When you're diagnosing a problem, try the easiest things first before you try to find the receipt and warranty card. There is a setting on the TV that tells it whether it should get its signal from the airwaves or from the cable line. The problem you have is finding where you can change this setting. On my old TV, there was a button on it labeled 'Air/Cable' and when I first got cable installed, I had to press it to switch from antenna to cable. My new TV doesn't have a button on the set or the remote. I have to go into the onscreen menu and change it there. I can't tell you where the setting could be hiding in the menus on your TV so just hunt through all the options until you find it. Make sure you do a channel scan so it knows about all the new channels (it may do this automatically). The next simple thing to check is that the wire you are using from the wall to the TV is good. There should be a little metal pin sticking out of the middle of the connector on each end (see below for example images). If either of those broke off, the signal can't get through. If you are at all in doubt, go buy another cable. They are pretty cheap. If you already had it set properly and the cable is good, chances are there is something wrong with the TV. Grab a flashlight and check the place you plug the cable into. Is there any obvious damage around it? If not, it's possible the connection broke inside the set. It may be time to call the place you bought it from and see if you have 1 day left on your warranty or if it expired yesterday (I'm a consistent 'expired yesterday' person). Not too many places repair TVs anymore because it's usually cheaper just to buy a new one. You'll have to find out how much it would cost to fix it and decide whether it's worth it. ---Update 9/7/06--- I forced two images into video answers. I removed them and put the images in the proper way.

my engineer friend thinks that either A. the input signal jack doesn't work and that it would be an easy fix with the right part. or B the signal decoder chip is fried and therefore the tv is useless if i want to watch cable. if A is the case, what part do i need?