January 22, 2008Bunnie Investigates/Analyzes RROD Motherboard
Posted by The Ori
Bunnie has been looking for an RROD Xbox360; and he found, and actually sent one off to MEFAS to get digested for solder joint inspection at the GPU through a process called “dye and pry”. In this process, the motherboard is flooded with red ink, and then the GPU is mechanically pried off the board. The red ink flows into any of the tiny cracks in the solder balls, and at least, in theory, when you pry the GPU off the cracked regions will shear first so you will be left with visible red spots at the points of failure.
TOP: Is what a normal solder ball looks like after the test
BOTTOM: One of several balls on the GPU that exhibited signs of partial failure.
As you can see, by these results, you don’t see any “catastrophic” failure, which would be pools of red ink over a connection interface, here we see it’s just partial cracking. Partial cracking isn’t terribly uncommon, and many products work quite well despite such artifacts. However, after reading the [SeattlePI RRoD] article, if Microsoft shorted safety margins around many of the design parameters to get the product out on time, it makes sense that the summation of many partial failures could lead to a total system failure, and those are failures that have symptoms that vaguely cluster together, but are difficult to point to any single root cause; See Heisenbugs.
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