Just thought I'd update here on my repair process with my Batch 23 Antminer S9.
It arrived last week and this week 2 boards stopped operating. I contacted bitmain and was told to return the unit to Hong Kong as per usual. After I complained about the shipping cost being too high bitmain offered to cover the return shipping. So far I must say the service is excellent and did not expect this from bitmain due to the high complaints about warranty. I was pretty shocked when they said they would pay for all round shipping. Great service so far and really gives me hope that they still care about customers.
I hope other people dealing with repairs get the same treatment as this