Pioneer-CX958-cdm-sm 维修电路原理图.pdf

Model No.Order No.CD Mechanism ModuleMechanism UnitDEH-P410/X1N/UCCRT2414CXK5201CXB4800DEH-P4100/X1N/UCDEH-P310/X1N/UCDEH-P41/X1N/UCCRT2415CXK5201CXB4800DEH-P3100/X1N/UCDEH-P4150/X1N/ESCRT2416CXK5201CXB4800DEH-P3150/X1N/ESDEH-P4100R/X1N/EWCRT2417CXK5201CXB4800DEH-3110/X1N/EEDEH-3130R/X1N/EWCRT2418CXK5201CXB4800DEH-3100R-B/X1N/EWDEH-3100R/X1N/EWPIONEER 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 ELECTRONIC EUROPE N.V. Haven 1087 Keetberglaan 1, 9120 Melsele, Belgium PIONEER ELECTRONICS ASIACENTRE PTE.LTD. 253 Alexandra Road, #04-01, Singapore 159936C PIONEER CORPORATION 1999 K-ZZA. OCT. 1999 Printed in JapanORDER NO.CRT2423CD MECHANISM MODULECX-958- This service manual describes the operation of the CD mechanism incorporated in models listed in thetable below.- When performing repairs use this manual together with the specific manual for model under repair.CONTENTS1. CIRCUIT DESCRIPTIONS.22. MECHANISM DESCRIPTIONS.173. DISASSEMBLY .18RadioFans.CN 收音机爱 好者资料库2CX-9581. CIRCUIT DESCRIPTIONSThe LSI (UPD63711GC) used on this unit comprises six main blocks ; the pre-amp section, servo, signal processor,DAC, CD text decoder (not used on this model) and LPF. It also equips with nine automatic adjustment functions.1.1 PRE-AMP SECTIONThis section processes the pickup output signals tocreate the signals for the servo, demodulator andcontrol.The pickup output signals are I-V converted by the pre-amp with the built-in photo-detector in the pickup, thenadded by the RF amp to obtain RF, FE, TE, TE zero crossand other signals.This pre-amp section is built in the servo LSIUPD63711GC (IC201). The following describes functionof each section.Since this system has a single power supply (+5V), thereference voltage for this LSI and pickup are set toREFO (2.5V). The REFO is obtained by passing theREFOUT from the LSI through the buffer amplifier. TheREFO is output from Pin 89 of this LSI. Allmeasurements are done using this REFO as reference.Note : During the measurement, do not try to short theREFO and GND.1) APC Circuit (Automatic Power Control)When the laser diode is driven with constant current,the optical output has large negative temperaturecharacteristics. Thus, the current must be controlledfrom the monitor diode so that the output may beconstant. APC circuit is for it. The LD current is obtainedby measuring the voltage between LD1 and V+5. Thevalue of this current is about 35mA.71727476AGCI77RFO757879807391909392C-3TFEOFE-TEOTE-858687E97PD99PNFD828384BCARF-EQ1EQ2AGCORFIASYEFMPEAK DET.LPFBOTTOM DET.S/HD/AA/DD/AA/D9498TE2LDVREGGNDAPNLDONEFMDEFECTFOKA3TMIRRTo thefollowing stageof the LSIVrefVrefVrefVrefVrefVrefVrefVrefVrefVrefVrefVrefVrefVrefVrefVref(+2.5V)97PD99PN98LDVREGGNDAMP_PN(H:Nch L:Pch)LDON(H:LD MOVE L:STOP)VrefVref(+2.5V)145R10210R10112Q1012SB1132C1020.1FC103100F/6.3VPU UNITR1032.2kC1050.33F+5V1k110k3p3p150k100k100k16k1kFig.1 : BLOCK DIAGRAM OF BUILT-IN RF AMPLIFIERFig.2 : APC CIRCUITRadioFans.CN 收音机爱 好者资料库CX-95832) RF Amplifier and RFAGC AmplifierThe photo-detector outputs (A + C) and (B + D) areadded, amplified and equalized on this LSI and thenoutput to the RFI terminal as the RF signal. (The eyepattern can be checked by this signal.)The RFI voltage low frequency component is :RFI = (A + B + C + D) 3.2RFI is used on the FOK generator circuit and RF offsetadjusting circuit.R207 is an offset resistor for maintaining the bottomreference voltage of the RFI signal at 1.5 VDC. The D/Aoutput used for the RF offset adjustment (to bedescribed later) is entered via this resistor.After the RFI signal from Pin 77 is externally ACcoupled, entered to Pin 76 again, then amplified on theRFAGC amplifier to obtain the RFO signal.The RFAGC adjustment function (to be described later)built-in the LSI is used for switching feedback gain ofthe RFAGC amplifier so that the RFO output may go to1.5 0.3Vpp.The RFO signal is used for the EFM, DFCT, MIRR andRFAGC adjustment circuits.3) RFOK CircuitThis circuit generates the signal that is used forindicating the timing of closing the focus or state of thefocus close currently being played. This signal is outputfrom Pin 4 as the FOK signal. It goes high when thefocus close and in-play.The RFOK signal is generated by holding DC level of theRFI at its peak with the succeeding digital section, thencomparing it at a specific threshold level. Thus, theRFOK signal goes high even if the pit is absent. Itindicates that the focus close can take place on the discmirror surface, too.This signal is also supplied to the micro computer viathe low pass filter as the FOK signal and used for theprotection and the RF amplifier gain switching.CN10184613838210k10k85FOKCIRCUITA/D4A+C16kB+D10k16k10kR20712kC216 3pFR20510kR2061.8kC21727pFR20410k807974757677D/A12k6610kRFOAGCIRFIC2150.1FC2133900pFFOKTO EFMCIRCUITFig.3 : RFAMP, RFAGC AND FOK CIRCUIT4CX-958Fig.5 TRACKING ERROR AMPLIFIER AND TRACKING ZERO CROSSING AMPLIFIER4) Focus Error Amplifier The photo-detector outputs (A + C) and (B + D) are passedthrough a differential amplifier and an error amplifier, andthen (A + C B D) is output from Pin 91 as the FE signal.The FE voltage low frequency component is :FE = (A + C B D) = (A + C B D) 5Using REFO as the reference, an S-curve of approximately 1.5Vpp is obtained for the FE output. The final-stage amplifiercutoff frequency is 11.4 kHz.5) Tracking Error AmplifierThe photo-detector outputs E and F are passed througha differential amplifier and an error amplifier, and then(E F) is output from Pin 93 as the TE signal. The TEvoltage low frequency component is :TE = (E F) = (E F) 6.6 (Effective LSI output is 5.0).Using REFO as the reference, the TE waveform ofapproximately 1.3 Vpp is obtained for the TE output.The final-stage amplifier cutoff frequency is 20 kHz.6) Tracking Zero Crossing AmplifierTEC signal (the tracking zero crossing signal) isobtained by multiplying the TE signal four times. It isused for locating the zero crossing points of thetracking error. The zero cross point detection is done forthe following two reasons :1 To count tracks for carriage moves and track jumps.2 To detect the direction in which the lens is movingwhen the tracking is closed (it is used on thetracking brake circuit to be described later).The TEC signal frequency range is 300 Hz to 20 kHz.TEC voltage = TE level 4Theoretical TEC level is 5.2V. The signal exceeds D-range of the operational amplifier and thus is clipped.It, however, can be ignored since this signal is used bythe servo LSI only at the zero crossing point.20k5kCN10184613838210k20k5k85A+C16kB+D48k16k10k9190D/A80k110kFEC219 180pFA/DFE OFFSETTO DIG. EQ48k48.7kCN10191186112k48.7k87FEF224kE48k224k112k9392D/A80k110kTEC220 51pF80k110kA/DTE OFFSETTO DIG. EQ48k60k20k9594TE2TECC2216800pF16k10k80k(20k + 5k)Fig.4 : FOCUS ERROR AMPLIFIER224k112k160k48.7kCX-9587) DFCT (Defect) CircuitThe DFCT signal is used for detecting defects on themirrored disc surface. It allows monitoring from theHOLD pin (Pin 2). It goes high when defects are foundon the mirrored surface.The DFCT signal is generated by comparing the RFamplified signal (which is obtained by bottom holdingthe RFO signal) at a specific threshold level by thesucceeding digital section.Stains or scratches on the disc can constitute thedefects on the mirrored disc surface. Thus, as long asthe DFCT signal remains high in the LSI, the focus andtracking servo drives are held in the current state sothat a better defect prevention may be ensured.8) 3TOUT CircuitThe 3TOUT signal is generated by entering disturbanceto the focus servo loop, comparing phase offluctuations of the RF signal 3T component against thatof the FE signal at that time, then converting the signalto DC level. This signal is used for adjusting bias of theFE signal (to be described later). This signal is notoutput from the LSI, thus its monitoring is not available.9) MIRR (Mirror) CircuitThe MIRR signal shows the on track and off track data,and is output from Pin 3.When the laser beam isOn track : MIRR = LOff track : MIRR = HThis signal is used on the brake circuit (to be describedlater) and also as the trigger to turn on track countingwhen jumping take place.The MIRR signal is supplied to the micro computer, too,for the protection purpose.A/DMIRRCIRCUIT3TCIRCUITDFCTCIRCUITBOTTOM DETECTBOTTOM DETECTPEAK DETECTLPFS/HA/DA/D7675733240k20k20k40k40k40k200k200kC2120.1FC3TAGCIRFO12k10k20k30kMIRRHOLDFig.6 : DFCT, MIRR AND 3T DETECTION CIRCUITFig.7 : HOLD OUTPUT WAVEFORM(When surface defects are present)Fig.8 : MIRR OUTPUT WAVEFORM(When an access is made)5Surface defectsRFIHOLDRFIMIRROFF TrackON Track6CX-95810) EFM CircuitThis circuit is used for converting the RF signal todigital signal consisting of “0” and “1”. The RFO signalfrom Pin 75 is externally AC coupled, entered to Pin 74,then applied to the EFM circuit.Loss of the RF signal due to scratches or stains on thedisc, or vertical asymmetry of the RF due to variationsin the discs manufactured cant be eliminated by ACcoupling alone. This circuit, therefore, controls thereference voltage ASY on the EFM comparator by useof the fact that “0” and “1” appear fifty fifty in the EFMsignal. By this arrangement, the comparate level isconstantly maintained at almost center of the RFOsignal level. The reference voltage ASY is generatedwhen the EFM comparator output is passed throughthe low pass filter. The EFM signal is output from Pin71. It is a 2.5 Vp-p amplitude signal centering on REFO.74RFI40k40kC2133900pF7271ASYEFM40k40k15k75k2kR20210kR20339kC2110.1FC2103300pFEFM. SIGFig.9 : EFM CIRCUIT7CX-9581.2 SERVO SECTION (UPD63711GC :IC201)The servo section controls the operations such as errorsignal equalizing, in focus, track jump and carriagemove. The DSP is the signal processing section usedfor data decoding, error correction and interpolationprocessing, among others.This circuit implements analog to digital conversion ofthe FE and TE signals generated on the pre-amplifier,then outputs them through the servo block as the drivesignal used on the focus, tracking and carriage system.The EFM signal is decoded on the signal processingsection and finally output via the D/A converter as theaudio signal. The decoding process also generates thespindle servo error signals which is fed to the spindleservo block to generate the spindle drive signal.The focus, tracking, carriage and spindle drive signalsare then amplified on the driver IC BA5985FM (IC301)and fed to respective actuators and motors.1) Focus Servo SystemThe focus servo main equalizer is consisted of thedigital equalizer. Fig.10 shows the focus servo blockdiagram.When implementing the focus close on the focus servosystem, the lens must be brought within the in-focusrange. Therefore, the lens is moved up and downaccording to the triangular focus search voltage to findthe focus point. During this time, the spindle motor iskicked and kept rotating as a set speed.The servo LSI monitors the FE and RFOK signals andautomatically carries out the focus close at anappropriate point.The focus closing is carried out when the followingthree conditions are met :1 The lens approaches the disc from its currentposition.2 RFOK = H3 The FZC signal is latched at high after it has oncecrossed the threshold set on the FZD register (Edgeof the FZD).As the result, the FE ( = REFO) is forced to low.FEAMPDIG.EQ82A+CB+DFDFOPFOMIC301BA5985FMLENSIC201 UPD63711GC8562271615FOCUS SEARCHTRIANGULAR WAVE GENERATORDACCONTROLA/DFig.10 : FOCUS SERVO BLOCK DIAGRAM8CX-958When the above conditions are all met and the focus isclosed, the XSI pin goes to low from the current high,then 40 ms later, the microcomputer begins to monitorthe RFOK signal after it that has been passed throughthe low pass filter.When the RFOK signal is recognized as low, the microcomputer carries out various actions includingprotection.Fig.11 a series of operations carried out relevant to thefocus close (the figure shows the case where focusclose is not available).You can check the S-curve, search voltage and actuallens behavior by selecting the Display 01 for the focusmode select in the test mode, and then pressing thefocus close button.REFOFDLENS POSITIONRELATIVE TO DISCNEARFARJUST FOCUSEDMDREFOExpanding around Just Focused PointREFORFIFOKFEFZDTHRESHOLDLEVEL FZD(INTERNAL SIGNAL)Focus closing would normally take place at these points XSI(IN THE EVENTFOCUS ISCLOSED)LEVELFig.11 : FOCUS CLOSE SEQUENCE9CX-9582) Tracking Servo SystemThe digital equalizer is employed for the main equalizeron the tracking servo. Fig.12 shows the tracking servoblock diagram.a) Track jumpWhen the LSI receives the track jump command fromthe microcomputer, the operation is carried outautomatically by the auto sequence function of the LSI.This system has five types of track jumps used for thesearch : 1, 4, 10, 32 and 32 3. In the test mode, inaddition to three jumps (1, 32 and 32 3), move of thecarriage can be check by mode selection. For trackjumps, the microcomputer sets almost half of tracks (5tracks for 10 tracks, for instance) and counts the setnumber of tracks using the TEC signals. When themicrocomputer has counted the set number of tracks, itoutputs the brake pulse for a fixed period of time(duration can be specified with the command) to stopthe lens. In this way, the tracking is closed and normalplay is continued.To improve the servo loop retracting performance justafter the track jump, the brake circuit is turned on for 50ms after the brake pulse has been terminated toincrease gain of the tracking servo.Fast forward and reverse operations are realized bythrough consecutive signal track jumps. The speed isabout 10 times as fast as that in the normal mode.TEAMPDIG.EQ86FETDTOMTOPIC301BA5985FMLENSIC201 UPD63711GC876325221718JUMPPARAMETERSDACCONTROLA/DR30310kR30215kt1t2GAIN NORMALTDKICKBRAKETECT. BRAKEEQUALIZERT. SERVOCLOSEDOPENNORMALGAIN UPOFFONt1TDTEC(10 TRACK)EQUALIZERT. BRAKESERVOSD2.9mS (4.10 TRACK JUMP)5.8mS (32 TRACK JUMP)GAIN UPNORMALONOFFOPENCLOSEDt250mStFig.12 : TRACKING SERVO BLOCK DIAGRAMFig.13 : SINGLE TRACK JUMPFig.14 : MULTI-TRACK JUMP10CX-958b) Brake CircuitThe servo retracting performance can be deteriorateduring the setup or track jump operation. In thisconnection, the brake circuit is used to ensure steadyretract of the tracking servo. The brake circuit detects inwhich direction the lens is moving, then slows down itsmove by outputting the drive signal that moves thelens into the opposite direction alone. Track slippagedirection is determined by referencing the TEC andMIRR signals and their phase.TECTZC(TEC SQUARED UP )(INTERNAL SIGNAL )MIRRMIRR LATCHED ATTZC EDGES=SWITCHING PULSEEQUALIZER OUTPUT(SWITCHED)DRIVE DIRECTIONNote : Equalizer output assumed to hava same phase as TEC.FORWARDLENS MOVING FORWARDS(INNER TRACK TO OUTER)LENS MOVING BACKWARDSTimeREVERSEFig.15 : TRACKING BRAKE CIRCUIT11CX-9583) Carriage Servo SystemThe carriage servo supplies the tracking equalizersl