Yeah, you have to change the output from monitor to tv. Using either the visiontek drivers, some newer versions of the Detonator drivers (I think 28.32 or 30.82 work and probably more recent ones) or a utility like tv-tool you change the output from monitor to tv. Note that on all GeForce 3 cards, you can only run one output at a time: you get either VGA, DVI or tv-out, but not more than any two at once 🙁.