I purchased a "parts" early 2015 13" Air that had liquid damaged for its screen. I took the machine apart and removed as much of the coffee residue as I could. The trackpad works but not the keyboard. I was able to load High Sierra but it was kind of slow and the fan always ran at full speed. The Apple diagnostics (held down the "D" key during boot up with an external keyboard) said there was a problem with the SMC which I expected. There are several places in my city that claim to repair liquid damage. If the SMC is damaged, I assume that a keyboard SMC reset would not be enough to get rid of the SMC error in the Apple diagnostics program. Here are my questions: how do repair shops get rid of the SMC error? Do they replace the SMC chip? Presumably, fixing the SMC issue will stop the fan from running at full speed 100% of the time. Any information would be appreciated. Thanks.