Hitachi-DVW1U-cd-sm维修电路原理图.pdf
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1、TK No.9006E SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT DVD PLAYER . CD RECORDER SERVICE MANUAL 2000MayDigital Media Products Division, Tokai DV-W1U RadioFans.CN 收音机爱 好者资料库 NOTICE: Comply with all cautions and safety related notes located on or inside the cabinet and on the chassi
2、s. 1. When replacing a chassis in the instrument, all the protective devices must be put back in place, such as barriers, non-metallic knobs, adjustment and compartment covers/shields, isolation resistors/ capacitors, etc. 2. When service is required, observe the original lead- ress. Extra precautio
3、ns should be taken to assure correct lead dress in the high voltage circuit. 3. Always use the manufacturers replacement components. Especially critical components as indicated on the circuit diagram should not be replaced by other manufacturers. Furthermore, where a short-circuit has occurred, repl
4、ace those components that indicate evidence of overheating. 4. Before returning an instrument to the customer, the service technician must thoroughly test the unit to be certain that it is completely safe to operate without danger of electrical shock, and be sure that no protective device built into
5、 the instrument by the manufacturer has become defective or inadvertently defeated during servicing. Therefore, the following checks should be performed for the continued protection of the customer and service technician. Leakage Current Cold Check With the AC plug removed from the AC120V, 60Hz sour
6、ce, place a jumper across the two plug prongs. Turn the AC power switch on. Using an insulation tester (DC500V), connect one lead to the jumpered AC plug and touch the other lead to exposed metal parts (antennas, screwheads, metal overlays, control shafts, etc.), particularly any exposed metal part
7、having a eturn path to the chassis. Exposed metal parts having a return path to the chassis should have a minimum resistor reading of 0.3 Mohm and a maximum resistor reading of 5 Mohm. Any resistor value below or above this range indicates an abnormality which requires corrective action. Exposed met
8、al parts not having a return path to the chassis will indicate an open circuit. Leakage Current Hot Check Plug the AC line cord directly into a AC120V, 60Hz outlet (do not use an isolation transformer for this check). Turn the AC power switch on. Using a Leakage Current Tester, measure for current f
9、rom all exposed metal parts of the cabinet (antennas, screwheads, metal overlays, control shaft, etc.), particularly an exposed metal part having a return path to the chassis, to a known ground (earth) (water pipe, conduit, etc.). Any current measured must not exceed 0.5 mA. SAFETY PRECAUTIONS AC Le
10、akage Test ANY MEASUREMENTS NOT WITHIN THE LIMITS OUTLINED ABOVE ARE INDICATIVE OF A POTENTIAL SHOCK HAZARD AND MUST BE CORRECTED BEFORE RETURNING THE UNIT TO THE CUSTOMER. PRODUCT SAFETY NOTICE Many electrical and mechanical parts have special safety- related characteristics. These are often not ev
11、ident from visual inspection nor can the protection afforded by them necessarily be obtained by using replacement components rated for a higher voltage, wattage, etc. Replacement parts which have these special safety characteristics are identified in this Service Manual. Electrical components having
12、 such features are identified by marking with aon the schematics and the parts list in this Service Manual. The use of a substitute replacement component which does not have the same safety characteristics as the HITACHI recommended replacement one, shown in the parts list in this Service Manual, ma
13、y create shock, fire, or other hazards. Product safety is continuously under review and new instructions are issued from time to time. For the latest information, always consult the current HITACHI Service Manual. A subscription to, or additional copies for, HITACHI Service Manual may be obtained at
14、 a nominal charge from HITACHI SALES CORPORATION. DEVICE UNDER TEST (READING SHOULD NOT BE ABOVE 0.5mA) LEAKAGE CURRENT TESTER TEST ALL EXPOSED METAL SURFACES 2-WIRE CORD ALSO TEST WITHPLUG REVERSED(USING AC ADAPTER PLUG AS REQUIRED) GROUND (EARTH) RadioFans.CN 收音机爱 好者资料库 Notes When Using Service Ma
15、nual The following shows the contents to be noted when using service manual: 1. Value units used in parts list This table shows locations of each part on circuit board diagrams. The locations are indicated using the guide scales on the external lines of diagrams. 1) One diagram indicated for each bo
16、ard The values, dielectric strength (power capacitance) and tolerances of the resistors (excluding variable resistors) and capacitors are indicated in the schematic diagrams using abbreviations. Resistors Certain symbols are indicated below for value units of resistors, capacitors and coils in parts
17、 list. When you read them note the following regular indications: Indication in listRegular indication KOHM.k UF.F PF.pF UH.H MH.mH Parts Resistor Capacitor Coil 2) Two diagrams indicated for each board 2. Values in schematic diagrams Item Value Tolerance Power capacitance Indication No indication.
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