Chosen Solution
I had the same problem with the scalding hot MagSafe, but I must’ve killed something in my Mac, because now it won’t turn on. I replaced the DC-In Board and am not seeing the light on my power adapter light up at all. I’ve used two different power adapters with the same result. When I did replace the DC-In Board, I failed to connect the keyboard ribbon because I didn’t have the battery’s ridiculous Tri-Wing Drivers. What would be the next logical step in order to get the device to turn on? I’m ordering the tools I need for the battery so I can connect the keyboard, but would that even matter for booting the Mac? Do I need to replace the Logic Board?
See if the DC-in Board pins 2&4 (2nd from either side). Magsafe connector 2&4 pins are pressed down and not fully popped out. Hence these pins while touching DC-in Board connector, do not make full contact. They are making loose contact which in turn makes arcing/sparking which generates heat to make Magsafe hot. Use a wooden toothpick to depress and release them. It is a typical phenomenon you see on household electric plugs getting fused and burnt. I suggest you clean both sides with alcohol and there is high chance that it should be working good.
