Advertisements I have TIVOHD with 1 MCard from Comcast SF. I got a mystery here. Randomly I could not watch DiscoverHD, ESPNHD, ESPN2HD in one tuner. The other tuner can show those channels. After I switched back from the good one, the bad one can show the channels again. This has happened twice in 24 hours. I do not know whose responsibility. Comcast or TIVO?