Jvc UXM 5 Service Manual

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UX-M5 1-2 1. 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 manufacturer`s 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 method Plug 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 each exposed 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.). 1. 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 exposed metal part. AC VOLTMETER (Having 1000 ohms/volts, or more sensitivity) 1500 10W 0.15 F AC TYPE ! Burrs 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. In regard with component parts appearing on the silk-screen printed side (parts side) of the PWB diagrams, the parts that are printed over with black such as the resistor ( ), diode ( ) and ICP ( ) or identified by the " " mark nearby are critical for safety. (This regulation does not correspond to J and C version.)

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UX-M5 1-3 Short land CD pickup unit Connector Conductive material (conductive sheet) or iron plate (caption) Anti-static wrist strap 5. Attention when traverse unit is decomposed *Please refer to "Disassembly method" in the text for the CD pickup unit. Apply solder to the short land before the card wire is disconnected from the connector on the CD pickup unit. (If the card wire is disconnected without applying solder, the CD pickup may be destroyed by static electricity.) In the assembly, be sure to remove solder from the short land after connecting the card wire. Electrostatic 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. Preventing static electricity 1. Grounding to prevent damage by static electricity Static electricity in the work area can destroy the optical pickup (laser diode) in devices such as CD players. Be careful to use proper grounding in the area where repairs are being performed. 2. About the earth processing for the destruction prevention by static electricity 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. 2-1 Ground the workbench 2-2 Ground yourself Use an anti-static wrist strap to release any static electricity built up in your body. 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.) 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. 3. Handling the optical pickup 1. 2. Do not subject the traverse unit (optical pickup) to strong shocks, as it is a sensitive, complex unit. Remove solder of the short land on the card wire 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. Handle the card wire carefully as it may break when subjected to strong force. It is not possible to adjust the semi-fixed resistor that adjusts the laser power. Do not turn it. 4. Handling the traverse unit (optical pickup) 1. 2. 3. 4.

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UX-M5 1-6 1 2 34 Fig.4 Fig.5 D D E E Right side plate Fig.6 D D E E Right side plate Claw b Fig.7 Left side plate Left side plate Claw c Bottom case Bottom case Removing the right side plate (See Figs. 4 and 5.) 1. 2.From the right side of the main body, remove the three screws D and three screws E retaining the right side plate. (See Fig.4.) Slide the right side plate toward the rear (in the direction of the arrow 1) until the claw b at the back of the right side plate is hooked by the bottom case and then lift the right side plate upward (in the direction of the arrow 2) to remove it. (See Fig.5.) Removing the left side plate (See Figs. 6 and 7.) 1. 2.From the left side of the main body, remove the three screws D and three screws E retaining the left side plate. (See Fig.6.) Slide the left side plate toward the rear (in the direction of the arrow 3) until the claw c at the back of the left side plate is hooked by the bottom case, and then lift the left side plate upward (in the direction of the arrow 4) to remove it. (See Fig.7.)

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UX-M5 1-15 Cassette amplifier section Item Measuring condition Check and adjustment procedure Standard value Adjusting part Play back the test tape VT702 (8kHz). Adjust the head azimuth adjusting screw so that the phase difference between the R and L channels is minimized at an output level that is within (0+2dB-2dB) of the maximum output level. After this adjustment, lock the head azimuth adjusting screw with screw sealant to cover more than a half of the screw head. When the head azimuth is maladjusted, correct it with the head azimuth adjusting screw. Test tape: VT702 (8kHz) Signal output terminal: PHONES (with 32 ohm load) Head azimuth adjustment1. 2. 3. Output level: Within (0+2dB-2dB) of maximum output level Phase difference R and L channels: Minimum Head azimuth adjusting screw (To be used only after head replacement) See Fig.1 on page 1-16. Play back the test tape VT712 (3kHz) by the end portion. Connect a frequency counter and check that it reads between 2940 and 3090Hz. If not, adjust the frequency with the motor semifixed resistor. Check that the wow/flutter is within 0.38% (unweighted). Test tape: VT712 (3kHz) Signal output terminal: PHONES (with 32 ohm load) Tape speed and wow/flutter check and adjustment1. 2. 3.2940 to 3090Hz Within 0.38% (unweighted) Tape speed: Motor semifixed resistor See Fig.2 on page 1-16. Check only Play back the test tape VT702 while con-firming that deviation between the 1kHz signal and 8kHz signal should be (0+3dB-6dB). Test tape: VT702 Signal output terminal: PHONES (with 32 ohm load) PB frequency response checkDeviation between 1kHz and 8kHz: (0+3dB-6dB) Set the TUNER or CD function and with TAPE to record. Check to see if the frequency at the measuring point P201 is (67kHz+1kHz-1kHz) if not adjust L203 until the frequency counter indicates (67kHz+1kHz -1kHz). Tape: Normal Signal output terminal: Cassette REC./PLAY HEAD Bias frequency checkL203, P201 See Fig.3 on page 1-16. At TUNER, set the BAND to the FM position, and record the reference 1kHz signal and 8kHz signal alternately repeatedly. While playing back the recorded signal differ from that of the 1kHz signal by within (0+3dB-6dB). Test tape: AC225 Signal input: FM 22.5 DEV 60dBu with emphasis Signal output terminal: PHONES (with 32 ohm load) REC and PB frequency response adjustmentLevel difference between REC and PB: Within (0+3dB-6dB) Tuner section Item Measuring condition Check and adjustment procedure Standard value Adjusting part Set the intermediate frequency sweep generator to AM 450kHz. Adjust the T101 for maximum and center output. Signal input: Loop antenna Signal output: IC101 pin19 AM IF adjustment 1. 2.T101 See Fig.3 on page 1-16. Set the TUNER at 87.5MHz, adjust the L104 until the test point P105 voltage at (2.3V+0.1V-0.1V). Set the TUNER at 108MHz, check the test point P105 voltage at (6.5V+0.3V-0.3V). Set the TUNER and S/G at 90.1MHz, adjust L103 for maximum output. Set the TUNER and S/G at 106.1MHz, adjust the TC102 for maximum output. Repeat the above steps 3 and 4. Signal input: Dummy antenna FM ANT FM GND Signal output: PHONES (with 32 ohm load) FM tracking adjustment1. 2. 3. 4. 5.L104, P105 L103 TC102 See Fig.3 on page 1-16. Set the TUNER at 522kHz, adjust the L101 until the test point P107 voltage at (1.1V+0.1V-0.1V). Set the TUNER at 1629kHz, check the test point P107 voltage at (7.0V+0.3V-0.3V). Set the TUNER and S/G at 603kHz, adjust the L102 for maximum output. Set the TUNER and S/G at 1404kHz, adjust the TC101 for maximum output. Repeat the above steps 3 and 4. Signal input: Loop antenna Signal output: PHONES (with 32 ohm load) AM tracking adjustment1. 2. 3. 4. 5.L101, P107 L102 TC101 See Fig.3 on page 1-16.