Postagem original de: lemerise ,
Could be a bad top case. I would remove the battery, remove the top case, use known working ram, disconnect the optical drive, remove airport card, connect the ac adapter and try to power the macbook directly from the logic board by tripping the two power contact points located at the bottom of the fan. To find the contact points check for PWR white letters or the power switch icon. If the macbook boots normally this way then reconnect components but restart after each connection until you find the culprit. If nothing works then the problem is probably related to the logic board. Any liquid spilled on this macbook ?