SAMSUNG DIGIMAX MS15 Precaution

Samsung Electronics 1-1

1. Precautions

1-1 Safety Precautions

1) Before returning an instrument to the customer,
always make a safety check of the entire instrument,
including, but not limited to, the following items:

(1) Be sure that no built-in protective devices are

defective or have been defeated during servicing.
(1)Protective shields are provided to protect both
the technician and the customer. Correctly replace
all missing protective shields, including any
removed for servicing convenience.
(2)When reinstalling the chassis and/or other as­sembly in the cabinet, be sure to put back in place
all protective devices, including, but not limited to,
nonmetallic control knobs, insulating fish papers,
adjustment and compartment covers/shields, and
isolation resistor/capacitor networks. Do not oper­ate this instrument or permit it to be operated with­out all protective devices correctly installed and
functioning.

(2) Be sure that there are no cabinet openings through

which adults or children might be able to insert
their fingers and contact a hazardous voltage. Such
openings include, but are not limited to, excessive­ly wide cabinet ventilation slots, and an improper­ly fitted and/or incorrectly secured cabinet back
cover.

(3) Leakage Current Hot Check-With the instrument

completely reassembled, plug the AC line cord
directly into a 230V(220V ~ 240V) AC outlet. (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)
1270 (40.7). With the instrument’s AC switch first in
the ON position and then in the OFF position, mea­sure from a known earth ground (metal water pipe,
conduit, etc.) to all exposed metal parts of the
instrument (antennas, handle brackets, metal cabi­nets, screwheads, metallic overlays, control shafts,
etc.), especially any exposed metal parts that offer
an electrical return path to the chassis.

Any current measured must not exceed 0.5mA.
Reverse the instrument power cord plug in the out­let and repeat the test. See Fig. 1-1.

Any measurements not within the limits specified
herein indicate a potential shock hazard that must
be eliminated before returning the instrument to
the customer.

Fig. 1-1 AC Leakage Test

(4) Insulation Resistance Test Cold Check-(1) Unplug

the power supply cord and connect a jumper wire
between the two prongs of the plug. (2) Turn on the
power switch of the instrument. (3) Measure the
resistance with an ohmmeter between the
jumpered AC plug and all exposed metallic cabinet
parts on the instrument, such as screwheads,
antenna, control shafts, handle brackets, etc. When
an exposed metallic part has a return path to the
chassis, the reading should be between 1 and 5.2
megohm. When there is no return path to the chas­sis, the reading must be infinite. If the reading is
not within the limits specified, there is the possibil­ity of a shock hazard, and the instrument must be
repaired and rechecked before it is returned to the
customer. See Fig. 1-2.

Fig. 1-2 Insulation Resistance Test

LEAKAGE
CURRENT

TESTER

(READING SHOULD

NOT BE ABOVE

0.5mA)

EARTH

GROUND

DEVICE
UNDER

TEST

TEST ALL

EXPOSED METER

SURFACES

2-WIRE CORD

ALSO TEST WITH

PLUG REVERSED

(USING AC ADAPTER

PLUG AS REQUIRED)

Antenna
Terminal

Exposed
Metal Part

ohm

ohmmeter

Precautions

1-2 Samsung Electronics

2) Read and comply with all caution and safety re­lated notes on or inside the cabinet, or on the chas­sis.

3) Design Alteration Warning-Do not alter or add to
the mechanical or electrical design of this instru­ment. Design alterations and additions, including
but not limited to, circuit modifications and the
addition of items such as auxiliary audio output
connections, might alter the safety characteristics of
this instrument and create a hazard to the user. Any
design alterations or additions will make you, the
servicer, responsible for personal injury or property
damage resulting therefrom.

4) Observe original lead dress. Take extra care to
assure correct lead dress in the following areas:
(1) near sharp edges, (2) near thermally hot parts (be
sure that leads and components do not touch ther­mally hot parts), (3) the AC supply, (4) high voltage,
and (5) antenna wiring. Always inspect in all areas
for pinched, out-of-place, or frayed wiring, Do not
change spacing between a component and the
printed-circuit board. Check the AC power cord for
damage.

5) Components, parts, and/or wiring that appear to
have overheated or that are otherwise damaged
should be replaced with components, parts and/ or
wiring that meet original specifications.
Additionally, determine the cause of overheating
and/or damage and, if necessary, take corrective
action to remove any potential safety hazard.

6) Product Safety Notice-Some electrical and mechani­cal parts have special safety-related characteristics
which are often not evident from visual inspection,
nor can the protection they give necessarily be
obtained by replacing them with components rated
for higher voltage, wattage, etc. Parts that have spe­cial safety characteristics are identified by shading,
an ( )or a ( )on schematics and parts lists. Use
of 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.

Precautions

Samsung Electronics 1-3

1-2 Servicing Precautions

CAUTION : Before servicing units covered by this
service manual and its supplements, read and follow
the Safety Precautions section of this manual.

Note : If unforseen circumstances create conflict
between the following servicing precautions and any
of the safety precautions, always follow the safety pre­cautions. Remember: Safety First.

1-2-1 General Servicing Precautions

(1) a. Always unplug the instrument’s AC power cord

from the AC power source before (1) re-moving
or reinstalling any component, circuit board,
module or any other instrument assembly, (2)
disconnecting any instrument electrical plug or
other electrical connection, (3) connecting a test
substitute in parallel with an electrolytic capaci­tor in the instrument.

b. Do not defeat any plug/socket B+ voltage inter-

locks with which instruments covered by this
service manual might be equipped.

c. Do not apply AC power to this instrument and

/or any of its electrical assemblies unless all
solid-state device heat sinks are correctly in­stalled.

d. Always connect a test instrument’s ground lead

to the instrument chassis ground before connect­ing the test instrument positive lead. Always
remove the test instrument ground lead last.

Note : Refer to the Safety Precautions section ground
lead last.

(2) The service precautions are indicated or printed on

the cabinet, chassis or components. When servic­ing, follow the printed or indicated service precau­tions and service materials.

(3) The components used in the unit have a specified

flame resistance and dielectric strength.
When replacing components, use components
which have the same ratings. Components identi­fied by shading, by( ) or by ( ) in the circuit dia­gram are important for safety or for the characteris­tics of the unit. Always replace them with the exact
replacement components.

(4) An insulation tube or tape is sometimes used and

some components are raised above the printed
wiring board for safety. The internal wiring is
sometimes clamped to prevent contact with heat­ing components. Install such elements as they
were.

(5) After servicing, always check that the removed

screws, components, and wiring have been in­stalled correctly and that the portion around the
serviced part has not been damaged and so on.
Further, check the insulation between the blades of
the attachment plug and accessible conductive
parts.

1-2-2 Insulation Checking Procedure

Disconnect the attachment plug from the AC outlet
and turn the power ON. Connect the insulation resi­stance meter (500V) to the blades of the attachment
plug. The insulation resistance between each blade of
the attachment plug and accessible conductive
parts(see note) should be more than 1 Megohm.

Note : Accessible conductive parts include metal pan­els, input terminals, earphone jacks, etc.

Precautions

1-4 Samsung Electronics

1-3 ESD Precautions

Electrostatically Sensitive Devices (ESD)

Some semiconductor (solid state) devices can be dam­aged easily by static electricity.
Such components commonly are called Electrostati­cally Sensitive Devices(ESD). Examples of typical ESD
devices are integrated circuits and some field-effect
transistors and semiconductor chip components. The
following techniques should be used to help reduce
the incidence of component damage caused by static
electricity.

(1) Immediately before handling any semiconductor

component or semiconductor-equipped assembly,
drain off any electrostatic charge on your body by
touching a known earth ground. Alternatively,
obtain and wear a commercially available dis­charging wrist strap device, which should be
removed for potential shock reasons prior to apply­ing power to the unit under test.

(2) After removing an electrical assembly equipped

with ESD devices, place the assembly on a conduc­tive surface such as aluminum foil, to prevent elec­trostatic charge buildup or exposure of the assem­bly.

(3) Use only a grounded-tip soldering iron to solder or

unsolder ESD devices.

(4) Use only an anti-static solder removal devices.

Some solder removal devices not classified as
“anti-static” can generate electrical charges suffi­cient to damage ESD devices.

(5) Do not use freon-propelled chemicals. These can

generate electrical charges sufficient to damage
ESD devices.

(6) Do not remove a replacement ESD device from its

protective package until immediately before your
are ready to install it.(Most replacement ESD
devices are packaged with leads electrically short­ed together by conductive foam, aluminum foil or
comparable conductive materials).

(7) Immediately before removing the protective ma-

terials from the leads of a replacement ESD device,
touch the protective material to the chassis or cir­cuit assembly into which the device will be
installed.

CAUTION : Be sure no power is applied to the ch­assis or circuit, and observe all other safety precau­tions.

(8) Minimize bodily motions when handling unpack-

aged replacement ESD devices. (Otherwise harm­less motion such as the brushing together of your
clothes fabric or the lifting of your foot from a car­peted floor can generate static electricity sufficient
to damage an ESD device).