MP 1,1-5,1 4,1 DP Missing screw w/spring on tray

[darkgoob]

Primary Question:​

What can I use as a replacement for a missing plastic tab on the 4,1 dual CPU tray's small heat-sink? (The one that is normally held down by a circular black plastic tab with a metal spring under it. See details & pics below.)

Thanks.

Background Details:​

Been having intermittent kernel panics in Mac and Windows with MP 4,1 2x2.26ghz DP.

So, figured it was bad RAM. Upgraded to 6x matched OWC DIMMs (new). While swapping the RAM, I noticed this little spring just sitting there between DIMMs and 7 (audio cassette for size ref.):

So I removed the spring (not yet realizing where it came from) and replaced the RAM, yet still the panic issue persisted.

So I decided to do a CPU swap.

With CPU heat sinks removed I saw where spring came from:

The other side of this small heat sink is held to the PCB by a little plastic tab with a spring under it. I could not see that before because the right-side CPU heat sink sits on top of it.

Somehow the plastic tab on the left side of the small heat sink broke, and the spring popped off and landed between the DIMMs to its left. I also found half of the plastic tab rattling around inside the CPU tray.

And now the small heat sink is not being held down to the PCB like it is supposed to be. I'm guessing that is leading to inevitable panics since cooling won't be working as expected.

So what can I use as a replacement for that plastic tab? Can I use a metal screw, and if so, what kind? Thanks.

 

[Macschrauber]

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

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...

forums.macrumors.com

 

[darkgoob]

OK. I removed all the heatsinks including the northbridge one. I cleaned the NB chip and heatsink and reattached it with two M3x12 machine screws and M3 5.5mm bolts with the original springs. Hopefully I left enough space for the heat flexing... guess time will tell. By the time it fails I'll already have my new 2019-era MP, just need a couple more good years out of this one.

I flashed the firmware to 5,1 and tossed in 48gb of DDR3 CL9 1333mhz RAM and 2x 3.46ghz Xeons. For $400 even.

The thing is lightning fast now, and no more random freezes (so far, knock on wood).

Thanks for the tips. Today I breathed new life into an old friend!

 

[fatespawn]

Don't sweat the heat flexing. I replaced my rivets 2 years ago with nylon nuts and bolts. I'm sure others will be aghast.... but hey, still going strong.

Hot Northbridge only on boot?

This is what I installed: https://www.amazon.com/gp/product/B076CLPGD3/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1 It was $14.99, but I wanted a bunch of different lengths to see how it worked. I ended up using the ones pictured. I reused both stock springs. If anyone is using springs...

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