MP 1,1-5,1 Opened up Mac Pro 3,1 - found disturbing scene. Help please Apple gurus!

[dMajor]

What is it then? I've tried to find a diagram naming all the visible parts but haven't succeeded thus far.

For the second time in three years I just discovered that one of the loops that holds those two spring clips down has popped out of the board in my own Mac Pro 3,1. The first time this happened, the heat sink completely fell off, as it did in the OP's first pic. I have no idea how long it operated in that state, as it had been quite some time since I had had occasion to open the case.

This time it was still attached but had skewed a bit. Fortunately, the popped-out loop didn't short anything out and I was able to shake it out of the machine. Taking it to a repair guy on Monday, as I'm not about to attempt the removal and solder job the courageous OP did. ?

I know the machine is ancient, but it seems like poor design to expect solder to withstand the pressure exerted by the spring clips over time. Is there an alternative way to affix the heat sink that doesn't require the clips? Or will the fact that it's applied to a vertical surface mean that any kind of thermal paste will eventually start to give, causing the heat sink to slide off?

Hey Buddy,
I would agree - seems a weakness in the design. Considering all the other heatsinks on the board are attached with plain old screws - I don't understand the thinking. I searched high and low and the consensus seems to be that the chip is known as the "SouthBridge".

There is a link earlier in the thread to a different older thread where a guy used thermal epoxy to do the job. Old thread so I tried to contact him to see if it held up, but no response.

My solder job is still holding after a week, so it is possible to do successfully. With the right tools / the service manual / ziplock bags to keep stuff organised in / camera phone to document your steps / macRumours forum full of helpful and generous people / it's pretty straight forward.

My biggest tip would be to get nice long hex wrenches for pulling the CPU heatsinks. Due to stage 4 lockdown here, I was stuck with pissy little Allen keys. Took a lot of fiddling. And swearing.

 

[macguru9999]

What is it then? I've tried to find a diagram naming all the visible parts but haven't succeeded thus far.

For the second time in three years I just discovered that one of the loops that holds those two spring clips down has popped out of the board in my own Mac Pro 3,1. The first time this happened, the heat sink completely fell off, as it did in the OP's first pic. I have no idea how long it operated in that state, as it had been quite some time since I had had occasion to open the case.

This time it was still attached but had skewed a bit. Fortunately, the popped-out loop didn't short anything out and I was able to shake it out of the machine. Taking it to a repair guy on Monday, as I'm not about to attempt the removal and solder job the courageous OP did. ?

I know the machine is ancient, but it seems like poor design to expect solder to withstand the pressure exerted by the spring clips over time. Is there an alternative way to affix the heat sink that doesn't require the clips? Or will the fact that it's applied to a vertical surface mean that any kind of thermal paste will eventually start to give, causing the heat sink to slide off?

Its some sort of chip that integrates the functions of the backplane board i/o. I know thats not much of an answer, but given the age and value of this model are quite low, i would install some temp monitoring software and move on ! I would probably lay the computer over and glue the heatsink on with some kind of thermal transfer/epoxy and let it set and blow out all the dust. I would definitely not waste my time pulling out the Mobo and resoldering as its probably gonna work fine even without the heatsink there.

 

[KeesMacPro]

its probably gonna work fine even without the heatsink there.

If this heatsink didn't have a purpose, it wouldn't be there in the first place...

 

[doctormelodious]

Hey Buddy,
I would agree - seems a weakness in the design. Considering all the other heatsinks on the board are attached with plain old screws - I don't understand the thinking. I searched high and low and the consensus seems to be that the chip is known as the "SouthBridge".

There is a link earlier in the thread to a different older thread where a guy used thermal epoxy to do the job. Old thread so I tried to contact him to see if it held up, but no response.

My solder job is still holding after a week, so it is possible to do successfully. With the right tools / the service manual / ziplock bags to keep stuff organised in / camera phone to document your steps / macRumours forum full of helpful and generous people / it's pretty straight forward.

My biggest tip would be to get nice long hex wrenches for pulling the CPU heatsinks. Due to stage 4 lockdown here, I was stuck with pissy little Allen keys. Took a lot of fiddling. And swearing.

Thanks for the quick reply, and for identifying the mystery chip. Here's a quote from what I presume to be the other thread you mentioned:

Southbridge maintains I/O functions (in general) and does not run particularly hot. But if they put a heatsink on it, it's certainly not without a purpose. If you're not experiencing any USB or disk problems, most likely no damage is done.

I appreciate the repair advice, but I'm definitely dropping it off with a repair guy. Glad to hear that you were successful! It's still a great machine, despite its years. I actually have two of them. One is my audio production machine, and the other I use for streaming my music show on Twitch.

macguru9999 and KeesMacPro: thanks for your replies as well!

 

[macguru9999]

If this heatsink didn't have a purpose, it wouldn't be there in the first place...

Maybe, but how many years ago did it drop off ? Anyways thats why I said I would glue it back on just in case. Its a bit like the question, do i do a repair or a restoration ?

 

[KeesMacPro]

Its a bit like the question, do i do a repair or a restoration ?

I totally agree on that.
I guess that depends on the purpose it fulfills and the value the Mac has, seen through the eyes of the owner...

 

[doctormelodious]

EDIT: Okay, now I realize that that's thermal tape. I'm assuming that you removed it.

My solder job is still holding after a week, so it is possible to do successfully. With the right tools / the service manual / ziplock bags to keep stuff organised in / camera phone to document your steps / macRumours forum full of helpful and generous people / it's pretty straight forward.

Well, I decided that rather than taking it to the repair guy I would try reapplying the thermal paste and just using the one clip/loop, checking the machine periodically to see if / how long it might hold. I'm ready to do that now, but I have another question for you.

I notice in one of your pics at the beginning of the thread that the black heatsink had a square of what appears to be some kind of mesh, which was gunked up with the original thermal paste. How did you deal with that? Did you just peel that off and apply thermal paste directly to the heatsink?

Mine has no such mesh. I don't know if that was something the repair guy removed three years ago when he repasted the heatsink and resoldered the loop, or if they didn't all ship that way originally. But given that the heatsink covers so much more surface area than the chip itself (which is pretty small), it seems counterintuitive to just apply a "pea" of thermal paste to the chip and the have it squish out from the sides.

Thoughts, anyone?

 

[doctormelodious]

Yet another question. When I boot the Mac Pro 3,1 with the currently removed Northbridge heatsink in Snow Leopard, the version of Macs Fan Control that runs in SL shows a sensor reading for "Northbridge chip." However, when I boot it into El Capitan, that version of MFC does not list that sensor. It does list something called MCP diode. In both cases, the temperature remains at 64ºC at all times. I try setting different fans to reduce that temperature, just as a test, but nothing brings it down.

Also, on my other Mac Pro 3,1 (also running El Capitan), whose Northbridge heatsink is in place, the same thing happens with the MCP diode sensor. It always reads 64ºC, and no amount of fan fiddling can change it.

So, my question (finally) is: Is the MPC diode the same thing as the Northbridge sensor? And why is it / are they stuck at 64?

Thanks!

 

[dMajor]

Bad news:
Noticed some weird fan activity the other night as I was going to bed.
Figured I'd check it out in the morning.
4am - distinct "Crack - ping!" noise was heard.
Solder failed.
So here we are back at step one:

I just got a "new" secondhand MacBook Pro, so I'm working on that, and Mac Pro can go **** itself for the moment.
When I can find the motivation - going to try the epoxy paste route. Seems like much less hassle with possibly same chance of success.
Can always go back for another solder if that doesn't work.

 

[bvhprods]

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

I have the exact same issue/problem, the heat sink fell off, I found the missing ring lock/loop on my floor, luckily I don't vacuum my studio very often. So you are saying don't bother putting back the heat sinks, don't worry about it?! Would it do to just glue the heat sink back without reattaching the clips? Or can I use a small screw eye into the MB, or would that be a no no? What is the processor or unit that heat sink sits on?! Thanks in advance for you reply.

 

[macguru9999]

I would lay the machine down and glue the heatsink back with a SMALL amount of 5 minute epoxy. The less messing around you have to do with the mobo the better, unless you have above average skills. It would be interesting comparing the temps before and after ......

 

[KeesMacPro]

Mac Pro can go **** itself for the moment.
When I can find the motivation - going to try the epoxy paste route. Seems like much less hassle with possibly same chance of success.
Can always go back for another solder if that doesn't work.

Sorry to hear that!

I got good experiences with Phobia thermal glue.
I doubt that the heatsink will come off ever again.

 

[bvhprods]

I would lay the machine down and glue the heatsink back with a SMALL amount of 5 minute epoxy. The less messing around you have to do with the mobo the better, unless you have above average skills. It would be interesting comparing the temps before and after ......

One of the hooks for the heat sink is broken (same as original posters problem), which means there would be no pressure on the heat sink, so the thermal glue wouldn't hold the heat sink to the mobo, is that correct? If that is the case would the epoxy do the trick?

 

[KeesMacPro]

there would be no pressure on the heat sink, so the thermal glue wouldn't hold the heat sink to the mobo, is that correct? If that is the case would the epoxy do the trick?

Thermal glue will hold the heatsink , no problem.
Actually e.g. Phobia is a 2-components epoxy but highly thermal conductive .
Anyway, a "normal" epoxy has a very high thermal resistance, and in fact could be even worse than leaving the heatsink off.
A good thermal glue applied the correct way (a thin layer) is extremely strong and thermal conductance equals a thermal paste.

 

[Pezimak]

Bad news:
Noticed some weird fan activity the other night as I was going to bed.
Figured I'd check it out in the morning.
4am - distinct "Crack - ping!" noise was heard.
Solder failed.
So here we are back at step one:

View attachment 949243



I just got a "new" secondhand MacBook Pro, so I'm working on that, and Mac Pro can go **** itself for the moment.
When I can find the motivation - going to try the epoxy paste route. Seems like much less hassle with possibly same chance of success.
Can always go back for another solder if that doesn't work.

I know his is an old thread, but it's been really intriguing reading your woes, did you ever manage to fix the heat sink and RAM issues? I admire the 3,1 still chugging along happily.

 

[cdocqui]

That was an interesting journey but sad to hear the repair didn't make its way.
Also curious to know the outcome...
3,1 deserve it to make them to continue their life.
Just found mine has also the same issue when I did open it today for some dust cleaning. Currently it is working okay without the heatsink but I will probably bring it to the repair shop to get it fixed. I can't afford enough time to try a repair by myself (also had a bad experience trying to fix the fan of a Mac Mini ).
Let's rely on a professional. 🤞

 

[ThunderSkunk]

My hunch is it fell off this thing.

Ah you guys, overthinking it as always. Just slather thermal paste all over it like mayonnaise on a balogna and cheese sandwich and slap it back on there, give it a good kick to make it stick & Bob’s yer oncle.