Chosen Solution
I have a Macbook Air A1359 with a problem I can’t find a solution to anywhere online, so I figured I would ask for help here. A couple of months ago I spilled a mouthful of tea in the keyboard. I quickly turned it off and let it dry out bottom up over the next days. I turned it on when I was sure it had dried – It worked perfectly fine for two months. Then something happened, and I am unsure whether it’s related to the other problem. When I turn it on, nothing happens. The screen is black, no audio, no keyboard backlight, no beep codes or anything. The only thing indicating that it is running is the fan which starts out normally and slowly ramps up to full speed over a couple of minutes and stays at full speed. The only thing I can do, is to turn it off by holding the power button. When turning it on again the fan ramps up again, just as before. No signs of life other than that. I disassembled it to inspect it, I have done this many times before with other laptops. Everything seemed normal, around the logic board. The only thing I noticed is that the logic board on the right side of the fan had some dried-out stains which I believe comes from the spillage. I chose to clean the logic board in 99% alcohol which didn’t change anything – still just the fan ramping slowly up… Things I have tried: Attached external monitor. No output to that either.Reset PRAM and SMC.Removed battery, holding power button to drain the last power from the logic boardChecking all internal cables/connections, all seems fine.Detach keyboard cable to start it without any keyboard/touchpad.Detach all internal cables, to start it without any unnecessary parts. Didn’t change anything.Visual inspection of logic board – nothing seems suspicious.Cleaned logic board twice in 99% alcohol. No change. I have Googled “MacBook Air black screen fan slowly ramping up” and things like that, without any luck. I am willing to try anything as it can’t get any worse and my data is safe. It is not covered under any warranty either. If nothing comes up here, my next best guess is to try to reflow the logic boards in an oven. For me, the logic board(s) seems dead but it could be any other hardware – any ideas? What can I do to try to fix it? :-) Best regards Joe
If you have tried it with minimal parts plugged in, it will be a logic board issue. Does the CPU get hot? If not, check ALL_SYS_PWRGD signal on the logic board and if missing, back track from there. This signal appears when the other power rails are present and you can check this on U1950. This then enables the CPU to turn on. Grab a schematic and board view to find and measure the point I mentioned on the board. If you have no tools/experience required to replace a soldered IC or component, don’t waste time troubleshooting it and send it somewhere to fix this, unless you want to spend out to learn.
