bga_repairs wrote:
...This is a Chipset replacement on a Macbook Pro 2011 6490m with GPU Failure we have recently repaired. Here are some pictures if anyone is interested.
Below: New GPU fitted and Logic board cleaned of flux residue.
This is the repair you need done if you get one. Brand New GPU in lead With picture proof...
Since you did such a beautiful job removing that cornerbond, maybe you can tell us what it actually is? I've gone back and forth on this. Is it actually cornerbond in the traditional sense of the term? I can't tell by looking at mine or looking at the pictures. (FYI: There has been some drift in how these terms are used, but cornerbond traditionaly means something that is heat-cured as part of the reflow process and edgebond, even when placed in the corner, means something that is cured post assembly by other means like time, UV light, or lower heat).
The first time that I saw the iFixit teardown, the thing that caught my eye was the lower left corner of the GPU package. What do you think is going on there? You can find similar pictures of boards for sale on eBay. My first impression was that the bonding material was beginning to harden in the middle of the package collapse. It seems like a weird thing to happen in 2011, but they appear to have used at least two different types of compounds for both early and late assemblies? Why? Supply problems? One not behaving as expected?
I'd think that switching between two compounds would at least raise the possibility of human error when it comes to storage temperature. A small mistake there (or a faulty thermostat on a refrigeration unit) would be all that is needed to change the properties of the material just enough. It's supposed to allow enough movement for self-center and collapse before it cures. A second or two can mean the difference between perfect joints and opens (fails QC and will not make it out the door). But somewhere in the middle and you end up with what we're seeing here. You've got machines that pass QC, but go to market with solder joints under constant stress. You start seeing infant mortality spread over a wide timeframe.
Just a shot in the dark, but I get the feeling that it's going to come down to something mundane like this. Apple generally does get the math right on the complicated stuff like CTE variables. Heck, they wrote the book on half that stuff. It would be nice if we can rule out both a design flaw and a problem with the AMD solder (either on its own or in relation to other variables). Then the solution would be very simple and straightforward: A new GPU installed by a competent professional with high-end equipment will put your MBP like it was originall intended. Would you agree? If evidence eventually leads in this direction, would you stop reballing with lead and just install the packages like they come? Actual evidence would also be very handy for people when they send the bills for this repair work to Apple!
Thoughts?
Also, have you had a chance to do an endoscopic inspection of these joints prior to your rework?
Here is that other picture for reference:
I get that some of what we're seeing here are just stray fibers that got caught before it cured, but it's the thicker lines right at the corner that look like cracks to me. You can see a few smaller fibers elsewhere on the board, but I guess that actually raises another question. Why did so many get caught there at that particular time? Was too much heat invading from another reflow zone? Was the i7 getting greedy with territory?
