Meshing around with my SL-C760 and looking for trasnlated Japanese sites, I found 2 more ways of accesing the Service menu and the Diagnostic menu.
AS you can see, the lat one (Fn+D+P) shows every option that is hidden in the others menus. I canīt take advantage of that information but Iīm sure somebody will . Probably it will work with the others models.
I didnīt still mesh around with the whole menus, but maybe it will bu usefull.