The infamous 'yellow light of death'
repairs went smoothly using the IfixIt guide and took about an hour of work and 30 mins of cool down after reflowing the CPU/GPU
The magnetic project mat is worth every penny here, write the step number down next to the screws u remove and its a breeze.
Unplug the motherboard side of the ribbon cable for the bluray drive and power switch board first and leave the ribbon cable attached to each. this makes it far easier to keep track of where and how they go. just be sure to be easy on them.