DAEWOO DTH29U9FSA
Service Manual

Improtant Service Notes

PRODUCT SAFETY SERVICING GUIDELINES FOR AUDIO - VIDEO PRODUCTS
CAUTION : Do not attempt to modify this product in any way Unauthorized modifications will not only void the warranty, but may lead to your being liable for any resulting property damage or user Injury. Service work should be performed only afters you are thoroughly familiar with all of the following safety checks and servicing guidelines. To do otherwise, increases the risk of potential hazards injury to the user. SAFETY CHECKS After the original service problem has been corrected, a check should be made of the following : SUBJECT FIRE & SHOCK HAZARD 1. Be sure that all components are positioned in such a way as to avoid possibility of adjacent component shorts. This is especially important on those chassis which are transported to and from the repair shop. 2. Never release a repair unless all protective devices such as Insulators, barriers, covers, shields, strein reliefs, and other hardware have been reinstalled per original design. 3. Soldering must be inspected to discover possible cold solder joints frayed leads, damaged insulation (Including A.C. cord), solder splashes or sharp solder points. Be certain to remove all loose foreign particals. 4. Check for physical evidence of damage or deterioration to parts and components, and replace if necessary follow original layout, lead length and dress. 5. No leads or components should touch a receiving tube or a resistor rated at 1 watt or more. Lead tension around protruding metalsurfaces must be avoided. 6. All critical components such as fuses, flameproof resistors, capacitor, etc must be replaced with exact factory types. Do not use replacement components other than those specified or make unrecommended circuit modifications. 7. After re-assembly of the set always perform an A.C. leakage test on all exposed metallic parts of the cabinet, (the channel selector knob, antenna terminals, handle and screws) to be sure the set is safe to operate without danger of electrical shock. Do not use a line Isolation transformer during this test. Use an A.C voltmeter, having 5000 ohms per volt or more sensitivity, in the following manner : connect a 1500 ohm 10 watt resistor, paralleled by a 15 mfd. 150V A.C. type capacitor between a known good earth ground ( 9 water pipe, conduit, etc ) and the exposed metallic parts, one at a time. Measure the A.C. voltage across the combination of 1500 ohm resistor and 0.15 MFD capacitor. Reverse the A.C plug and repeat A.C. voltage measurements for each exposed metallic part. Voltage measured must not exceed 0.75 volts R.M.S. This corresponds to 0.5 milliamp A.C. Any value exceeding this limit constitutes a potential shock hazard and must be corrected immediately Fuse symbol is printed on pcb adjacent to the fuse, with "RISK OF FIRE REPLACE FUSE AS MARKED". The symbol is explained in the service manual with the following wording or equivalent. "CAUTION : FOR CONTINUED PROTECTION AGAINST FIRE HAZARD, REPLACE ONLY WITH SAME TYPE (6.3A, 250V)" and "ATTENTION : AFIN D'ASSU UNE PROTECTION PERMANENTE CONTRE LES RISQUES D'INCENDIE, REMPLACER UNIQUEMENT PAR UN FUSIBLE DE MEME TYPE ET DE "6.3A, 250V". SUBJECT : X-RADIATION 1. Be sure procedures and instructions to all service personnel cover the subject of X-rays in current T.V receivers is the picture tube. However, this tube does not emit X-rays when the high voltage is at the factory specified level. The proper value is given in the applicable schematic. Operation at higher voltages may cause a failure of the picture tube or high voltage supply and, under certain circumstances, may produce radiation in excess of desirable levels. 2. Only factory specified C.R.T anode connectors must be used. Degaussing shields also serve as X-ray shield in color sets. Always re-install them. 3. It is essential that the serviceman has available an accurate and reliable high voltage meter. The calibration of the meter should be checked perio - dically against a reference standard. Such as the one available at your distributor. 4. When the high voltage circuitry is operating properly there is no possibility of an X-radiation problem. Every time a color chassis is serviced, the brightness should be run up and down while monitoring the high voltage with a meter to be certain that the high voltage does not exceed the specified value and that it is regulating correctly. We suggest that you and your service organization review test procedures so that voltage regulation is always checked as a standard servicing procedure. And that the high voltage reading be recorded on each customer's invoice. 5. When troubleshooting and making test measurements in a receiver with a problem of excessive high voltage, avoid being unnecessarily close to the picture tube and the high voltage compartment. Do not operate the chassis longer than is necessary to locate the cause of excessive voltage. 6. Refer to HV, B+ and Shutdown adjustment procedures described in the appropriate schematic and diagrams(where used). GRAPHIC SYMBOLS : The lightning flash with arrowhead symbol, within an equilateral triangle, is intended to alert the service personnel to the presence of uninsulated "dangerous voltage" that may be of sufficienty magnitude to constitute a risk of electric shock. The exclamation point within an equilateral triangle is intended to alert the service personnel to the presence of important safety information in service literature.

SUBJECT : IMPLOSION 1. All direct viewed picture tubes are equipped with an integeral implosion protection system, but care should be taken to avoid damage during installation. Avoid scratching the tube. If scratched, replace it. 2. Use only recommended factory replacement tubes. SUBJECT : TIPS ON PROPER INSTALLATION 1. Never install any receiver in closed-in recess, cubbyhole or closely fitting shelf space over, or close to heat duct, or in the path of heated air flow. 2. Avoid conditions of high humidity such as : Outdoor patio installations where dew is a factor. Near steam radiators where steam leakage is factor, etc. 3. Avoid placement where draperies may obstruct rear venting. The customer should also avoid the use of decorative scarves or other coverings which might obstruct ventilation. 4. Wall and shelf mounted installations using a commercial mounting kit, must follow the factoryapproved mounting instructions. A receiver mounted to a shelf or platform must retain its original feet (or the equivalent thickness in spacers) to provide adequate are flow across the bottom, bolts or screws used for fasteners must not touch and parts or wiring. Perform leakage test on customized installations. 5. Caution customers against the mounting of a receiver on sloping shelf or a tilted position, unless the receiver is properly secured. 6. A receiver on a roll-about cart should be stable on its mounting to the cart. Caution the customer on the harzards of trying to roll a cart with small casters across thresholds or deep pile carpets. 7. Caution customers against the use of a cart or stand which has not been listed by underwriters laboratories, inc. For use with their specific model of television receiver or generically approved for use with T.V.� of the same or larger screen size. s

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