Ursprünglicher Beitrag von: lemerise ,
Do you use the genuine Apple Magsafe 45W charger or the chinese replica ? Did you connect the battery before the other cables ? Yes it could be the I/O board or the flat cable that connect the a I/O board to the logic board or a damaged charging circuitry (U7000 IC, SMC, etc). You should check carefully all the cables and connectors, remove the logic board and the I/O board from the chassis and inspect them both sides for any sign of corrosion or damage to the components. It helps to have spare known working parts to troubleshoot this kind of issue.