Any hardware nerds in here???    I suppose I could post this question in a more-specific sub-forum but figured I would post it here first. Purchased a broken S9 because the price was stupid, $110. Question is, the boards are all bad or have some issue. Can I just buy different boards and switch them out? I know there was one guy on here attempting to figure out what was wrong with the boards and fix them. I am no genius with circuitry so not going down that path. Also, what makes a miner a 12.5, 13.0, 13.5, 14.0. Is it just the variance from manufacturing or was this due to upgraded chips etc...? Thanks.