Television Secret Code

For Sony TV:

First power off ur TV using remote, then Press + 5 + Vol Up + Power button simultaneously on remote. To save the changes, just press Mute + 0.

For LG TV:

Press and Hold button on remote as well as TV panel at the same time for a few minutes. To save the changes press in Remote.

PS: Be very careful while playing with the service menu. If something goes wrong, just swicth off the TV and switch on it again.