Re-tune the TV it's self. You need to do this periodically to insure you are receiving all the channels that your areal can reach. This is especially important as channels may change frequencies during this era of transition, but the TV won't automatically adjust. A loss of channel is is usually due to either a shift in frequency or a problem with the areal. Digital TV is much more directional sensitive. I'd re-tune first though, as you admittedly blew off a recommended re-tune date.
xx
