My sony KP3T90 has showing 2 colors on the screen,red & green

If you wish to get some details; check the site linked here. Pull up older posts. Surf the site with patience. http://electronicshelponline.blogspot.com/
Faults & possible causes to LCD & Plasma screen are given with illustrations. You can get an idea about the fault to an extent.

hello docstove!
looks like it has some cooling liquid problem, please contact service for repair.
regards

This problems ur tv have can't not be fix by adjustment.The tv have a problems known as convergence problems,it dead.Tv have colors lines R,G,B mis alignments,have colors shadow pictures or 3D pictures look alike?The tv convergence board have dead 2 STK convergence ICS and some or all of it resistors too.These parts on the tv convergence board,must be replaced to repair the tv convergence board to solved the tv convergence picture problems.The shop,will cost u like $300-350 for parts and labors.

Yes. Could be the color signal jacks in the back. Make sure you have them plugged in properly, green for green, blue for blue, and red for red.

have you connected up correctly, have you selected correct EXTERNAL inputs, you do NOT "tune" a Channel to see picture, you choose external AV input on set. Must connect color to color. 3 for Composite Video AV.Yellow, Video, Red & White Audio. and 5 cables for Component 3 for Video , & 2 for Audio Blue, Green, Red, Also Red & White, Audio.
AV

It is rear projection TV that use 3 picture tubes of red-green-blue to show color picture on tv front screen.
Do you see standby red light blinking when TV shuts off after showing blue image for a while?
If red standby light is blinking, please count it how many times it blinks, there would be 3 seconds pause between blinks so count pause to pause and post it here to find out possible solution.
Thanks.

According to the manual:
1) go to the "TV Main Menu"
2) Select "Screen"
3) Select Adjust Projection TV (obviously only if a projection TV).
This then allows you to adjust the TV's 3-colors. Selecting GREEN CENTERING brings up a control panel that lets you center the green projection tube on the screen. Selecting RED CONVERGENCE or BLUE CONVERGENCE lets you align the Red & Blue projector tubes. Centre the green projector tube 1st. Then adjust the red & blue until the test pattern on the TV screen appers white.
Good Luck!

Problem solved. I tried playing DVD and the TV picture was fine. So I double-checked cable wires from cable box - one of the wires was loose (obviously it was the red color input). After tightening, the TV picture is good as new.

Your green CRT socket may have a solder crack, or it could be the CRT developing a short. You can switch the green CRT socket with the one from the red RT and see if it still flashes green. If it does then its your CRT, But if it now flashes Red, Its a problem in the green drive circuitry.Thts the quickest way to locate exactly where your trouble is. If you need anything further let me know.

Sounds like a convergence issue. Call Sony for an ASC that can come out and give you an estimate. You are probably looking at $200-400 to do the repair.