Last Friday I found my FP4 at the bottom of my wet backpack. That morning I put a thermos with 250ml of hot tea (clean but hot water I am afraid) in my backpack but had not closed it properly. I don’t know exactly how long the phone was in there. It could be around 30 minutes. When I found my phone the screen was black. I was on the train and tried to turn on the phone (unfortunately). Only that evening I took the phone apart and let it dry that way for days. At first glance everything seemed to look dry. Except that there were still drops visible at the cameras (if you look from the outside). Those are gone meanwhile.
Does anyone have a suggestion on what to do?
The phone still ‘vibrates’ when turned on.
One more idea: When I disassembled and reassembled the FP4 for the first time, it behaved the same way as yours – apparently normal booting indicated by vibration, but the display stayed black. Eventually I figured out that when I had pressed the display connector back into the FP4 core/midframe, I had not positioned it 100 % correctly. As a consequence, the tiny metal “teeth” in the little metal rectangle at the every end of the connector had gotten bent. They were no longer standing vertically. I was only able to re-establish the connection (and make the display work again) after I had carefully straightened the bent “teeth” again.