So my batch 21 13.5 s9  purchased from Bitmain Colorado 5 Nov was actually getting pretty decent numbers, took a look at it one morning and pow, one board not hashing…power down/up multiple times etc etc .. no change, contacted Colorado, sent them the appropriate screen shots, they offered an exchange of the entire unit, bundled it up and shipped it off yesterday.  I don’t recall reading anyone else exchanging an entire unit, could this be the beginnings of EXCELLENT customer service?