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2 SAFETY PRECAUTIONS
GENERAL GUIDELINES
1. IMPORTANT SAFETY NOTICE
There are special components used in this equipment
which are important for safety. These parts are marked by
which are important for safety. These parts are marked by
in the Schematic Diagrams, Circuit Board Layout,
Exploded Views and Replacement Parts List. It is essential
that
that
these
critical
parts
should
be
replaced
with
manufacturer’s specified parts to prevent, shock, fire, or
other hazards. Do not modify the original design without
permission of manufacturer.
other hazards. Do not modify the original design without
permission of manufacturer.
2. An Isolation Transformer should always be used during the
servicing of AC Adaptor whose chassis is not isolated from
the AC power line. Use a transformer of adequate power
rating as this protects the technician from accidents
resulting in personal injury from electrical shocks. It will also
protect AC Adaptor from being damaged by accidental
shorting that may occur during servicing.
the AC power line. Use a transformer of adequate power
rating as this protects the technician from accidents
resulting in personal injury from electrical shocks. It will also
protect AC Adaptor from being damaged by accidental
shorting that may occur during servicing.
3. When servicing, observe the original lead dress. If a short
circuit is found, replace all parts which have been
overheated or damaged by the short circuit.
overheated or damaged by the short circuit.
4. After servicing, see to it that all the protective devices such
as insulation barriers, insulation papers shields are properly
installed.
installed.
5. After servicing, make the following leakage current checks
to prevent the customer from being exposed to shock
hazards.
hazards.
LEAKAGE CURRENT COLD CHECK
1. Unplug the AC cord and connect a jumper between the two
prongs on the plug.
2. Measure the resistance value, with an ohmmeter, between
the jumpered AC plug and each exposed metallic cabinet
part on the equipment such as screwheads, connectors,
control shafts, etc. When the exposed metallic part has a
return path to the chassis, the reading should be between 1
M
part on the equipment such as screwheads, connectors,
control shafts, etc. When the exposed metallic part has a
return path to the chassis, the reading should be between 1
M
Ω
and 5.2 M
Ω
. When the exposed metal does not have a
return path to the chassis, the reading must be infinity.
LEAKAGE CURRENT HOT CHECK
(See Figure 1.)
1. Plug the AC cord directly into the AC outlet. Do not use an
isolation transformer for this check.
2. Connect a 1.5 k
Ω
, 10 W resistor, in parallel with a 0.15 µF
capacitor, between each exposed metallic part on the set
and a good earth ground, as shown in Figure 1.
and a good earth ground, as shown in Figure 1.
3. Use an AC voltmeter, with 1 k
Ω
/V or more sensitivity, to
measure the potential across the resistor.
4. Check each exposed metallic part, and measure the
voltage at each point.
5. Reverse the AC plug in the AC outlet and repeat each of the
above measurements.
6. The potential at any point should not exceed 0.75 V RMS.
A leakage current tester (Simpson Model 229 or equivalent)
may be used to make the hot checks, leakage current must
not exceed 1/2 mA. In case a measurement is outside of
the limits specified, there is a possibility of a shock hazard,
and the equipment should be repaired and rechecked
before it is returned to the customer.
may be used to make the hot checks, leakage current must
not exceed 1/2 mA. In case a measurement is outside of
the limits specified, there is a possibility of a shock hazard,
and the equipment should be repaired and rechecked
before it is returned to the customer.
Figure. 1
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NV-GS6EE NV-GS6GC
3 PREVENTION OF
ELECTRO STATIC
DISCHARGE (ESD) TO
ELECTROSTATICALLY
SENSITIVE (ES) DEVICES
DISCHARGE (ESD) TO
ELECTROSTATICALLY
SENSITIVE (ES) DEVICES
Some semiconductor (solid state) devices can be damaged
easily by static electricity. Such components commonly are
called Electrostatically Sensitive (ES) Devices. Examples of
typical ES devices are integrated circuits and some field-effect
transistors
easily by static electricity. Such components commonly are
called Electrostatically Sensitive (ES) Devices. Examples of
typical ES 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 electro static
discharge (ESD).
incidence of component damage caused by electro static
discharge (ESD).
1. Immediately
before
handling
any
semiconductor
component or semiconductor-equipped assembly, drain off
any ESD on your body by touching a known earth ground.
Alternatively, obtain and wear a commercially available
discharging ESD wrist strap, which should be removed for
potential shock reasons prior to applying power to the unit
under test.
any ESD on your body by touching a known earth ground.
Alternatively, obtain and wear a commercially available
discharging ESD wrist strap, 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 ES
devices, place the assembly on a conductive surface such
as aluminum foil, to prevent electrostatic charge buildup or
exposure of the assembly.
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
ES devices.
4. Use only an antistatic solder removal device. Some solder
removal
devices
not
classified
as
"antistatic
(ESD
protected)" can generate electrical charge sufficient to
damage ES devices.
damage ES devices.
5. Do not use freon-propelled chemicals. These can generate
electrical charges sufficient to damage ES devices.
6. Do not remove a replacement ES device from its protective
package until immediately before you are ready to install it.
(Most replacement ES devices are packaged with leads
electrically shorted together by conductive foam, aluminum
foil or comparable conductive material).
(Most replacement ES devices are packaged with leads
electrically shorted together by conductive foam, aluminum
foil or comparable conductive material).
7. Immediately before removing the protective material from
the leads of a replacement ES device, touch the protective
material to the chassis or circuit assembly into which the
device will be installed.
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.
observe all other safety precautions.
8. Minimize
bodily
motions
when
handling
unpackaged
replacement ES 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 (ESD) sufficient to damage an ES device).
as the brushing together of your clothes fabric or the lifting
of your foot from a carpeted floor can generate static
electricity (ESD) sufficient to damage an ES device).
4 ABOUT LEAD FREE
SOLDER (PbF)
Distinction of PbF PCB:
PCBs (manufactured) using lead free solder will have a PbF
stamp on the PCB.
stamp on the PCB.
Caution:
·
Pb free solder has a higher melting point than standard
solder; Typically the melting point is 50-70°F (30-40°C)
higher.
solder; Typically the melting point is 50-70°F (30-40°C)
higher.
Please use a high temperature soldering iron. In case of
the soldering iron with temperature control, please set it
to 700±20°F (370±10°C).
the soldering iron with temperature control, please set it
to 700±20°F (370±10°C).
·
Pb free solder will tend to splash when heated too high
(about 1100°F/600°C).
(about 1100°F/600°C).
When soldering or unsoldering, please completely remove all
of the solder on the pins or solder area, and be sure to heat the
soldering points with the Pb free solder until it melts enough.
of the solder on the pins or solder area, and be sure to heat the
soldering points with the Pb free solder until it melts enough.
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NV-GS6EE NV-GS6GC
5 OPERATION GUIDE
Followings are the Operation Guide for NV-GS35EB/21EB/17EB as a sample.
For other models, refer to each original Operation Guide.
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NV-GS6EE NV-GS6GC
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NV-GS6EE NV-GS6GC
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