Any idea why on my new sharp 32" lcd tv, all cable channels except 57 & 58 (CNN) work fine, but on these channels the sound goes off and on, like there is a short in the sound. all other tvs and cable work fine in the home. Have reprogammed the channels already.

If you do not have problems with picture and sound on all the other working channels, then the problem you are having with 57 & 58 cannot be a short. The problem you are having is that those channels will not tune in properly through your tuner and this is why you get intermittent sound when they are trying to tune in. The sound tunes in easier than the picture. You said that you have programmed the channels again and I am assuming you are talking about the autoprogramming mode. Try to program those channels individually by deleting them and then readding them. If you cannot do that then you need to take the tv back since it is new or have warranty service look at your tuner and setup your tuner by making adjustments to it directly. Good luck and God bless.