Chosen Solution
My macbook was getting pretty hot doing medium stress task, so I thought it was due for a thermal replacement. I popped open the macbook, being careful of all the wires, and replaced the paste with pea size MX-4 thermal paste. When I put everything back together I tried turning it on and it made the boot up sound and everything, but no lights came on. No LCD, no keyboard light and no apple logo on the front of the laptop. The hdd light came on and so does the charging light. I tried all of the pram and smc resets to no avail. I tried taking out the battery and still nothing, I also tried connecting it to hdmi and nothing there either. Can anyone point me in the right direction on what may be happening? Oh btw i disassembled replaced thermal and reassembled again to make sure i didnt miss anything and still got the same results, just a boot up sound.
I would rule out the thermal paste as it is listed to be non-conductive, but while I am sure you have checked that every cable is properly seated in it’s socket, one thing that can cause an insane amount of problems is putting screws where they don’t belong. Try removing every screw that you had to take out and and boot the MacBook again and see if that works. Incorrect screw lengths can touch PCBs and cause them to short.
Its been fixed somehow. I left it overnight with the battery off and with silica packets underneath the motherboard and this morning i put everything back together and its working once again!
