Suddenly my channel 3 is not showing just color bars. All other channels ok, any thoughts? It is a valid local channel, not connected to cable box or anything else.
Is this channel 3 through the ReplayTV? Usually, in my limited experience, color bars mean that the TV station itself is not sending a program on that channel and the station is broadcasting the color bars. Have you tried that channel through a direct hookup into your TV (for example, coax cable into the TV's antenna input? If you get the same color bars, it has nothing to do with your ReplayTV. This happens when a cable company changes their channel lineup and currently is not using that particular channel and/or is planing something different for that channel in the future.
The tuner in one of my Replays has a hard time with channel 5 (CBS in our area). Sometimes when we play back the show, all we'll see is a blue screen through the Replay with a note that there was no signal received and the program did not record, shown as "less than one minute" recorded. But color bars are something different.