excuse me.
help me please  

please help me to fix my hashrate on antminer s9 11.5 th.
Im get a low hashrate from 11.5th to 10.5th, but the longer it will go down to 7,5th.
after the restart hasrate will return to normal 11.5th, but later will fall back  

have tried to replace with some pool (antpool, slushpool, f2pool, btc.com), but the result is same as that.

there is an oddity in chain 8, the temperature does not appear and the ASIC status is different from the other ASIC status chain.
has anyone ever experienced and know the solution?
before and after thank you very much  

here I include screenshoot my miner status.

https://image.ibb.co/fGKczQ/2017_09_23_09_41_37.png
https://image.ibb.co/i7q6tk/2017_09_17_20_04_11.png