FYI, I have the same story: First a red vertical line, then a blue vertical line, and then, not wanting to be left out, a green one. There is also now a wider red line on the very left.
I called Daewoo CS (about 4 days before warranty expiration, phew) and got a case number. They said a tech would call. Noone ever called so I called them back and they said they sent me an RMA letter and would be sending a carton. I got the RMA about a week ago and got the carton today. As no tech called I assume the problem is well known. Now I have to call them and they will arrange pick-up.
Frankly, I don't know how the broken TV is going to survive the trip given the state of this carton. And what ever happened to the "must be kept vertical" warnings? No such thing here. They don't seem to be too concerned with fixing this TV and turning it around.
Well, so far no problems with the Daewoo CS. I was quite happy with the TV but certainly expected more than a year of service. We'll see how it goes.
Does anyone have any idea on turn-around times?