I rewired the cable coming form the main splitter to the cable box. The box is an Explorer 3250HD and now certain channels do not show at all or are very choppy. The splitter is one from TW that they used when they installed the cable modem and it worked before so I know its not the splitter. Why would some channels work while others dont even though everything is digital? I realize I must have done something since the only thing that changed is the wire and will troubleshoot but first I would like to know why its doing it in the first place.

First thing I would do is put everything back. If that fixes the problem, then that will help isolate the problem. It sounds like you introduced a splitter. Splitters can interfere in several ways. They reduce the power of the transmission passing through them, thereby perhaps making it so low that you cannot get a reliable signal lock. Also, sometimes, a splitter gets in the way of transmissions from the STB back to the head-end.

It's just as important for the 3250HD to get "good" signal, than it is for the cable modem. Make sure that the 3250HD and your cable modem are off the first spitter (cable company rated) to ensure "good" signal. Choppy HD pics indicate low signal strength or poor signal quality. These are two different issues that you have to keep in mind, when working with the digital and HD world. If all else fails, call for a cable service tech to check things out.

- Cable Tech