Thank you to all who may share some insight and thanks for all who contribute to this forum! You guys ROCK!

Posted on Jan 30, 2013 11:34 AM

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11 replies
User profile for user: Grant Bennet-Alder
Grant Bennet-Alder
User level: Level 10
126,907 points

Jan 30, 2013 1:49 PM in response to desertwest

The flashing power light is an indication of memory problems. You may make them temporarily better by re-seating, but the memory problems will be back.


Your situation is dire. The way to proceed is not to swap. It is to remove everything not essential to getting a chime. Remove all hard Drives, all CD drives, all PCIe cards, all graphics cards, and all memory except one pair on one riser.


¿ Chime?

--No, measure the power at the Molex connectors at the CD readers looking for a bit over 5 Volts on red, a bit over 12 Volts on yellow, referenced to the black wires. If not there when the fans are on, your power is not good enough.

--Yes, add in the graphics card and see if you can get a picture.

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User profile for user: The hatter
The hatter
User level: Level 9
60,980 points

Jan 31, 2013 6:47 AM in response to desertwest

Something wrong. Either it ain't a 3,1 2008 which by your specs I am sure of, or something else.


X1900 only works in pre-2008


you are also using FBDIMM 667s which are generally from 2006-7 also


And quad 3.0 is pre-2008.


WHAT does syst em profile header say "about this Mac"


2008 Apple Mac Pro "Quad Core" 3.0GHz dual Xeon (A1186-EMC2113)

8GB of Ram (4x: Samsung 2gb 2Rx4 PC2 -5300f-555-11-EO)

Graphic: Radeon X1900XT (512 VRAM)

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User profile for user: desertwest
desertwest Author
User level: Level 1
10 points

Jan 31, 2013 9:50 AM in response to The hatter

Hatter: not sure what you are saying. That the machine is pre-2008? Is that relevant to the problem... if so I'm not sure how to confirm the year. It won't boot up so i cant read the "about this mac" but I do know it is a 3.0 Quad and I did confirm the video card model as well as memory.


Grant: I pulled everything but one memory tray with one pair, and the main hd. Powered up: fans very quiet but not sure how to tell if it's working. Hd isn't making any noise.. just a slight rumble at the beginning. If I add in the graphics card, its fan comes on full speed. All the wires are black so I randomly checked dc voltage at the dvd's and am only getting 1v. Doesn't sound right but that's what the meter says with everything unplugged and machine on.


I'm wondering about the graphics card fan running full speed. Does this sound wrong or is it just a symptom of not getting info from the computer to slow down? Just wondering.

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User profile for user: The hatter
The hatter
User level: Level 9
60,980 points

Jan 31, 2013 9:51 AM in response to desertwest

It is not 2008. Can't use X1900, which you can remove and replace with Apple's ATI 5770.

Also 10.6.8 works better -- and w/o the X1900.


FBDIMMs fail over time. Get the ones from Amazon


Hardware Monitor


Same for X1900


http://www.xlr8yourmac.com/Graphics/X1900XT_Overheating/ATI_X1900_artifacts.html http://www.xlr8yourmac.com/Graphics/radeon_X1900XT/X1900XT_dust_buildup.html#sto rytop
They had to be pulled and cleaned every 3-4 months, dust bunnies and clogs and causes the fans and system to work harder and overheat.
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User profile for user: desertwest
desertwest Author
User level: Level 1
10 points

Jan 31, 2013 10:02 AM in response to The hatter

Thanks Hatter! Just read the article above (on the X1900 overheating). Now that i think about it, I think I did see some of those mentioned pink particles (or something similar) just prior to the shutdown. If the card has "burned itself up", would that keep my machine from booting? Can it be as simple as replacing the video card and all might be well?

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User profile for user: Grant Bennet-Alder
Grant Bennet-Alder
User level: Level 10
126,907 points

Jan 31, 2013 11:39 AM in response to desertwest

The CHIME is created and played by Software after the first part of the Power-On Self Test has passed. If you have no chime, there is no point putting anything back in the machine -- you are going nowhere.


If you are still getting power-indicator flashing, you still have memory problems.


The Voltages at the Molex connectors are on the OUTER two leads, and the INNER two are (the same) ground. If you do not have a proper 12 Volts and 5 Volts, your Mac will not run.

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Mac Pro now won't boot... had been acting strange

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