I have just connected a DTA box to my Sylvania TV, Model LC195SSX S/N DS1A0918114917. I have had the TV activated by Comcast Xfinity cable company and have been trying to program the Comcast remote control to work with the TV. We've put in all the codes. Only 1 code makes the remote partially work. It will change channels but will not work the power button or the volume. Is there anything you can tell me that might help me get this remote to function with all its features. The cable company walked us through all the codes we've already tried and then said we'll just have to use 2 remotes.