That does not seem to address the high-pitched part of the sound. Here are several possibilities:
“There are several parts inside the TV that can potentially make this noise. These include the horizontal flyback transformer, deflection yoke, other transformers, even ferrite beads in the horizontal deflection circuits. In addition, transformers or chokes in the switching power supply if this is distinct from the horizontal deflection circuitry. Or even a portion of the sheetmetal used for shielding if in close proximity to a magnetic component.
You have several options before resorting to a 12 pound hammer:
* As much as you would like to dunk the TV in sound deadening insulation, this should be avoided as it will interfere with with proper cooling. However, the interior of the entertainment center cabinet can be lined with a non-flammable sound absorbing material, perhaps acoustic ceiling tiles. Hopefully, not a lot of sound energy is coming from the front of the set.
* Move the TV out of a corner if that is where it is located – the corner will focus sound energy into the room.
* Anything soft like carpeting, drapes, etc. will do a good job of absorbing sound energy in this band.”