I bought a new controller the other day (wanted the newer D-pad mainly) but couldn't get it to sync. The sync button on the controller would work just fine, but the one on the system was doing nothing. Even took off the faceplate and used a screwdriver to push the actual button, no dice. Finally, after a bunch of googling, and all but resigning myself to having to get a play and charge kit (which will sync controllers without the button) I came across one post someplace suggesting that the HDMI connection was to blame. I thought it sounded absurd, but stranger things have happened (like a USB fan preventing me from running an update from a USB drive) so I took out the HDMI and put in a component cable, and sure enough, the sync button started working. After syncing, I of course went back to HDMI, and the controller stayed synced no problem. But I tried the sync button again, just out of curiosity, and sure enough, it's back to not working. It's not a huge deal, I probably won't ever need to use it again, and it's hardly a burden to swap to component if I do need to for some reason, but I just wonder, what in the world is going on that would make a video cable cause a button to not work. Mainly I'm posting this so if anyone else is having the same issue, they'll know to try syncing without HDMI.