Chosen Solution
I have a macbook I got for free that doesn’t get a green light this is my first attempt at laptop repair, so I checked a few voltages: PP3V42 - OK PPBUS_G3H - 0.03V NOT OK ! So I checked to see if the onewire circuit was working, 0V on SYS_ONEWIRE, and I think the PPBUS is not being created because SMC_BC_ACOK is at 0V, so I checked to see if the SMC was being told to turn on, SMC_RESET_L was at 3.3V and PP3V3_S5_SMC_VDDA PP1V2_S5_SMC_VDDC were present, but SYS_ONEWIRE and SMC_BC_ACOK are not coming out of the SMC. Can anyone confirm my smc is bad or has an idea on what else it could be ? I can also add that the only places I was corrosion were on the dc in board that I think still works fine, and the SMC had gunk around it, but nothing green or blue and it was small.
Really can’t diagnose logic boards remotely. The best I can offer you is to review Loius Rossmann’s YouTube channel to see how he diagnoses power issues. But before you go deep into debugging the logic board make sure you have a good MagSafe power adapter and it’s a real one as well! Apple Portables: Troubleshooting MagSafe adapters & EM MagSafe Chargers vs Cheap Imposters: Teardown for Truth
