Why is my Northbridge Chip running at dangerously high temperatures?

Question

Why is my Northbridge Chip running at dangerously high temperatures?

I noticed my computer was getting hot to the touch, and warming my computer room significantly.. So I checked my temperatures for the system and noticed everything seemed normal except for the Northbridge Chip (127 C) and Northbridge Heat Sink (62 C). I am running no applications, CPUs are basically idle.

I am concerned that this temp is WAY higher than it should be, using Google, I found that many users were concerned that 80 C was too hot for the northbridge when the 2009 Mac Pros came out. What should my course of action be?

Is there a hardware button to reset everything back to factory without reinstalling Mac OS X?

Thank you, Apple People! 🙂nor

Mac Pro, Mac OS X (10.7.4), Early 2009 Mac Pro

Posted on Jun 21, 2012 2:49 PM

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Answer 1

X423424X

Level 6

14,271 points

Jun 21, 2012 3:11 PM in response to Chris Fitzgerald

Extremely high!

Are all your fans running?

Not sure smc reset would affect this or not but try it anyhow.

Make sure all the dust is blown out.

And check the heat sink to see if it has shifted somehow.

Maybe run Apple Hardware Test as well.

Incidentally, I don't think reinstalling will change anything.

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Answer 2

Jun 21, 2012 3:12 PM in response to X423424X

Wow fast response!

I'm using smcfancontrol to test and make sure my fans are working properly... If I dial the knob up, the corresponding fan goes up properly.

With the Intake and Exhaust at 100% I can bring the northbridge chip down to 114 C and the heat sink to 40 C.. good start! I was looking into resetting the SMC and seeing what happens. Just now.

Thoughts?

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Answer 3

X423424X

Level 6

14,271 points

Jun 21, 2012 3:13 PM in response to Chris Fitzgerald

I suggested smc reset in my first post. Dust can be a good insulator keeping heat in so that is why I suggest trying to blow it out. If it's really dusty do it outside so you don't breath it in.

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Answer 4

Jun 21, 2012 3:39 PM in response to X423424X

I couldn't get the Apple Hardware Test to boot up and I already ran the SMC reset to no avail. I have the daughter board out on an ESD mat now and I'm trying to figure out how to pop one of the CPU heat sinks off to get at that Northbridge heat sink!

If I can figure it out I'll update this post of course... Thank you for the support so far!

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Answer 5

Jun 21, 2012 3:49 PM in response to Chris Fitzgerald

I don't have a 3mm hex driver long enough to get down through the CPU heat sink, but I did notice that the Northbridge Heat Sink looked crooked so I gave it a little push and VOILA! The thing isn't mounted to the board correctly. I just need to remove that CPU heat sink and get some thermal grease and I may be able to fix it (if nothing is physically broken of course!).

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Answer 6

Jun 21, 2012 4:05 PM in response to Chris Fitzgerald

I've found the problem! After bugging my neighbor for his 3mm Allen wrench, I got the CPU heat sink off quite easily to uncover the culprit... One of the two plastic pop-on retainer clips has broken, leaving the Northbridge Chip vulnerable.

NOW my question is... Is there a way I can order this single part ?!

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Answer 7

X423424X

Level 6

14,271 points

Jun 21, 2012 5:34 PM in response to Chris Fitzgerald

That may be a problem without a part number. Here's a link to download the 2009 Mac Pro service manual:

http://tim.id.au/laptops/apple/macpro/macpro_early2009.pdf

If it isn't in there (and I don't think that level of part would be) then I don't know what to suggest on where to find it.

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Answer 8

Jun 21, 2012 5:51 PM in response to X423424X

I just dug through that manual and it seems the closest I can get is the part # for the processor board (661-4998)

Which costs around $370 online. Ouch. All for a little cheap plastic spring clip.

I guess I'll have to wait and see what the genius bar says at my local store. Hopefully they'll understand how simple my solution is and can help me out.

You've been super helpful this afternoon. Thank you so much for looking into my problem for me!

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Answer 9

X423424X

Level 6

14,271 points

Jun 21, 2012 6:09 PM in response to Chris Fitzgerald

I just dug through that manual and it seems the closest I can get is the part # for the processor board (661-4998)

I'm confused. Yes 661-4998 is the processor board which means I am not too surprised at the price. But you said it was "plastic pop-on retainer clips" that broke, not the board. It's parts at the level of a clip which is what I said you might not find in that service manual.

I don't know what the clips would cost, probably overpriced too, but certainly not $370! Of course I am not counting the professional labor charges.😉

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Answer 10

Jun 21, 2012 6:12 PM in response to X423424X

The $370 board is just the narrowest thing I could find in the manual. Everything in there is pretty broad and focused on bigger assemblies in the machine. I'm sure if I bought this board then it would come with the little plastic push pin spring clip I would need... I would never spend that kind of money for something that probably costs 25 cents from a supplier!

I work at an electronics manufacturer... if the Apple geniuses can't get me this part for a reasonable price, then I may be able to use some calipers, take some measurements, and buy a few pushpin spring clips myself!

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Answer 11

X423424X

Level 6

14,271 points

Jun 21, 2012 6:59 PM in response to Chris Fitzgerald

Ok. Good luck with the "geniuses". Hope they can give you the part.

Another possibility is to call someone who specializes in repairing macs. Mac-pro comes to mind. They may be able to help you locate the specific part, maybe even sell it. Give them a call.

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Answer 12

trozsa

Level 1

0 points

Aug 16, 2012 4:37 PM in response to Chris Fitzgerald

rather than fabricating your own clip or trying to find the right one why dont you just use some thermal adhesive? its like epoxy but thermal and designed for gluing heatsinks to chips without the need of any extra hardware, i've used this stuff in the past and its great

http://www.arcticsilver.com/ta.htm

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Answer 13

Aug 16, 2012 7:48 PM in response to X423424X

X423424X wrote:

That may be a problem without a part number. Here's a link to download the 2009 Mac Pro service manual:

http://tim.id.au/laptops/apple/macpro/macpro_early2009.pdf ...

Thanks for the gold mine! 🙂

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Answer 14

rlx01

Level 1

0 points

Aug 23, 2012 3:07 PM in response to Chris Fitzgerald

Hey Chris,

Did you ever figure this out?

I have the exact same problem -- I think that Apple actually forgot to screw down the northbridge heatsinks properly on a lot of 2009 Mac Pros:

https://discussions.apple.com/thread/3184175?start=0&tstart=0

My screw is also missing, and it's impossible to find online.

As soon as the northbridge temperature reaches 128c, my entire system locks up.

I can stop this by running fans at 100%, but that's not really an option since it sounds like a jet engine. 🙂

Did you end up buying a new processor board for this one screw? 🙂

Thanks!

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Answer 15

Aug 23, 2012 4:42 PM in response to rlx01

I wish I could tell you it was a cheap fix, my friend... Unfortunately I ended up buying a whole new processor board... But at least I had the peace of mind that the job was done right at the Apple Store.

It's a bummer this problem is happening to people. Good luck!!!

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