Jvc UXG 6 Service Manual
This is the 108 pages manual for Jvc UXG 6 Service Manual.
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Extracted text from Jvc UXG 6 Service Manual (Ocr-read)
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1-2 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. UX-G6/FS-6G
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1-3 UX-G6/FS-G6 Important for laser products 1.CLASS 1 LASER PRODUCT 2.DANGER : Invisible laser radiation when open and inter lock failed or defeated. Avoid direct exposure to beam. 3.CAUTION : There are no serviceable parts inside the Laser Unit. Do not disassemble the Laser Unit. Replace the complete Laser Unit if it malfunctions. 4.CAUTION : The compact disc player uses invisible laserradiation and is equipped with safety switches whichprevent emission of radiation when the drawer is open and the safety interlocks have failed or are de feated. It is dangerous to defeat the safety switches.5.CAUTION : If safety switches malfunction, the laser is able to function. 6.CAUTION : Use of controls, adjustments or performance of procedures other than those specified herein may result in hazardous radiation exposure. VARNING : Osynlig laserstrålning är denna del är öppnad och spårren är urkopplad. Betrakta ej strålen. VARO : Avattaessa ja suojalukitus ohitettaessa olet alttiina näkymättömälle lasersäteilylle.Älä katso säteeseen.ADVARSEL : Usynlig laserstråling ved åbning , når sikkerhedsafbrydere er ude af funktion. Undgå udsættelse for stråling. ADVARSEL : Usynlig laserstråling ved åpning,når sikkerhetsbryteren er avslott. unngå utsettelse for stråling. REPRODUCTION AND POSITION OF LABELS WARNING LABEL DANGER : Invisibie laser radiation when open and interlock or defeated. AVOID DIRECT EXPOSURE TO BEAM (e) VARNING : Osynlig laserstrålning är denna del är öppnad och spårren är urkopplad. Betrakta ej strålen. (s) VARO : Avattaessa ja suojalukitus ohitettaessa olet alttiina näkymättömälle lasersäteilylle.Älä katso säteeseen. (f) ADVARSEL :Usynlig laserstråling ved åbning , når sikkerhedsafbrydere er ude af funktion. Undgå udsættelse for stråling. (d) CLASS 1 LASER PRODUCT ! CAUTION Please use enough caution not to see the beam directly or touch it in case of an adjustment or operation check.
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2-41 UX-G6/FS-G6 Procedures for adjusting the electrical circuit The following adjustments should be performed after adjusting the tape traveling and head angles. - The sequence of adjustment should in principle be according to the following order of description. - The adjustment items denoted by asterisk should be performed whenever the head has been changed. Items Adjusting position Reference value RemarksAdjusting position [0dBs = 0.775V] Items Adjusting and confirmation methods frequency level deviation of output up and down values Confirmation of Dolby circuit recording (Recording mode)Recording Dolby B1kHz Cal-40dB 5kHz Cal-20dB 1kHz Cal 0dB+5.7dB 2dB +3.5dB 1.5dB 0dB +0.5/-1 dB Frequency level Deviation of output up and down values Input:[Line IN] (-8dBs) Measuring points:Pin 8 of IC635 and pin 2 of CN641 Reference level at measuring points 400Hz -8dBs (=Cal. level) Adjustment of playing level Adjustment of playing equalizer Reference value of recording input Adjustment of bias frequency Adjustment of recording and playing frequency characteristicsWhile playing the test tape VT724 (1kHz), adjust the CN641 output to -25.5dBs with VR611 and VR621. (The L - R channel output difference should be within 0.5dB). While playing the test tape TMT7063 (1kHz and 12.5kHz), adjust the test point TP (CN641) output to the reference values at 1kHz and 12.5kHz outputs with VR612 (Lch) and VR622 (Rch). Confirm that the input level at the test point TP (CN641) terminal is -25.5dB when 1kHz -28.2dBs has been applied to the line input. Connect the frequency counter to the test points TP631 and TP632 and adjust the bias frequency to 100kHz with Record 1kHz/12.5kHz with a normal tape, and adjust the deviation at 12.5kHz to +0 0.5dB with reference to 1kHz by means of VR613 (Lch) and VR623 (Rch). *2 *3 4 5 *6L:VR611 R:VR621 L:VR612 R:VR622 L6351 L:VR613 R:VR623 -25.5dBs 0.5dB (L-R difference: within 0.5dB) With reference to 1kHz, the deviation of 12.5kHz should be 1.5 0.5dB Output level: -25.5dBs 1dB 100kHz +9kHz -1kHz Normal tape: 0 0.5dB Chrome tape: 0 4dBAdjust the playing level since this level will be changed whenever the head has been changed. At this time, the impedance of electronic voltmeter should be 100 or more. NR : OFF By using the test tape TMT7063 (12.5/1kHz/63Hz), confirm that 63Hz:+2dB 3dB with reference to 1kHz. Tape : chrome Mode : recording Ref-20dB : [Value reduced by as much as -20dB from the reference input value] 28.2dB The bias value in the case of chromium tape will be set by shifting the voltage with reference to that in the case of normal tape. Unless the bias current has been adjusted correctly, the recording characteristics will become as indicated in the diagram on the left hand side. Response (dB) High frequency area up High frequency area downBias current is smaller. Bias current is appropriate. Bias current is greater. Frequency 050Hz 1kHz 12.5kHz 1
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2-57 UX-G6/FS-G6 ABCDE FG 3 4 5 2 1 System control & Analog IN / digital OUT board (XT-UXG6)