Jvc UXV 10 GN Service Manual

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1-2 UX-V10GN Safety Precautions 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 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.). Warning 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 ! CAUTION 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.

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1-3 UX-V10GN Warning 1. Service should be performed by qualified personnel only. 2. This equipment has been designed and manufactured to meet international safety standards. 3. It is the legal responsibility of the repairer to ensure that these safety standards are maintained. 4. Repairs must be made in accordance with the relevant safety standards. 5. It is essential that safety critical components are replaced by approved parts. 6. If mains voltage selector is provided, check setting for local voltage. Safety precautions 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. 2. Any unauthorised design alterations or additions will void the manufacturer's guarantee ; furthermore the manufacturer cannot accept responsibility for personal injury or property damage resulting therefrom. 3. Essential safety critical components are identified by ( ) on the Parts List and by shading on the schematics, and must never be replaced by parts other than those listed in the manual. Please note however that many electrical and mechanical parts in the product have special safety related characteristics. These characteristics are often not evident from visual inspection. Parts other than specified by the manufacturer may not have the same safety characteristics as the recommended replacement parts shown in the Parts List of the Service Manual and 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. ! CAUTION 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. (U.K only)

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1-15 UX-V10GN Main adjustment Measurement Instruments Required for Adjustment 1. Low frequency oscillator This oscillator should have a capacity to output 0dBs to 600 at an oscillation frequency of 50Hz-20kHz. 2. Attenuator impedance : 600 3. Electronic voltmeter 4. Distortion meter 5. Frequency counter 6. Wow & flutter meter 7. Test tape VTT703L : Head azimuth VT712 : Tape speed and running unevenness (3kHz) VT724 : Reference level (1kHz) 8. Blank tape TYPE : AC-225 TYPE : AC-514 9. Torque gauge : For play and back tension FWD(TW2111A), REV(TW2121a) and FF/REW(TW2231A) 10. Test disc: CTS-1000 Radio Input signal AM frequency --------------------------------------- 400Hz AM modulation ---------------------------------------- 30% FM frequency --------------------------------------- 400Hz FM frequency deviation ------------------------ 22.5kHz Tuner section B/E/EN version FM Band cover: 87.5 108MHz MW Band cover: 522 1,629kHz LW Band cover: 144 288kHz EE version FM Band cover: 65 74MHz, 87.5 108MHz MW Band cover: 522 1,629kHz LW Band cover: 144 288kHz UB/UF/US/UX/U version FM Band cover: 87.5 108MHz MW Band cover: 531 1,602kHz, 530 1,710kHz SW Band cover: SW1 2.3 6.995MHz : SW2 7 21.85MHz Voltage applied to tuner +B : DC5.7V VT : DC 12V Reference measurement output 26.1mV(0.28V)/3 Input positions AM : Standard loop antenna FM : TP1 (hot) and TP2 (GND) Standard measurement position of volume Function switch to Tape Beat cut switch to Cut Super Bass/Active hyper Bass to OFF Bass Treble to Center Adjustment of main volume to reference output VOL : 28 Precautions for measurement 1. Apply 30pF and 33k to the IF sweeper output side and 0.082 F and 100k in series to the sweeper input side. 2. The IF sweeper output level should be made as low as possible within the adjustable range. 3. Since the IF sweeper is a fixed device, there is no need to adjust this sweeper. 4. Since a ceramic oscillator is used, there is no need to perform any MIX adjustment. 5. Since a fixed coil is used, there is no need to adjust the FM tracking. 6. The input and output earth systems are separated. In case of simultaneously measuring the voltage in both of the input and output systems with an electronic voltmeter for two channels, therefore, the earth should be connected particularly carefully. 7. In the case of BTL connection amp., the minus terminal of speaker is not for earthing. Therefore, be sure not to connect any other earth terminal to this terminal. This system is of an BTL system. 8. For connecting a dummy resistor when measuring the output, use the wire with a greater code size. 9. Whenever any mixed tape is used, use the band pass filter (DV-12). Measurement conditions Power supply voltage : AC230V (50Hz)----B/E/EE/EN : AC110/127V/230V(50/60Hz) : UB/UF/US/UX/U Reference output : Speaker : 0.775V/4 : Headphone : 0.077V/32 Reference frequency and input level ------------------------------ 1kHz, AUX : -8dBs MIX MIC: -54dBs (UB/UF/US/UX/U) Input for confirming recording and playback characteristics ------------------------- AUX : -28dBs Measurement output terminal ------- at Speaker J3002 Load resistance --------------------------- 4