welcome to the forum.
Having a defective screen is bad news for the Sony reader and changing the screen is a scary task needing special testing equipment to get it setup properly (from what I've read).
Best bet - act now before 11/27 and go to a retail Sonystyle store. Trade in your 505 for $75 credit toward a new one -- now at reduced prices. The new Model 650 will cost about $125 and will give a much nicer screen than the 505.
see
https://www.mobileread.com/forums/sho...d.php?t=107436
good luck!