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dMajor

macrumors member
Original poster
Aug 17, 2016
71
49
Melbourne, Australia
Hi guys,
My 2008 Mac Pro 3,1 has been acting up recently so I thought I'd open her up and do a bit of a clean etc.
This is what I saw when I took off the side panel:

IMG_1016.JPG


Now, I'm no computer technician, but I'm pretty sure that black thing is not meant to be just lying there next to the video card!

Here is a close up of this rogue part - Am I right thinking it's a heat diffusing item? "Heat-sink" in the proper parlance?

IMG_1017.JPG


My hunch is it fell off this thing -

IMG_1018.JPG


Here are my questions for the enlightened ones:
1.) Am I right thinking that the "Heat Sink" fell off this circled item? Why would that have happened?
2.) Can it be re-attached?
3.) How do I do that, and what is needed?
4.) If it can't be re-attached, is that catastrophic? Should I give up my hardware upgrade plans?

Background on unit: In the last week I decided I would do a bunch of upgrades to try and wring a few last years out of the old girl. First step was to install High Sierra via "dosdude's" instructions and software patches etc. That all went smoothly. After a few days I installed Microsoft Office, and Photoshop & Illustrator. After that machine started to do random Re-starts. Sometimes in a loop. Still ran ok when booted from El Capitan. Did a full 4.5 hour Hardware Test yesterday. Did not report any errors. Opened up this morning, and here we are...

Background on Me: I'm reasonably good with computers and problem solving in general. Done some web development. Done some soldering. Recently rebuilt 2 x mercedes carburetors from written instructions. If anybody wants to offer challenging advice/instructions - I will definitely have a red hot crack at doing them.

Thanks in advance.
Dan
:)
 

ADDvanced

macrumors regular
Nov 8, 2015
133
19
Completely unrelated to your problem, sorry I can’t help. But your title choice made me think of this.


 
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Wowfunhappy

macrumors 65816
Mar 12, 2019
1,337
1,581
Yep, that's a heatsink! It's absolutely fixable. You'll need to wipe off the old Thermal paste and reapply some new paste.

I'll let some people who have more Mac-specific hardware experience give more details—but, do not power the computer back on until this is fixed. The CPU will overheat without that heatsink. Really, it should refuse to boot to protect itself, but no need to tempt fate.
 
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dMajor

macrumors member
Original poster
Aug 17, 2016
71
49
Melbourne, Australia
Yep, that's a heatsink! It's absolutely fixable. You'll need to wipe off the old Thermal paste and reapply some new paste.

I'll let some people who have more Mac-specific hardware experience give more details—but, do not power the computer back on until this is fixed.
Ok, good start - thanks man.
No power on till fix. Got it.
Anybody care to chime in with more specifics on the use of thermal paste?
Have had no experience with it's use.
 

tsialex

macrumors G4
Jun 13, 2016
10,657
11,190
The heatsink is fixed by two ring locks/loops, one is broken and it is probably short-circuiting somewhere inside the case:

IMG_1018.JPG


You will need to find it and solder it back to the correct place on the PCB.
 
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dMajor

macrumors member
Original poster
Aug 17, 2016
71
49
Melbourne, Australia
Give the inside of the Mac Pro a good cleaning while you're at it... all that dust isn't going to help with airflow ;)

How very dare you. ;)
[automerge]1596085844[/automerge]
"Give the inside of the Mac Pro a good cleaning while you're at it..." Agreed! The interior of your 3,1 should look like this. ?
View attachment 938761

Damn! Nice job. I used to have printed instructions on how to get all the housing and drives out for cleaning for my 1,1.
Anyone know where I can download the same thing for a 3,1?
 

macguru9999

macrumors 6502a
Aug 9, 2006
522
199
Well its not the cpu for a start, thats/they are under the huge heatsink lower down. It would be nice to reattach but it may have been lying there for years ..... set it aside and give everything a big clean with compressed air (not vacuum) . I think its some sort of system integration chip. If you really want to fix it you are going to need to remove the mobo and get something to hold the upper clip under tension, applying thermal paste etc, OR you can just ignore it and carry on , if it fails in the next 10 years you can always upgrade to a 5,1 :)
 
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dMajor

macrumors member
Original poster
Aug 17, 2016
71
49
Melbourne, Australia
Ok - back on deck.
Stripped most stuff out, gave it a decent blow out - but need another can of air to finish job.
IMG_1024.JPG


I found our little missing hook on top of the upper RAM deck.

IMG_1023.JPG


I gather the next job is to use some isopropyl alcohol to clean this grey gunk of the back of the heatsink and the chip?

IMG_1025.JPG


IMG_1026.jpg
 
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Ludacrisvp

macrumors 6502a
May 14, 2008
784
355
Correct, you’ll need to clean them both up and apply new thermal compound. You’ll also need to reattach the hook.
 

dMajor

macrumors member
Original poster
Aug 17, 2016
71
49
Melbourne, Australia
Both bits cleaned up nice.
I have some saying to pull motherboard and solder loop bracket back on, and reattach with heatsink hooks.
Others saying heatsink may have fallen off ages ago and not be too bothered re-attaching.
I'm in favour of third approach - not bothering with loop bracket, but reattaching heatsink using thermal epoxy.
Dude talks about it in this thread here, he appears to have had exact same problem as me:

Here is the stuff suggested:

What say ye, oh wise ones?
 

Nguyen Duc Hieu

macrumors 68000
Jul 5, 2020
1,819
509
Ho Chi Minh City, Vietnam
I need to check my MP1,1 again. North-bridge seems to be overheated and this same black heat-sink is not very firmly affixed to the mainboard. I could move it a bit by my hand.

@dMajor : Don't you think you need a more powerful GPU for your MP3,1?

Two weeks ago, I obtained a 2nd Gigabyte GTX680 2GB for just 35$, got it flashed (no effect) and it works perfectly in my MP1,1 now. (Still no pre-boot configuration support screen, though)
 

dMajor

macrumors member
Original poster
Aug 17, 2016
71
49
Melbourne, Australia
Has anyone had experience hooking these hooks back under these loops before?
Seems a fair bit of force required. Do the hooks just squeeze past the loops and then under and up to fit in place?
 

dMajor

macrumors member
Original poster
Aug 17, 2016
71
49
Melbourne, Australia
In your own words:


I agree with @tsialex. You might as well bust out the soldering iron and fix the loop. It's a quick soldering job and it gets your 3,1 back to stock form instead of rigging some thermal epoxy up.

I'm getting geared up to tackle this on the weekend. My previous soldering experience had all been splicing wires together on cars and such. No PCB stuff. Is there anything I need to know? Special solder? Temperature specifications?
I'm having a surf around the net looking at tutorials etc.
 

KeesMacPro

macrumors 65816
Nov 7, 2019
1,453
573
Is there anything I need to know? Special solder? Temperature specifications?

Use solder for electronics, which has a core of resin to make the solder flow well.
Solder for copper waterpipes etc is not adequate for the job.
Dont use liquid for cleaning surfaces (like for copper).
Use a soldering iron with a clean tip (you can sand it/use a file to clean it before plugging it in).
I'd use a soldering iron with a power of ~25-80 Watts.

Once soldering keep the parts absolutely still when the solder flows ,and check after cooling down that the solder is still a bit shiny, not dull.
 
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