Hi,
I see that this topic is a bit old and nobody respond so I will. I just received my replacement screen from china and I had similiar problem to one described here so I think I should answer. My problem looked similiar to this one -
http://imageshack.us/photo/my-images/24/40328529.jpg/ . Some shades were missing, pictures were hard to read. I was thinking that it was due to poor quality of screen from China. But...
After I played with it and written to the seller on aliexpress - it suddenly started working perfectly. I don't know what happened. I think that such problem lies in some kind of not making for example the screws tight enough or maybe not strong enough pluging the screen? I don't know but it can be surely solved.
Mine solved itself.
EDIT: The problem with refreshing also existed - it was really bad, and images were on top of each other.