Denon DVD-1740/558 Service Manual

2DVD-1740/558Please heed the points listed below during servicing and inspection.Heed the cautions!Spots requiring particular attention when servicing, such asthe cabinet, parts, chassis, etc., have cautions indicated onlabels or seals. Be sure to heed these cautions and the cau-tions indicated in the handling instructions.Caution concerning electric shock!(1) An AC voltage is impressed on this set, so touching inter-nal metal parts when the set is energized could causeelectric shock. Take care to avoid electric shock, by for ex-ample using an isolating transformer and gloves whenservicing while the set is energized, unplugging the powercord when replacing parts, etc.(2)There are high voltage parts inside. Handle with extra carewhen the set is energized.Caution concerning disassembly and assembly!Though great care is taken when manufacturing parts fromsheet metal, there may in some rare cases be burrs on theedges of parts which could cause injury if fingers are movedacross them. Use gloves to protect your hands.Only use designated parts!The set's parts have specific safety properties (fire resis-tance, voltage resistance, etc.). For replacement parts, besure to use parts which have the same properties. In particu-lar, for the important safety parts that are marked ! on wiringdiagrams and parts lists, be sure to use the designated parts.Be sure to mount parts and arrange thewires as they were originally!For safety reasons, some parts use tape, tubes or other insu-lating materials, and some parts are mounted away from thesurface of printed circuit boards. Care is also taken with thepositions of the wires inside and clamps are used to keepwires away from heating and high voltage parts, so be sure toset everything back as it was originally.Inspect for safety after servicing!Check that all screws, parts and wires removed or discon-nected for servicing have been put back in their original posi-tions, inspect that no parts around the area that has beenserviced have been negatively affected, conduct an insulationcheck on the external metal connectors and between theblades of the power plug, and otherwise check that safety isensured.(Insulation check procedure)Unplug the power cord from the power outlet, disconnect theantenna, plugs, etc., and turn the power switch on. Using a500V insulation resistance tester, check that the insulation re-sistance between the terminals of the power plug and the ex-ternally exposed metal parts (antenna terminal, headphonesterminal, microphone terminal, input terminal, etc.) is 1M orgreater. If it is less, the set must be inspected and repaired.Concerning important safety partsMany of the electric and structural parts used in the set havespecial safety properties. In most cases these properties aredifficult to distinguish by sight, and using replacement partswith higher ratings (rated power and withstand voltage) doesnot necessarily guarantee that safety performance will be pre-served. Parts with safety properties are indicated as shownbelow on the wiring diagrams and parts lists is this servicemanual. Be sure to replace them with parts with the designat-ed part number.(1) Schematic diagrams ... Indicated by the ! mark.(2) Parts lists ... Indicated by the ! mark.Using parts other than the designated partscould result in electric shock, fires or otherdangerous situations.SAFETY PRECAUTIONSThe following check should be performed for the continued protection of the customer and service technician.LEAKAGE CURRENT CHECKBefore returning the unit to the customer, make sure you make either (1) a leakage current check or (2) a line to chassisresistance check. If the leakage current exceeds 0.5 milliamps, or if the resistance from chassis to either side of the powercord is less than 460 kohms, the unit is defective.LASER RADIATIONCaution - Class 1M visible and invisible laser radiation when open.Do not view directly with optical instruments.CAUTIONCAUTION