I'm sorry, you said HDTV, so I assumed you were using the other DVI port. If you have one DVI and one Svideo, switch to the other DVI. I had this exact setup with my x1800XT. One monitor worked fine, but as soon as I tried to use the Svideo port, it would "click on" for a split second, then turn off. I found out that when using the "Svideo" port, it turns off the second DVI. Stupid me (and I assume you to) had the one monitor plugged into the second DVI, not the primary. Leave the Svideo cable where it is, move the monitor to the other DVI. Your probably plugged into the secondary.