Why does my onn 50 inches tv screen flickers?

try changing picture size

If your LCD TV or monitor has stopped working, or is displaying one of the following symptoms, then it's a candidate for some new capacitors
- Flickering screen
- Screen image disappears after several seconds
- Dim screen
- Slow start
- Power LED on, but no picture
- Unusual colors and/or lines
The primary cause of LCD TV and monitor failure is caused by faulty capacitors. You can examine the capacitors in your LCD TV or monitor and actually see if they are bad.
If they appear bulged on top, then they need to be replaced.
New capacitors will solve a host of problems in LCD monitors and TV's and will extend the life of your monitor or TV by several years.
Check the cables, connectors and connections.
Take it to a repair shop.

You now have a 55" parts unit !!! A replacement 55" panel will most llikely cost as much as a new set !

screen is going bad which is why its flickering and has the lines across the screen. Theres a board behind the lcd and when that doesn't process the voltage properly it can cause the screen to flicker. White lines across the screen means the screen is going bad. At this point unless your monitor is under warranty, go ahead and replace it.

Hi,
It seems color wheel problem in your tv that gets problem after some time and you hear high pitch noise along with picture flicker.
Color wheel need to be replaced to solve this issue. Required color wheel is available with PartStore.com (click to view image of part and price info) and it is job of qualified tv repairman because light engine will take apart for that.
Hope these info will help you.
Thanks.

Set the screen format using your TV's menu. Do not set the format of the screen using your provider's receiver. I had this prob with a few channels with a dish provider when I set the format with the remote from the dish provider. I picked up the TV's remote, went into the menu, set the format, problem fixed.

This sounds like tiling. are you using a cable box?

The single line means that the vertical deflection doesn't work. And since it is working when you kick the tv or has warmed it's clearly a bad connection - open the case and reseat the wires going to the tube coil.

My color wheel went out on mine and it looks to be the same on yours'. RCA cannot find a replacement for my model and there are none available on an on-line search. RCA may end up replacing my set.

Your tv has a video problem, leak capacitor in video section, near in flyback need to replace it.