Схема телевизора Samsung SCT53A chassis

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1. Precautions
1-1 Safety Precautions
1. Be sure that all of the built-in protective
devices are replaced. Restore any missingprotective shields.
2. When reinstalling the chassis and its
assemblies, be sure to restore all protectivedevices, including: nonmetallic control knobsand compartment covers.
3. Make sure that there are no cabinet openings
through which people?particularly children?might insert fingers and contactdangerous voltages. Such openings includethe spacing between the picture tube and thecabinet mask, excessively wide cabinet
ventilation slots, and improperly fitted back
If the measured resistance is less than 1.0megohm or greater than 5.2 megohms, anabnormality exists that must be correctedbefore the unit is returned to the customer.
4. 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 StandardsInstitute (ANIS C101.1, Leakage Current forAppliances), and Underwriters Laboratories(UL Publication UL1410, 59.7).
5. With the unit completely reassembled, plug
the AC line cord directly into the power outlet. With the unit?s AC switch first in theON position and then OFF, measure the current between a known earth ground (metalwater pipe, conduit, etc.) and all exposedmetal parts, including: antennas, handlebrackets, metal cabinets, screwheads and control shafts. The current measured shouldnot exceed 0.5 milliamp. Reverse the power-plug prongs in the AC outlet and repeat thetest.
Fig. 1-1 AC Leakage Test
6. Antenna Cold Check:
With the unit?s AC plug disconnected from theAC source, connect an electrical jumper acrossthe two AC prongs. Connect one lead of theohmmeter to an AC prong. Connect the otherlead to the coaxial connector.
7. X-ray Limits:
The picture tube is especially designed to pro-hibit X-ray emissions. To ensure continued X-ray protection, replace the picture tube onlywith one that is the same type as the original.Carefully reinstall the picture tube shields andmounting hardware; these also provide X-rayprotection.
8. High Voltage Limits:
High voltage must be measured each time ser-vicing is done on the B+, horizontal deflectionor high voltage circuits. Correct operation ofthe X-ray protection circuits must be reconfirmed whenever they are serviced.
(X-ray protection circuits also may be called
?horizontal disable? or ?hold-down?.)
Heed the high voltage limits. These includethe X?ray Protection Specifications Label, andthe Product Safety and X-ray Warning Note onthe service data schematic.
Precautions
Samsung Electronics
DEVICEUNDER
EXPOSED METAL
2-WIRE CORD
ALSO TEST WITH
PLUG REVERSED
(USING AC ADAPTER
PLUG AS REQUIRED)
(READING SHOULD
NOT BE ABOVE
Follow these safety, servicing and ESD precautions to prevent damage and protect against potentialhazards such as electrical shock and X-rays.