Phone was in a sports bag with a water bottle that leaked. I dissembled the phone (just like the teardown posted on this...

Hi, When you power on the phone, does the screen come on at all and show the Samsung logo? If so then it is likely to be a software or firmware problem, and a factory reset might fix it. If there is nothing at all during power up then my research into my own "blank screen" suggests it is hardware. Did it sustain any sort of physical impact, like dropping on the floor? If so, then there is a chance that the main pop connector has come loose, as the answer above suggests. If it has sustained environmental damage (water, heat etc) then it is more likely that one or more components have failed. I've seen a lot of posts on various android and samsung forums that suggest replacing the lcd/digitizer assembly, but all of these have described the soft keys (back and menu) lighting up during power on. In the case of my "blank screen", I don't get anything at all on startup, not even the soft keys light up and I have confirmed my screen *does* work in a different phone, so the fact your screen is blank does not...