Not "sold for parts" now.

Mi Problema

Phone would randomly shut down to the point of becoming almost unusable. The charge would not hold for long.

Mi Solución

Fifteen minutes? Yeah, maybe if you're used to having a soldering iron in your hands. For a mere mortal, allow much more time: for me, almost 2 hours.

But, got 'er done. So far, so good: charge is holding.

Mi Consejo

The instructions are generally solid and clear apart from the #3 ribbon attachment. It is not made clear that, unlike all the other attachments, this one does not completely unclip in a father/mother setup like the others. Instead, it is a ribbon which is held in a slot and clamped into place. I didn't get that and spent a long time trying to get it back into place. I had to resort to a YouTube search to figure it out.

If this process was made a lot clearer, it would have taken me far less time to complete. It's the only really fiddly part of the entire operation, and clearer pictures & instructions for this particular attachment would have simplified things.