Since you purchased it for $300 in 2012 you definitely got your money's worth. It's great to hear that your wire traces were clean. It might just be something minor that's blown out. I would seek a person that can repair it or at least look for that video of that person that fixed their Hexar AF on Youtube. It might be worth a try. Truthfully, if you're not thinking of buying another Hexar AF then I'd give it to your friend since you're not going to do anything with it. I knew beforehand I was going to buy another one which was why I declined a person that asked for the broken one. Apparently there were a couple parts that I needed from the broken one to put onto the new one so it was good I kept it.
Just an FYI, I had to fix the sticky shutter too. I think all Hexar AF need that fix.
Good luck!