Chosen Solution
Injecting power without understanding the logic I suspect is the root issue here. The MOSFET is part of a Buck inverter circuit to boost the voltage Buck Converter: Basics, Working, Design and Operation So when you bypassed its operation by directly injecting G3H I suspect you failed to conceder the rest of the logic. I would check the caps and inductor as well as the traces if you have a liquid damaged board you shouldn’t need to make so many jumpers to get this to work. Update (09/04/2021) At this point I would replace the logic board LVDS connector as it still looks like it has damage. Given its history does it make sense spending so much effort on this board instead of using it as a parts board to fix your other boards in the other systems you have? Liquid damaged boards are always iffy!
