The screen turns yellowish

I too have this problem and am unable to find a solution. Someone please post a fix for this issue if possible??????

The red "gun" of your CRT monitor is going bad. You will need to get a new monitor, and you should seriously consider an LCD flat screen. It will save you allot in electricity.

A CRT monitor is a very cool piece of technology inside... even though they are going obsolete with the advent of modern LCD displays.

In every CRT (Cathode Ray Tube) monitor, there is a trio of "Electron Guns"- they fire electrons at the front of the screen, hitting it with billions upon billions of electrons... the "bullets". Each gun is aimed at a set of colored targets, called "pixels"... one gun hits red ones, one for green, and one for blue. Combinations of these colors make up everything we can see.

When the red "gun" cannot fire enough electron "bullets" at the screen, the blue and green together make the picture appear yellowish.

If you want to learn more, look up "cathode ray tube" on wikipedia for starters!

A word of warning- the technology is very cool (I used to teach how CRT screens worked as part of my job teaching Missile fire control radar for the Navy), BUT:

THERE ARE VERY HIGH VOLTAGES INSIDE A CRT MONITOR THAT CAN KILL!!! DO NOT OPEN
THE CASE!!!!

Remember- the electron "guns" inside are shooting billions and billions of electrons at the front of the screen. They are being collected from the screen by a high voltage "supply". Most CRT's operate with anywhere from 15 to 45 THOUSAND VOLTS!

Yellowish green colour is usually caused by a burnt blue LCD Panel or the light engine requires servicing.

If the glycol is bad, there is a easy way to tell:

Remove the back cover and with the set on use a small mirror--put it over each of the three Lens--red will never be bad this way.

What you want to see is a green picture on the green tube and a blue picture on the blue tube.

If instead of a picture either the green or blue look like a floodlight with no picture--the glycol is contaminated.

What happens is bacteria grows in the blue or green glycol--never the red--for some reason it does not like the red color.

Usually the blue will be the one first affected---picture will have a yellowish look over most or all of the screen (turn the color all the way down and stand back at least 10 feet and look at it,

Changing Glycol involves some important things---this stuff is like antifreeze bit ten times more toxic.

If you find yellow and want to know what is really involved respond to this posting and I will assist you.

If this information told you something you did not know, rate this solution as I do this here for free.

SD TECH

COLORS OF LCD SCREEN HAS TURNED TO PINK AND PURPLE WHAT TO DO NOW?

This sound like the color wheel needs to be replaced!
That should fix ya!

if the model number you provided is correct, you need to look at this ASAP:
http://ciscdb.sel.sony.com/perl/news-item.pl?news_id=206&mdl=KDF50WE655

Copy and paste that link into your browser. Sony is covering the repairs for this problem, but only until the end of December, so you must hurry. Be sure to rate this solution, Thanks!

You have a bad optical block, the block has a 2 year warrnty but you will have to pay labor to have a tech change it

Your blue crt has a short - you can verify this by unplugging the socket from the blue crt and powering up the set and you should see a yellowish looking picture with just the red and green crt's operating. You can try turning down the screen control pot (B) for blue with the blue crt on (just to the point where you no longer see retrace lines in the picture on a blank input)Sony has had a lot of problems with the crt's on these models and sooner or later all the crt's will fail - For a permanent repair all must be changed.

your problem is in blue color cathode circuit. as you say that it becomes ok tha5t means 1 cable wire is loose from computer to monitor. 2 crt base loose. 3 loose contact in blue video ckt. 4 signal processor cable to crt board connector loose.(blue wire)