Sorry I didn't get this. Do you mean I should read the service manual of the K850? And then open the case to see if there is a water damage?

In this case: I opened the case already in the afternoon and can't find something that looks like a water damage (so far a noob like me can check/discover that). It looked all right for me, but a pro would maybe find out more...maybe I should post some pictures when the phone case is opened?