Denon SYS 57HT Service Manual
This is the 20 pages manual for Denon SYS 57HT Service Manual.
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Extracted text from Denon SYS 57HT Service Manual (Ocr-read)
Page 1
2 SYS-57HT Please heed the points listed below during servicing and inspection. Õ Heed the cautions! Spots requiring particular attention when servicing, such as the cabinet, parts, chassis, etc., have cautions indicated on labels or seals. Be sure to heed these cautions and the cau- tions indicated in the handling instructions. Õ 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 cause electric shock. Take care to avoid electric shock, by for ex- ample using an isolating transformer and gloves when servicing while the set is energized, unplugging the power cord when replacing parts, etc. (2)There are high voltage parts inside. Handle with extra care when the set is energized. Õ Caution concerning disassembly and assembly! Though great care is taken when manufacturing parts from sheet metal, there may in some rare cases be burrs on the edges of parts which could cause injury if fingers are moved across them. Use gloves to protect your hands. Õ Only use designated parts! The set's parts have specific safety properties (fire resis- tance, voltage resist ance, etc.). For replacement parts, be sure to use parts which have the same properties. In particu- lar, for the important sa fety parts that are marked ! on wiring diagrams and parts lists, be sure to use the designated parts. Õ Be sure to mount parts and arrange the wires as they were originally! For safety reasons, some parts use tape, tubes or other insu- lating materials, and some parts are mounted away from the surface of printed circuit boards. Care is also taken with the positions of the wires inside and clamps are used to keep wires away from heating and high voltage parts, so be sure to set everything back as it was originally. Õ 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 been serviced have been negatively affected, conduct an insulation check on the external metal connectors and between the blades of the power plug, and otherwise check that safety is ensured. (Insulation check procedure) Unplug the power cord from the power outlet, disconnect the antenna, plugs, etc., and turn the power switch on. Using a 500V 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, headphones terminal, microphone terminal, input terminal, etc.) is 1M or greater. If it is less, the set must be inspected and repaired. Concerning important safety parts Many of the electric and structural parts used in the set have special safety properties. In most cases these properties are difficult to distinguish by sigh t, and using replacement parts with higher ratings (rated power and withstand voltage) does not necessarily guarantee that sa fety performance will be pre- served. Parts with safety properties are indicated as shown below on the wiring diagrams a nd parts lists is this service manual. 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 parts could result in electric shock, fires or other dangerous situations. SAFETY PRECAUTIONS The following check should be performed for the continued protection of the customer and service technician. LEAKAGE CURRENT CHECK Before returning the unit to the customer, make sure you make either (1) a leakage current check or (2) a line to chassis resistance check. If the leakage current exceeds 0.5 milliamps, or if the resistance from chassis to either side of the power cord is less than 460 kohms, the unit is defective. CAUTION CAUTION ±Ïµz :UÌtxmWw\qt] «™&M‡b{ Õ «™Äò›S Xi^M‚
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3 SYS-57HT DSW-76(Black) Section DSW-76(Black) BLOCK/LEVEL DIAGRAM VOL DIRECT MODE ATT CROSSOVER CONTROL HPFDIRECT MODE SWSW202 LINE INPUT ALC POWER AMP REVERSE PHASE NORMAL SPEAKER U201U203 U203 20 0 40 -10(dB) 20 0 40 -10(dB)+20dB +1.84dB +4.34dB +4.34dB+27.2dB +50.5dB 20V/4ohrm THD 0.7% (ALCON) 20V/4ohrm THD 0.7% (ALCON)at 55Hz at 55Hz -1dB -1dB 830mV 75mV