my samsung galaxy is getting low signal

[AC Question]

I have a Samsung galaxy s4 and i recently changed the mother board and a few days later my phone starts to drop signal i got another mother board and it worded for a few days then start dropping signal too........ Dose anyone have any solution to this problem.... What could be the cause of this?

 

[AlphaTango414]

Poor connection maybe? Bad terminals or failing wires.