The accepted norm is "stay out of the service menu" unless directed by the maker. Now it is your set but the story so far is that this menu is undocumented as well as "where there be dragons" issues.
One wrong move and folk have had to replace a mainboard or get a service call.
I'd find out if there is a way to solve your issues without a trip to the service menu.
I have 48” Samsung smart tv. Model UA48H6400AR
Last time to enable Bluetooth headphones I entered and changed options in service menu.
Some figured changed I presumed. When I watch Programmes from u tube, USB, HDMI my picture quality is excellent, but when I watch aerial tv (not set up box) picture too dark to watch. Changed eco settings but no luck. I checked the cable with other tv & result good. I need to changed my default settings in service mode. Can anyone help me.