Aporte original por: rob ,
There are open / High resistance contacts under the Att GPU , these contacts are on the top left corner of the GPU . a simple reflow will correct this . but some after 1-3 month it will be repeat problem . Just replacing the heat sink compound will fix the problem 20% of the time , But the console is on the edge of instability. So it's best to just reflow the GPU only and replace all heat sink compound . If you want to get 12-24 mouths out of a standard reflow , then you will need special hardware C.C.A (Conformal Compression Assembly ) it's like a X clamp on steroids , and evenly compress the GPU die to the board and supports the board , so ZERO pc board stress . I'll post some links if anyone is interested .