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i-rui

macrumors member
Original poster
Feb 11, 2010
94
3
So I just picked up a Mac Pro on the weekend. I tested it prior to purchase with the ASD S3132 diagnostic. It passed everything EXCEPT the TNOD test, where it gave an error that the IOH sensor was above operating temp. Knowing this i purchased the unit at a reduced rate in hopes of fixing it.

So researching this it seems the Northbridge heatsink and thermal sensor is not properly seated. There is a small plastic clip that is supposed to hold down the Northbridge heatsink that is gone, so it is not flush against the board.

this thread has a picture of the processor board stripped down, and the Northbridge missing the 2 clips that secure it to the processor board :

https://discussions.apple.com/thread/4501912?start=0&tstart=0

i think i'm only missing the one clip, as the processor heatsink is holding it down on one side already. Searching the web it seems that Apple does not sell just the clips, and the route most people are going seems to be to buy a whole new processor board. This seems like ridiculous overkill to me since the clip surely must be a 25 cent part. This thread has someone suggesting using glue to hold down the heatsink :

https://discussions.apple.com/thread/3099476?start=0&tstart=0

I'm not crazy about this solution, but may try it as a last resort.

I was thinking that a simple nut and bolt solution would work, but i'm not sure if using a metal part here could short something on the processor board. There might be a reason apple went with a plastic clip (although looking at my other 2009 mac pro processor board there does seem to be a spring mechanism on the clip, but i doubt this extends past the heatsink to make contact with the actual board....)

I could also try to find a plastic nut/bolt combination, but trying to find the right size may be more difficult because of the limited selection for plastic nuts & bolts.

Has anyone else run into this same problem? were you able to find a solution other than replacing the entire board?

Any other thoughts on a possible solution? I'm all ears...
 
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DanielCoffey

macrumors 65816
Nov 15, 2010
1,207
30
Edinburgh, UK
If the plastic clips are broken and lost, I would consider buying some of the Arctic Silver Thermal Epoxy. it is a permanent heat-conductive glue designed for permanent fixing of heat-sinks in computers.

I used some when I changed the stock cooler on my Apple 5870 for a third-party one and wanted to attach the VRAM and VRM heat-sinks with something better than thermal tape.

It goes nicely with the ArctiClean solution for removing the old thermal paste from the Northbridge and its old heat-sink.

Remove the old heat-sink and clean both surfaces. Lay the machine down on its side and mix a small amount of Thermal Epoxy. Spread it on the Northbridge very sparingly and place the heat-sink in the correct place without any clips. Allow it the FULL hour to cure and then you are done.
 

i-rui

macrumors member
Original poster
Feb 11, 2010
94
3
my concern with using thermal adhesive (or any glue based solution) would be that it's permanent and may present a problem if i ever need to strip it down. I may end up going this route, but ideally i'd like a fix that most resembles the original solution.

my other concern about using adhesive is i'm not sure it will be strong enough. the original apple clip seems to have a spring in it that pulls the heatsink towards the processor board. without the clip the heatsink naturally pulls away and lifts from the board. perhaps because the other clip is pushing the opposite side down , or perhaps because the cpu heatsink is pressing it down on the other side. Maybe i'll have to disassemble the cpu heatsinks off to have a better look. i don;t think i can remove the other clip without destroying it in the process. if i go with a adhesive solution that's probably what i'll have to do to remove the northbridge heatsink.

my initial feeling is still that a nut and bolt solution would work best. However, i am worried about a metal bolt possibly making contact with the board and creating a short. I'm going to try and find a plastic nut and bolt small enough to fit, or failing that, maybe i'll use a plastic washer between the bolt and the processor board.
 
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DanielCoffey

macrumors 65816
Nov 15, 2010
1,207
30
Edinburgh, UK
You would still have to take the northbridge heat-sink off for cleaning anyway as the thermal paste layer is now defective.

You would remove the other clip too, clean up and then apply the thermal epoxy. There would be no need for the remaining clip once you are done as the epoxy does the job.

If you don't ant to use the epoxy, you would have to remove the remaining clip, clean up, source a replacement part, test fit it, remove the heat-sink again, apply normal thermal paste and then apply both clips without lifting the heat-sink in the process.
 
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comatory

macrumors 6502a
Apr 10, 2012
738
0
Maybe it is possible to have the plastic part printed? At some placcelike Shapeways. You need to have all the measurements though.

Just an idea.
 

i-rui

macrumors member
Original poster
Feb 11, 2010
94
3
You would still have to take the northbridge heat-sink off for cleaning anyway as the thermal paste layer is now defective.

You would remove the other clip too, clean up and then apply the thermal epoxy. There would be no need for the remaining clip once you are done as the epoxy does the job.

If you don't ant to use the epoxy, you would have to remove the remaining clip, clean up, source a replacement part, test fit it, remove the teat-sink again, apply normal thermal paste and then apply both clips without lifting the heat-sink in the process.

if i can find a proper nut & bolt solution I was hoping i'd be able to test it first with the ASD before stripping it off and reapplying thermal paste. Not sure it would pass the TNOD test with just the heatsink properly seated though....

Maybe it is possible to have the plastic part printed? At some placcelike Shapeways. You need to have all the measurements though.

Just an idea.

This could potentially be an ingenious solution. I've never used shapeways so I'm not sure exactly what's entailed. I imagine I would have to 3D model the part first? Are they expensive? there does seem to be a spring on the clip, so that may be a problem in creating an exact match.

thanks for the input guys. i appreciate it. My next step is to remove the cpu heatsinks and remove the processor board from the tray so i can see exactly how the remaining clip holds the northbridge heatsink to the board. i'm going to have to get a 3mm hex key for that.
 

comatory

macrumors 6502a
Apr 10, 2012
738
0
yes you would need a 3D model. but you have only 1 clip missing? maybe you could send it to them and they would scan it and make a duplicate.

i think its pretty neat solution but definitely not the easiest. dont know how much they cost though.
 

gobsmacked

macrumors member
Jul 7, 2013
36
0
Alberta, Canada
...
I was thinking that a simple nut and bolt solution would work, but i'm not sure if using a metal part here could short something on the processor board. ...

Any other thoughts on a possible solution? I'm all ears...

Try a robotics supply place. Most of them sell metric nylon nuts and bolts.
Here's an example at dfrobot. It's m3 x 6mm they have other sizes as well.
http://www.dfrobot.com/index.php?route=product/product&filter_name=nylon&product_id=643#.UjoB2BZ-RZ4

If you can source them locally that would be better as you'll pay more for shipping than the nuts and bolts.
 

i-rui

macrumors member
Original poster
Feb 11, 2010
94
3
I removed the CPU heatsinks and then the processor board from the tray. Initially i had thought that the only way to remove the nothbridge heatsink would be by cutting away the clip, but looking at the bottom of the board it became apparent that that clip was in fact a snap rivet that i could remove using needle-nose pliers. I was able to rescue the 1 remaining rivet and have photographed it against a ruler to get accurate measurements. I'll try to include the pics in this post:


I was actually able to find what seems to be an exact match online here :

http://www.alibaba.com/product-gs/512818021/Fan_Plastic_Snap_Rivet.html

they even have a diagram, and the measurements match the same used in the 2009 mac pro.
The bad news is their minimum order is 10,000 pieces. :mad:
I contacted them to see if it would be possible to buy a sample pack or do a much lower run. Hopefully i'll get a reply.

I actually just happened to meet someone who designs parts for the aerospace industry yesterday (talk about serendipity!) and i was lucky enough to share this dilemma with him. I mentioned my idea of simply using a nylon nut & bolt solution and he said that it would only work if i somehow wound a spring between the top of the bolt and the heatsink. The spring is important because there will be a lot of movement in the heatsink as the temperatures fluctuate.

Also, now knowing that the snap rivet can fairly easily be removed from the processor board i'm wondering if i could track down someone with a broken processor board and buy the rivet from them. I know there are a few unfortunate souls who have bungled a processor upgrade job. Would i be able to post a "wanted" ad in this forum or would that be frowned upon?
 

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ActionableMango

macrumors G3
Sep 21, 2010
9,612
6,907
Would i be able to post a "wanted" ad in this forum or would that be frowned upon?

It's technically against the rules. You have to use the Marketplace forum for a wanted ad and you cannot access the Marketplace forum until you've been here 6 months and have some number of posts (I cannot remember). It's all listed in the FAQ/Rules link in the banner.
 

i-rui

macrumors member
Original poster
Feb 11, 2010
94
3
It's technically against the rules. You have to use the Marketplace forum for a wanted ad and you cannot access the Marketplace forum until you've been here 6 months and have some number of posts (I cannot remember). It's all listed in the FAQ/Rules link in the banner.

Ya, i can't even see the marketplace forum since i don't have enough posts (I've been a member for a while though)

I'm in the same boat, my IOH Tdiode is working at 128C, the Processor board is $500.

If i was to place an order for the snap rivet would you be willing to split the cost with me? I haven't heard back from the supplier yet, but if the minimum order is 10,000 and the cost is 2 cents each that equals $200 + plus shipping and duty charges from china. Still should be cheaper than a new processor board, but if two (or more) people split the cost it at least becomes a viable option.

----

Any other users have the same problem and would be interested in splitting an order?

--

Since i can't place a wanted ad I'm hoping that anyone here who has had the misfortune of having a dead processor board might consider selling me just the clips from the northbridge heatsink. Please PM if at all possible.
 
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i-rui

macrumors member
Original poster
Feb 11, 2010
94
3
I am interested. Have you purchased the bulk pack already?

no i haven't. the original supplier for the match i was able to find never responded to any of my messages.

i was able to find another manufacturer who claimed they could make the same part, and offered to send me a sample pack. unfortunately that was over 2 months ago. i contacted them for an update but the Chinese to English language barrier is difficult to deal with.

i'll keep this thread updated if i can source the proper part.
 

i-rui

macrumors member
Original poster
Feb 11, 2010
94
3

terlman

macrumors newbie
Dec 5, 2013
7
0
So how do you guys deal with this problem for now?

Now I can't even turn the machine on... unless I push down the northbridge heatsink itself with a finger or something.
 

i-rui

macrumors member
Original poster
Feb 11, 2010
94
3
i'm not running the machine until i can solve this. it was a second machine anyway, so i'm not really missing it.

i'd recommend anyone else in the same position not to run their machine. if the north bridge gets fried then you really will need an entire new processor board.
 

i-rui

macrumors member
Original poster
Feb 11, 2010
94
3
This looks like an exact match as well, and the minimum order is only 1000pcs.
http://www.alibaba.com/product-gs/1358933823/Plastic_Fan_Snap_Rivet.html

I don't know how much each piece costs though.

that's hilarious. that's the 2nd manufacturer i contacted after the first one never got back to me. i sent them pics of the clip and the schematic i got from the original alibaba link. they told me they could make it and would send me some samples. that was over 2 months ago. About a month ago i messaged them asking about it, and once again they said they'd send me samples. I guess they just decoded to list it on alibaba. I'll have to message them again...

Would this this work?

http://www.amazon.co.uk/gp/product/B00G7OGZZ2/ref=oh_details_o03_s00_i00?ie=UTF8&psc=1

I have the kit and only used the smallest stick on hs. All the clips i have.

If you pm me and want to pay postage i can send em to you to try?

the actual heatsink is completely different than the one used by apple, so that definitely won't work. the amazon link doesn't have any images of the clips, so i can't venture to say if they'll work. do they look similar to the pics i posted earlier? measure how long they are against a ruler and compare if you can.
 

costabunny

macrumors 68020
May 15, 2008
2,466
71
Weymouth, UK
i-rui said:
the actual heatsink is completely different than the one used by apple, so that definitely won't work. the amazon link doesn't have any images of the clips, so i can't venture to say if they'll work. do they look similar to the pics i posted earlier? measure how long they are against a ruler and compare if you can.

hows this?
 

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costabunny

macrumors 68020
May 15, 2008
2,466
71
Weymouth, UK
This looks about right. Where did you get it?

Amazon.co.uk :)

Bought as part of a kit because I wanted the adhesive heat sink that cam in the kit.

I have posted the little plastic clips to i-rui, so he can at least try them for size. I am never going to need them.

The kit is made by Akasa
 
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