Sony KDL-40HX750 Service Training Manual page 10

CAUTIONS AND WARNINGS
HOW TO FIND A GOOD EARTH GROUND
The cover-plate retaining screw on most AC outlet boxes is at earth ground.
Verify the AC outlet box retaining screw ground by connecting a 60W to
100W incandescent (not a neon or fluorescent lamp) between the hot side of
the receptacle and the retaining screw. Try both slots, if necessary, to locate
the hot side on the line; the lamp should light at normal brilliance if the screw
is at ground potential. (see Figure B)
Trouble Light
AC Outlet Box
Figure B. Checking for earth ground.
KDL-40HX750/46HX750/46HX751/55HX750/55HX751 vii