Thanks for the reply Cade. There are honestly three different components that make up the processing for the video, and either of which could cause this problem.
I will try to explain this the best that I can here.
There are several things which could cause your problem. One is the Power Supply, the other is the T-Con (LCD
Timing controller), or the LCD panel itself has failed. The only one of these issues that is NOT repairable is a failed LCD panel.
If you're looking to repair the set yourself, the first thing you'd want to do is visually inspect the Power Supply Board for signs of any swollen, or leaking capacitors and replace any that you see which are exhibiting this failure OR replace the Power Supply Board if you don't want to solder.
Next, you would want to use a Multi Meter to measure all of the Power supply Outputs to make sure that none are dropped, or fluctuating (a sagging, or out of spec output rail can cause the problem you're having on your screen).
IF the Power Supply's Outputs are all proper, then the next thing you would move to is to replace the T-Con, this is the processor for the LCD panel and a failing T Con will also cause these problems.
The T Con is a very inexpensive board to replace, (usually around $60), and is not easily tested aside from replacing it to see if it cures the problem. If it does NOT, then your LCD panel itself has failed and is what is causing your problem. This would cost you almost as much as a new TV to replace it and the set would then be considered "Non-repairable".
This is the protocol with which we repair LCD TV
's, and without a Meter and the ability to measure live voltages, you can only go so far in terms of being able to isolate the problem and not "guessing" as to which board to replace.
If you don't want to go inside the set measuring voltages, or swapping boards, the bare minimum that this would cost to repair is $200, and can range up to having to replace the LCD panel which is fatal breakdown.
If you need further assistance let me know and please do not forget to rate my service accordingly.