Samsung SDC-30 Service Manual

Contents

Samsung Electronics 1-11. Precautions1. Be sure that all of the built-in protective devices arereplaced. Restore any missing protective shields.2. When reinstalling the chassis and its assemblies, besure to restore all pretective devices, including :control knobs and compartment covers.3. Make sure that there are no cabinet openingsthrough which people--particularly children--might insert fingers and contact dangerousvoltages. Such openings include the spacingbetween the picture tube and the cabinet mask,excessively wide cabinet ventilation slots, andimproperly fitted back covers.If the measured resistance is less than 1.0 megohmor greater than 5.2 megohms, an abnormality existsthat must be corrected before the unit is returnedto the customer.4. Leakage Current Hot Check (See Fig. 1) :Warning : Do not use an isolation transformerduring this test. Use a leakage current tester or ametering system that complies with AmericanNational Standards Institute (ANSI C101.1,Leakage Current for Appliances), and UnderwritersLaboratories (UL Publication UL1410, 59.7).5. With the unit completely reassembled, plug the ACline cord directly the power outlet. With the unit’sAC switch first in the ON position and then OFF,measure the current between a known erathground (metal water pipe, conduit, etc.) and allexposed metal parts, including : antennas, handlebrackets, metal cabinets, screwheads and controlshafts. The current measured should not exceed0.5 milliamp. Reverse the power-plug prongs in theAC outlet and repeat the test.6. X-ray Limits :The picture tube is designed to prohibit X-rayemissions. To ensure continued X-ray protection,replace the picture tube only with one that is thesame type as the original.Fig. 1 AC Leakage Test7. Antenna Cold Check :With the unit’s AC plug disconnected from theAC source, connect an electrical jumper across thetwo AC prongs. Connect one lead of the ohmmeterto an AC prong.Connect the other lead to the coaxial connector.8. High Voltage Limit :High voltage must be measured each timeservicing is done on the B+, horizontal deflectionor high voltage circuits.Heed the high voltage limits. These include theX-ray protection Specifications Label, and theProduct Safety and X-ray Warning Note on theservice data schematic.9. Some semiconductor (“solid state”) devices areeasily damaged by static electricity.Such components are called ElectrostaticallySensitive Devices (ESDs); examples includeintegrated circuits and some field-effect transistors.The following techniques will reduce theoccurrence of component damage caused by staticelectricity.10. Immediately before handling sny semiconductorcomponents or assemblies, drain the electrostaticcharge from your body by touching a knownearth ground. Alternatively, wear a dischargingWrist-strap device. (Be sure to remove it prior toapplying power--this is an electric shockprecaution.)DeviceUnderTest(Reading shouldnot be above0.5mA)LeakageCurrantTesterEarthGroundTest allexposed metalsurfacesAlso test withplug reversed(using AC adapterplug as required)2-Wire Cord