Stills when I don't want them

Up-to-date FCP7 and an ioHD with latest firmware, octocore mac pro. Everything I can find is set the same, for an SD analog component output, like I've had hundreds of times before. Video plays in the canvas, but the video output on the switcher fed by the io HD is a still frame, that updates to whatever still frame I stop on when I stop the timeline. Hit play, and the live output again is stuck in a still frame while the canvas plays just fine. Spent 4 hours today rebooting, re-rendering, re-setting settings. Thinking of buying a puppy so I can kick it, I'm so frustrated. What else should I try?