What is and HDTV turner in an LCD TV?

I want to buy an LCD tv and I found a 42” at a really good price, but it has a problem, the actual owner says that the HDTV turner doesn’t work, you just can’t use hdmi or component cables. It only works with the red yellow white cables. I don’t know much about all these stuff so what does this mean, is the quality of the tv still good or is it going to affect the images that I see on the screen? or what does that mean? and most importantly is it worth buying?

Thanks!