What is the red line on my lcd tv

Alan,

What you are describing sounds like a failing LCD panel. It's time for a new set!

HP-R4252 NOT LCD TV
IF LCD TV has vertical lines try cleaning T-con board to lcd panel cable or replaced t-con board

Is this an LCD TV or and LCD Projection TV.

This sound like a convergence problem that sometimes can be adjusted in the user menu. Definintely can be adjusted in the Service Menu.

Hey habo,

The red light you are referring to most likely is the power indicator light. On many newer TV's this light will appear red when the TV is off or in "standby" mode, and green when the TV is in operation.

Please keep in mind that some TV models may use the power indicator light to notify owners of ay potential hardware problems as well, so you may wish to refer to your owner's manual documentation if you have been encountering any problems during TV operation.

Hope this helps you out.

Sincerely,
Aaron
Go Ahead. Use Us.

Both sound like bad LCD panels. The following must be answered to confirm this:
Do the lines appear on all inputs/all signal sources?
Can they be seen in the OSD/menu?
If yes to both questions, it is likely that the LCD panel is bad

Sounds like an IC on the LCD panel went out of TV. Only thing to do is replace panel (it won't go away only get worse) It will probable be cheaper to just get another tv.

I had a similar problem with my LCD screen TV, and to my dismay, my warranty just ran out. A thin red line began to appear on the right side of the screen, and since many online and expert sources pretty much say replace the expensive LCD screen or get a professional to fix it (in which I suspect to be a business plot to get people to go to pricey experts), I decided to look for other possible alternatives. 
Here is some tips/solutions I was given (and it worked! at least for me): 
1) Turn off the LCD and unplug the power source and let it rest for 5-10 minutes. Turn it back on and see if it disappears or improve. (This is the one I used.)
2) While turned off, try jiggling gently all chords connected to the TV (cables, power chords, etc.); you could even try unplugging and replugging the chords/cables. Turn the TV back on and see if the red line disappeared or improve. (This is the one I heard worked for others.)
If the above doesn't work then I'm afraid you do have a bad panel on your screen and will need to call in the experts or get a new TV. I hope this will help. Best Wishes. 

I have a thin red vertical line on the left side of my Philips LCD TV

This should be repairable. It may be the LVDS Cable or the Main board problem. The only other problem is the T-Con Board.

The LCD Panel is defective. You will need to replace the LCD Panel. It will probably be cheaper to replace the monitor since the LCD Panel may exceed the monitor cost.

Single lines of single color (red,green, blue) are LCD panel failures.

1 or 2 lines of single color are LCD Panel failures.

Multple color lines could be anything so in this case you start by checking the power circuit.