Ok, i am not sure what is happening here. Let me start by saying though, that I know a lot when it comes to hooking up electronics. Now i have never hooked up a set for hdtv, but i figured it can't be too hard. I am setting this up for a friend, he has has comcast cable, with a motorola hd box. The box has all the range of connections that you need. I hooked up the component cables(yr,rg,rb), since the tv doesn't have a dvi connection. I hooked up to the video 4 of the tv, which is the hd area. I checked at least 5 times to make sure that i didn't mixed any of the cables ( wrong color to port). When i have it hooked up in this configuration, i am able to get any hd channel that i want, the channel menu is able to come up also. When i switch to a channel that is not hd, the picture is scrambled. So i figured maybe i did something wrong. So disconnect the box and hooked it up using the composit cables instead. I new this shouldn't give me hd, but wanted to see if this would work for regular cable. To my suprise, now all of the regular cable channels worked, but when i switched to an hd channel I see a picture, but it does not go full screen and you can tell it looks like a good digital signal, but not hd. Also on the hd channels i can not bring up the comcast channel menu. I also called comcast and they told me i had it hooked up right with the componet cables and they don't know why it isn't working. They are going to come out and look at it, but i can't be there during there times until next wednesday so i want to try and fix it before they come. I am doing something really stupid or do you think it sounds like it is hooked up correctly. any help you can give would be helpful. I am at work right now so i don't have the exact model number of the set i can put that up later if the would help. Thanks in advance.
I have basically the same setup. Go into the Comcast setup menu, second level (press setup twice), and there is a place where you can set the conversion of the signal. Set it to Upconvert-1, this will convert all non-hd channels to 480P and pass through 1080i signals so that everything is HD.