In my opinion it should have been included in both the class action law suit and ensuing
MacBook Pro Repair Extension Program for Video Issues
I wouldn't take it to Apple for the repair as the problem was theirs in the first place but they were so unethical as to not admit it or fix it. Of course they say they know exactly what it is. Why would you trust these guys with doing the repair? They don't plan to fix it but sell you a new logic board and the labor and charge you through the nose for it. That'll fix it even if it is just a $1.00 fuse and they don't have to even think to do it. And your warranty? 60 days. What a peachy deal! Then in2018 they're going to tell you its a "legacy machine" and they aren't allowed to even work on it.
First let's not trust what Apple told you as far as what's wrong with it. Did you get it writing? Did they charge you for the diagnostic? What exactly did they say failed and why did it fail?
Let's do our own diagnostic. Please tell us what is happening with it.
It's Apple Part # 661-6491
Here's how to install it:
MacBook Pro 15" Unibody Mid 2012 Logic Board Replacement
The problem is that because of supply and demand (so many failures of their board) they are in short supply.
I'll do some research on this today to see if I can find a competent company that will do a repair on this board and replacement of the chip. This best person to look at will be Louis Rossman. I'll get back to you.