Chosen Solution
I’ve bought a secondhand (non-functional) MacBook a while ago. It doesn’t seen to want to boot. The progress bar sometimes gets to around 25-50%, and then the laptop just shuts off. I’ve already tried booting from USB without the SATA cable attached, and the same issue still exists. Weird thing is, it sometimes boots. I’ve replaced the thermal paste because it was getting pretty warm to the touch. Afterwards, it worked just fine. The next morning I tried waking the MacBook from sleep, and it immediately shut off. I’ve tried resetting the SMC. After resetting it, the MacBook turns on with the fans on full blast and the battery indicator not working. I need to reboot the MacBook multiple times to get it to “work” again. When I press the Shift+Ctrl+Option buttons during boot, the machine instantly powers off. Right now when I try booting it up, I get a flashing globe on screen. If I hold any key, it goes to the normal boot screen and shuts off after 25-50%. Any idea what to do here? EDIT: It wasn’t working again, so I took out the logic board. And now it’s booting up again. The magsafe light is nice and green now, and it’s dim when the MacBook isn’t working. Coconutbattery shows good health right now, but it was at 47% a few days ago. I think it’s shot.
The logic board has some problems as the MagSafe charger LED should be solid green if charged and Amber if needing charge. A dim LED is telling me the charging logic on the logic board has issues. As your system is struggling to stay on it your battery may need replacing. If you can get it to start up again try running CoconutBattery on it and get a snapshot with the MagSafe connected and a second with it disconnected and paste them here so we can see Adding images to an existing question
