Help locate my Iphone?

I lost my iphone last week and now i'm reading somewhere that if someone changes the logical board the phone will be as good as new, i icloud on it so the phone is locked and i have find my phone as well, still can't find it. So is it possible that someone could have changed the logical board and be using it hence that s why i can't locate my iphone 6? Please help. Because my cousin told me that the locator is also set in the battery as well as the screen so that if someone diassamble the phone and sell the part you will be able to locate it. How true is all that and how can i really find my phone please?

There's no "locator" in the screen or the battery. But if you lost your phone last week - "find my iPhone" only works as long as the phone is switched on, has power and a data connection.

It is true that if the logic board is replaced that it is unlocked because it is not the same phone anymore. But there's no GPS in the screen and battery, that is crazy. Those are replaced all the time. It isn't likely to be done though as logic boards aren't cheap, and your average theif isn't going to put that much effort into it. If you ahve the find my phone stuff enabled, it can't be disabled. So, if you're not seeing it that means that the more like scenario is that your phone is damaged. Hasn't been turned on since you lost it meaning that whoever found it just has it sitting some where or hopefully it is lost somewhere in your home.