Only one of my TV tuners is detected, but not the other, how can I make them both work?
If you have a Digital Cable Tuner (DCT) and the second tuner is a combination tuner, only one tuner will be available in Media Center if the combo tuner is configured as anything other than as having a digital Over-the-Air signal (ATSC). Doing so will require a HDTV terrestrial antenna.
To resolve this, power down your system, eject your Cable Card from your DCT, connect your antenna to the combo tuner, restart, and enter Media Center setup again to reconfigure the combo tuner as ATSC. Once complete, insert your Cable Card and setup your DCT as well.
If you would like to utilize the full function of the combo tuner, third-party TV software would allow you to view TV apart from Media Center.