The 6412 is connected to our Mits with component cables. Have had it for one month. About half the time when we change channels from the digital range to HD channels, we get a blank screen, audio but no video. Have swapped the box out once already with CableAmerica/Mesa AZ. If we set the DVR to record off an HD channel, we've even gotten an hour of the blank gray screen with audio. Very frustrating. Before I rip out all the connections and call the cable guys for the 5th time,....are there any ideas?