I have 3 S7s, two are working great.  Having a few issues with the 3rd, I'm thinking it could be a bad IO board... 

Issues for concern:

1. High Fan speed needed otherwise overheat.  Even If I under clock, unable to set fan manual otherwise it cause temps to go high.  Even @ 80% Temps are in the low 70s.  Tried only running 2 board, same issue.  Other miners have fans set @ 45 and 43.  I have tried a different power supply with the same results.  Auto set with only 2 boards hashing, temps are 63.  Manually move to 90% Temp shoots up to 68.  80% low 70s. 

2.  Burnt ASIC.  One board has large burnt area on the upper row.  It does hash fine, no error, but it is burnt very bad. 

3. Replaced fans, still did not help with temp.

Would a bad IO Board cause the issues.  The environment location is the exact same as the other miners...

Thoughts??