Pioneer-CX961-cdm-sm 维修电路原理图.pdf

ModelService ManualCD Mechanism ModuleDEH-P90DAB/EW, ESCRT2556CXK5301PIONEER CORPORATION4-1, Meguro 1-Chome, Meguro-ku, Tokyo 153-8654, Japan PIONEER ELECTRONICS SERVICE INC. P.O.Box 1760, Long Beach, CA 90801-1760 U.S.A.PIONEER EUROPE NV Haven 1087 Keetberglaan 1, 9120 Melsele, Belgium PIONEER ELECTRONICS ASIACENTRE PTE.LTD. 253 Alexandra Road, #04-01, Singapore 159936C PIONEER CORPORATION 2000 K-ZZA. NOV. 2000 Printed in JapanORDER NO.CRT2503CD MECHANISM MODULECX-961ServiceManual- This service manual describes the operation of the CD mechanism module incorporated in modelslisted in the table below.- When performing repairs use this manual together with the specific manual for model under repair.CONTENTS1. CIRCUIT DESCRIPTIONS.22. MECHANISM DESCRIPTIONS.153. DISASSEMBLY .17RadioFans.CN 收音机爱 好者资料库2CX-9611. CIRCUIT DESCRIPTIONSThis unit is roughly divided into the preamplifier stage, servo unit, power supply unit and loading control unit. ThisLSI (large scale integrated circuit) implements eight automatic adjustments according to the combination of thepreamplifier stage and servo unit used.Besides, because this system conforms to the single power supply (+5 V) specifications, the reference voltages ofservo systems (preamplifier, servo DSP and pickup) are all Vref (2. 1 V).1.1 Preamplifier (TA2150FN; IC201)The preamplifier processes output signal from thepickup, then generates signals to the servo unit,demodulator unit and control unit at the next stage, andcontrols power for the pickups laser diode. The signalfrom the pickup is I-V converted by the preamplifierbuilt into the pickups photodetector, then added by theRF amplifier to obtain such signals as RF, FE and TE.Reference voltage Vref (2.1 V) is output from pin 19 ofthis IC and 2 Vref (4.2 V) is supplied as the referencevoltage which determines the D range of the servo DSPA/D input.Fig.1:TA2150FN CIRCUITRadioFans.CN 收音机爱 好者资料库3CX-9612) Tracking error amplifier unitThis tracking error amplifier unit outputs photodetectoroutput E or F from pin 14 of IC201 (TA2150FN)via anamplifier and an error amplifier assuming (E - F) as a TEsignal. The low frequency component of voltage TE isexpressed asTE = (E - F) 300 k / 100 k 155 k / 328 k 82 k / 20 k =5.8 times.A TE waveform of approximately 1.51 Vpp is obtainedin the TE output on the basis of Vref. The cutofffrequency is 44.5 kHz or 29.4 kHz.1) Focus error amplifier unitThis focus error amplifier outputs photodetector output(A + C) or (B + D) from pin 16 of IC201 (TA2150FN) via adifferential amplifier and an error amplifier assuming(A + C - B -C) as an FE signal. The low frequencycomponent of voltage FE is expressed asFE = (A + C - B - D) (150 k / 62 k) (60 k / 60 k) (12 k /60 k) = 4.84 times.An S curve of approximately 1.45 Vpp is obtained in theFE output on the basis of Vref. The cutoff frequency is26 kHz or 133 kHz.Fig.2:FE CIRCUITFig.3:TE CIRCUIT4CX-9613) RF amplifier unitThe head amplifier LSI, TA2150FN, adds, amplifies andequalizes photodetector output (A+C) and (B+D), thenoutputs RF signal to the RFI pin. (This signal enableschecking eye patterns.) Low frequency elementcontained in RFI voltage is formulated as follows: RFI = (A + B + C + D) 5.43.RFI is used for RF Offset Control circuit. RFI signaloutput from Pin 28 is AC-coupled externally, and thenre-input to Pin 27 and amplified by the RFAG amplifierto obtain RFO signal.As described later, TA2150FN has a built-in RFAGCfunction that controls the RFAGC amplifier gain so thatRFO output stays within 1.2 0.3V p.p. range.This RFO signal is used for EFM and RFAGC controlcircuit and for generating RFRP and RFCT signals fortrack counting.Besides, the frequency characteristics of an RFequalizer are switched at double-speed reproduction.(Switching using the HSSW terminal)Further, with RWSW the gain at the RF amplifier stageis raised by 13db, compared with that in normaloperation, when the gain lowers because of stains onthe lens or while playing a CDRW.Fig.4:RF CIRCUIT5CX-9614) RFRP and RFCT signal circuit unitThe RFCT signal which is the difference signal betweenthe peak and bottom levels of the RF signal isgenerated through head amplifier (IC201). RFRP andRFCT can be monitored at TP203 (pin 20 of IC201TA2150FN) and TP204 (pin 22 of IC201) respectively.The TE, RFRP and RFCT signals are compared by ahysteresis comparator inside IC301 (TC9495FP)respectively and generate track information (TEZCsignal or RFZC signal). Based on this signal, thetraveling speed information about a lens disk isgenerated and the number of tracks is counted.5) SBAD signal circuit unitThis SBAD signal circuit unit outputs photodetectoroutput E and F from IC201 (pin 15 of TA2150FN) via anaddition amplifier assuming (E + F) as an SBAD signal.This SBAD signal is used as the internal decisionconditions of focus ON/OFF with a focus error signal.Further, the SBAD signal is also used for detectingdefects when disk scratches are passed.Fig.5:RFRP AND RFCT SIGNAL CIRCUITFig.6:SBAD SIGNAL CIRCUIT6CX-9616) APC circuit sectionA laser diodes driving current must be controlled so thatoptical output could remain constant by using a monitoringdiode, because optical output has high negativecharacteristics that causes a heat hang-up if the laser diodewere driven at constant current. This is exactly where APCcircuit works. LD current can be obtained by measuringvoltage between LD1 and GND, which value is about 35 mAat room temperature.1.2 Servo DSP (TC9495FP; IC301)1) Focus servo systemThe main equalizer of the focus servo is comprised with adigital equalizer unit. Fig. 8 shows a block diagram of thefocus servo.Fig.7:APC CIRCUITIC401BA5811FMFOPIC301TC9495FPDACA/DFOCUSEQUALIZERFEFEIFOOFDFOMCNOTRLOFOCUS SEARCHWAVEFORMGENERATION CIRCUIT431348145Fig.8:FOCUS SERVO CIRCUIT BLOCK7CX-961The operation of detecting an adjusted focus point andturning on the focus servo is called focus search. In afocus servo system, a lens needs to move to theadjusted focus point to enable focus close.Accordingly, the adjusted focus point is detected bymoving the lens up and down according to the focussearch voltage of a triangular wave. Further, in themeantime, a spindle motor enters the simplified FGmode and maintains a constant speed of rotation. Thefocus servo turns on under the following threeconditions:1. FOK = H2. A focus error signal exceeds a focus standby levelthreshold.3. A focus error signal reaches a zero cross.At this time, while the lens is fully separated from theadjusted focus point, cancel the SBAD offset and setthis level to SBOFF. If the SBAD level exceeds the FOKthreshold from the SBOFF standard, FOK = “H” is set.When the lens moves up and down, a focus error signalchanges at the adjusted focus point. However, CD-LSIremoves an offset component by passing through abypass filter after it has A/D-converted this error signal.When this FEHPE signal (LSI signal) level exceeds afocus standby high level, the servo standby stateoccurs because the adjusted focus point approaches.Subsequently, the FEHPF signal reaches the adjustedfocus point and turns on the focus servo.The microcomputer monitors an FOON signal (Active atservo ON; L for a probe) at focus search, and startsmonitoring a FOK signal in 40 ms after it has been setto Active). If it is judged that FOK is not active, themicrocomputer performs protection operation.Besides, when the Focus Close button is pressed withthe focus mode select set to Display 01 in the testmode, a focus error, search voltage and the action of apractical lens can be checked.2) Tracking servo systemThe main equalizer of the tracking servo is comprisedwith a digital equalizer unit. Fig. 10 shows a blockdiagram of the tracking servo.Fig.9:FOCUS SEARCH TIMINGOFFSETFOCUS SERVO ONFEI INPUT WAVEFORM : FEHIGH PASS FILTER OUTPUT : FEHPFHIGH PASS FILTERSTANDBYLEVELF1F1FOCUS SERVO ONREF LEVELSTANDBY LEVEL : F115.(3)FOCUS SERVO ONREF LEVELFEHPFSBADFOKFOONFOK LEVEL88.1kHz127 SAMPLESBOFF LEVELDEFECT(SCRATCHES)=TOKIC401BA5811FMCARRIAGEMOTORCOMTOPIC301TC9495FPDACA/DTRACKINGEQ+AT THE TIME OF LENS KICKTETEITROMTDTOMCOPCARRIAGEEQ+PWMFMOAT THE TIME OF FEED KICKJUMPCONTROLTEZIRFRPSD46474953616151211252642Fig.10:TRACKING SERVO CIRCUIT BLOCK8CX-961 Track jumpA track jump is automatically performed with amicrocomputer command using the LSI auto(automatic) sequence function.This system has one to 99 lens kick modes as the trackjump used at search and the carriage move used in thejump exceeding 1,000 tracks. The test mode can checkthe jump of lens kick modes 1, 32 and 99 and thecarriage move according to the mode selection. Lens kick JumpLens Kick jump is executed as soon as the LSI receivesthe Lens Kick command from the microcomputer. Thedirection of jump and the number of tracks aredetermined by the commands parameters. When theLSI receives the Lens Kick command, the jump isperformed by inputting a kick pulse to the tracking EQ.The LSI controls lens traveling speed, referencing to thetable held internally. By doing so, the lens travels fasterwhen there are a good number of tracks to go, whilethe lens traveling speed gets slower as the remainingtracks decrease. After track count has been completed,tracking close is performed. During jump, an RFRPsignal is watched to perform track count and thedirection of the jump is detected according to the phaseof RFRP or TEZI. Besides, to improve the servo feed attrack jump, the tracking servo gain increase andhysteresis operation are performed for 50 ms aftertracking close has been completed. The FF/REVoperation in the normal mode is implemented bycontinuously performing a single jump. The speed isabout 10 or 20 times the normal mode. (It depends ondestinations). Carriage move jumpA carriage move jump is executed by issuing a carriagemove command from the microcomputer. Thedirection of the move and the number of tracks arespecified with the command. When the LSI accepts thecarriage move command, the jump is performed byopening the tracking servo, applying a kick signal to thecarriage equalizer and driving the carriage motor. Theprofile of a signal applied in this time is provided with atime constant at rise time. As the remaining tracksdecrease, voltage is lowered that results in slowercarriage traveling speed.The servo feed at the end of the jump is improved byreducing the speed in this manner immediately beforethe jump terminates.Besides, to improve the servo feed at the end of thejump, the tracking servo gain increase and hysteresisoperation are performed for 60 ms after the jump hasbeen performed.EQUALIZERHYSTERESISCLOSEGAIN UPNORMALTERFZC(LSI INTERNAL SIGNAL PRODUCED FROM RFRP)(LSI INTERNAL SIGNAL PRODUCED FROM TEI)TEZCSERVOOPENONOFF50msTHE HYSTERESIS OPERATION OF THE1-4 TRACK JUMP IS 2 ms.50msFig.11:LENS KICKSDTESERVOEQUALIZERHYSTERESISOPENCLOSEGAIN UPNORMALONOFF60ms60msFig.12:CARRIAGE MOVE9CX-961 Hysteresis operationBecause the servo feed is deteriorated at setup andtrack jump, hysteresis is operated to perform a servofeed to a stable servo loop. The hysteresis operationholds a TE signal and improves the convergence of thetracking servo when a beam spot arrives at an off track.3) Carriage servo systemThe carriage servo inputs the output of the lowfrequency component (lens position information) of thetracking equalizer to the carriage equalizer, and outputsa drive signal from the LSI after a fixed gain has beenobtained. The signal further applies to the carriagemotor via the driver. Specifically, because the entirepickup needs to move to the forward direction whenthe lens offset during play reaches a certain level, thegain of the equalizer is set so as to output a highervoltage than the starting voltage of the carriage motorat that time. Besides, as a practical operation, onlywhen a threshold level against the equalizer output isexceeded inside the servo LSI, a drive voltage is output.The threshold level is set slightly higher than thestarting voltage of the motor to reduce powerconsumption and stabilize operation. This drive outputwaveform has a pulse shape.Fig.14:CARRIAGE SERVO CIRCUIT BLOCKFig.15:CARRIAGE SIGNAL WAVEFORMDIGITAL EQUALIZERCONTROLPMW OUTPUT CIRCUITCOPCOMCRGMOTORIC401BA5811FMSDFMOMIC301 TC9495FPfromTRACKINGEQUALIZER1615252653TRACKING DRIVE(LOW FREQUENCY)LENS POSITIONCRG MOTOR VOLTAGEDRIVE ON/OFF THRESHOLDCRG DRIVE(INSIDE TC9495FP)CRG moved at these point4) Spindle Servo SystemFig. 16 shows a block diagram of the spindle servo.The spindle servo has the following modes: CLV servoThis CLV servo mode is the servo until the brake isapplied to stop the disk after focus close. The spindleservo operates in this mode before tracking close andat normal reproduction.In the EFM demodulation block inside the CD-LSI, thespindle servo performs synchronous detection andoperates so as be kept in a specified speed of rotation.The synchronous detection is also enabled beforetracking close by using the VCO speed control of theinside of the LSI in the PLL circuit. After tracking close,the VCO speed control is muted and switched to thespeed and phase control by a master clock (a ceramicoscillator is used).IC401BA5811FMIC301 TC9495FPPWMSYNCHRO-NOUS DETECTIONMDDIGITALEq.EFMECBrushlessMotor UnitMechanism UnitSPEEDERRORPHASEERRORFGVCOMasterClock232254TE SIGNALDIRECTION OF THE EXTERNAL SURFACEDIRECTION OF THE INTERNAL SURFACERFRP SIGNALAFTER TE SIGNAL HOLDON TRACKON TRACKON TRACKON TRACKFig.13:HYSTERESIS OPERATIONFig.16:SPINDLE SERVO CIRCUIT BLOCK10CX-961 Simplified FG servo modeThis simplified FG servo mode is used to maintain thenumber of disk rotations in the state of the approximatenumber of regular rotations. In this mode, controllingdriving voltage for the spindle motor is enabled byletting the microcomputer monitor FG signal thatoutputs pulses based on the number of rotations. Themode is used in the following conditions:a) Until focus close is performed from POWER ON atsetupb) Until focus is out of order during play and recoveredlater Brake modeThis brake mode is used to stop the spindle motor. Thebrake sequence is started by issuing a CD-LSIcommand from the microcomputer. The LSI sets a flagon by detecting that the number of disk rotations wasset to approximately one twentieth. This flag ismonitored by the microcomputer to set the servo off.When no flag is set on even if a fixed time elapses, thebrake mode enters the stop mode until it is checkedthat the rotation was delayed by monitoring the FGpulse. If the mode is switched to the stop mode atejection, the operation moves to the ejection operationafter the timeout time elapses. Stop modeThis stop mode is used at POWER ON and ejection.The drive output is 0.1.3 Automatic Adjustment FunctionThis system automates all circuit adjustments insideCD-LSI (IC301: TC9495FP). All the adjustments areperformed every time at disk insertion or source key CDmode selection.The contents of each automatic adjustment aredescribed.1) Automatic TE and FE offset controlsThese controls are used, at powering on, to have the TEand FE amplifiers offset value