I have the same issue on an HR20-100. On any of the mpeg4 mirrored channels (hdnet, discovery home theater, etc.) I get the 771 message. If I leave it there, the channel will usually appear after about 4 minutes of displaying the message, but changing to another channel and back gives the 771 message again. The original mpeg2 channels still work fine. I've tried swapping the lines between tuner 1 and 2 and that didn't make any difference. Usually when I test the signal level on the new satellite, it shows all zeros, but sometimes shows 90s. Someone at DirecTV said it was a multiswitch problem. There is supposed to be a service guy here tomorrow afternoon to check it out. I'll report the results after he's finished. I have a pretty old multiswitch from way before any of the mpeg4 channels so I guess that could be the problem.