Pioneer-SX550-rec-sm 维修电路原理图.pdf

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1、. $F) */;i.,.,3 lj j j()rrroNEEFIRadioFans.CN 收音机爱 好者资料库The following locations in the text are incorrect. Please perform the corrections shownbelow.O CIRCUIT DESCRIPTIONo EACH MODEL (SX-ssO/KU, HG.S)Power supply transformer connected to AF amplifier assembly is not a lead wire type,but instead, it

2、is connected by a terminal strip. Delete lead wire color indications andwrite in terminal numbers indicated below.sx-550/KU sx-550/HG SX-550/SAC nov60 HrO PAGE 50Change printed board fuse Fu5 0.5A to 1.5A. Change fuse FuB 1.5A to 0.8A.t3tI s - aIIffi *ilve-l: TMWER IND8v 50iAO , FUSE HoLDER No.Incor

3、rectCorrectPage 9 AM tuner line 1dualsinglePage 9 phono equalizer amplifier line Bmetal oxidecarbon filmPage 10 tone control line 10- gdB- 10dBRadioFans.CN 收音机爱 好者资料库This Service Manual is applicable only to the KC, KU model.sx-s5CCONTENTS1 .2.3.4.FRONT PANEL FACILITIESCONNECTION DIAGRAMCIRCUIT DESC

4、RIPTIONSSPECIFICATIONSBLOCK DIAGRAMLEVEL DIAGRAM467I121314165.6.7.8.9.DIAL CORD STRINGINGDISASSEMBLY9.1 AM Section9.2 FM SectionADJUSTING PROCEDURES9.3 MPX Section1718192021232527293133349.4 Power Amplifier (ldle Current)10. PARTS LOCATION10.1 Front Panel View1O.2 Rear Panel View10.3 Top View10.4 Fr

5、ont View1 1 .EXPLODED VIEWS11.1 Exterior11.2 Part 11 1.3 Part 2 AF As-sembly (AWKO5611.4 Part 3 RF Assembly (AWE-072)12. SCHEMATIC DIAGRAMS. P.C. BOARD PATTERNS ANDPARTS LISTS12,1 MiscellaneousParts12.2 Schematic Diagram12.3 RF Assembly (AWE-072-0)12.4 AF Amplifier Assembly (AWK-056)12.5 AF Muting A

6、ssembly (AWM-101)13. PACKINGL ist.363740475355SX-550/KU. HG. S Additional Service Manual . Enclosed Herewith1. SPECIFICATIONSSemiconductorsF E T s . . . . . . . .| C s . . . . . . . . . .T r a n s i s t o r s . . . .D i o d e s . . . . . . .Power Amplifier SectionContinuous Power Output from 20 Hert

7、z to 20,000 Hertz(Both channels driven). . . 20 watt5 per channel (8 ohms)Total Harmonic Distortion (20 Hertz to 20,000 Hertz, from AUX)Continuous Rated PowerOutput . . . . . . .10 watts per channel power output,8 o h m s . .I watt per channel power output,8 ohms. . . . . No more than Q.07%Intermodu

8、lation Distortion (50 Hertz : 7,000 Hertz = 4 : 1, fromAUX)Continuous Rated PowerOutput . . . . . .10 watts per channel power output,8 o h m s . .I watt per channel power output_8 o h m s . .Damping Factor.3.5. 2 8. 2 1No more than 0.3%No more than 0.07%. No more than O.3o/oNo more than 0.07%No more

9、 than 0.07%(20Hr to 20,000H2,8 ohms) .I nput Sensitivity/l mpedancePHONO .M t c . . . .A U X . . .T A P E P L A Y I . . . . . .T A P E P L A Y 2 . . . . . .TAPE PLAY 2 (DlN connector)PHONO Overload Level (T.H.D. 0.1 7o)PHONO .Output Level/lmpedanceT A P E R E C l . . . . . .TAPE REC 2TAPE REC 2 (DlN

10、 connector)SPEAKERHEADPHONES.Frequency ResponsePHONO (RIAA equalization) .AUX, TAPE PLAY . . .Tone ControlB A 5 5 . . . . . . . . . . . . 2 52.5mV/50k ohms7.5mV/50k ohms150mV/50k ohms150mV/50k ohms150mV/50k ohms150mV/50k ohms200mV (l kHz). . . . 1 5 0 m V. . . . . . . 1 5 0 m V. 30mV/80k ohms. . . .

11、 . A , B , A + B. Low lmpedance30Hz to 15,00OH2 10.3d8. loHz to 60,000HzlidB. . +9d8, -10d8 (100H2)TREBLE. . t8dB (10kHz)Loudness Contour (Volume control set at -40d8position). . . . +6dB (100H2), +rag 119kH.1Hum and Noise (lHF, short-circuited, A Network, rated power)P H o N o . . . . . . . . . 7 0

12、 d 8A U X T A P E P L A Y . . . . . . . . . . . 9 0 d 8FM SectionUsable SensitivityI l.2dBf (2.0!v)20.0dBf (s.spv)18.3dBf (4.ssv)50dB Quieting Sensitivity . . . . . MONO . . . . .sTEREO. . 39.2dBf (509V)Signal to Noise Ratio at 65dBf . . . . . . . MONO . . . . . . . 70dBS T E R E O . . . . . . 6 5 d

13、 BD i s t o r t i o n a t 6 5 d B f 1 0 0 H 2 . . . . . . . M O N O . . . . . . . . O S %s T E R E O . . . . . . . 0 3 %M O N O . . . . . . .S T E R E O . . . . . .M O N O . . . . . . . . O . 1 5 %S T E R E O . . . . . . . 0 . 3 %M O N O . . . . . . . . . o . 4 %S T E R E O . . . . . . . O . 4 %. 30

14、Hz to 15,000H2 r3:3dB. . . . . . l . O d B. . . . . . 6 0 d 8. . . . 65d8Built-in Ferrite Loopstick Antennasix-s5C,NOTE:Specificotios ond the design subject toposcible modificotion without notice dueto improoementg.Spurious Response Ratio . . . .75d8l m age Resp o n s e Ra t io . . . . . . . . . .65

15、d8lF Response Ratio . . 90dBA M S u p p r e s s i o n R a t i o . . . . . . . . . . 5 0 d 8MutingThreshold . t4dBf (2.8pV)Stereo Separation 40dB (1kHz), 30dB (30H2 - 15kHz)Su bcarrie r P ro d u c t R a t io . . . . . . . .40d8S C A R e j e c t i o n R a t i o . . . . . . . . . . . 4 0 d 8Antenna Inp

16、ut . 300ohms balanced75 ohms unbalancedAM SectionSensitivity (lHF, Ferrite antenna). I kHz6 k H 2 . . . . . .frequency Response .Capture RatioAllernate Channel Selectivity . . .(lHF, Ext. antenna)SelectivitySignal-to-Noise Ratio. . . . .lmage Response Ratio . . . .lF Regoonse Ratio. . . . . .Antenna

17、.MisceilaneousPower Requirements .PowerConsumption.Dimensions. . l2OY 6QHz. . . UL; 80W, 185W (max.)c s A ; l 5 5 v A. . . . . . . .148(w)x141(H)x307(D) mm1 7al8(w)xs-9/16(H)x12-l /1 6(D) inWeight . Without package . . . . . . . 9.4kg (20 |b 11 oz)With package 10.5kg (23 lb 2 oz)Furnished PartsFM T-

18、type AntennaOperating InstructionsT-TYPEFM ANTENNA2. CONNECTION DIAGRAMOUTDOORFM ANTENNA 3ooaAM ANTENNA(lndoor or Outdoor)FM DE.EMPHASIS SWlTCHNormaf ly, set this switch to 751ts.Be sure to set it to 251rs only whenlistening to an FM broadcast (pre-emphasis; 25rrsec.) with a Dolby* systemNR adaptor

19、connected between theTAPE terminals.CONVENIENCE OUTLUnswitched (3OOW max.l: Less frequently used components, which do not re-quire coupled power, can be plugged intoeither of these outlets.Switched (200W max.l: A frequenused component (turntable, tape deck,etc.) can be plugged into this outlet. Byle

20、aving the power switch of that compo-nent in the ON position, power supplyto the component will be coupled withthe SX-550 switch operation.GROUNDTURNTABLECARTRIDGETAPE PLAYEROUTPUTTAPE DECKRIGHT LEFTSPEAKER SYSTEMS AII DIN TYPEI CORDloureurINPUTTAPE DECK(Open-reel, cassettel.m,ffilTilLEFTRIGHT6.ffi)

21、75oLI-lcoax rall lcable I Ir-1 _*.r _!- _l*-t: B E E E E E : -(Open-reel, cassette)SPEAKER SYSTEMS B3. FRONT PANEL FACILITIESSPEAKERS SWTTCH (POWER)A combined power ON/OFF switch and speaker systemselector switch.POWER OFF:A:OFF:B :A + B :To listen simultaneously to speakersystems connected to A and

22、 B speakerterminals.NOTES:. After turning this switch ON there is a delay of some Zto 9 seconds, during which time the muting circuitoperates to eliminate unpleasant noise.c For easier operation, plug powgr cord for turntable, etc.into the switched convenience outlet.PHONES f ACKTo listen through st

23、ereo headphones, plug them firmlyinto this jack.WARNING:Dct not plug a microphone into the PHONES jach as youmay damage the microphone.BASS & TREBLE CONTROLSControls for adjusting the tone. Adjust low frequencieswith the BASS control and high frequencies with theTREBLE control.Turn controls toward t

24、he right (MAX) to enhance, andtoward the left (MlN) to reduce, their respective fre-quency ranges.Receiver off.To select speakersspeaker terminals.Speakers cut offused).Operates speakersspeaker terminals.connected to the A(headphones can beconnected to the BFM STEREO INDICATORWith rhe FUNCTION switc

25、h ser to FM, the STEREOindicator lights while an FM stereo broadcast is being re-ceived.AM/FM TUNING METERWhen tuning in FM stations, position the needle in thecenter FM area for optimum reception. In the case of AMstations, tune for maximum meter deflection toward theright of the scale.PILOT LAMPFM

26、 MUTING OFF BUTTONLeave this button undepressed (in the ON position) tosuppress unpleasant interstation noise while tuning be-tween FM stations. Low-strength signals may also be sup-pressed by this function, so to pick up a weak stationdepress this button to the OFF position.MODE SWTTCH (MONO)For st

27、ereo playback leave this switch undepressed. Whendepressed for MONO playback, left and right channelstereo signals will be mixed to produce monophonicsound from both speaker systems.NOTE:Recording stereophonically with the MODE switch in theMONO position moy cause channel separation to deterio-rate.

28、Jwnre t/N.EREOring re-in theof AMrud theI LAMPon) tong be-)e sup-rtation. Whenhannelphonicin theeterio-TUNING KNOBSelect the desired station while observing the AM/FMmeter for optimum tuning.FUNCTIONVOLUME CONTROLClockwise rotation increases volume from speakers orheadphones.LOUDNESS BUTTONDepress t

29、his button when listening at low volume. Thefrequency response of the human ear varies according tothe listening level, and the depressed position compensatesfor hearing characteristics by emphasizing the bass andtreble.BALANCE CONTROLControl for adjusting volume balance between left andright speake

30、rs or headphones. Clockwise rotation fromcenter increases right channel volume, while counter-clockwise rotation increases left channel volume.FUNCTION SWITCHSwitch for selecting desired program source.AM:FM:PHONO:AUX/MIC:sx-s5clFor AM broadcast reception.For FM stereo reception. Automaticallyreceiv

31、es monophonically during FMmonophonic broadcasts. The STEREOindicator lights up when the broadcast isin stereo.To operate a turntable connected toPHONO iacks.For listening to an audio component(cartridge tape player, TV sound tuner,etc.) connected to the AUX jacks. Alsoset to this position when usin

32、g the micro-phone.Note, when the microphone is pluggedin, the component connected to the AUXiacks cannot be used.(approx. 50k-ohms) dynamic tYPestandard plug can be connected to(1 &.2) BUTTONSin the ON (depressed) .position aslNM rcNOLruOMSrc JAcKA high impedancemicrophone with athis lack.TAPE MONIT

33、ORSet these switchesfollows:1 . . . For playback or for monitoring of a recording inprogress with a tape deck connected to the TAPE1iacks (REC & PLAY).2 . . . As in 1 above, with a tape deck connected to theTAPE 2 jacks (REC & PLAY) oTTAPE REC/PLAYjack (DlN type).NO?ES:o Leaue both of these buttons

34、in the undepressed posi-tion when not using tape dechs as the sound source.The signat from the source selected by the FUNCTIONswitch will be interrupted if switches are left in the depressed position.a When record.ing with two tape dechs simultaheously,do not operates the TAPE MONITOR I button as th

35、iswill interrupt .the signal to the TAPE 2 dech.a4. CIRCUIT DESCRIPTIONSF ig. 1 Tuner SectionTUNER SECTIONFM Front EndA frequency linear 3-gang variable capacitor isused with a single stage FET RF amplifier. TheFET possesses high input impedance comparedwith a transistor, and allows simple coupling

36、withthe input tuning circuit, plus a significant advan-tage in terms of noise.The local oscillator is a variation of a Clapp circuitand its excellent temperature compensationprovides stable frequency even without AFC.Local oscillator voltage is passed through a lowvalue capacitor to the mixer transi

37、stor base.lF Amplifier and DetectorComposed of two dual element ceramic filters andone IC (HA1137). The HAl1BT is a high densityIC and contains a limiter amplifier, FM detector(quadrature detector), muting, and meter drive *21circuits.Multiplex DemodulatorThe IC (HA1156W) used in this section does n

38、ot -1srequire a tuning coil and in addition to a pLLstabilized switching signal generator circuit, itcontains a double balanced differential amplifierswitching system demodulator circuit and an auto_matic stereo-mono selector circuit. An extemalswitching transistor controlled by the FM mutingsignal

39、provides automatic monophonic reproduc-!t_91 t input sigrrals below the muting level (FMMUTING switch OFF). The stereo demodulatorsignal passes through the de-emphasis circuit, thenthrough an amplifier that combines carrier filterand crosstalk canceller to produce the demodula_tor output.AM TunerCom

40、posed of a single IC (HA11BS) and dualelement ceramic filter. A 2-gar,:rg variable capacitoris employed with one stage providing tuning be_tween the antenna and RF amplifier and theother stage tuning the local oscillator. The RFamplifier itself is not tuned but feeds direcfly tothe mixer followed by

41、 a 2-stage IF amplifier.PHONO EOUALIZER AMPLI FIERIC (TA7136P1) is used with independent left andright channels. Tolerances !2Vo styrole capacitorsand tolerances !1Vo metal oxide resistors comprisethe equalizer elements, leading to an RIAA devia-tion within 0.3dB from 30Hz to 15kHz.Fig.2 PHONO Equal

42、izerMICROPHONE CIRCUITA single transistor amplifier (monophonic) isprovided in addition to the phono equalizer ampli_fier. A selector switch cuts the AUX jack iniutwhen a plug is inserted into the MIC jack. iheamplified microphone signal is then supplied toboth the left and right channels. The FUNCT

43、IONswitch is set to the AUX position when using amicrophone.When the power switch is set to OFF, point Cpotential instantly becomes - 16V. Q4 becomesON and C2 is immediately discharged. Since thisinterval is extremely brief, the muting time remainsconstant even if the power switch is again set tooN.

44、Fig. 3 Microphone CircuitTONE CONTROLA CR network tone control circuit is employed inwhich each attenuator circuit consists of a capaci-tor and a resistor. These function to increase anddecrease the relative levels of low and high fre-quency sounds. Since relative control over the fre-quency respons

45、e by the attenuator results in aconstant loss, an amplifier (Q1 & Q2) is used priorto this stage for compensation. The control rangesare +8dB to -8dB for the highs (at 10kHz) and+9dB to -gdB for the lows (at 100H2).YR1:TREBLE CONTfuLVRz: BA55 CONJROLFig.4 Tone ControlAF MUTING AMPLIFIERWhen the powe

46、r switch is set to ON, the potentialof point C in Fig. 5 instantly rises due to C3 &Rb time constant, and Q4 becomes OFF. Point Bpotential at this time gradually increases with theC2 & Rg time constant and normally reaches -19V.Q3 becomes OFF when point B is below -15.4V,from which time point A pote

47、ntial rises with theCL & Rl time constant and normally reachesapproximately 8V from R1 & R2. FET Q1 & Q2operate when point A potential is above 0V. Themuting interval (T) extends from the time thepower supply is set to ON to when point A poten-tial reaches 0V. This interval is set f.or 6 - 7seconds.

48、F ig. 5 AF MutingFis. 6POWER AMPLI FIER CIRCUITComposed of differential first stage, all stagesdirect coupled plementary OCL circuit.Open gain at lkHz is approximately 80dB andNFB amount is approximately 50d8. R3 and R4are provided with this circuit in order to obtainadequate stability even with the

49、 NFB disconnected.Q1 form a differential amplifier: IIOVo d.c. feed-back is applied from the junction point of thepower stage to the base of Ql so the potential ofthe junction point is always maintained at thesame level.Control amP.0UTPower amp. I NConlrol amp. OUTPowef amo. lNPornt BPOWER OFFFig.7

50、Power AmPlifiersx-55clPOWER SUPPLYHigh stability (ripple cancelling efficiency) isrequired in the power supply circuit due to itsminimized output impedance. In the circuit shownin the Fig. 8, Q1 is controlled by Q2, which detectsits output variations. Tuner power is taken fromQ3 emitter. Since this