Diagonal lines across picture

This a Normal Intensive Use Defects, this a Screen Burnout. Sorry

The most likely cause is shorted convergence chips and possibly a few pico fuses.

These sets need to have all three colors - RED - BLUE - GREEN - lined up correctly on the screen in order for the picture to look normal. This is called convergence.

When its out of alignment the video will look 3-D, wavy, distorted, etc. Most of the time you just need to adjust your convergence in the menu. If you cannot adjust it in the menu - then your convergence is broken and needs to be repaired. Convergence problems are very common on all Projection TV sets including Sony,Samsung,JVC,Philip Magnavox,Panasonic,Akai,Pioneer Hitachi,Mitsubishi,Zenith and others.
You can get a convergenece repair kit with instructions from the links below.

Here are some of the most common problems with these sets...

Problem #1) Convergence

Yours may have one or more of the following symptoms...

*Screen Looks 3-D
*Colors wont align
*Screen may look distorted or warped
*No Audio/Video - TV Shuts down - May also make a constant chirping sound

Problem #2
Another common problem is dull or washed out video.

Your set may have one or more of the following symptoms....

*Dull looking picture
*White looking picture
*Halos around objects
*Red/Orange looking picture

You can see some more examples and find a fix here http://www.fixya.com/support/r2861467-solution_video_looking_whiteish_dull

Hi There,
Sounds like your Horizontal Output Circuit is leaking current causing diagonal lines across the screen. I hope this will help and thank you for using FixYa!

this is a resistor gone on the board easily fixed

if you mean line across middle no vertical deflection prob circuit prob. need tech.

The lines you saw, i;m sure they are the ones called retrace lines but know the failure could be located on the red CRT board. Most likely the video amplifier is defective and not necessarily the CRT.
What is the model number of your TV?

Ran into the same problem with this DVD player and my LG tv. Try this:
Open the DVD tray, with the DVD tray open press the HDMI select button until the proper resolution for your tv is illuminated, put the DVD back in, close the tray and try again. Simple fix -- worked beautifully for me.

Good luck

Sounds like dropped pixels.  My first guess is the computer has been dropped on its corner, with the pixel dropout radiating diagonally from the corner.
My saint bernard sat on my g3 lombard, and I have vertical pixel dropout because of it, from the top of the screen to the bottom.
And no, it is not normal for a macbook to have lines across the screen.
Linda h.

Find out the board number, contact LG Zenith company tell them your problem.This way it lets you know wheather or not you want to fix it ask them how much is board.www.LG zenith.com. Good Luck. ThankYou for using FixYa. Have a NIce Day.

it sounds like an ECU has gone due to a trip in the tube, that may meen the tube might be slowly on its way out, or just a slight glitch. mine had the same thing and it cost me £45 to fix. now its great. i hope that helped. Jay.