Cable ready tv components

Question

I have two television sets (Sanyo DS19380) and an Orion) that have the same problem. The components inside the tv that the coaxial cable connects to need to be replaced. What are these components? In one set the coaxial connects to a component which connects to another one and the tv picks up the signal. In the other set the coaxial connects to a componet which is made up of two components which allows the tv to pick up the incoming signal. I am not sure if you understand my explanation but I need to replace the components the coaxial connects to.