GTX680 won't detect second monitor

My husband and I both got new PCs yesterday. Our setup is such that we each have our primary monitors, and then we also connect to our Sony HD TV to use as a second monitor occasionally. (Mostly for watching TV/movies)

Our graphics cards are NVidia GTX 680’s. He is connecting to the TV with the second DVI port that the cards have. However, our TV only has one DVI input, but the cards have a HDMI port, so I tried to connect my PC to the TV with an HDMI cable, but the PC just won’t detect the second display.

Here’s what I’ve done so far:

1.) The guy who built the PCs for us said to shut the machine down, unplug the DVI and only connect the TV via HDMI, which should force the PC to detect the only display it has available. I followed his steps exactly, to no avail. The system boots, I can hear the startup sounds, but nothing ever displays on the TV.

2.) Tried a second HDMI cable to make sure the cable isn’t bad. Same result.

3.) Within the NVidia control panel, under the “set up multiple displays” menu, I tried the “Rigorous Display Detection” which did nothing. There is another option for “Force Television Detection” but it is greyed out. When the Rigorous Display Detection fails, it offers me a choice to use Force TV Detection, and the checkmark appears, but is still greyed out. Upon rebooting, the display is still not detected, and the Force TV Detection has gone back to being unchecked (and still greyed out)

4.) Scanned for hardware changes within the Device Manager.

I’m not sure what else to try at this point. A Google search has found very few people having this problem, but they are out there, yet there are no answers… at least nothing that’s worked. The only thing I haven’t tried yet is having my husband try to connect his PC via the HDMI, to rule out whether it’s just a bad card in my PC. We’ll try that later on.

But other than that possibility (that my card’s HDMI port is borked), is there something else I haven’t thought to try?

How recent is your TV? It’s possible that it’s not DHCP compliant (which would be enforced on HDMI, and not necessarily on DVI), and the NVidia card is being picky.

It’s about three years old I think? Not more than four, definitely. It’s a Sony Bravia.

Well, it’s looking like a bad HDMI output on the graphics card. My husband connected his PC to the TV through his HDMI port with zero problems, and I was able to access the TV with the second DVI port. He’s going to talk to the guy that built the PCs to see if there’s anything else we may have missed, but I expect we’ll be replacing the graphics card.