[skybar]

Not sure if I'm posting in the right section, and this probably isn't the best site for this type of thing but I've tried 3 other sties just for Macs and there hasn't been any help. You guys seem to know a lot about logic boards and thermal paste, so I hope you can help.

I've taken apart 2 2011 MacBook Pros that have graphics card failures - it's very very common in this model. So at this point it was throw them in the trash or try to reflow them in the oven, and I opted for the latter. I prepped the first one - removed the heat sink and thermal paste that goes over the cpu and gpu, and 2 smaller heatsinks on an IO Controller chip and a Thunderbolt? chip, and removed any plastic that I was able - and baked the first one on 365 F for 7 minutes.

When I was reassembling, I noticed that there was a gap between the small square heatsinks and the chips that didn't seem to be filled by the appropriate amount of thermal paste. So I put a little bit of extra and just bent the screw tabs upwards so that the heat sink sat lower closer to the chip. Reinstalled the OS successfully and everything seemed okay. It seemed a little sluggish, but that could have had something to do with the 0% capacity battery or Spotlight indexing. I didn't really want to do much else with it until I replace the battery.

So my question is, on this 2nd motherboard, is it okay to leave the 2 smaller heatsinks on the board when I bake it? Is there a thicker thermal paste than the arctic silver that I should use for those 2? Or is bending the heat sinks probably okay to do? Someone elsewhere on the internet modded it with some copper pieces to fill in the gap, but I don't have any lying around and am not terribly thrilled with that course of action.

Here are a few pictures so you have a basic idea what I am talking about.

Chips without heat sinks - the red and blue are the 2 in question

Here they are in the top right with the square heat sinks covering them

 

[bajer29]

You'll probably need a thick thermal pad in lieu of paste. You can buy a sheet and cut to size. Can you take a picture of the gap in question. How big was the gap?

I'm not exactly sure what you're looking at. Is there a blown up picture of the chip in question?

I'd recommend not installing without thermal interface material if it was meant to have it/ had it when you tore it down. I'd also remove the existing thermal paste before baking. If it's electrically conductive it could flow onto your main board when baked and short some traces when you boot it up.

 

[skybar]

I tried to take a picture from the side view but I can't get it to focus well enough to be worth anything. Like, instead of the heat sink sitting flush against the chip, there's a space in between it, like a good millimiter gap. The paste that was on the board from the factory overflowed off of all the chips, and it's thick and crumbly. I haven't taken apart any other motherboards before, so I don't know if that is normal or not, but I've been under the impression that it isn't. The laptops are notorious for running very hot all the time. >.<

I don't know if they use a special type of paste or what. The CPU and GPU sit flush with their heat sink, but the type of paste seems to be the same.

In the pic with the heat sinks you can see it is a square with 2 tabs on the corners where they are screwed into the board. I bent those 2 tabs up so it would sit closer to the chip.

I'll try to get a hold of some thermal pads and do it that way though. I had never even heard of those until the past few days - are you supposed to use paste with them or by themselves? Thanks for replying!!!!

 

[skybar]

I should add that before scraping all the paste off the gap seems to be filled with a thick layer of paste.

 

[bajer29]

Quote:

Originally Posted by skybar

I tried to take a picture from the side view but I can't get it to focus well enough to be worth anything. Like, instead of the heat sink sitting flush against the chip, there's a space in between it, like a good millimiter gap. The paste that was on the board from the factory overflowed off of all the chips, and it's thick and crumbly. I haven't taken apart any other motherboards before, so I don't know if that is normal or not, but I've been under the impression that it isn't. The laptops are notorious for running very hot all the time. >.<

I don't know if they use a special type of paste or what. The CPU and GPU sit flush with their heat sink, but the type of paste seems to be the same.

In the pic with the heat sinks you can see it is a square with 2 tabs on the corners where they are screwed into the board. I bent those 2 tabs up so it would sit closer to the chip.

I'll try to get a hold of some thermal pads and do it that way though. I had never even heard of those until the past few days - are you supposed to use paste with them or by themselves? Thanks for replying!!!!

Quote:

Originally Posted by skybar

I should add that before scraping all the paste off the gap seems to be filled with a thick layer of paste.

Edit: And even a dust bunny stuck to the side of the paste layer in the smaller chip. >.<

You'll want to use the pads most likely rather than trying to pool a bunch of paste. The paste will have no cooling value if it isn't making solid contact with the cooler and the IHS/ cooler of the component you're cooling. Those pads are your best bet. They'll fill in the gap and all the microscopic pits in the IHS and cooler.

They do not require any past, they are basically a thick paste that has some rigidity to it. It will fill in the gap you're describing better than a liquid/ paste and won't run much (if at all) when heated.

 

[skybar]

Oh ok. Thanks!