Samsung CKA4217, CKA5227 Precautions

1-1-1 Warnings

1. For continued safety, do not attempt to
modify the circuit board.

2. Disconnect the AC power before servicing.

3. When the chassis is operating, semiconductor
heatsinks are potential shock hazards.

1-1-2 Servicing the High Voltage System and

CRT

WARNING: Empty or damaged E2PROM may

cause excessive x-ray emissions.

Caution: When replacing the E2PROM, IC203 a

high voltage step must be adjusted
until high voltage becomes 24.5 kV.
Standard dump from Softjig does
this.

1. When servicing the high voltage system,
remove the static charge by connecting a 10k
ohm resistor in series with an insulated wire
(such as a test probe) between the chassis and
the anode lead. (Disconnect the AC line cord
from the AC outlet.)

2. High Voltage Adjustment
This monitor does not need to adjust high
voltage, standard dump from Softjig
automatically adjust the high voltage to

24.5kV.

3. It is essential that service technicians have an
accurate high voltage meter available at all
times. Check the calibration of this meter
periodically.

4. When troubleshooting a monitor with
excessively high voltage, avoid being
unnecessarily close to the monitor. Do not
operate the monitor for longer than is
necessary to locate the cause of excessive
voltage.

5. High voltage should always be kept at the
rated value, no higher. Be sure all service
personnel are aware of the procedures and
instructions covering X-rays.

The only potential source of X-ray in current
solid state display monitors is the tube.
However, the CRT does not emit measurable
X-ray radiation if the high voltage is at the
high voltage adjustment value.

Only when high voltage is excessive are
X-rays capable of penetrating the shell of the
CRT, including the lead in glass material.
Operation at high voltages may also cause
failure of the CRT or high voltage circuitry.

6. When the high voltage regulator is operating
properly, there is no possibility of an X-ray
problem. Test the brightness and use a meter
to monitor the high voltage each time a color
monitor comes in for service. Make sure the
high voltage does not exceed its specified
value and that it is regulating correctly.

7. The CRT is especially designed to prohibit
X-ray emissions. To ensure continued X-ray
protection, replace the CRT with only one that
is the same or equivalent type as the original.
Carefully reinstall the CRT shields and
mounting hardware; these also provide X-ray
protection.

8. Handle the CRT only when wearing
shatterproof goggles and after completely
discharging the high voltage anode.

9. Do not lift the CRT by the neck.

CKA42*7L/5227L 1-1

1 Precautions

Follow these safety, servicing and ESD precautions to prevent damage and to protect against potential
hazards such as electrical shock and X-rays.

1-1 Safety Precautions

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.

Figure1-1. Leakage Current Test Circuit

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).

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 schmatics
and parts lists. Asubstitute 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.

Components identified by on schematics and
parts lists must be sealed by a soldering iron after
replacement and adjustment.

1 Precautions

1-2 CKA42*7L/5227L

DEVICE
UNDER
TEST

TEST ALL

EXPOSED METAL

SURFACES

(READING SHOULD

NOT BE ABOVE 0.5mA)

LEAKAGE
CURRENT

TESTER

2-WIRE CORD

ALSO TEST WITH

PLUG REVERSED
(USING AC ADAPTER
PLUG AS REQUIRED)

EARTH

GROUND

!