I just tried this solution as well and it worked PERFECT! This advice just saved me a few hundred dollars of repair work. Thank you!
There is a great how-to guide here for this with pictures: http://www.somelifeblog.com/2007/06/sony-projection-tv-red-line-repair.html
Sounds like you are seeing retrace lines. you will have to adjuste the screen control. (it would be like a master brightness.) you will have to removed the front bottom plastic from the tv, look for 2 to 4 screws. then gently remove the front. sometimes the also add velcro to help hold it in place. now you need to remove the small plastic or wooden panel/door. in the upper right side you will see a small box with 6 controls.i do nor remember if the top 3 controls are for screen or focus, use a flashlight it is marked on the box which is which. adjusted the screen control to the left slightly to decrease the color you need. the green is the center control. like you said it is more noticable on dark screens, so try & adjust it in a dark romm with a drak seen. good luck.
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