Hi,
the way I usually diagnose trusrod problem is to press the string around the 14th fret and then play the string between the nut and your finger, so the part that usually isn't vibrating. I do this at various locations or work my way towards the nut and if the string can vibrate freely, i.e. if it produces a clear note, it's not likely to be a trusrod problem.
The string is much closer to the frets when you do this as opposed to normal play, if you strike the string with force you'd initially hear it hit the frets after this a normal soft note should be audible.
If it's resonance vibration from something in the guitar or battery compartment the problem should also occur when you play the same note on other strings. Flageolettes of the same note should do the same thing.
Ludwig