On CW 700 and 800, you do NOT see anything on TV screen when you press F1 key at the bottom left of the remote. However, it is active, and you should CONTINUE like F1 forllowed immediately by 555 to allow Card sharing F1 followed by 000 to allow patch. the screen will show the response Card sharing enable or Patch enable. If you do it once more it will show Card sharing disable or Patch disable.
Two days ago I went to a friend to look at the same problem - F1 key not working. I discovered that pressing F1 key on CW 800s does not even show that you have pressed anything. After a lot of fumbling I discovered that F1 key is to be followed by 000 and then it shows the words "patch enable" Same happens when you do F1 followed by 555 - only then you see "Card Sharing Enable" I did not have time to actually look at he final setup or whether it worked.