SERVICING PRECAUTIONS
CAUTION : Before servicing the COMBI HOME THEATERElectrostatically Sensitive (ES) Devices
SYSTEM covered by this service data and its supplementsSome semiconductor (solid state) devices can be damaged
and addends, read and follow the SAFETY PRECAUTIONS.easily by static electricity. Such components commonly are
NOTE : if unforeseen circumstances create conflict betweencalled Electrostatically Sensitive (ES) Devices. Examples of
the following servicing precautions and any of the safety pre-typical ES devices are integrated circuits and some field
cautions in this publications, always follow the safety pre-effect transistors and semiconductor chip components.
cautions.The following techniques should be used to help reduce the
Remembers Safety First:incidence of component damage caused by static electricity.
General Servicing Precautions1. Immediately before handling any semiconductor compo-
1. Always unplug the COMBI HOME THEATER SYSTEM ACnent or semiconductor-equipped assembly, drain off any
power cord from the AC power source before:electrostatic charge on your body by touching a known
(1) Removing or reinstalling any component, circuit board, earth ground. Alternatively, obtain and wear a commer-
module, or any other assembly.cially available discharging wrist strap device, which
(2) Disconnection or reconnecting any internal electricalshould be removed for potential shock reasons prior to
plug or other electrical connection.applying power to the unit under test.
(3) Connecting a test substitute in parallel with an elec-
trolytic capacitor.2. After removing an electrical assembly equipped with ES
Caution : A wrong part substitution or incorrect devices, place the assembly on a conductive surface such
polarity installation of electrolytic capacitors may resultas aluminum foil, to prevent electrostatic charge buildup or
in an explosion hazard.exposure of the assembly.
2. Do not spray chemicals on or near this COMBI HOME3. Use only a grouned-tip soldering iron to solder or unsolder
THEATER SYSTEM or any of its assemblies.ES devices.
3. Unless specified otherwise in this service data, clean4. Use only an anti-static solder removal device. Some
electrical contacts by applying an appropriate contact solder removal devices not classified a Oanti-static� can
cleaning solution to the contacts with a pipe cleaner,generate electrical charges sufficient to damage ES
cotton-tipped swab, or comparable soft applicator.devices.
Unless specified otherwise in this service data, lubrication
of contacts is not required.5. Do not use freon-propelled chemicals. These can
generate electrical charge sufficient to damage ES
4. Do not defeat any plug/socket B+ voltage interlocks withdevices.
whitch instruments covered by this service manual might
be equipped.6. Do not remove a replacement ES device from its protec
tive package until immediately before you are ready to
5. Do not apply AC power to this COMBI HOME THEATERinstall it. (Most replacement ES devices are packaged with
SYSTEM and/or any of its electrical assemblies unless allleads electrically shorted together by conductive foam,
solid-state device heat sinks are cerrectly installed.aluminum foil, or comparable conductive material).
6. Always connect test instrument ground lead to the
appropriate ground before connection the test instrument7. Immediately before removing the protective material from
positive lead. Always remove the test instrument ground the leads of a replacement ES device, touch the protective
lead last.material to the chassis or circuit assembly into which the
device will be installed.
Insulation Checking Procedure
Disconnect the attachment plug from the AC outlet and turnCaution : Be sure no power is applied to the chassis or
the power on. Connect an insulation resistance meter(500V)circuit, and observe all other safety precautions.
to the blades of the attachment plug. The insulation resis-
tance between each blade of the attachment plug and acces-8. Minimize bodily motions when handling unpackaged
sible conductive parts (Note 1) should be more than 1M-replacement ES devices. (Normally harmless motion such
ohm.as the brushing together of your clothes fabric or the lifting
Note 1 : Accessible Conductive Parts including Metal pan-of your foot from a carpeted floor can generate static elec-
els, Input terminals, Earphone jacks, etc.tricity sufficient to damage an ES device.)
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ACEC
LG-GOLDSTAR
