Chosen Solution
I have a 5S that I cannot get to turn on or even charge. I am needing to recover the data for a customer. I have a spare 5C lying around. Is there any way I can plug the motherboard into the 5C and get the data from it or is that a long shot? I have a new battery on the way to see if that is the problem but if I can do it without the new battery then I can charge them less. Could this be the charger port? How could I check this?
You find the problem by swapping it yourself. There is no way we can be sure what the problem yourself. The 5s logic board may squeeze into a 5c case, however what’s the point? It is likely that the board is dead and if you swap the board, you still end up with a dead phone.