TV Samsung 40" LE40a330j1XXH - flickering on 60hz ? 50hz clear completely

[dsr07mm]

So I have this issue, couple weeks ago I bought TV Samsung 40" LE40a330j1XXH (not new), it was perfect until I realized that on dark colours (STATIC picture) as dark grey (mostly), you can see some sort of flickering with horizontal lines, in movies/games anything which movies it can't be noticable really. Since I've been using TV via HDMI to watch content from my LapTop, I tried lowering refresh rate to 50Hz and flickering was gone COMPLETELY. Sure you could see some sort of screen tearing due to fact that its lowered to 50Hz but for video and multimedia content it was perfectly fine.

Now I bought PS4, I wanna game on very same TV, picture and colours are outstanding for my taste BUT, console works at 60hz by default and there is no option to lower that. It's same thing, visible only on dark grey parts if picture is static.

What I find interesting is that if I put backlight to 10 (maximum), flickering is gone completely, also if I lower to 1 or 2 its gone again (but its too dark), so my question would be can something happen to TV on longer stage if I keep using backlight option at 7 ? Since that is perfectly fine for my eyes and ignore that flickering ?

Not sure what to do, I love this TV.

 

[dsr07mm]

Any idea ?

I changed VGA/HDMI cables, other power outlet and other things.

Literally only 50hz instead 60hz solves the problem, or putting backlight either on maximum 10, or minimum 0-1-2, while 3-4-5-6-7-8-9 create that weird effect on static background colour.