Weird problem with using S-video out to TV on my DV2000

So I ordered an S-video to composite adapter cable off eBay and it arrived yesterday. Right when I opened it I hooked it up to my RCA 25" TV downstairs, plugged it into my DV2000, pressed Fn + F4 and right away the computer desktop was up on the screen, hooray.

So today I hook the same cable up to my 20" Panasonic TV from the same era that I have upstairs, press Fn + F4 and nothing, just a brief flicker on the screen. I think, OK maybe it's looking for audio also, so I hook up audio RCAs to the input and same result. Try restarting my computer, play with the display settings, yada yada still nothing.

Next what I try is plugging the computer back into the 25" RCA TV downstairs to make sure that still works, and it does. So I leave the computer in external monitor mode with the S-video cable plugged in, run the computer upstairs and plug it into the Panasonic TV and like magic it works. However, if I press Fn + F4 again the notebook screen goes back on and it won't switch back to the TV. I tried this a couple of times and it works everytime.

Now I suppose I can just prime the computer everytime I want to use it upstairs by plugging it into the downstairs computer, but I would really like to know what the heck is going on. My best guess is that the RCA connections have a trivial amount of voltage that signals back to the device that it is connected to the TV, and that maybe this voltage is too low on my Panasonic TV. Any ideas??