Jvc-UXA-70-MD-Service-Manual电路原理图.pdf

1-1UX-A70MDSERVICE MANUALMICRO COMPONENT MD SYSTEMNo.20901Jan. 2001COPYRIGHT 2001 VICTOR COMPANY OF JAPAN, LTD.UX-A70MDUX-A70MDContentsSafety precautionsPreventing static electricityImportant for laser productsDisassembly methodMain adjustmentFlow of functional operation until TOC read (CD)Flow of functional operation until TOC read (MD)Maintenance of laser pickupReplacement of laser pickup Maintenance of MD pickupProcedures of changing the MD pickupDescription of major ICs1-21-31-51-61-281-321-331-341-341-351-351-3656This service manual is printed on 100% recycled paper.Area SuffixUBUSUTUFUJHong KongSingaporeTaiwanChinaU.S.MilitaryCOMPACTDIGITAL AUDIO21 354 687010 +10ABCMARKGHI JKL MNOPQRS TUV WXYZDEF91-2UX-A70MDSafety Precautions1. This design of this product contains special hardware and many circuits and components specially for safety purposes. For continued protection, no changes should be made to the original design unless authorized in writing by the manufacturer. Replacement parts must be identical to those used in the original circuits. Services should be performed by qualified personnel only.2. Alterations of the design or circuitry of the product should not be made. Any design alterations of the product should not be made. Any design alterations or additions will void the manufacturers warranty and will further relieve the manufacture of responsibility for personal injury or property damage resulting therefrom.3. Many electrical and mechanical parts in the products have special safety-related characteristics. These characteristics are often not evident from visual inspection nor can the protection afforded by them necessarily be obtained by using replacement components rated for higher voltage, wattage, etc. Replacement parts which have these special safety characteristics are identified in the Parts List of Service Manual. Electrical components having such features are identified by shading on the schematics and by ( ) on the Parts List in the Service Manual. The use of a substitute replacement which does not have the same safety characteristics as the recommended replacement parts shown in the Parts List of Service Manual may create shock, fire, or other hazards.4. The leads in the products are routed and dressed with ties, clamps, tubings, barriers and the like to be separated from live parts, high temperature parts, moving parts and/or sharp edges for the prevention of electric shock and fire hazard. When service is required, the original lead routing and dress should be observed, and it should be confirmed that they have been returned to normal, after re-assembling.5. Leakage currnet check (Electrical shock hazard testing)After re-assembling the product, always perform an isolation check on the exposed metal parts of the product (antenna terminals, knobs, metal cabinet, screw heads, headphone jack, control shafts, etc.) to be sure the product is safe to operate without danger of electrical shock.Do not use a line isolation transformer during this check.Plug the AC line cord directly into the AC outlet. Using a “Leakage Current Tester“, measure the leakage current from each exposed metal parts of the cabinet , particularly any exposed metal part having a return path to the chassis, to a known good earth ground. Any leakage current must not exceed 0.5mA AC (r.m.s.)Alternate check methodPlug the AC line cord directly into the AC outlet. Use an AC voltmeter having, 1,000 ohms per volt or more sensitivity in the following manner. Connect a 1,500 10W resistor paralleled by a 0.15 F AC-type capacitor between an exposed metal part and a known good earth ground.Measure the AC voltage across the resistor with the AC voltmeter. Move the resistor connection to eachexposed metal part, particularly any exposed metal part having a return path to the chassis, and meausre the AC voltage across the resistor. Now, reverse the plug in the AC outlet and repeat each measurement. voltage measured Any must not exceed 0.75 V AC (r.m.s.). This corresponds to 0.5 mA AC (r.m.s.). Warning1. This equipment has been designed and manufactured to meet international safety standards.2. It is the legal responsibility of the repairer to ensure that these safety standards are maintained.3. Repairs must be made in accordance with the relevant safety standards.4. It is essential that safety critical components are replaced by approved parts.5. If mains voltage selector is provided, check setting for local voltage.Good earth groundPlace this probe on each exposedmetal part.AC VOLTMETER(Having 1000 ohms/volts,or more sensitivity)1500 10W0.15 F AC TYPE!CAUTIONBurrs formed during molding may be left over on some parts of the chassis. Therefore, pay attention to such burrs in the case of preforming repair of this system.1-3UX-A70MDPreventing static electricityElectrostatic discharge (ESD), which occurs when static electricity stored in the body, fabric, etc. is discharged, can destroy the laser diode in the traverse unit (optical pickup). Take care to prevent this when performing repairs.1.1. Grounding to prevent damage by static electricityStatic electricity in the work area can destroy the optical pickup (laser diode) in devices such as DVD players. Be careful to use proper grounding in the area where repairs are being performed. 1.1.1. Ground the workbench1. Ground the workbench by laying conductive material (such as a conductive sheet) or an iron plate over it before placing the traverse unit (optical pickup) on it.1.1.2. Ground yourself1. Use an anti-static wrist strap to release any static electricity built up in your body. 1.1.3. Handling the optical pickup1. In order to maintain quality during transport and before installation, both sides of the laser diode on the replacement optical pickup are shorted. After replacement, return the shorted parts to their original condition. (Refer to the text.)2. Do not use a tester to check the condition of the laser diode in the optical pickup. The tester's internal power source can easily destroy the laser diode. 1.2. Handling the traverse unit (optical pickup)1. Do not subject the traverse unit (optical pickup) to strong shocks, as it is a sensitive, complex unit. 2. Cut off the shorted part of the flexible cable using nippers, etc. after replacing the optical pickup. For specific details, refer to the replacement procedure in the text. Remove the anti-static pin when replacing the traverse unit. Be careful not to take too long a time when attaching it to the connector. 3. Handle the flexible cable carefully as it may break when subjected to strong force. 4. It is not possible to adjust the semi-fixed resistor that adjusts the laser power. Do not turn itConductive material (conductive sheet) or iron plate(caption)Anti-static wrist strap1-4UX-A70MD1.3. Cautions on removing the CD traverse unit* For removing the CD traverse unit in detail, refer to the “Adjustment Method“ section of this manual.1. Before disconnecting the flexible wire from the connector CN601 on the CD SERVO board, solder the part shown in the figure below.(Note:If the flexible wire is disconnected from the CN601 without presoldering, it may cause breakdown of the CD pickup assembly.)2. When reassembling the CD traverse unit, be sure to remove the solder from the soldered part after reconnecting the flexible wire to the CN601. CD SERVO boardCD SERVO boardSoldering partCN601CN601CN321CN451PickupSoldering part bMAIN boardCD SERVO board1-5UX-A70MD1-6UX-A70MDRemove the nine screws A attaching the rear cover on the back of the body.Remove the two screws B attaching the rear cover on the bottom of the body.Unlock the speaker terminal and the antenna terminal, then remove the rear cover backward with releasing the hooks.1.2.3.Disassembly methodRemoving the rear cover (See Fig.1 and 2)Prior to performing the following procedure, remove the rear cover.Remove each side panel backward while releasing the joints a. 1.Removing the side panels (See Fig.3 and 4)Fig.1Fig.2ABBAFig.3SpeakerterminalAntenna terminalSide panel (Right)Joints aJoints aFig.4Joints aJoints aSide panel (Left)ARear coverRear cover1-7UX-A70MDPrior to performing the following procedure, remove the rear cover and the side panels.Remove the two screws C on each side of the body.Release the joint b on each side of the body and remove the top cover backward and upward.1.2.Removing the top cover (See Fig.5 and 6)Prior to performing the following procedure, remove the rear cover, the side panels, the top cover and the fan assembly.Disconnect the card wire from connector CN721 on the tuner & function board.Remove the four screws D and the MD mechanism assembly backward and upward while pulling the front panel assembly forward.1.2.Removing the MD mechanism assembly unit (See Fig.7)*Prior to performing the following procedure, remove the rear cover, the right and left side panels.Remove the two screws D on the right side of the body and pull out the fan assembly sideward.Disconnect the wire from connector CN807 on the main board.1.2.Removing the fan assembly (See Fig.6)Fig.5Fig.6Joint bCTuner & function boardTop coverJoint bFig.7DDDMD mechanism assemblyFront panel assemblyCTop coverFan assemblyDDCN807CN7211-8UX-A70MDRemoving the tuner & function board(See Fig.8)Removing the AC jack board (See Fig.9)For the card wire connected to CN707, disconnect it after performing the following procedure 2 and 3.CAUTION: Prior to performing the following procedure, remove the rear cover, the side panels and the top cover.Disconnect the card wire from connector CN701, CN705, CN707, CN708 and CN721 on the tuner & function board on the right side of the body. Similarly, disconnect the harness from CN706.1.2.3.Disconnect connector CN711 and CN712 on the tuner & function board from CN801 and CN802 on the main board by pulling them outward.Disconnect connector CN703 and CN704 on the tuner & function board from CN603 and CN604 on the CD servo board by pulling them upward.Prior to performing the following procedure, remove the rear cover and the right side panel.Remove the screw E on the right side of the body and release the AC jack board from the two joints c.Disconnect the harness from connector CN805 on the AC jack board.1.2.Removing the antenna terminal board(See Fig.10)Prior to performing the following procedure, remove the rear cover and the left side panel.Disconnect the card wire from connector CN1 on the left side of the body.Remove the screw F and release the antenna terminal board from the joint d upward.1.2.CN703CN705Fig.8CN708CN706CN721CN701CN707CN712 CN704CN711Joints cEAC jack boardCN1FJoint dAntenna terminal boardFig.9Fig.10AC jack board1-9UX-A70MDRemoving the front panel assembly unit (See Fig.11 to 15)Prior to performing the following procedure, remove the rear cover, the side panels, thetop cover, the MD mechanism assembly and the tuner & function board.Disconnect the wire from connector CN804 and CN806 on the main board. Disconnectthe wire from W802 pin terminal.Remove the two screws G on the bottom of the body.Remove the lower screw H on each side of the body.Release the lower joint e on each side of the body. Pull out the front panel assemblytoward the front.1.2.3.4.Fig.11Fig.12GCN804CN806Front panel assemblyMain boardJoint eJoint eFront panel assemblyFig.15Fig.13Fig.14Front panel assemblyFront panel assemblyW802Front panel assemblyW802Main boardHH1-10UX-A70MDRemoving the main board / heat sink (See Fig.16 to 18)Prior to performing the following procedure, remove the rear cover, the side panels, thetop cover, the MD mechanism assembly and the tuner & function board.Disconnect the wire from connector CN803, CN804 and CN806 on the main boardrespectively. Disconnect the wire from W802 pin terminal.Remove the screw I attaching the main board and the screw J attaching the wireterminal.1.2.Remove the three screws K on the heat sink bracket.Remove the two screws L on the back of the main board.3.4.When reasse mbling, fit the slots of the main board to the two bosses.CAUTION: When removing the heat sink bracket, disengage the two joints d on theback of the main board.CAUTION: CN806CN804ICN803Fig.16Main boardFig.17Fig.18LHeat sinkKHeat sink bracketMain boardMain boradHeat sinkLJJoint dBosseBosseW802