akira VCR-S208, Руководство по обслуживанию, Страница: 6 / 54

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Model No.: VCR-S208
Version: 1.0
PRECAUTIONS
1. Be sure that all of the built-in protective devices are replaced. Restore any missing protective
shields.
2. When reinstalling the chassis and its assemblies, be sure to restore all protective devices, including:
control knobs and compartment covers.
3. Make sure that there are no cabinet openings through which people--particularly children --might
insert fingers and contact dangerous voltages. Such openings include the spacing between the
picture tube and the cabinet mask, excessively wide cabinet ventilation slots, and improperly fitted
back covers.
If the measured resistance is less than 1.0 megohm or greater than 5.2 megohms, an abnormality
exists that must be corrected before the unit is returned to the customer.
4 Leakage Current Hot Check (See Fig. 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).
5 With the unit completely reassembled, plug the AC line cord directly the power 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: antennas, handle
brackets, metal cabinets, screw heads 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.
6 X-ray Limits:
The picture tube is designed to prohibit X-ray emissions. To ensure continued X-ray protection,
replace the picture tube only with one that is the same type as the original.
7 Antenna Cold Check:
With the unit’s AC plug disconnected from the AC source, connect an electrical jumper across the
two AC prongs. Connect one lead of the ohmmeter to an AC prong. Connect the other lead to the
coaxial connector.
8 High Voltage Limit:
High voltage must be measured each time servicing is done on the B+, horizontal deflection or high
voltage circuits. Heed the high voltage limits. These include the X-ray protection Specifications
Label, and the Product Safety and X-ray Warning Note on the service data schematic.
9. Some semiconductor (“solid state”) devices are easily damaged by static electricity. Such
components are called Electrostatically Sensitive Devices (ESDs); examples include integrated
circuits and some field-effect transistors. The following techniques will reduce the occurrence of
component damage caused by static electricity.
10. Immediately before handling any semiconductor components or assemblies, drain the electrostatic
charge from your body by touching a known earth ground. Alternatively, wear a discharging
Wrist-strap device. (Be sure to remove it prior to applying power--this is an electric shock
precaution.)