Pioneer-SX3800-rec-sm1 维修电路原理图.pdf

Sefvice nualFM Ouartz LockedSTEREO RECEIVERii,i i, i,., s r - ft3rc:rl ttr:;!; L *,.ir*.ts(/ -i- pSc2.ies- -borf o Sla&t-1r,:.-i,six-gaoo(DrrroNER.RadioFans.CN 收音机爱 好者资料库MODEL SX.38OO COMES IN FOUR VERSIONS DISTINGUISHED AS FOLLOWS:TypeVolt4eRemarksKU120V onlyU.S.A. models/G1 10V, 120V, 22QV, and 240V (Switchable)U.S. Militarv models1 10V, 12OV, 22OY , and 24OV (Switchabte)General exDort modelKCl20V onlyCanada modelr This service manual is applicable to the KU type. When repairing the S/G and S Wpe, pleasesee the additional service manual lp 47 -p571. When repairing the KC type. olease see the a-dditional service manual (ART-519).CONTENTSI;tHHHnIHHHHTHHIitII+1. SPECIFICATIONS2, FRONT PANEL FACILITIES3. BLOCK DIAGBAM4. CIRCUIT DESCRIPTIONS4.1 FM Tuner4.2 AM Tuner4.3 Display Circuit4.4 EqualizerAmplifier4.5 Tone Control Amplifier4.6 Power Amplif ier . . .4.7 Power Indicator Circuit4.8 Protection CircuitD I S A S S E M B L Y . . . .PARTS LOCATIONDIAL CORD STRINGINGADJUSTMENTS8,1 FM Tuner8.2 AM Tuner 228.3 PowerAmplifier. 238.4 FL Indicator Circuit 249. EXPLODED VIEW 2510. SCHEMATIC DIAGRAM, P.C. EOARDCONNECTION DIAGRAM AND PARTS LIST10. 1 Schematic Diagram 3l10.2 P.C. Board Connection Diagram 351 0 . 3 P a r t s L i s t . . . , . . . 4 11 1 . P A C K | N G . . . . 4 6ADDITIONAL SE RV ICE MANUALI . S P E C | F | C A T | O N S . . . . . 4 72. CONTRAST OF MISCELLANEOUS PARTS . . . . 483. SCHEMATIC DIAGRAM, P.C. BOARDPATTERNS AND PARTS LIST3. 1 Schematic Diagram 493.2 Switch Assembly AWS.148) 575.18.357Ioo1 21 21 214141 61 71 920eRadioFans.CN 收音机爱 好者资料库IItrttttIttTttttItI1. SPECTFTCATIONSPower Ampl if ier SectionContinuous Power 0utput of 60watts* per chan-nel, min., at Sohms from 20Hertz to 20,000Hertz with n0 m0re than 0.005% total harmonic distortion,Total Harmonic Distortion (20 Hertz to 20,000 Hertz,I ohms)continuous rated power output . . No more than 0.005%30 watts per channel power outputNo more than 0.005%Intermodulation Distortion (50 Hertz : 7,000 Hertz = 4 : 1)continuous rated power output No more than 0.0057o30 watts per channel power outputNo more than 0,005%Frequency Response. . . . . 5 Hertz to 200,000 Hertz l! OAlnput Sensitivity/lmpedance (POWER AMP lN)or,rri 1v/50 kilohmsSpeaker A, B, A+B-: : : 1*: 1o i* He*z 8 0hms)Hum and Noise (lHF, short-circuited, A network)115d8Preamplifier SectionI nput (Sensitivity/l mpedance)PHONO 2.5mV/50 kilohmsAUX,TAPE PLAY 1,2 . . . . . . 150mVl50kilohmsPhono Overload Level T.H.D.0.005%, 1,000 Hertz)PHONO . . . 250mVOutput ( Level/l mpedance)T A P E R E C I , 2 . . . . , . 1 5 0 m VPREAMP OUT (Rr_: 50 kilohms)- . . . . 1 V / l k i l o h m s V o l u m e : m a x . Total Harmonic Distortion (20 Hertz to 20,000 Hertz)Tone ControlBASS . tSdB (100H2)T R E B L E . . . . . r , l 0 d B ( 1 0 , 0 0 0 H 2 )Subsonic Filter . 15Hz (-6dB/oct.)Loudness Contour (Volume control set at *40d8 position). . . . +6dB (100H2),+3dB (10,000H2)Hum and Noise (lHF, short-circuited, A network)P H O N O . . . . . . 8 2 d 8A U X , T A P E P L A Y 1 , 2 . . , . . . . 1 1 O d BAttenuator. .-20d8FM Tuner SectionPHONO (REC OUT)AUX,TAPE PLAY 1,2 . . . . . .Frequency BesponsePHONO (RIAA Equalization)or, iori ,ro i ,;ou to 20000 Hertz t02dBUsable Sensitivity (lH F )50dB Ouieting SensitivityMONOSTEREOSignal-to-Noise RatioMONOSTEREODistortion (at 65dBf)MONO l00Hz.l k H z .6kHz .STEREO IOOHz.lkHz .6kHz -Capture Ratio. ,Alternate Channel Selectivity4 0 0 k H z . . , . . , 7 f t 8Stereo Separation1 k H z . . . . . . . 4 5 d 83 0 H 2 t o 1 5 k H 2 . . . . . . . 3 5 d BFrequency Response. . . . 2 H z t o 1 5 k H z 1 ! l o eSpuriousResponse Ratio, . . . . . . 65dBlmageResponseRatio . 65dBl F R e s p o n s e R a t i o . . . . . . 9 0 d BAMSuppressionRatio . 55dBSubcarrierProduct Ratio . . . . . . . 50dBSCARejectionRatio . 64dBMuting Thteshold 19.2dBf (5pV)Antenna lnput . 300 ohms balanced,75 ohms unbalanced.10.3dBf 1.8itv)16.2dBf (3.6sV)37dBf (39pV)83dB (at 65dBf)78dB (at 80dBf,0.1o/oa.a7%0.15%O.2Yo0.15%0.25%r.odBNo more than 0.005%10V outputNo more than 0.005%(10V output)7Hz to 8o,0oo Hertz f aaEix-3El00Itr|r|ttt;ttttrltrltil+AM Tuner SectionSensitivity (lHF, Ferrite antenna). . 300pV/mlHF, Ext.antenna . . . 15pVS e l e c t i v i t y . . . . . 3 0 d 8Signal-to-NoiseBatio . 50dBlmageResponseRatio . 40dBl F R e s p o n s e R a t i o . . . . . . 4 0 d BAntenna . FerritelooostickantennaAudio SectionOutput ( Level/l mpedance)F M ( 1 0 0 % M o d . ) . . . . . . 6 5 0 m V l 1 k i l o h m sA M ( 3 O % M o d . ) . . . . . . 2 0 0 m V / 1 k i l o h m sSemiconductorsf C s . . . . . . . . . . 1 7F E T s . . . . . . . . 6T r a n s i s t o r s . . . , . 7 1D i o d e s . . . . . . . 5 8MiscellaneousPowerRequirements . ACi20V,60HzPowerConsumption . . 200W(ULlDimensions .506W x164H) x434Dmm19-15116(W) x6-7/16(H) x 17-1116(D) inWeight (without package) 16.2k9 (351b 12oz)Furnished PartsOperatinginstructions . . . . . . . . . 1F M T - t y p e a n t e n n a . . . . . I* Measured Dursuant to the Federal Trade Commissions TndeRegulation rule on Power Output Claims for Amplif iers,NATE:Specifications and the design subject to poisible modificationswithout notice due to improvements.tTttrIttrtITrTt2. TRONT PANEL FACILITIESc POWER SWTTCHSet this switch to ON to supply power to the receiver.There will be a short delay when it is set to ON, becausethe muting circuit has been actuated to suppress theunpleasant noise that is sometimes generated when thepower is switched on and off .O spERrER swtrcHEsDepress the switch corresponding to the speakers con-nected to the SPEAKERS terminals (A or B) on the rearpanel.You can depress both of these buttons to listen to thesound from two pairs of speaker rystems at the sametime. gnlcHrNEss sELEcroRUse this switch to select the brightness of the powermeter and the frequency displav.BRIGHT: When using the receiver in daylight or otherDIM:bright locations.At night or in dark locations when the exist-ing brightness is too high.CI POWER METERThis meter allows you to read out the rated power levelon the fluorescent display tube when speakers with anominal impedance of g ohms are connected to thespeaker terminals. orel PoINTERThis pointer indicates the broadcasting stations. bunnrz LocKED tNDtcAToRThis indicator lights up after the optimum tuning pointhas been obtained and displays that the receiving state isstabilized by the built-in quartz lock circuit.O TTU STEREO INDICATORThis indicator lights up when receiving an FM stereoprogram if the FM muting off switch is released.,o SIGNAL INDICATORThis indicator lights in sequence from left through rightduring the tuning of an AM or FM broadcast in accord-ance with the strength of the signals being received.The optimum tuning point is where the maximumnumber of indicators light. rururruc tNDtcAToRWhen tuning in an FM station, the optimum receptionpoint is indicated when the center indicator lights up.When the left indicator has come on. rotate the tuningknob slightly clockwise. When the right indicator comeson, rotate the knob slightly counterclockwise- rnEouENCY DTSPLAYThis indicates the frequency which is tuned.With FM reception, the letters ,FM., appear on the leftof the display and ,MHz, on the right. With AM recep.tion, AM appears on the left and ,kHz. on the right.These change when the function selector position ischanged.0 rururruc KNOBUse this knob to tune in to broadcasting stations.c FM MUTTNG OFF SWTTCHWhen this switch is released and an FM broadcast tunedin, the muting circuit is activated inside to suppress theannoying interstation noise between the broadcastingfrequencies for noise-free reception. When the broadcast-ing station is far away or when receiving a station in afringe area, set the switch to the OFF position and thentune in. lf there is a broadcasting station with a strongr-signal level on the air next to a station whose programyou want to receive. you may not be able to tune insatisfactorilv because the sound will be drowned outby the stronger signals. ln cases like this, set the FMMUTING OFF switch to OFF depressed position) andtune in. The muting circuit does not work when thetuner is receiving AM broadcasts. lf tuning has beenperformed after the FM MUTING OFF switch has beendepressed and a station selected, the quartz lockedcircuit is set to the OFF mode and the LOCKEDindicator does not light. FUNCTTON SELECTORDepress the function switch which corresponds to theprogram source. Turn the volume control down firstbefore selecting a different function switch while thesound from one program source is being reproduced.FM:AMrDepress this switch for FM broadcasts.Depress this switch for AM broadcasts.AUX: Depress this switch when listening to anaudio component connected to the AUXjacks.PHONO: Depress this switch when playing a recordon the turntable connected to the PHONOjacks.NATE:Only one function swirch should be deplessed at a time. volunnE coNTRoLUse this control to adjust the output level to thespeakers and headphones. Turn it clockwise to increasethe output level . No sound will be heard if you set it too.( MUTING SWITCHSet this switch to the *20d8 position to attenuate theaudio output by 20d8. There is no need to adjust thevolume control if you this switch when turning downthe audio output temporarily and when changing overrecords or tapes.LOUDNESS SWITCHWhen listening to a performance with the volumecontrol turned down, depress this switch and the bassand treble will be accentuated.When the volume is low, the human ear finds it harder tohear the bass and treble than when the volume is high.The loudness switch is thus designed to compensate forthis deficiency. By depressing this switch, the bass andtreble come through much more strongly and the soundtakes on a punch even when the volume control isturned down, gRl-RrcE coNTRoLUse this control to balance the volume of the left andright channels. First, however, set the mode switch toMONO. lf the sound appears to be louder on the right, itmeans that the volume of the right channel is higher.Turn the balance control to the left and adjust. Con-versely. if the sound appears to be louder on the left, itmeans that the volume of the left channel is higher.Therefore, turn the balance control to the right andadjust. After adjusting. return the mode switch toSTEREO.) TAPE MONTTOR SWTTCHESEmploy for tape playback or to monitor a recording inprogress.1: Playback or monitoring of a tape deck connected tothe TAPE l jacks.2:, Playback or monitoring of a tape deck connected tothe TAPE 2 iacks.NOTES:l. 8e sure to set the switches to the upper IOFF) positionwhen playing records or listening to broadcasts.2. When recording with tvvo tape decks simultaneausly. do natoperate the tape monitor I switch as this will interrupt thesignat to the T,APE 2 deck.G MODE SWITCHUse this switch for selecting mono or stereo perform.ances.STEREO: Set to this position for normal operations.MONO: When set to this position, the left and rightchannel signals will be mixed and repro-duced monophonically from both speakersystems.AD LOW FILTER SWITCHWhen this switch is set to l SHz, a 6dB/oct attenuationcan be provided or f requencies below 15H2. Thismeans that you can cancel out noise in the ultra-lowfrequencies which is generated by low-pitched rumblefrom a turntable and other forms of distortion.Although this noise cannot be heard, it can generateintermodulation distortion and damage the speakers. BASS AND TREBLE CONTROLSWhen turned clockwise from the OFF position, theresponse in the bass and treble range, respectively, isboosted. Turning counterclockwise attenuates thereSponse.At the OFF position the tone control circuit is bypassedand frequency response is flat. HEADPHONE JACKPlug the headphones into this jack when you want tolisten through your stereo headphones.Release both speaker switches if you want to listen tothe sound through your headphones only.HHHHHtIHHHtIl|IIItttItIIItIIlj1 6 l l a r a M e l - r v o - - l ) l l F v / t p t q l - -I * I | ,r dve cfrfc-.,a Il-ll-lhTjl -rr- |r-; r l-68-l;l I;l-, J l I l f : r e IpacNo aux 3. BLOCK DIAGRAMR F Block7 5 n O:conoo.til i,-qilglAUD IOU U I I N O,TarC HA120r ) 1 , F 0 F F S E T.J AOJ,lOW FILTgFrc PA3007-A )46.468ll1-.! :r9:i;f,.-6: -, l l l1-a-f-*-el-8 -O,. .*,i 1l :, n or. !uoa sc E NTrnorcAron IuBe-F-.o SPEA(ER Basix-3aooOUTPUTLR5rffEO!NOlCnI0RovaRTz locKf,oril9rcaToRSP(.AXERSSPeAXlP rOICAIORS-*9-f-q-*rc ( PA4O06-A l6!5 eS1 PFrscalla l_1 FM.id I_T-*F;* 1l , r E r , III;(9PL AYP E .PLAY.AIi+ t 5 . 5 v- 5 . 5 VIIIIItIIt-POrtT StcxaLllOa.AtOA 0AtvER CHANNL5AME A5 L CHAAIii.it L F.AI IRAISORMR/_- -*-1 orL s(aLEv L 4 9 p S4. CIRCUIT DESCRIPTIONS4.1 FM TUNERFront EndThe FM front end of SX-3800 includes a 3ganged tuning capacitor, a dual-gate MOS FET-equipped L-stage RF amplifier, and a modifiedClapp circuit local oscillator. This oscillator is avoltage controled oscillator employing a vari-cap(variable capacitance diode). When the quartz-locksystem (refer to Quartz-lock system) is not inoperation, a constant voltage is applied to thediode.lF Amplifier and DetectorThese employ 3 ICs and 3 dual-element ceramicfilten. The IC (HA1201) of the first 2 stage con-stitutes a single-stage differential amplifier current-limiting limiter. The IC (PA3007-A) in the thirdstage,an improvement on the former IF system IC(PA3001-A), includes an IF limiter amplifier,quadrature detector, meter drive, and other cir-cuits. Performance in terms of distortion, S/Nratio, delay characteristics, and other parameters,shows a marked improvement in comparison tothe PA3001-4.Multiplex DecoderThe recently developed multiplex decoder IC(PA4006-A) combines MPX decoding with mutingfunctions in a single IC, thereby handling thefunctions of the more conventional MPX IC(PA1-001-A) and AF MUTING IC (PA1002-A).Distortion ratings and SIN ratio have beenfurther improved by incorporating a chopper typeMPX decoder. The chopper type switching circuit(see Fig. 4-1) operates by switching the signaleither to ground or to the through circuit, therebyeliminating the generation of unwanted noise ordistortion. Furthermore, since the PA4006-A fea-tures DC direct-coupled switching with the detec-InOut OutputJU1IIIUIJIJUUI . ISwitchins ,is.rc-1q/ - |thLFig.4-1 Chopper type switching circuitouartz-Lock systemThe quartz-lock system featured in the SX-3800stereo receiver is a frequency servocontrol systememploying a crystal resonator. Any displacement inthe intermediate frequency (iF) is detected as a DCvoltage by the discriminator (equipped with acrystal resonator), resulting in the local oscillatorfrequency being corrected and subsequentlylocked. This extremely stable frequency servo-control system thus ensures that tuned frequenciesremain tuned securely for as long as required.When the IF signal appears at pin no.l? of theIF system IC (PA300?-A), it is amplified andapplied to crystal detector (see Fig. 42) whichconsists of diodes connected in parallel in a seriesresonance circuit equipped with a crystal resona-tor. The resonance freque