Blue tint across screen and black shadow of sort

Its a DLP and it may indicate (as you suggested) a coming problem.

Set uses a optical light engine and heat from the lamp can damage that engine inside---guess what? Blue is the part of the engine closest to the lamp and its heat.

Pray it is not that as most engines alone are over 500 dollar part.

Your convergence board is in need of reworking on a component level or replacing the board! And you will most undoubtedly need to resolder the vertical IC and all ICs mounted on heatsinks on the power supply board. This TV is showing its age. You may choose to repair and that may last a year more or so! Good Luck and thank you for asking!

Convergence ICs are bad. STK392-120

You have possibly contaminated fluid in your blue picture tube if it has a hazy look.Blacks and whites look bluish and whites have a blue bloom to them.The other problem could be bad convergence amps.This would be double image around letters on the screen.

Colorimetre HCFR software
AVC HD 709 calibration disk
Spyder2 colorimeter (I know most prefer the Eye-One meters, but the Spyder2 was available from my job at no cost)

Here are the settings:

PS3 Blu-Ray player

Output Format (HDMI): Y Pb/Cb Pr/Cr (important!!! NOT RGB output)
BD 1080p 24hz Output (HDMI): On (this TV can reproduce video at 48hz for accurate 2:2 pulldown)
Y Pb/Cb Pr/Cr Super White (HDMI): On (not sure if this matters)

42LG50 Settings

Aspect Ratio: Set By Program (Personal Preference)
Picture Mode: Expert 1
Backlight: 50 (Personal Preference)
Contrast: 54
Brightness: 54
Sharpness: 40 (Personal Preference)
Color: 50
Tint: 0

Fresh Contrast: Off
Noise Reduction: Off
Gamma: Medium
Black Level: Low
Real Cinema: On

White Balance: Warm
Method: 10 Point IRE

10 (-3,8,-16)
20 (15,24,-21)
30 (20,36,-22)
40 (3,19,-40)
50 (8,34,-41)
60 (10,50,-20)
70 (-5,50,-8)
80 (-16,50,18
90 (-14,50,30)
100 (-22,38,21)

Red Color: -3
Red Tint: 0
Green Color: 10
Green Tint: 0
Blue Color: 14
Blue Tint: 0
Yellow Color: 0
Yellow Tint: 1
Cyan Color: -11
Cyan Tint: 0
Magenta Color: 0
Magenta Tint: -2

Take time to get used to the settings, you may think the screen looks dull at first. The truth is most people have way too much contrast on their TVs.
These settings will also work for Cable or Dish hookups, in which case you may change the Noise Reduction option to Medium to reduce signal noise.

OR....

2POINT IRE

Backlight: 65
Contrast: 55
Brightness: 45
Sharpness: 50
Color: 45
Tint: 0

Fresh Contrast: Off
Noise Reduction: Off
Gamma: Medium
Black Level: Low
Real Cinema: On

White Balance: Warm
Method: 2 Point

Red Color: 3
Red Tint: 0
Green Color: 9
Green Tint: 2
Blue Color: -1
Blue Tint: 0
Yellow Color: 6
Yellow Tint: 5
Cyan Color: -1
Cyan Tint: 1
Magenta Color: 2
Magenta Tint: -1

Good Day;
Suspect Convergence IC's STK4274, part Number 2003191. Replace all three IK04(red), IK05(green), IK06(blue).
Good Luck, big IRISH.

Need more information:
Can you isolate which color is causing the banding?
Is there something ON the lense itself?
Is the projection mirror broken or bent?

S

Replace FL231 400ma fuse. this will fix your problem.

The STK392-040 Is Convergence correction circuit! but the question is... what is the result when he replace the said parts? ok lets see... the probs. of your TV is a small parts like capacitor maybe this capacitor has change of value thats why the convergence is not in align...

Those lines sound like "retrace lines" and several things can cause them. The most common are shorts inside the picture tube and shorted semiconductors in the video driver circuits. They can also be seen if the blue screen voltage is too high or if someone has tampered with the screen voltage control.