I have a sony grand Wega KDF-kdf50e2000 and when you turn the TV on it will work fine for 40 seconds and then go off with the green power/standby indicator flashing. After 40 seconds the TV will come back on with the green indicator solid.

SOURCE: I have a sony grand Wega KDF-kdf50e2000 and when

If this is the model I am thinking of, Sony has a recall on the light engine. They are going bad in many of the Grand Wegas. Call them up and they should offer a new tv. You can either get a BRAND NEW lcd tv for free, but it is going to be smaller than your current one. Or you can get a different size for a reduced price. Late last year (november 2009) my grandma saw a red band at the top of the display. We called up Sony and we got a BRAND NEW 46" 120hz Sony Bravia for about $250 if I remember correctly. And since it is a new tv, you get a new warrenty. You also get to keep your current grand wega because they simply don't want them. I stongly recommend calling them up because this will give you a new tv. Spread the word.