Pioneer-SX5-rec-sm 维修电路原理图.pdf

cDrJroNEErShot/,n tn thb photo b Model SX-7.ORDER NO.ARP-047-OCOMPUTER CONTROLLEDSTEREO RECEIVERsx-7sx-6SX-s.SiX-EiLSX-,QISX-4L. The AM tuner of SX-4Lwave-band tuner with MWLW (long wave).and SX-SL is a two(medium wave) andModel SX-7 (and SX-6, SX-5 and SX-4) are newtypes of receivers featuring microcomputers foreasier operation. The AM/FM tuner stages incorpo-rate quartz PLL synthesizers for high stability,while the power amplifier stage is a non-switchingamplifier which achieves class A quality with classB efficiency (not included in the SX-4 model).PIoNEEF| ELECTFICINTC CCtFtFCtFtATtCtN 1 chome. Mesu.o ku. rokyo 153. J5p5nU.a. tfcritlaF alaC?Flo|llca CCFFC,;|AY|C|N a5 orro.d o. ve. Moonach e. New Je.sey O7O74, t)S AFlONaaE aL:ClFlC,lIC ll(rFCPC N.V. Lu thasen Haven I 2O3O A.we.p BergumFroNaatl an.actFctNlca aua?FAl-ra ETY. LYo. 1 7a 1Ba Bound ro. s 31 95. aust.6r,F H O AUG.1981 Printed in lapanRadioFans.CN 收音机爱 好者资料库BLOCK DIAGRAMSSX.4/KUFM FRONT ENOFM IF AMP A DETECTORFM MPX STEREO OEMOOULATORFREQUENCY OISPLAY-toonFx l-GNo !IF AHP A DETECTOR ICii#n i*- lTUNING OETECTORIC P06004R6R7 vooR 8R 9,o ffiR t lK OK IK 2K 3. I R QPOblPLL SYNTHESIZER CIRCUITFT4,/AM SLECTOR8CO TO OECIHAL OECOROER-4-r.:-:ItPx STEREooEcooR IcPOWER AMPLIFIERAUX / vroEoR . C HRECT FlADAPToiPLAYFUXCTION SELECTORi-X U T I N GCONTROL3 9 . 6 d 8 A T r t H r +rr r*S*_.Qp-q oFFTAPE,/AOAPT SW I HOOE SW-Ot moro orLOU0llESSsw: SPEAKERStfrl pxoHesr-_+_zi II f-)t *#l + - f lt -R.cx JlUN ERsEcrroflEq AXPFUIClOliSELECTOR2AC l2Ov 60HrRadioFans.CN 收音机爱 好者资料库SX-s/KUFH FROIIT EiTOFM IF AMP. A OETECTORFREQUETCY OISPLAYMPX STEREOocooER IcLEO tUTERIC OISPLAYIF AMP A OETECTOR IC,L- L-nnI l_t l_t .l_t l_tI oerscronII stGrALI METERI ourTUNING OETECTORIC P0500rrR t O R E S E TR r lKOr ( tK 2K !P Il R OPOd - _- stAlto.BYO lo:o! 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E( ) N | r ) o = t r ie3L*6CIRCUIT DESCRIPTIONSOutline of Main StageThe overall composition is outlined in the block diagnms on pp.2-6.r Tuner Stageo AM/FM Synthesizer Stage*MANUAL : Frequency changed in single steps each time the TUNING UP or DOWN hey is pressed. Frequencies scannedwhen pressed continuously, the scanning being stopped as soon as the hey is released.*STATION SCAN : Frequencies scanned. when either TUNING UP or DOWN key is pressed. Scanning pauses for 5seconds when a broad.casting station b tuned, and stops altogether if the MEMORY/STOP key is pressedwithin that 5 second period. Otherwise, the scanning is resumed.,*STATION SEARCH : Frequencies scanned when either TUNING UP or DOWN key is pressed, and stopped when abroadcasting station is tuned.sx-7sx-6sx-5sx-4l.D. MOS FET single-stage RFamplifier plus twin vari-captuning circuit (equivalent to4-ganged tuning capacitor) inFM front-end.Same as SX-7J-FET single-stage RF amplifierplus twin vari-cap tuning circuit(equivalent to 3anged tuningcapacitor) in FM front-end.Same as SX-SPLL lC stereo decoder stageSame as SX-7Same as SX-7Same as SX-7Vari-cap tuning circuit (equiva-lent to 2-ganged tuning capaci-torl in AM tuning stage and AMtuner lC lLA1247l.Same as SX-7Same as SX-7Same as SX-7sx-7sx-6sx-5sx-4lmproved S/N ratio achieved bypulse-swallow system for FMreception.S/N ratio 80dB(Mono)75dB (StereolSame as SX-7S/N ratio 8od8(Monol75dB(Stereo)Same as SX-7S/N ratio 75dB(Mono)TOdB(Stereo)Same as SX-7S/N ratio 75dB(Monol70dB(Stereo)Frequency memory (presetting)capability for up to 8 stations ineach band.Same as SX-7Frequency memory (presettinglcapability for up to 6 stationsin each band.In models including two AMbands (LW and MW), any LW orMW frequencies may be storedin the 6 AM memories.Same as SX-53 tuning modes:MANUALSTATION SCANSTATION SEARCHSame as SX-72 tuning modes:MANUALSTATION SCANonly the sTATloN scANtuning mode is available.o Amplifier Stageo Display Stagesx-7sx-6sx-5sx-4Equalizer amplifier features low-noise twin FET ICL differentialamplifier in first stage, and oper-ational amplifier (lC) in secondstage for MC cartridges.S/N ratio 8OdB(MM)67dB(MC)Equalizer amplifier features low-noise transistors differentialamplifier in first stage. and oper-ational amplifier (lC) in secondstage.S/N ratio 79dBOperational amplif ier (lC)euqalizer amplifier.S/N ratio 70dBSame as SX-SS/N ratioMicrocomputer controlled elec-tronic switching lC (PA40O8lfor function selector.Same as SX-7Same as SX-7Same as SX-7Microcomputer controlled VCAlC(PA5O04) volume controlfeatures 32-step control, pre-settable levels and audio rnuting(-2sdBl.Same as SX-7Conventional volume controlwith variable resistor.Same as SX-5Non-switching amplifier em-ployed in power amplifier stage.Output power 60W+60Wl2OHz-20kHzlRated distortion O.009%Same as SX-7Output power 45W+45W(20H2-20kHz)Rated distortion 0.OO9%Same as SX-7Output power 30W+30Wl2OHz-20kHzlRated distortion O.O2/Conventional class B ampli-f ierOutput power 20W+2OWl2OHz-2OkzlRated distortion O.O4%sx-7sx-6sx-5sx-4s-digit LED numeric display oftuned frequency.Same as SX-7Same as SX-716-point scale LED display oftuned frequency.LED numeric display of elec-tronic volume control levels.Same as SX-7Not featured in SX-5Not featured in SX-4LED numeric display of time(built-in quartz clock function).Not featured in SX-6Not featured in SX-SNot featured in SX-46-point LED display of outputpower.Same as SX-7Not featured in SX-5Not featured in SX-43-point LED SIGNAL indicarorindicating signal strength oftuned frequency.Same as SX-7TUNED indicator to show thatbroadcast station has beentuned.Same as SX-5Tuner StageO I.D. MOS FETThe FM front-end RF amplifier in model SX-?(and SX-6) features an I.D. MOS FET (ion-implan-tation dual gate MOS FET) - P001 manufacturedby Pioneer Semiconductor Laboratory. The majorfeatures of this FET - P001 include high gain,Iownoise, Iow distortion and low IM (P.G. 25dB/100MHz, N.F. 2dBl100MH2, I.M. -54d8/107dBp)as a result of an extremely accurate short channelobtained by a self aligning operation involvinga local silicon oxidation process. Furthermore,a O.4p narrow channel (1/3rd to 1/5th the widthin normal components) has been achieved by theion-implantation double diffusion construction.Use of this FET in the FM front-end greatlyassists in improving sensitivity and reducing inter-ference.o Pulse-Swallow PLL SynthesizerWhen the VCO (Voltage Controlled Oscillator)frequency is very high and the CMOS progmmm-able divider operating frequency is exceeded, thePLL will cease to function. Two methods arepresently available to resolve this problem. In oneof these methods (the fixed divider system), anECL (Emitter to Emitter Coupled Logic) prescaleris positioned in front of the programmable divider.And when, for example, a 1/10 prescaler is em-ployed to obtain 25kHz step frequencies, thereference frequency will be 2.5kHz. This frequencyis very low and cannot be adequately removed bythe low-pass filter. As a result, signal componentsare leaked into the mixer leading to deteriorationin the S/N ratio. This is one of the main dis-advantages of the fixed divider system.The other method available is the pulse-swallowsystem which employs a special frequency dividercalled a two-modulus prescaler instead of theprescaler used in the fixed divider system. In thismethod, a 25kHz step synthesizer will generate a25kHz reference frequency and a 50kHz stepsynthesizer will generate a 50kHz referencefrequency, resulting in a much higher S/N ratiothan in the fixed prescaler system.The pulse-swallow system employed in the SX-7is incorporated in an IC (M54922P) controlled bymicrocomputer.Amplifier Stageo Non-Switching Amplifier (SX-7, SX-6, SX-s)In non-switching amplifiers, the output stagetransistor bias is controlled on the basis of class Boperating point in order to maintain the operationwithin the operating region (between cutoff andsaturation) and thereby suppress the generation ofswitching distortion.The basic non-switching amplifier circuitry isoutlined in Fig. 1-2. To simplify the diagram,transistor Vgn and diode Vg, E1 and E2 areassumed to be 0.6V and the transistor base currentis disregarded. While no input signal is applied, thevoltage drop across R5 and R6 may also be dis-regarded. And if the voltage across R1 and R2 dueto idle current is ignored, the voltages at differentpositions will be as shown in the diagram.When an input signal is applied, a voltage will begenerated across Rt by NPN stage (Q1/Q3) oper-ation during the positive portion of the signal. Thisvoltage is applied to the Q5 emitter-follower(voltage gain of about 1) resulting in almost thesame voltage being generated across Rb. Thisvoltage is then added to the output stage biasvoltage. Hence, the PNP stage (Q2/Q4) maintainsthe same bias conditions as when no signal wasapplied, which means there is no cutoff. Likewise,the NPN stage maintains the same bias conditionsduring the negative portion of the signal as whenno signal was applied, again eliminating any cutoff.Fis. 1-1Pulse swallow systemIFig. 1-2 Basic circuitry of Non Switching AmplifierGontrol StageThe incorporation of microcomputers in thesereceivers has further simplified operationalprocedures. The PD6007 (SX-7) and PD6004(SX-6, SX-5 and SX-4) ICs are both basically thesame 4-bit microcomputer (with 2k-bit memorycapacity), the main difference lying in the softwareprogram. Whereas the PD6007 incorporates a clockfunction, the PD6004 features a 2 band (LW/MW)AM tuner switching function.The PD6007 and PD6004 pin configurations areshown in Fig. 1-3.E XlolXlolREEEitRososlscz roTroP rP2PrOoO lO zU 3O 5O 6V3sKIK2K lKOSTBYFiaRr5R r 2H t lRtoR eR ER7R6d5R4R5R2R rROFig. 1-3 Pin configuration of PD6007 (PD6004)iSETrRoSF5UfpII P .IlLPol-xoIl*l*LKoTCRl3Rt2-n,rII Ro1LRet l-nzILR6R5R.AF MUTE IND R3VOL. MEMORY R2VOL. lND. R rfoVOL. OATA I -our PUT | lolooLo.fo.DArA l-our PUT | loLooEXTALCLOCK INPUTKEY INPUTCLOCK INPUT(5OOHz)SCAN STOPMUTING OtITP.O.DATA /o)4.,INPIJT5-THDIGITo oR5ol _ _ M54s22P! | 5i- aM/AJ cPs RE.ETPA4lc4 FilC3 AMc2 PHOilOC AXIVIDOi, : ,.:, .,FUIICTIONSELECTfi IC10Fig. 1-4 System diagram of control section (SX-7)o Synthesizer ControlFig. 1-5 outlines the tuner-related computeroperation command input key matrix.Key description9k/10k : AM-MW band frequency step switch.ON for 9kHz steps, and OFF for 10kHzsteps.9k/1k (PD6004) : AM-LW band frequency stepswitching. ON for 9kHz steps, and OFFfor lkHz steps.TUNING AUTO/MANUAL : ON for auto tuning(x1), and OFF for manual tuning.SCAN/SEARCH : ON for short-time hold search(x2), and OFF for operation accordingto TUNING AUTO/MANUAL switch(*6).FM : Display of tuned frequency by singlepush (*3), and pin 16 of synthesizer IC(M54922P switched to L level (x4).AM : Display of tuned frequency by singlepush (*3), and pin 16 of synthesizer IC(M54922P) switched to H level (x).LW/MW (PD6004) : LW-MW switching with eachpush.M1 - M8 : Trned frequency presetting keys. Cor-responding STATION indicator lightsup (*5).TUNING UP, DOWN : Frequency tuning keys.MEMORY/STOP : Memory store enable key.STATION indicators (1 to 8) and thePRESET STEP indicator blinks on andoff for 5 seconds when pressed once.A broadcasting station and volume stepmay be stored in memory during this 5second period. And when pressedduring frequency scanning, the scann-ing operation is halted.EL,E2 : Switching for different regions (USA,Europe etc.) Wired up according toregion without switching.81, B2 (PD6004) : FM IF offset adjustment.(*1) Station search where frequencies are scanned bypressing ?UN/NG UP or DOWN key once. Scanningstops when broadcast station frequency is tuned.(*2) Station scan where frequencies are also scanned bypressing TUNING UP or DOWN key once. Scanningpauses for 5 seconds when broad,casting stationfrequency is tuned. Scanning will be resumed afterthe 5 second pause unless the MEMORY/STOP heyis pressed.(*3) 16-bit serial d.ata from the SO pin is sent to thefrequency display d,riuer IC (TD6301P), conuertedto 7-segment decimal data by transfer cloch (outputfrom Pg and P1 pins) for driuing the LED numericdisplay.LOCK SW. NON-LOCK SW.IlnAnjJFig. 1-5 Switch key matrix for synthesizer control(*4) The data transfened to M54922P contains 2O bits.These are diuided into 5 groups of 4 bits each by the4 pins Rg to R1y The transfer output clock isobtained from R6 and R7. The first 4 data items(16 bits) are used in programmable diuider frequencydiuision, while the Sth data item (4 bifs) is used foroperation mode designation.(*5) BCD encoded data from pins Og - Og is applied tothe BCD to decimal decoder IC (M74LS42P). Pins Ito 9 (excluding pin 8) correspond. to Ml to M8, andare switched to L leuel resulting in the LEDs beinglit up.(*6) Actual circuits are wired so that the K6 line to theSCAN/SEARCH switch is cut when the AUTO/MANUAL switch is in the MANUAL position. TheSCAN/SEARCH switch will be operatiue only whenin the AUTO position.NON - LOCK SW.r Function Selector ControlThe computer operation command input keymatrix for function selector control is outlined inFig. 1-6.Key descriptionPHONO : Pin 10 of the IC (M74LS42P) refenedto above (*5) is switched to L level (*7), andvolume st