I just bought a 65 inch RCA 4k tv, what would cause flickering or flashing over top of the picture?

The back light and the LCD need to be replaced for the TV.Also I would try unpluging the wires to the TV and see if the problem stops.

return it

Sounds very like so. If you wish to get some details; check the site linked here. Pull up older posts.
http://electronicshelponline.blogspot.com/
https://elektrotricks.blogspot.com/
faults & possible causes to LCD screen are given with illustrations. You can get an idea about the fault to an extent. Search the site by type in the brand name and model of your set, in its search bar at the right side column, and press enter.

Check up power supply to your TV.( Stabilizer,TV Cord /Plug point )

Use the TV's picture mode control on the remote to change the aspect ratio.

Hi!


Check your power amp circuit. Or, check if it is feed by the power supply circuit. Good luck,


Serge.

If the picture on your TV flickers, there may be a simple fix. Here are some possible answers and suggested solutions:

1. Your set-top box may need a simple reboot. Unplug the power connection to the set-top box for about 30 seconds. Reconnect the power and turn the set-top box back on.

2. Check all of your cables for a loose connection by tightening each one with your fingers.Flickers can sometimes be caused by bends in rigid cables, too.

3. If your picture flickers to a black or blue screen, you could have a bad set-top box. Contact your cable or satellite service provider about installing a new one.

4. If you still have audio, the flickering could also mean that you have a failing backlight.

For additional troubleshooting information, check out the chart at TV flickering for more solutions. I hope this helps!

check signal-input connections.

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

I changed my lamp in the 65dr650 but the picture still looks like a black and white tv and flickers