Samsung SDC-30 Service Manual

Contents

Precautions1-2 Samsung Electronics11. High voltage is maintained within specified limitsby close-tolerance, safety-related components andadjustments. If the high voltage exceeds thespecified limits, check each of the specialcomponents.12. Design Alteration Warning :Never alter or add to the mechanical or electricaldesign of this unit. Example : Do not addauxiliary audio or video connectors. Suchalterations might create a safety hazard. Also, anydesign changes or additions will void themanufacturer’s warranty.13. Hot Chassis Warning :Some TV receiver chassis are electricallyconnected directly to one conductor of the ACpower cord. If an isolation transformer is notused, these units may be safely serviced only ifthe AC power plug is inserted so that the chassisis connected to the ground side of the AC source.To confirm that the AC power plug is insertedcorrectly, do the following : Using an ACvoltmeter, measure the voltage between thechassis and a known earth ground. If the readingis greater than 1.0V, remove the AC power plug,reverse its polarity and reinsert. Re-measure thevoltage between the chassis and ground.14. Some TV chassis are designed to operate with 85volts AC between chassis and ground, regardlessof the AC plug polarity. These units can be safelyserviced only if an isolation transformer insertedbetween the receiver and the power source.15. Never defeat any of the B+ voltage interlocks.Do not apply AC power to the unit (or any of itsassemblies) unless all solid-state heat sinks arecorrectly installed.16. Always connect a test instrument’s ground lead tothe instrument chassis ground before connectingthe positive lead; always remove the instrument’sground lead last.17. Observe the original lead dress, especially nearthe following areas : Antenna wiring, sharpedges, and especially the AC and high voltagepower supplies. Always inspect for pinched, out-of-place, or frayed wiring. Do not change thespacing between components and the printedcircuit board. Check the AC power cord fordamage. Make sure that leads and componentsdo not touch thermally hot parts.18. Picture Tube Implosion Warning :The picture tube in this receiver employs“integral implosion” protection. To ensurecontinued implosion protection, make sure thatthe replacement picture tube is the same as theoriginal.19. Do not remove, install or handle the picture tubewithout first putting on shatterproof gogglesequipped with side shields. Never handle thepicture tube by its neck. Some “in-line” picturetubes are equipped with a permanently attacheddeflection yoke; do not try to remove such“permanently attached” yokes from the picturetube.20. Product Safety Notice :Some electrical and mechanical parts have specialsafety-related characteristics which might not beobvious from visual inspection. These safetyfeatures and the protection they give might belost if the replacement component differs from theoriginal--even if the replacement is rated forhigher voltage, wattage, etc.Components that are critical for safety areindicated in the circuit diagram by shading,( or ).Use replacement components that have the sameratings, especially for flame resistance anddielectric strength specifications. A replacementpart that does not have the same safetycharacteristics as the original might create shock,fire or other hazards.