I have on the bench an 820-3115 that was originally working but had some corroded components around SMC area so I decided to clean up the areas and now the board turns on but no green/orange magsafe light. the other odd thing is PPBUS_G3H is 12.29V. But it is showing a blinking ? folder. I checked SYS_ONEWIRE and ADAPTER_SENSE, as well as SMC_BC_ACOK, all are present. I decided to reball the SMC because of local corrosion. I am reaching out because I am not sure what else to consider.