Why is there a blue streak on the screen of my 50'' HDLP television screen ?

The problem it's not on the Lamp, the problem is the color wheel, you need replace it and the TV will work like new again. I hope this help you :D

I have exact problem. Is anybody know how to fix it? tv is 4 years old

Your hdlp lamp is burning out. You need a new lamp. Look online for lamp by your model number. In instruction manual of tv it shows you how to change. Takes 20 minutes to change

light engine is bad call sony and see if your model is on their extended warranty list.

The Optical Block / Light Engine is the problem. Very expensive repair / over $1000

the issue is the optical block. replace the optical block

Hello,

You have the classic "blue blobs," In most of Sony's rear projection LCD's, the Optical block is bad. Manufacturer's defect. The blue panel inside of the optical block starts de-laminating (due to heat from the lamp). This is a very common problem. I have changed about 70-80 optical blocks myself over the course of about 4 years.

There is no other fix but to replace the optical block. Unfortunately, it will get worse, and will probably develop "stars," or stuck pixels, as well. You can call Sony and try to get some assistance, but the extended warranty on these sets has recently expired.

Hope this helps you in some way...

I would suggest getting another optical block from the repair man. Apparently even some replacement blocks have had issues...

I had the same problem w/ the same TV about 6 months ago. You need a new optical engine. Hopefully you are still under warranty. Once that was replaced, the tv looks great.

Research at www.HitachiServiceUSA.com .....T.