Samsung cea455 series Service Manual page 5

lodged between the chassis and other metal
parts in the display monitor.
2. Inspect all protective devices such as non-
metallic control knobs, insulating materials,
cabinet backs, adjustment and compartment
covers or shields,isolation resistor-capacitor net-
works, mechanical insulators,etc.
3. To be sure that no shock hazard exists,check
for leakage current in the following manner:
• Plug the AC line cord directly into a 120volt AC
outlet. (Do not use an isolation transformer for
this test)
• Using two clips leads, connect 1.5 kohm, 10 watt
resistor paralleled by a 1.5uF capacitor in series
with all exposed metal cabinet parts and a known
earth ground such as electrical conduit or
electrical ground connected to earth ground.
• Use a SSVM or YOM with 1000 ohms per-volt
or higher sensitivity to measure the AC voltage
drop across the resistor. (See Figure 1.)
• Connect the resistor to all exposed metal parts
having a return path to the chassis(metal cabinet,
screw heads, knobs and shafts,escutcheon,etc.)
and measure the AC voltage drop across the
resistor.
• Any reading of O.3volt RMS (this corresponds to
0.5milliamp.AC) or more is excessive and
indicates a potential shock hazard which must
be corrected before returning the display monitor
to the user.
SAFETY NOTICE
Many electrical and mechanical parts which have
special characteristics in this chassis often pass
unnoticed and the protection afforded by them
can not necessarily be obtained by using re-
placement components rated for higher volt-
age, wattage, etc.
Replacement parts that have these special safety
characteristics are identified in this manual,and
its supplement; electrical components having
such features are identified by a ! in the Parts
List and Schematic Diagrams.
Before replacing any of these components,read
the Parts List in this manual carefully. The use
of substitute replacement parts that do not have
the same safety characteristics as specified in
the Parts List may create shock, fire, or other
hazards.
-4-
AC
VOLllETER
1500
n
TO EXPOSED
METAL PARTS
TO KNJWEN
EARTH GROUND
FIG. 1 LEAKAGE CURRENT TEST CIRCUIT