Upgrade ram to 16GB

So this is what I would do If I had no choices...

Find a junker system (exact same model as yours) which has 16 GB or RAM carefully desolder the chips and solder them onto your system (32 chips 16 per side).

But, I still wouldn't do it! The better solution here is to just buy a good logic board which has 16 GB or RAM and just swap it out. Cheaper and less risky in the long run! You might even be able to swing a more powerful CPU in the process.

Sorry, Apple controls access to their service and schematics quite tightly these days. Unless you are qualified by Apple you can't get access to them. True, some older models are out in the wild. Now its just not possible, as most of new stuff is not accessible unless you log into their service network. Where copying or even printing is prevented so people can't walk off with it.

The only hope is buying from a reverse engineering company the diagrams ($$$) but they may not be correct or complete!

And yes, the chips are soldered! ;-}