If you wish to get some details, check the site linked here.
http://electronicshelponline.blogspot.com/ Pull up older posts. Service mode entry, adjust and exit procedure to many popular brand TVs are given. Before entering service mode, a close look at the procedure is necessary, because, you have to exit from the service mode, after entry. In service mode, a few buttons on the front panel of the TV, and remote controls will only operatabe. If you want to operate all the button function, as it was, have to exit this mode.