Mac Air 11 inch came in not working. Liquid damage many month ago, not too much but some sign of corrosion. No red/green light, after reflow SMC light came back but 0.1v on PPBUS. Replaced U7000 and I get 8.6 and fan spin but then the voltage is dropping slowlyy to about 6.5-7v. Also it doesnt boot I only have fan spin. CPU Vcore is present and the CPU gets hot. I guess this might be related to the SPI ROM data lines? Some corrosion around there so will check all of those. However I am wondering about the voltage drop on PPBUS, there is no short in that line.