Hey there, I'm what they call a newbie here I think...first reply, or post.
       Just wanted to warn you about the Bitmain repair facilities. I bought a S19jPro 100th(basiclly the same thing) in August of 2021 and it ran for 1 1/2hrs and dropped a hashboard. Sent it in to Delaware, they fixed it(suposedly) and sent it back. During shipping FedEx pretty much played football with it and banged it up bad. Plus it got wet. I wouldn't accept it and it went back to Delaware. They supposedly scrapped my brand new miner and sent me another one, but it's really the same exact one except now it has all the original external damage plus mixed hashboards and hashes at a much slower rate. I'm now in the process of getting an attorney and going to have to sue them to get a new one. Their customer reps in China are worthless.
      The moral of this story is make a mark on your unit, brand new or not, that only you know about before you send it in for repairs, or they'll send you a old piece of scrap junk and say it's yours and it got damaged in shipping. I took a lot of pictures and kept records of every email and text so I'm gonna be ok. Just a crappy thing to happen to someone on their first Antminer purchase and it doesn't leave a warm feeling with you after dealing with Bitmain.