Samsung LA46M81BX tv keeps on flickering on/off

hi, hope you’re all doing fine.

i have a Samsung LA46M81BX TV that i had since 2012.

but recently this last year it began to flicker and switch on/off multiple times until it displays “MODE NOT SUPPORTED”.

the only way to fix it for me is to either turn the tv off completely for at least a minute then back on OR by decreasing the backlight option to 3/10.

this also happens when choosing the “DYNAMIC” mode regardless of the backlight setting. but the standard and movie modes are ok.

i took it apart today and cleaned every part of it but cant see any visible damage or burns on any capacitor or IC. even the flat cables and connectors Looks good.

any idea what’s wrong with it or what to do to narrow the problem down?