What's your electronics repair ability level? Got a schematic?

The noise can go louder if turning up the volume.

Er, the volume control of....? Your TV?

Sounds like you've likely got a noisy junction in a transistor or amp
IC somewhere in your audio section. Depending on your ability and what
equipment you have (and whether or not you have a schematic diagram),
it could be easy to find, or a real hassle.

If you've got to pay someone else to repair this for you, unless you're
in love with it, I wouldn't bother.