I sent my bad S9 board only to Bitmainwarranty and they fixed it. I did not have to send the whole miner. I just looked on the website and they show you how to pack the boards
https://bitmainwarranty.com/how-to-prepare-item-for-sending-to-bitmainwarranty/(They charged me I think like $175 total and after a week the board went out again. Sent it back in and got charged another $125 I think and its worked great since.)