Jvc MXGT 98 V Service Manual
This is the 65 pages manual for Jvc MXGT 98 V Service Manual.
Read or download the pdf for free. If you want to contribute, please upload pdfs to audioservicemanuals.wetransfer.com.
Extracted text from Jvc MXGT 98 V Service Manual (Ocr-read)
Page 1
MX-GT98V/MX-GT95V/MX-GT88V MX-GT85V/MX-G78V/MX-G75V 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 current 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 measure 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. When replacing them, be sure to use the parts of the same type and rating as specified by the manufacturer. (Except the J&C version)
Page 2
MX-GT98V/MX-GT95V/MX-GT88V MX-GT85V/MX-G78V/MX-G75V 1-3 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 laser radiation and is equipped with safety switches which prevent emission of radiation when the drawer is open and the safety interlocks have failed or are defeated. 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. Position of labels WARNING LABEL !CAUTIONPlease use enough caution not to see the beam directly or touch it in case of an adjustment or operation check. 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. (d) ADVARSEL :Usynlig laserstråling ved åbning , når sikkerhedsafbrydere er ude af funktion. Undgå udsættelse for stråling. (f) CLASS 1 LASER PRODUCT CLASS 1 LASER PRODUCT
Page 31
MX-GT98V/MX-GT95V/MX-GT88V MX-GT85V/MX-G78V/MX-G75V 1-32 Items Measurement conditionsMeasurement methodStandard valuesAdjusting positions 1.With the recording and playback mechanism, load the test tapes(AC-225 to TYP ),and set the mechanism to the recording and pausing conditions in advance. 2.After connecting 100 in series to the recorder head,measure the bias current with a valve voltmeter at both of the terminals. 3.After resetting the [PAUSE] mode,start recording. At this time,adjust VR101 for LcH and VR201 for RcH so that the recording bias current values become 4.0 A (TYP ). 1.With the recording and playback mechanism,load the test tape(AC-225 to TYP ),and set the mechanism to the recording and pausing condition in advance. 2.While repetitively inputting the reference frequency signal of 1kHz and 10kHz from OSC IN, record and playback the test tape. 3.While recording and playing back the test tape in TYP ,adjust VR101 for LcH and VR201 for RcH so that the output deviation between 1kHz and 10kHz becomes -1dB 2dB. Adjustment of recording bias current (Reference value) Adjustment of recording and playback frequency characteristics*Mode : Forward or reverse mode *Recording mode *Test tape : AC-225 Measurement output terminal :Both recording and headphone terminals Reference frequency :1kHz and 10kHz (REF:-20dB) Test tape :TYP AC-225 Measurement input terminal :OSC INAC-225 :4.20 A Output deviation between 1kHz and 10kH :-1dB 2dBLcH :VR101 RcH :VR201 LcH :VR101 RcH :VR201 Electrical performance Items Measurement conditionsMeasurement methodStandard valuesAdjusting positions 1.While changing over to and from BIAS 1 and 2, confirm that the frequency is changed. 2.With the recording and playback mechanism. load the test tape (AC-225 to TYP ),and set the mechanism to the recording and pausing conditions in advance. 3.Confirm that the BIAS TP frequency on the P.C.board is 100kHz 6kHz. 1.With the recording and playback mechanism, load the test tapes(AC-225 to TYP ),and set the mechanism to the recording and pausing condition in advance. 2.After setting to the recording conditions,connect 1M in series to the eraser head on the recording and playback mechanism side,and measure the eraser current from both of the eraser terminal. Recording bias frequency Eraser current (Reference value)*Recording and playback side forward or reverse *Test tape :TYP AC-225 *Measurement terminal BIAS TP on P.C.board *Recording and playback side forward or reverse *Recording mode *Test tape :AC-225 Measurement terminal Both of the eraser head100kHz +9kHz -7kHz TYP :75mA Reference values for electrical function confirmation items
Page 49
200109(V) VICTOR COMPANY OF JAPAN, LIMITED AUDIO & COMMUNICATION BUSINESS DIVISION PERSONAL & MOBILE NETWORK BUSINESS UNIT. 10-1,1chome,Ohwatari-machi,Maebashi-city,371-8543,Japan (No.21026) MX-GT98V/MX-GT95V/MX-GT88V MX-GT85V/MX-G78V/MX-G75V