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pprior

macrumors 65816
Aug 1, 2007
1,448
9
The first thing I'd do is try taking the heatsink off and putting new compound on it and reinstalling- sometimes CPUs "die" because they overheat immediately on boot. Seen this before in PC world, it's worth a try before taking drastic action. CPUs fail pretty infrequently after all.
 

snberk103

macrumors 603
Oct 22, 2007
5,503
91
An Island in the Salish Sea
Do a google search (or search the Apple support pages) .... but there are supposedly some LEDs on the logic board that will light/blink to denote certain diagnostic info. I only know this because the techs looking at my Mac Pro were reading the LEDs. I have no idea how to read them, and what info they can provide, but I think you have enough search terms to make a very quick and narrow google search to see if the LEDs can be helpful. Also check the Apple support pages, especially the community discussions. There are some smart crackers there.

Or you could pop the new CPU into slot one, leaving the the slot two with an old CPU, and if it still fails swap the old removed CPU into the slot two. That way you are handling the new CPU once, and the good old CPU twice (once to pull and once to re-install) - at most.

Good Luck.
 

bearcatrp

macrumors 68000
Sep 24, 2008
1,728
67
Boon Docks USA
Since you have to replace a CPU, why not buy a pair of 3ghz or even 3.2 to get a little more kick out of it. I know my 2.8 did a good job but if your going to try to keep it for awhile to extend the life of it, why not give it more kick. I replaced cpu's in my old 2006 2ghz to 2.33ghz. Not bad to do but not an easy task either. Then figure out which is still good and sell it to recoup some cash. Good luck either way you go.
 
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lixuelai

macrumors 6502a
Oct 29, 2008
957
326
Somehow I doubt it is the CPU itself... CPUs are nearly impossible to kill. Maybe you can swap out the PCB the CPU sits on if it is indeed that socket that has issues since the CPU is most likely fine.
 

supercooled

macrumors 6502a
Sep 6, 2007
737
1
Sorry to hear because I have the same machine. I wouldn't know what to do if mine died since parts aren't readily available.

Does anyone know if the computer will run if one cpu died?

Anyway, good luck OP. I just did a cleaning with canned air and the machine seems to run a lot quieter plus I'm not sneezing like crazy.
 

666sheep

macrumors 68040
Dec 7, 2009
3,686
291
Poland
Does anyone know if the computer will run if one cpu died?

MP 1.1 can run with only one CPU (in upper socket) without terminator in second socket. There was BTO 3.1 model with ony one CPU (I had one and its CPU was in upper socket too), so yes, it's possible.

I presume that if OP would be able to buy working logic board, his MP should run and he would confirm if one of CPUs is shot.
But he need to check all other mentioned possibilities first.

OP, if you need service manual for your MP, PM me your emai address.
 

scotttaylor

macrumors newbie
Original poster
Aug 15, 2010
21
0
MP 1.1 can run with only one CPU (in upper socket) without terminator in second socket. There was BTO 3.1 model with ony one CPU (I had one and its CPU was in upper socket too), so yes, it's possible.

I presume that if OP would be able to buy working logic board, his MP should run and he would confirm if one of CPUs is shot.
But he need to check all other mentioned possibilities first.

OP, if you need service manual for your MP, PM me your emai address.

PM, sent, thanks!

Well, that's interesting... I picked up my machine from the AASP yesterday and the tech said the machine would not boot with a single proc. I guess I will give it a try. It would be nice to get the machine running one one proc before I spend any money on it. First thing I need is a long 3mm hex driver to loosen the CPU cooling towers...
 

scotttaylor

macrumors newbie
Original poster
Aug 15, 2010
21
0
It's the GPU!

After a few other attempts I pulled the GPU (NVIDIA GeForce 8800 GT) from the machine and it booted right up off the Snow Leopard Installer DVD. Now I've got my original boot drive in and the machine is running (headless). I'm able to screen and file share to it from my MBP. Nice to know you can screen share to a headless Mac...

With the GPU installed I was seeing both CPU A and CPU B error diagnostic led's on the main logic board. Sometimes it would be A other times B, and sometimes both A and B would come on. They would come on late in the boot cycle. Probably when the machine was changing resolution to display the desktop. Putting the card back in causes the CPU A and/or CPU B error LED's to come on again.

I'm completely unimpressed that both the Apple Store Service Center and an independent AASP couldn't figure this out.

To top things off I noticed that the Apple tech who swapped out the main logic board broke my bluetooth antenna connection. So now I have to call and complain about that! When it rains it pours I guess...

Where's the best place to get a MacPro compatible NVIDIA 8800 GT -or- should I replace it with something else?

Oh, and big thanks everyone for all the help!! I really appreciate all the great tips and advise.
 

snberk103

macrumors 603
Oct 22, 2007
5,503
91
An Island in the Salish Sea
After a few other attempts I pulled the GPU (NVIDIA GeForce 8800 GT) from the machine and it booted right up off the Snow Leopard Installer DVD. Now I've got my original boot drive in and the machine is running (headless). I'm able to screen and file share to it from my MBP. Nice to know you can screen share to a headless Mac...

With the GPU installed I was seeing both CPU A and CPU B error diagnostic led's on the main logic board. Sometimes it would be A other times B, and sometimes both A and B would come on. They would come on late in the boot cycle. Probably when the machine was changing resolution to display the desktop. Putting the card back in causes the CPU A and/or CPU B error LED's to come on again.

I'm completely unimpressed that both the Apple Store Service Center and an independent AASP couldn't figure this out.

To top things off I noticed that the Apple tech who swapped out the main logic board broke my bluetooth antenna connection. So now I have to call and complain about that! When it rains it pours I guess...

Where's the best place to get a MacPro compatible NVIDIA 8800 GT -or- should I replace it with something else?

Oh, and big thanks everyone for all the help!! I really appreciate all the great tips and advise.

Really Good News!! I will just say, though.... I did mention a while ago to check the GPU.... my repair shop also read a bad CPU from the LEDs, and only swapped the GPU out when the new CPUs didn't fix the problem. I think the problem is with the diagnostics, and not the techs. I have the same system as you.

The good news is that the problem is identified and easily fixed.
 

666sheep

macrumors 68040
Dec 7, 2009
3,686
291
Poland
Congrats, good to know you sorted it out. And shame on AASP tech who has "diagnosed" your MP :eek:

Personally, I wouldn't get another 8800. If you want brand new card, get 5770 from Apple.
If you want to flash PC one from aftermarket (cheaper way), I'd recommend 4870 with reference design: https://forums.macrumors.com/posts/11425871/ - 512 MB or 1 GB.
 

666sheep

macrumors 68040
Dec 7, 2009
3,686
291
Poland
I think the problem is with the diagnostics, and not the techs.

I must disagree. Below is quote from Apple's Service manual corresponding to CPUs LEDs error:

Unplug AC cord and remove any added DIMMs and PCI Express cards. If this causes the
LED to go off, repopulate the DIMMs and/or PCI Express cards to find the combination that
caused the LED to come on. Overheated memory could be a possible cause for this CPU
error LED to come on. Check fan operation.

So, it's definitely RTFM thing ;)
 

snberk103

macrumors 603
Oct 22, 2007
5,503
91
An Island in the Salish Sea
I must disagree. Below is quote from Apple's Service manual corresponding to CPUs LEDs error:

Unplug AC cord and remove any added DIMMs and PCI Express cards. If this causes theL ED to go off, repopulate the DIMMs and/or PCI Express cards to find the combination that caused the LED to come on. Overheated memory could be a possible cause for this CPU error LED to come on. Check fan operation.

So, it's definitely RTFM thing ;)

Possibly - or the FM is not entirely accurate....

The point is... Mac Pro is fixed. I suspect a few people here learned a few new things as well. Time for me to move on to the next thread, of someone looking for assistance.... eh?
 

scotttaylor

macrumors newbie
Original poster
Aug 15, 2010
21
0
In the end, great customer service!

Just picked up my "fixed" MacPro and I'm typing this post on it...

After my last post I called the Apple Store service center manager and told him I thought they mis-diagnosed my system and that I pulled the video card and had been running it headless for the last several hours. He was pretty much speechless and set up a genius bar appointment for the next day. I dropped off the machine and a few days later got a call from the service manager saying they mis-diagnosed it and Apple would cover -all- costs to fix my system. They replaced the broken bluetooth card, and gave me an upgraded video card (ATI Radeon HD 4870). Given the situation it was the right thing for Apple to do but also nice I didn't have to raise a fuss and complain to make it happen...
 

johnnymg

macrumors 65816
Nov 16, 2008
1,318
7
Just picked up my "fixed" MacPro and I'm typing this post on it...

After my last post I called the Apple Store service center manager and told him I thought they mis-diagnosed my system and that I pulled the video card and had been running it headless for the last several hours. He was pretty much speechless and set up a genius bar appointment for the next day. I dropped off the machine and a few days later got a call from the service manager saying they mis-diagnosed it and Apple would cover -all- costs to fix my system. They replaced the broken bluetooth card, and gave me an upgraded video card (ATI Radeon HD 4870). Given the situation it was the right thing for Apple to do but also nice I didn't have to raise a fuss and complain to make it happen...

Big congrats on getting your MP finally repaired.

JohnG
 

TonyK

macrumors 65816
May 24, 2009
1,032
148
Just picked up my "fixed" MacPro and I'm typing this post on it...

After my last post I called the Apple Store service center manager and told him I thought they mis-diagnosed my system and that I pulled the video card and had been running it headless for the last several hours. He was pretty much speechless and set up a genius bar appointment for the next day. I dropped off the machine and a few days later got a call from the service manager saying they mis-diagnosed it and Apple would cover -all- costs to fix my system. They replaced the broken bluetooth card, and gave me an upgraded video card (ATI Radeon HD 4870). Given the situation it was the right thing for Apple to do but also nice I didn't have to raise a fuss and complain to make it happen...

Very good news indeed.
 

minifridge1138

macrumors 65816
Jun 26, 2010
1,175
197
I must disagree. Below is quote from Apple's Service manual corresponding to CPUs LEDs error:



So, it's definitely RTFM thing ;)

How did you get a copy of Apple's Service Manual?
If it is available for download, i'd love to get my hands on it.

Thanks!!!
 

JDMorse

macrumors newbie
Jan 8, 2013
1
0
To complete snberk103 advice: MP boots without graphics card installed. To check if the problem is here, try to boot it like this and access remotely via ssh or VNC.

How can I share the screen of my Mac Pro to a MacBook if the Pro will not boot, so I can't get to System Prefs?
 

Phrygian

macrumors regular
Nov 26, 2011
196
0
If you end up buying something else, make sure the spec code is SLAxx as those use C0 stepping which is compatible with your MP. SLBxx use E0 which is not

I hate it when a smart reply is posted and i'm left in the dust of knowledge... no idea what you are talking about there :(

and yes... i know you are talking about processor types... i think.

@OP hoorah for happy endings.
 

PowerPCMacMan

macrumors 6502a
Jul 17, 2012
800
0
PowerPC land
You don't

The Mac Pro MUST be on in order for your Macbook Pro to share its screen. You can't share a screen with a computer thats TURNED OFF! Now, if your video card is bad and it won't bring up anything on the screen you had better make sure you enabled allow screen share on the mac pro side, otherwise it won't work.

I run my Mac Pro with out a monitor and my main everyday system is my G5 Quad and it shares the mac pro's screen without any problems.

How can I share the screen of my Mac Pro to a MacBook if the Pro will not boot, so I can't get to System Prefs?
 

666sheep

macrumors 68040
Dec 7, 2009
3,686
291
Poland
How can I share the screen of my Mac Pro to a MacBook if the Pro will not boot, so I can't get to System Prefs?

If your MP does turn on, you can boot MacBook from MP's HDD in Target Disk Mode. Once you'll get there, you can enable screen sharing then reboot MP.
This method works if you have bad GPU or no GPU at all.
 
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