So my mid-2012 15" has been having issues ever since I got the logic board replaced (at my cost, later refunded by Apple due to warranty extension for graphics card problems) with random shutdowns and freezes. After a half dozen trips to the local repair shop, Apple issued me a "CS code" and had me bring it in once more. They ended up shipping it back to Apple where the techs were able to reproduce the problem. They ended up replacing the top case & battery, both fans, the heatsink, the magsafe board, and the audio board. When I heard it wasn't the logic board, I was expecting a bill to go along with the repair. Apparently Apple felt sorry for me and performed the out of warranty repair free of charge. That certainly wasn't expected and was very much appreciated. Maybe now I can make it to Skylake without issues.