buysolar has my batch 1 fan still works
and my batch 2 fan works.
I wonder if the dead ones were set at 100%
60% works far better.
I could tell long stories with lots of details but running fans 10 to 15% under the max rpms is really better then trying to max volt the fan.
I have not set mine on 100, I always felt like I should be doing it with a fan or something vs pushing so hard (and I could be wrong, but it's worked so far). Have owned MANY bitmain gear and all I have had die on fan's was a S4 fan. I ended up going with the Sanyo fan with higher RPM on it as replacement.... but really was kinda moot.
My mining area uses lot's of CFM's to cool it from fan's and a nice exhaust. So my miners live in a pretty easy life besides a few day's if it is really really hot in summer.