MacBook Pro A1990 "Braindead" repair

Problem description
Any shorted subrail on A1990 machines can cause the machine to hang on POST.

Symptoms

 * MacBook hanging on POST

Solution

 * Thermal imaging can reveal abnormal heat caused by a shorted component.
 * This condition is most frequently caused by a SSD subrail, such as the 2v7 SSD power line.