MP 1,1-5,1 Broken Northbridge pushpin enough to cause non-boot...or is it worse?

[fhturner]

Hey Everyone—

Troubleshooting a client Mac Pro 2009 (4,1 > 5,1; X5690) yesterday and found that after sitting a few weeks following replacement by a Mac Studio, it was no longer responsive, with a red glow inside. Rebooting yields no startup chime, even with NVRAM reset. CPU tray light DSI510 comes on immediately. After holding down power button to turn off, the CPUA OVERTEMP light comes on (but only after shutting down). Pulled the CPU tray out to look and one of the plastic Northbridge rivets spills out.

Is the mere loss of the rivet/pushpin and detachment of the heatsink enough to cause a complete failure to start up? Or does that mean the Northbridge itself is a goner? I would think it would work for a minute or 2 if it was just a lack or loss of cooling. Wondering if I should even bother w/ heatsink reapplication...

Thanks,
Fred

 

[Macschrauber]

you need to test it.

The Northbridge die might have been bent. If you are in luck the cure is fixing the pins.

If its a dual 2009 cpu machine taking off the CPU Heatsinks (at least the A is necessary, B for getting at the backside of the board) is a risk.

Especially if there are cpus with the lid on (what in my experience is to avoid). Should tell the client that this step can damage the cpu sockets when the cpu upgrade was not done properly.

 

[fhturner]

Okay, thanks for this! It's a lidded single-CPU model, so no worries about that. So, I need to just get new pins and try it again? If die is bent, can I see that easily? I think I saw @tsialex mention it being convex in another thread...this one looks flat to the naked eye.

Is there a "2022 consensus" on the best pin option? More plastic ones? Metal bolts and nuts? Saw something about one type being too tall and interfering w/ the CPU heat sink reinstallation.

Thanks again!
Fred

 

[Macschrauber]

For Dual CPU Boards you will need to snap off one side of plastic pins.

The forever lasting solution is a 3 mm screw and a self locking nut plus the original spring. Measure the old ones and rebuild it that way.

 

[majus]

Plastic rivets are best if you can find them. I doubt there is enough room to put an aluminum blind rivet in, and any other metal will eventually result in galvanic corrosion in contact with aluminum.

 

[tsialex]

You should test this Mac Pro with a working CPU tray before trying anything, not completing POST is a very bad sign, it's not just the heatsink that is stopping it to boot.

 

[fhturner]

You should test this Mac Pro with a working CPU tray before trying anything, not completing POST is a very bad sign, it's not just the heatsink that is stopping it to boot.

Hey Alex! Sorry, have been away for a bit. Yes, I was able to get the Mac Pro working temporarily w/ a CPU tray from another spare machine of mine. I tried the CPU tray w/ broken pushpin in that spare Mac Pro, and then it failed to boot/POST as well. So the problem is following the CPU tray. I'm going to get those pushpins, put everything back together, and see what we get.

 

[fhturner]

Would y'all recommend the white ones w/ the tall "cap" or black ones kinda like the originals? I only need 2 right now, but one pack has 10, the other 100 for about the same cost:

10x PC Heatsink Cooler Cooling Fan Spring Rivet Fastener Push Pin Mounting Screw | eBay

10pcs Fan Spring Rivet Fastener Push Pin Mounting Screw. Made of plastic.

www.ebay.com

100Pcs Heatsink Mount Pin 18.6mm Plastic Heat Sink Cooler Mounting Clip Set Kit | eBay

Item Type: Heatsink Mount Pin. Feature: 1. If you do not receive our reply within 48 hours, pls. If you are satisfied with our service, pls. Working Temperature: -20℃~120℃. Good Material: The application of high quality nylon plastic material ensures excellent durability for using.

www.ebay.com

 

[fhturner]

Sorry...bump. Is either one of those ^^^^ better than the other, or both work equally well?

 

[tsialex]

Best, cheapest and definitive solution is to do the same as in the the post below:

clip (snap rivet) for Northbridge heat-sink on 2009 Mac Pro 2X2.26

Just my 46 cents, here. I have just finished completely refurbishing 2 Mac Pro (5,1 - 2010-2012) CPU trays (and am about to do a third) and have had to deal with this problem. In both cases, the original plastic rivets and springs were intact but, after reading numerous reports of failure over...

forums.macrumors.com

Both usual third party push-pins crumble overtime, already had to replace two times with my oldest early-2009 Mac Pro. Now I only repair the northbridge heatsink with screws and nylon lock nuts.

 

[RolfNoot]

Had the same problem with one of my CPU boards. Broken Northbridge pin. Cleaned the chip and heatsink with IPA, reapplied thermal grease. Installed nylon M3 bolt and nuts I had laying around, replaced old 2x E5645 with 2x X5690 and board is running again. Delta T NB die / heatsink is about 10ºC for a NB diode temp @ 67ºC.

🥳​

 

[Franckymrs]

for those looking for compatible rivets black

4 PC Heatsink Cooler Cooling Fan Spring Rivet Black Mac Pro Heatsink northbridge | eBay

Les meilleures offres pour 4 PC Heatsink Cooler Cooling Fan Spring Rivet Black Mac Pro Heatsink northbridge sont sur eBay ✓ Comparez les prix et les spécificités des produits neufs et d'occasion ✓ Pleins d'articles en livraison gratuite!

www.ebay.fr

 

[RolfNoot]

Lol, I have a pack of 100 Nylon M3 for a few euros. Will never fail again, can withstand 250ºC unlike any ABS kind.

 

[gpm]

Lol, I have a pack of 100 Nylon M3 for a few euros. Will never fail again, can withstand 250ºC unlike any ABS kind.

So maybe something like this: https://www.amazon.com/QTEATAK-Plastic-Screws-Gasket-Assortment/dp/B0B17VVCMY

Is this solution perhaps better than using stainless steel M3 screws? Nylon is non-conductive and obviously cannot corrode.

I just lost one northbridge rivet (did recover the spring thankfully) so I am trying to decide on the best way to fix that will hold permanently so I don't have to worry about it).

 

[RolfNoot]

I had one with the spring missing, I have a spring assortment I could find a similar luckily. Unfortunately this one spring was a bit weaker. At first I noticed too much difference between the NB diode and the heatsink (about 23ºC). So I had to adjust one M3 to have the heatsink functioning properly. The Delta T (difference NB diode and NB heatsink) should be around 10ºC when running idle.

So maybe something like this: https://www.amazon.com/QTEATAK-Plastic-Screws-Gasket-Assortment/dp/B0B17VVCMY

Exactly, the 20mm (or maybe 15) should do. I had longer ones though which I did cut (after mounting).

The pin clips are plastic by design so this tells me this is done for a reason. I could be done because of isolating electrical currents. In that case, it's best to replace with anything non-conductive. The nylon bolts have another advantage of being capable of withstanding higher temperatures, it won't dry out and won't break.

Be careful of adjusting both nuts evenly tight. This can be checked easily by how close the nut is to the heatsink. Start the Mac and open iStat or similar and watch the NB diode temperature and NB heatsink temperature.

Good luck!