Paul, one detail question. Did you manage to change the topcase bundled soldered with Keyboard (maybe not on this previous model) or only the keyboard ?

What's the point about input source. Do you think it could be software related ? I'm eager to know as I'm in the same situation.

Hello Paul, I'm pretty much in the same situation (in the need to change the keyboard on a A1369 model) It's been 2 times I read somewhere on iFixit that you can try unweld/unsolder the keyboard from the topcase and get a new one. It could save a lot of money as it seems to be possible to find some on eBay less than 50$ As you mentioned "a friend of mine" I'm really curious to know if you could provide us more information. Thanks