Chosen Solution
I received a White Unibody MacBook (A1342), and it is not powering on. The MagSafe adapter does not illuminate on plugin, but every third or fourth time I plug it in, the fan will spin up really loud until I unplug the MagSafe again. However, there is no response to pressing the power button. First I thought the issue was a bad MagSafe board - so I replaced it - same behavior as before. My next instinct would be to replace the logic board, but thought I would ask the question here before doing so. In case the MagSafe adapter itself is at fault, I’ve ordered another which is on it’s way. The RAM slots are populated with 4 GB of compatible RAM. I’ve followed countless guides on how to reset the SMC and PRAM, all to no avail. Not sure what to do next. Thanks in advance for any help you may provide!
Scrubbed the logic board, same behavior as before. Ended up ordering a new one on eBay, powers on now! Unfortunately clearing the liquid corrosion didn’t do it in this particular case.
Sounds like you may be dealing with liquid damage. You may have to fully disassemble it and scrub the board with 92% rubbing alcohol and a toothbrush. You may also have to replace the keyboard and power switch. Also replace the magsafe board. If none of that helps then you could also be dealing with gpu damage. On a macbook it would be easier to just replace the mid top lid with the keyboard assembly already attached.
