Earlier I noticed the picture would dim briefly and then flash back to normal. Some time later I noticed the noise coming from the unit. It's a hard sound to describe so I created a video hoping that would help. It sounds like interference coming through a speaker, but the TV's speakers are on internal mute and pretty much always have been - they are never used. The odd thing is the noise seems to vary in intensity according to the display, for example when a commercial comes on and the brief moment of total black screen will cause the sound, and if the displayed image changes it affects the intensity of the noise. I tried turning the internal speaker on to see if that could be the issue and it plays audio fine.
Link to video - http://www.youtube.com/watch?v=-9On4MrGWmo
You may need to turn the sound up a bit to hear it well. Note that all audio from the TV and home theater are muted here, so all the noise is mechanical/electric in nature and not intentional audio. You will hear the creaking as I move the camera around but I think the noise issue can be heard clearly here. Toward the end of the video I move the camera to the rear of the TV and point to the base, which is where the noise comes from.
Any ideas on what it could be and where I should start? I'd hate to have a service call made if it's something that I could fix myself, I'm reasonably able to do minor things
