Don't take this the wrong way, OK?
Is the CAPS-LOCK on?
I've done that more than once. I also have some "laptop number-lock" stories. Could be a loose connector, too, or bad terminal. Check your S1 and the kbd-to-console connection.
Side note, you might want to disable root logins from everywhere EXCEPT the console... when you get a functional console, that is. Set "remote login" to false in "smitty chuser" but set "su to user" to true. Helps track machine usage.