My LB75P is only 5 days old, and already a problem. I replaced the strings with a SLIGHTLY heavier string, an the action jumped way up. I gave the truss two 1/4 turns in 2 days, and everything is fine. Action low, intonation good. Today at rehaearsal, I notice a rattle. It is most pronounced on the 15th fret on the G and D, but also on other frets and the open strings. Before I do anything else, I wanted to ask for advice.