I have a Macbook Air that I got in for repair that has had coffee spilled on it and no longer turns on. The charger light will change from green to orange and I can do a SMC reset with the keyboard combo and the light changes to indicate a reset. I have taken it apart and cleaned all the visible liquid damage off with a brush and then warm soapy water in a ultrasonic bath. It made no difference. I have confirmed that I am getting all the G3 Hot rails and that they are in spec. The PP1V2_S3 rail and the PP1V05_S0 briefly turn on when the charger is plugged in and the battery is disconnected (the battery is dead as the client left it in a closet for 1 year after the spill) and then turn off. When they do come up they are at the correct voltage (checked with a scope). What would be the next thing to start measuring?
a complete visual inspection would be good, not just measuring stuff, you may have corroded parts or ic's etc ...
Left for a year after the spill? RUN. Coffee is acidic, and after a year, part of which was with residual battery power present, there is guaranteed to be corrosion damage.
I have given it a quick visual inspection and there are some laces that look questionable but test fine. I will have to clean the brown rust like substance off the inductors though.
A “quick” visual inspection isn’t going to show you the problem areas, which are where capillary action kept them wet longer, like under chips.
I have ordered one of the cheap usb microscopes so hopefully it will get here by the end of this month. I am a bit concerned because I did have some corrosion around the CPU vrm and the side of the CPU that has the PCH on it. Will take a closer look when I get the microscope.
I got it working after a good cleaning with hot soapy water in an ultrasonic cleaner. Thanks for the help.