[Ti] damaged screen or graphic card?

[Daniel Rubinstein]

Hi list, my name is Daniel Rubinstein, a long time lurker on this list.

I would really appreciate help with this: The screen on my Ti 550 
developed a fault: few minutes after being switched on tiny blinking 
lines start appearing in one of the screen corners, after a few more 
minutes the lines grow into waves which run up and down the screen 
until it becomes impossible to use it. I would like to know if this is 
due to a faulty screen, faulty graphic card or hinges? from outside 
everything seems OK, and I don't remember ever dropping the machine. I 
want to buy a replacement screen from ebay, but want to be sure that it 
is the screen that needs repair. Please help.

Thank you guys,

Daniel