The screen has light blue discoloration than the rest of the screen.

Difficult to address the black screen problem without diagnosis but the blue discoloration is definitely a bad optical engine. Sony extended warranty coverage for this until June of 2010 but no more. Cost of the part is around $900 so I wouldn't pursue any further repair.

Bill W
integrityhomeworx.com

Light Engine Call Encompass Parts Distribution 1-800-638-3328

A discolored Blob, loss of one color or blotchy pattern usually in the center of the screen. The problem is becoming all too common with Hitachi projection sets. What happens is that one of the lenses in the optical block (or light engine) starts to burn or discolor due to overheating because of a blocked air filter causing poor air (cooling) circulation. Nothing can be done when the damage is too far-gone except to replace the light engine-at a cost that makes it not worth repair. if the damage is minimal than to reduce further damage, the air filter should be replaced. The Light engine needs to be removed in order to replace the air filter. Be sure to vote/rate me if this helped Thanks!
Also see link:
http://fyshere.blogspot.com/search/label/Hitachi%2050V500%2050%20in.%20HDTV-Ready%20LCD%20Television

A discolored Blob or blotchy pattern usually in the center of the screen. the problem is becoming all too common with Hitachi projection sets. What happens is that one of the lenses in the optical block (or light engine) starts to burn (in thi scase the blue one) or discolor due to overheating because of a blocked air filter causing poor air (cooling) circulation. Nothing can be done when the damage is too far-gone except to replace the light engine-at a cost that makes it not worth repair. if the damage is minimal than to reduce further damage, the air filter should be replaced. The Light engine needs to be removed in order to replace the air filter. Be sure to vote/rate me if this helped Thanks!

A discolored Blob or blotchy pattern usually in the center of the screen. the problem is becoming all too common with Hitachi projection sets. What happens is that one of the lenses in the optical block (or light engine) starts to burn or discolor due to overheating because of a blocked air filter causing poor air (cooling) circulation. Nothing can be done when the damage is too far-gone except to replace the light engine-at a cost that makes it not worth repair. if the damage is minimal than to reduce further damage, the air filter should be replaced. The Light engine needs to be removed in order to replace the air filter

Have it checked by a tech it's worth the service call to know for sure

the screen is yellow green color all the we have had it worked on once already does anyoblemne have any comments on how to solve this problems?

Try Moving The Speaker You Have There Away From It?
www.Myspace.com/CrossRoadsToNowhere2007

bonsoir!ce que vous avez ici c'est un probleme de light engine ;c'est surement un le filtre bleu qui est brule et cette tache va remplir tout l'ecran apres,il faut contacter lg et manifester parceque le light engine coute tres cher 900 us

unfortunately not. the discoloration is caused by the light filter getting fried due to excessive dust and heat. and you cannot purchase the parts individually. you'll have to replace the entire optical engine.

I have replaced alot of these light engines for this problem. Yesterday I received a letter from Sony saying they are going to give an additional warranty to have the optics replaced. I just checked, your model is one of them and Sony is replacing the optic block under an extended warranty, regardless of the purchase date, until the end of October 2008. Contact Sony for an Authorized Service Center in your area or go to this site to read about it: http://esupport.sony.com/perl/news-item.pl?news_id=185&mdl=KDSR60XBR1 Have this repair done on your set and it should save you about $1300.00 to $1500.00 on the repair. Hope this helps.