Originally Posted by richst
The TV screen is darker and skin tones are greenish. I hope it's the lamp. The rest of the picture is fine. This happened about 2 weeks ago. How can you figure out how many hours are on your lamp.
These TVs have what is commonly referred to as the "green blob" problem. I just had my optical block replaced this week because of this. I've had my TV for 3 years, but this problem got a lot worse over the last 6 months. It can be easily seen if you go to the memory stick screen and turn down the color so a solid grey screen is shown. After doing this, if it looks green and not grey, then your optical block has gone bad. Sony is fixing this, with no cost to you, until June 2009.
If your picture has started to look darker, then your lamp may be nearing the end of its life. They are rated at 6000-8000 hours.
To get into the SM(service menu) to check lamp hours follow this procedure: With your set already on, press the following keys on the remote control within 4 seconds:
[POWER] omit this step if TV is off
If you succeeded, you'll see a small green/cyan font display in the center of the screen.
To check Lamp Hours while in SM:
Press [JUMP] 3 times until you get a large neon green font display.
Press  5 times until you get to the 20 Timer, 0 LMP display. Hours are displayed to the right.
Other useful keys:
 /  = up/down categories
 /  = up/down items
Don't press these unless you want to make changes:
 /  = change values
Getting Out of SM:
Likewise, to get out and stay on: