Chosen Solution
Is there any method or lights to check if the logic board of my MacBook Pro A1278 Mid 2012 is working? I have installed two logic boards in my system and the computer is still not turning on? Neither fan movement, nor adapter green light!
Other than the MageSafe connector LED there is no other diagnostics to prove the system is able to get power. Are you sure the MageSafe power adapter is good? Is the battery charged (using a second system if you can)? Sometimes it’s a matter of tracing out the power feeds to see whats happening. Using a multimeter you should be able to trace out the power from your MagSafe connection to your logic board. Are you able to do that? Often times I need to replace the MagSafe DC-In board unit as the contacts are worn or damaged. Here’s the IFIXIT guide: MacBook Pro 13" Unibody Mid 2012 MagSafe DC-In Board Replacement
Did you spill something on it and short out the keyboard? If so you need to replace it. This is for the 2010 but will show you how: MacBook Pro 13" Unibody Mid 2010 Keyboard Replacement
