Original post by: Puru ,
There are 4 pins at the flex cable connector of the keyboard case that goes to the slot at the Logic board. Problem might be that the flex cable of upper case with Keyboard became faulty. Now, to isolate it, short circuit between right 2 and left 2 pins of the keyboard connection slot residing on Logic-board with a pair of tweezers. Be careful not to short anything else that may fry the logic board. If this act starts up your unit, replace the upper case with keyboard. Otherwise, the problem resides somewhere else and we will be discussing on that later.