Sorry for my English. The message has been translated by Google.

I have 4 devices Pandaminer B3 Plus. When the ether is mined, they give out a different hashreit. The lowest is 163, the highest is 178. Tell me why this is happening. Prior to this, about half a year other people used the apparatus. I do not know what they did with them and whether they issued the claimed hashed, but now I want to fix it.
I tried to install new drivers (by the way, after that, Claymore finally began to show the temperature on video cards). I tried to play with the parameters (frequency, voltage) of the start of the miner. Nothing helped.
Help diagnose faults and correct them.