I'm afraid this doesn't sound good...
I'm guessing these lines are there regardless of which input you select or what screen format you select, correct?
And these lines never move from one part of the screen to another, they are always in the exact same position, correct?
I wish I had better news for you, but if those lines show up in exactly the same place every time on all inputs and formats, the problem is the actual panel (the screen) itself.
Unless this is under warranty, this is going to be a major expense to fix, and is precisely why I urge anyone who buys a current technology HDTV to get an extended warranty. All of these TV's, regardless of whether it's plasma, LCD, or rear projection, have large and expensive assemblies that cannot be fixed, and must be replaced.
Definitely get an estimate from a tech, but be prepared for a real shocker.
Let me know if there's anything else I can do for you, and thanks for using JustAnswer!
Actually that does sound better, but no, it's not the power supply.
When this problem is happening, are you saying there is no picture at all, just these lines?
The next time this happens (and I guess it happens every time you turn the set on), press the TV's MENU button (not a cable box menu, but the TV menu). Does the menu come on screen, and if so, are the lines obstructing the menu?
And thanks for the Accept!
And when it starts working, everythihng is fine for the rest opf the time the set is on? If you turn the set off then immediately back on, is it still OK?
But if you just turn it on, it acts up, but then will always correct itself?
If it's cold, can you sometimes repeatedly turn it off and on and get it to work or must it always be warm?
Well, then it still sounds like it could be the screen, but there is a possibility thyat the problem is the digital main board, and there's really no easy way for you to tell.
There are basically 3 things in an LCD TV: the Power Supply, the Digital Main circuit board, and the actual LCD screen itself. The power supply isn't suspect because the set comes on, responds to commands, and otherwise works.
But the Digital Main and the screen have elaborate handshaking and communication that has to continually happen, and if one or the other interrupts this, then there are all sorts of picture problems that can happen. But that's also why I asked about the TV's menu, because if it looks OK, then the screen is obviously not at fault.
But if it has to warm to start working, the backlight in the screen will warm up the screen the longer it's on, so that makes the screen suspect, but there are also components on the Digital Main that get normally warm, too, so that complicates it.
If you are comfortable opening the set, I do have one test that may isolate this to the screen or the DM, and it involves "circuit cooling" spray (I think you can get this at any Radio Shack, but I can also tell you where to order it on line). And what you do is simply wait for the set to start working, turn it off, then spray this coolant on the DM board, turn it on, and see if the set comes right back on (because the screen is still warm) or if it's back to lines.
Let me know if you'd like to try that.
Otherwise, of course, you'd have to get a tech involved.
No, this definitely will not fix it, it will just tell you whether or not it's the screen (probably dump the TV) or whether it's this board (worth fixing).