Hello, it could be a problem with the video processing board or a problem with the horizontal output.
If you don't know how to work on tv,s don't try it. Even if the tv is not plugged in,it could electrocute you. You should search some tech. Where do you live? I recommend you (www.tvrepairjacksonvillefl.com), but you should search the best and cheaper option.
andrew
July 2012