From my experience, this sound comes from one of the capacitors, I'm not exactly sure why it occurs, but usually a good cleaning from all the dust can quiet it down a bit. Possibly look around inside and check if any of the caps or transformers are broken. If they are, then either get some place to repair it for you, or you can do it yourself if you know how to do it properly.
Thanks guys! I figured it was the same thing as when a PSU goes bad (I know much more about PCs than TV's.) Thanks for the headsup Mobius! I will poke around inside after it has been unplugged for the weekend. Clean some of the dust and check for bloated, broken or leaking caps. It's a cheap TV so probably not worth it to bring to a repair shop, unless it is really inexpensive to fix.