Jvc MXG 50 Service Manual
This is the 77 pages manual for Jvc MXG 50 Service Manual.
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Extracted text from Jvc MXG 50 Service Manual (Ocr-read)
Page 1
MX-G50 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. When replacing them, be sure to use the parts of the same type and rating as specified by the manufacturer. (Except the J and C version)
Page 2
MX-G50 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 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. Reproduction and 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. CLASS 1 LASER PRODUCT
Page 23
MX-G50 1-24 1) Before the actual adjustment, clean the play/recording head. 2) Measuring tape : i) VT-703(or equivalent 10kHz AZIMUTH control) 3) The cassette deck is connections as shown in figure 1-7. Notes AZIMUTH 1 SPK OUT (VTVM is connected to the scope) - Turn the control screw to as shown in Figure 1-6. Max output and same phase (both channels) After adjustment secure it with REGION LOCK.Remark Standard To Adjust Pre-Setup Item StepPre-Setup Condition AZIMUTH 1 2 SPK OUT (VTVM is connected to the scope) - Turn the control screw to as shown in Figure 1-6. Max output and same phase (both channels) After adjustment secure it with REGION LOCK. 7mV(mV) Turn JSR2L,JSR2R to the right and leftRemark Standard To Adjust Pre-Setup Item StepPre-Setup Condition Fig 1-8 After putting VT-703 into Deck B 1)Press FWD PLAY button. After putting AC-225 into Deck B 1)Press REC PLAY button. 2)MAIN PCB JCW3, connectted to VTVM Recording Bias Voltage To adjust plabyback level/REC 2. Adjust Deck B Play Level/REC BIAS 1. Adjust Deck A Play Level 0.5 ii) AC-225(or equivalent) After putting VT- 703 into Deck A - Press FWD PLAY button.
Page 41
MX-G50 1-42 D0 D1 CLK CS Vcc S GND D24 D23 D22 D21 D20 D19 D18 D17 GND M66010 (UIC2) : I/O control 1.Pin layout 2.Block diagram 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 DO DI CLK CS S D24 D23 D22 D21 D20 D19 D18 D17D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13 D14 D15 D16D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13 D14 D15 D16 1 2 3 4 5 6 7 8 9 10 16 32 31 30 CLOCK INPUT CLK SET INPUT S CHIP SELECT CS INPUT SERIAL DATA DI INPUT GND GNDVcc DO SERIAL DATA OUTPUT PARALLEL DATA I/OD1 D2 D3 D22 D23 D24 Control circuit Shift register 1 DO D24 D23 D22 D3 D2 D1 Q24 Q23 Q22 Q3 Q2 Q1 D24 D23 D22 D3 D2 D1 Q24 Q23 Q22 Q3 Q2 Q1 DI Parallel output latch Shift register 2 STK402-040 (AIC1) : 2channel AF power amp. 1.Pin layout 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ch.1ch.2 + _+ _ CH1 INCH1 NFNC Pre VccBIAS CH1 VECH1 -VEVcc -Vcc CH2 +VECH2 -VEPre -VcoSUB GNDCH2 NFCH2 IN 1 15 STK402-090 (AIC2) : 2channel AF power amp. STK402-040 1.Pin layout 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ch.1ch.2 + _+ _ CH1 INCH1 NFNC Pre VccBIAS CH1 VECH1 -VEVcc -Vcc CH2 +VECH2 -VEPre -VcoSUB GNDCH2 NFCH2 IN 1 15 STK402-040 1.Pin layout 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ch.1ch.2 + _+ _ CH1 INCH1 NFNC Pre VccBIAS CH1 VECH1 -VEVcc -Vcc CH2 +VECH2 -VEPre -VcoSUB GNDCH2 NFCH2 IN 1 15 STK402-090
Page 63
3-8 MX-G50 5 14 15 Cassette mechanism assembly and parts list Block No. MM M 4 88 2 12 12 4 5 11 3 13 6 7 8 1 10 8 9 7 6 1 Item Parts number Parts name Area A Parts list(Cassette mechanism) Q'ty Description Block No. M4MM 1 AH81-00141A REC/PB HEAD 1 2 AH81-00422A MOTOR ASS'Y 1 3 AH81-00364A MAIN BELT 1 1 4 AH81-00365A MAIN BELT 2 1 5 AH81-00101A FR BELT 1 6 AH81-00102A SOLENOID 1 7 AH81-00282A SPRING 1 8 AH81-00366A PINCH R.ASS'Y 1 9 AH81-00284A E-HEAD 1 10 AH81-00367A MOTOR BRACKET 1 11 AH81-00286A SWICH 1 12 AH81-00287A PHOT SENSER 1 13 AH81-00288ACONNECTOR 1 14 AH81-00289A LEEF SW 1 15 AH81-00375A PCB 1 TC881CB ADR2400-SHU2L ADR2400-MAIN0.5 ADR2400-MAIN1.3 ADR2400-MODE ADR2400-MXS00220 ADR2400-SENSOR ADR2400-16P ADR2400-1PCB ADR2400-FR34.7 ADR2400-1 S/PP/R(F) TC2131F ADR241SWBRKT 110 ADR2400-PINCH(F) Note: Parts listed on the Parts List below can be supplied. However, parts that are not listed below cannot be supplied individually but only by purchasing the whole Cassette Mechanism Assembly Unit. (When ordering, use the Parts No. AH59-00102A for Cassette Mechanism Assembly Unit.)