Chosen Solution
hi guys I have a clients 2012 12” MacBook Pro here, I have never seen an issue like this before. What happens is if you press the power button once the processor fan shakes for a second then nothing, if i hold my finger down on the power button the fan will spin but nothing happens no lights no display or anything but also I can hear a faint buzz noise coming from fan area? Things I have done already (removed hard drive, removed ram) still the same Here’s a short vid of the issue: https://vimeo.com/533800594
The noise I here is likely a bad power inverter on the logic board. Fully remove the logic board give it a dusting and inspect for staining or damaged components. Focus on the IC’s and Caps. Using a DVM measure the rail voltages are all of the present and at the correct values?
Try this: disconnect the battery and mag-safe. Press and hold the power button for ten seconds. Reconnect the battery then the mag-safe. See if you get a spontaneous reboot.
