Precautions - Samsung 910N Service Manual

1 Precautions

Follow these safety, servicing and ESD precautions to prevent damage and to protect against potential hazards such as
electrical shock.
1-1 Safety Precautions
1-1-1 Warnings
1. For continued safety, do not attempt to modify the
circuit board.
2. Disconnect the AC power and DC power jack
before servicing.
1-1-2 Servicing the LCD Monitor
1. When servicing the LCD Monitor, Disconnect the
AC line cord from the AC outlet.
2. It is essential that service technicians have an
accurate voltage meter available at all times. Check
the calibration of this meter periodically.
1-1-3 Fire and Shock Hazard
Before returning the monitor to the user, perform the
following safety checks:
1. Inspect each lead dress to make certain that the
leads are not pinched or that hardware is not
lodged between the chassis and other metal parts in
the monitor.
2. Inspect all protective devices such as nonmetallic
control knobs, insulating materials, cabinet backs,
adjustment and compartment covers or shields,
isolation resistor-capacitor networks, mechanical
insulators, etc.
3. Leakage Current Hot Check (Figure 1-1):
WARNING:
Do not use an isolation transformer during this test.
Use a leakage current tester or a metering system
that complies with American National Standards
Institute (ANSI C101.1, Leakage Current for
Appliances), and Underwriters Laboratories (UL
Publication UL1410, 59.7).
MJ15AS*/MJ17AS*/MJ19AS*/
MJ15BS*/MJ17BS*/MJ19BS*
DEVICE
UNDER
TEST
TEST ALL
EXPOSED METAL
SURFACES
2-WIRE CORD
*ALSO TEST WITH
PLUG REVERSED
(USING AC ADAPTER
PLUG AS REQUIRED)
Figure 1-1. Leakage Current Test Circuit
4. With the unit completely reassembled, plug the AC
line cord directly into a 120V AC outlet. With the
unit's AC switch first in the ON position and then
OFF, measure the current between a known earth
ground (metal water pipe, conduit, etc.) and all
exposed metal parts, including: metal cabinets,
screwheads and control shafts. The current
measured should not exceed 0.5 milliamp. Reverse
the power-plug prongs in the AC outlet and repeat
the test.
1-1-4 Product Safety Notices
Some electrical and mechanical parts have special
safety-related characteristics which are often not
evident from visual inspection. The protection they give
may not be obtained by replacing them with
components rated for higher voltage, wattage, etc. Parts
that have special safety characteristics are identified by
on schematics and parts lists. A substitute
!
replacement that does not have the same safety
characteristics as the recommended replacement part
might create shock, fire and/or other hazards. Product
safety is under review continuously and new
instructions are issued whenever appropriate.
(READING SHOULD
NOT BE ABOVE 0.5mA)
LEAKAGE
CURRENT
TESTER
EARTH
GROUND
1-1