Why my MacBook can't power up?
Today I followed the step to remove the logic board and the fan, and then I cleaned the dust, assembled again.
But.....no light on MagSafe, and when pressing the power button, there was no life sign....
I'd tried SMC, but no life sign neither.
I wonder what the problem might be?
If you removed the heat sink you must reapply a thin coat of thermal paste. (This would not cause a power on failure, but you don't mention reapplying thermal paste - it is an essential step to stop overheating)
Double check the reassembly of all the connectors, especially those to the internal mag-safe, keyboard and the HD. They are easy to destroy if you do not remove them carefully.
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