wow, lots of codes for Emerson TV's. From chapter 5 of the manual:
526, 534, 535, 536,
537, 538, 539, 541,
573, 590, 627, 652,
654, 655, 657, 658,
659, 660, 661, 662,
665, 666, 667, 669,
670
Often, more than one code will work, so keep trying to find the one that does the most. With any luck, you'll find a code that works and enables the TV/Video button to cycle through your TV's inputs. If that fails, you may want to pick up a OneForAll model 6131 universal remote. OneForAll remotes control almost anything, can be customized/taught new command and are pretty cheap. the 6131 has DVR specific buttons, and can be had for well under $20. I might pick one up myself (can't get the Dish remote to switch inputs on my Samsung TV). Too bad, to... I really like the Dish remote, really good ergonomics, IMHO. But, the 6131 looks nice, too and should control more stuff, and can learn new functions, should something be missing.
Hope that helps!