JVC-QLF6-tt-sm 维修电路原理图.pdf

JVCMODELtaL-FeQUARTZ FULLY AUTOMATICTURNTABLENo. 2464. FEB. 1979RadioFans.CN 收音机爱 好者资料库ContentsPages1. Specifications .2. ServicePrecautions.Features.4. NamesofPartsandTheirFunctions.5. Replacement Procedures(1) Stylus.(2) Headshell .,.(3) Cartridge.(4) Motor.(5) HO/VODampingKnobs 66. Lubrication(1) HO/VODampingMechanism .(2) Motor.(3) FullyAutomaticMechanism.7. Adjustment Procedures(1) UARTZ LOCK/PITCH CONTROL Meter .(2) OuartzLockAdjustment . 8Tonearm Section(3) HeadsheliAngle .(4) TonearmElevator.(5) Overhang .(6) Lead-in.(7) Lead-out.(8) TrackingForce.(9) Anti-skating.(10) HO/VODamping .8. OL-F6BlockDiagram .9. Troubleshooting Charts(1) Platter does not rotate. . (2) Platter rotates at high speed. .(3) Pitch Control operates abnormally. .10. Exploded Views and Parts List10-(1) Cabinet & Mechanism Assy .10-(2) Mechanism Assy .10-(3) TonearmAssy.11. Printed Circuit Board Assy and Parts List11-(1) MDC-938G .11-(2) TPS-206 .12. Accessories List .13. OL-F6 Schematic Diagram .14. PackingMaterialsandPartNumbers.15. Parts List with Specified Numbers for Designated Areas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Back pageOL-No. 24641 -RadioFans.CN 收音机爱 好者资料库SpecificationsMOTOR SECTION(These specifications apply only to the quartz lock mode.Motor : Core less, DC typeFG servomotor: Phase-locking to the quartzoscillator: Direct drive: 33-1/3Servo systemDrive systemSpeedsFine pitchadjustable rangeWow and flutterSignal-to-noise ratioSpeed detectionStarting torqueSpeed deviationLoad characteristicsDriftPower characteristicsTemperaturecharacteristicsPlatterTONEARM SECTIONTypeEffective arm lengthOverhangWeight rangeincluding headshell: :!: 6 % (at the pitch control mode): 0.025 % (WRMS): More than 78 dB (DIN-: Frequency generator: More than 1.2 kg-cm: Within 0.002 %: 0 % (with 170 g total trackingforce): 0.0001 %/H: 0 % (:!: 10 V): 0.00005 %tc: 32.7 cm: Statically-balam;ed oil-dampedtonearm: 233 mm: 15 mm: 13 - 20 g24 g (when using the providedsub-counterweight)2. Service Precautions. Be sure to use JVC standard parts. When repairing the speed control circuit board con-nect the m938 G motor in order to prevent damageto the transistor used.in the platter drive section. Be sure to adjust motor speed with the u nit levelotherwise fluctuations which make adjustment impos-sible may occur. When repairing circuit board with the heat sink re-moved, attach mobile heat-sink to prevent the tran-sistor temperature from rising.CARTRIDGE SECTION(Except for USA, Canada and U.Type : Moving magnet (MD-l025EB)Frequency response: 10 Hz - 25000 HzOutput : 3 mV (1 kHz)Channel separation: 25 dB (1 kHz)(using the test record TRS-: 47 - 100 k-ohms: 10 x 106 cm/dyne (dynamic)30 x 106 cm/dyne (static): DT-Zl EB, 0.3 x 0.7 mil.(diamond, elliptical)Optimum tracking force: 1.75 g :!: 0.25 gGENERALPower consumptionDimensionsLoad resistanceComplianceStylusWeightAccessoriesEP adapter: 15W: Height 14.2 cm (with closedcover)Width 45.6 cmDepth 40.0 cm(Since the dimensions show onlythe design measurements, con-sideration is requ ired wheninstalling the unit in a limitedspace such as a rack, etc.: 11 kg (without the packaging)Sub-counterweight: 1Place the adapter on the centerspindle when playing a recordhaving a bigger diameter centerhole such as a doughnut record.: 1Design and specifications subject to change without notice.3. Features. Newly developed oil-damped tonearm assures hightrackability.Highly sensitive, new gimbalsupport tonearm system. Double-quartz servo circu it and high torque, non-resonance coreless motor give high reliability. Extra-heavy aluminum diecast platter (2 kg includingthe mat, inertia 330 kg/cmHowling margin is greatly improved with the newsuper-compound (type-l) board used as the base.Operation buttons and controls are positioned at thefront for easy operation. NR-type headshell with minimum resonance is em-ployed.Moving-magnet cartridge with a elliptical stylus.Fine pitch control allows adjustment within:!: 6 %(approx. a half note). Quartz lock/Pitch control meter for convenient speedcheck.Fully automatic mechanism.QL-No. 24644. Names of Parts and TheirFunctionsMatDust coverCenter spindlePlatterFig. 11. OIL DAMPED TONEARMOrdinarily tonearms have a resonance frequency ofbetween 5 to 10Hz. If the peak of the range of atonearm is too high, accurate tracking of the tone-arm with the record groove cannot be obtained be-cause the tonearm resonates at a frequency generatedby ambient vibrations or sound pressure, or the tone-arm can be influenced by adverse conditions of therecord such as warps, etc. The OIL DAMPEDTONEARM i designed to suppress the range ofresonance by maintaining a low resonant point ofthe tonearm to prevent howling. With this OILDAMPED TONEARM, accurate tracking of therecord groove as well as a good resistant character-istic to howling is possible, thus resulting in an im-proveved SIN ratio. I n order to improve the soundquality, the OIL DAMPED TONEARM plays animportant role.QL-No. 24642. HQ DAMPING knobThis controls the horizontal movement of the tone-arm while aiding to keep the tonearms resonatingpoint low. Set the knob to the same indication num-ber as the optimum tracking force of this unit.3. VQ DAMPING knobThis controls the vertical movement of the tonearmwhile aiding to keep the tonearms resonating pointlow. Set the knob to the same indication number asthe optimum tracking force of this unit.4. Speed select knobSelect a proper position of the speed select knob inaccordance with the rpm of the record.33-1/3 rpm record (LP) . 3345rpmrecord(EP).455. QUARTZ LOCK/PITCH CONTROL select buttonQUARTZ LOCK:Depress the button to the QUARTZ LOCK position( ) for playing a record at an accurate rotationspeed in the quartz lock mode. In this case, themeter lights green.PITCH CONTROL:Depress the button a second time to obtain theP ITCH CO NT RO L position (-) in order to per-form fine pitch adjustment for the sound meetingyour preference. I n this case, the meter I ights orange.6. PITCH CONTROL meterWhen the QUARTZ LOCK/PITCH CONTROLselect button is set to the QUARTZ LOCK positionthe meter is green-lit and the indicator displays When the QUARTZ LOCK/PITCH CONTROLselect button is set to the PITCH CONTROL posi-tion, pitch control can be performed by turningthe PITCH CONTROL knob and the meter isorange-I it.#6 % means +6 %b6 % means -6 %7. PITCH CONTROL knobFine pitch control can be performed with theQUARTZ LOCK/PITCH CONTROL select buttonset to the PITCH CONTROL position. Pitch adjust-ment range is :!: 6 %. The indicator in the meterdeflecting to the left (#) from the center (0) indi-cates an increase to the accurate 33-1/3 or 45 rpmand the deflection to the right (b) means a decrease.8. ANTI-SKATING knobThis device cancels out the centripetal force thatpulls the tonearm to the center of the platter. Thisprevents the stylus tip from skating toward thecenter of the platter and at the same time eliminatesany excessive stylus tip force on the inner wall ofthe record groove. Use the 8 marked dial when em-ploying a spherical stylus. Use the marked dialwhen employing an elliptical stylus or a SHIBATAstylus.Turn the dial to the same number as on the track ingforce dial.9. REPEAT knobDecide how many times you want to re-listen to therecord by using this knob. When you set the knobto , the record will continue to play repeatedly.Note: This knob cannot be turned to indicate from1 - 0 or 0 - 1 if the START button is de-pressed with the power cord disconnectedfrom the outlet. For this, refer to the notein the section Necessary procedures priorto record playing on page 2.10. START/REJECT buttonsWhen you start playing a record, depress theST ART button. The tonearm moves automaticallythe position of the first groove of the record pre-selected and gently lowers itself onto the surface ofthe record to play it. When you stop playing therecord, depress the REJECT button. The tonearmlifts, returns automatically to its rest and the platterstops rotating., however, the REPEAT knob has been set for anumber of repeats, the tonearm performs the cor-respond ing number of prepeats before the platterstops rotating.Note: When the dial of the repeat knob has beenset to numbers other than , the plattercontinues to rotate and the power will notbe turned off even though you depress theREJECT button or even if the playingrecord has finished. When you want thepower to be turned off after the record hasplayed once, be sure to set the repeat knobto the 0 mark.11. RECORD SIZE select knobSet the knob to the corresponding position to thesize of the record before you play it.30 cm diameter record. . . . . . . . . . . . 30 (1225 cm diameter record. . . . . . . . . . . . 25 (1017cmdiameterrecord. 17(7)12. Arm lifter leverThis is used when you want to raise the tonearmgently or gently lower it. When you push it to theUP position, the tonearm will be lifted up, andwhen you pull it to the DOWN position, it willbe lowered down gently onto the record surface.QL-No. 24645. Replacement Procedures5-( 1) StylusStylus replacement (See Fig. 2)Replacement of the stylus can be easily made by simplyinserting the stylus plug (A) into the jack (B) of thecartridge. Service life of the stylus employed for thisunit (DT-Zl EB) is generally as follow; varying, depend-ing on the record condition (dirty record groove etc.Stereo LP record (30 cm) . . . Approx. 300 - 500 hoursStylus are disposable items. Therefore, it is recommendedto buy a supply of styli when you buy the unit. Whenpurchasing them, specify the DT-Zl EB (JVC standard).5-(2) HeadshellRemoval and mounting of the headshell (See Fig. 3)Turn the connector nut in the direction of A to removethe headshell from the tonearm. Turn it in the directionof B for mounting the headshell.5-(3) CartridgeMounting the cartridge (See Fig. 4)1. Remove the 2 screws securing the cartridge onto theheadshell.2. I nstall your cartridge onto the headshell provided oronto a headshell of your selection.3. The headshell lead wires are color-coded as followsconnect them correctly.White(+).L Red(+).BlueH LE Green(-) ., 4. Mount the cartridge properly onto the headshelland leave the set screws slightly loosened, then, aftercompleting the Overhang adjustment (See page 9)tighten them firmly. After this adjustment, be surethat the conditions concerning the 3 adjustments onpage 5 and 6 are satisfactorily met.5. After each cartridge replacement, be sure to performthe 4 adjustments described on page 9.(4) MotorHow to remove the motor (Fig. 5)Remove the motor in the following sequence. There isno need to remove the mechanisms base.1. Remove the stopper, main gear and spring attachedto the motor plate.2. Disconnect the plug connecting the motor with thespeed control circuit board.3. Remove the 4 screws securing the motor.4. Lift the trip lever as shown in the figure while takingcare not to deform it and remove the motor whiletilting it.5. Mount the motor, in the reverse order.QL-No. 2464Fig. 2Fig. 3, s-Cartridgewith stylusGreen: to RE or R- of cartridge Blue: to LE or L- of cartridg Red: to R+ or R of cartridge White: to L+ or L of cartrige j Headshell # lift 0Fig. 4Fig.(5) HQ/VQ Damping KnobsWhen replacement of VQ or HQ damping knob becomesnecessary, do it in the following sequence. How to replace the HQ damping knob (Fig. 6)1. Remove the 2 screws securing the HQ damping knoband remove the knob.2. Turn the HQ controller clockwise until it stops.3. Clamp the tonearm to its rest.4. Mount the new HQ damping knob on the HQ con-troller with the indication 3 on the knob alignedwith the index line. Secure it with the 2 screws.5. After replacing it, perform adjustment referring tothe section How to use on page 4. How to replace the VQ damping knob (Fig. 6)Replace in the same way as the HQ damping knob isreplaced.6. Lubrication6-(1) HQ/VQ Damping MechanismQL-F6 turntables are completely adjusted at the factoryprior to shipment. The damping mechanism cannot berepaired imd it is recommended that it be replaced ifit malfunctions.7. Adjustment ProceduresServo-motor Control SectionHa damping knobHa controllerIndex lineva controllerFig. 6Screwst.va damping knob6-(2) MotorThe motor needs no lubrication.6-(3) Fully Automatic MechanismApply high quality grease to connecting and sliding partsafter they are replaced.7 -( 1) QUARTZ LOCK/ PITCH CONTROL MeterHow to use the QUARTZ LOCK/PITCH CONTROLmeter (See Fig. 7-QUARTZ LOCK ():When the QUARTZ LOCK/PITCH CONTROL selectbutton (1) is depressed to tbe QUARTZ LOCK positionthe meter (2) becomes green-lit. In this mode the rota-tion speed is accurately controlled by phase-locking tothe quartz oscillator frequency. This means that correct33-1/3 or 45 rpm is obtained. The indicator (2) of themeter displays PITCH CONTROL (-):When performing fine pitch adjustment, depress theQUARTZ LOCK/PITCH CONTROL select button (1)to the PITCH CONTROL position and the meter be-comes orange-lit. In this mode, fine pitch adjustmentcan be performed by turning the PITCH CONTROLknob (3) within a range of :!: 6 %. Turning the knob inthe (+) direction (counterclockwise) increases the rpm.Turning it in the (-) direction (clockwise) decreases therpm. The meter indication of +6 % (#) shows the re-produced sound raised by approximately a half tone.Fig.The -6 % (b) indication shows the reproduced soundis lowered by approximately a half tone.By making these adjustments, record sound reproduc-tion meeting your preference can be obtained.QL-No. 2464How to make adjustments if the pitch control metershould indicate incorrectly (when the meter does notdisplay 0 in the QUARTZ LOCK operation). (SeeFig.1. Disconnect the power cord from the outlet.2. Remove the platter from the motor shaft.3. Turning the 0 position adjusting screw clockwisemoves the indication to the right.Turning this screw counterclockwise moves the indi-cation to tl:1e-left.Generally, there is no need for adjustment sinceproper adjustment has been performed at the factory.Should the indication of the meter be incorrectadjust it in the manner above.Adjustment of the FINE PITCH CONTROLmeter (See Fig. 7-Perform this meter adjustment referring to the itemsbelow after making mechanical adjustments pertainingto rpm or repairing the meter circuits.1. Function of the variable resistors used1) VRl (4.7k.Q):Connected in series with the meter and controlsthe current flowing into the meter. Used to adjustthe full-scale deflection (:1: 6 %) of the meter.2) VR2 (4.7k.Q).Employed for adjusting the pointer of meter toindicate the center position 0 at 33-1/3 rpmor 45 rpm.3) VR4 (47 k.Q):There is no need to adjust this variable resistorbecause of the automatic adjusting system. How-ever, adjustment in the following order is neces-sary after the motor is replaced or the circuit isrepaired. Turning VR4 to the right (clockwise) asseen from the circuit board decreases the speedand turning it to the left (counterclockwise)increases the speed and unlocks it. When it isunlocked platter rotation becomes unstable.Adj