Pioneer-SX-3800-Service-Manual (1)电路原理图.pdf

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1、Sefvice nual FM Ouartz Locked STEREO RECEIVER ii,i i, i,., s r - ft3rc:rl ttr:;!; L *,.ir*.t s(/ -i- pSc2.ies- -borf o Sla t H H H n I H H H H T H H I i t I I + 1. SPECIFICATIONS 2, FRONT PANEL FACILITIES 3. BLOCK DIAGBAM 4. CIRCUIT DESCRIPTIONS 4.1 FM Tuner 4.2 AM Tuner 4.3 Display Circuit 4.4 Equa

2、lizerAmplifier 4.5 Tone Control Amplifier 4.6 Power Amplif ier . . . 4.7 Power Indicator Circuit 4.8 Protection Circuit D I S A S S E M B L Y . . . . PARTS LOCATION DIAL CORD STRINGING ADJUSTMENTS 8,1 FM Tuner 8.2 AM Tuner 22 8.3 PowerAmplifier. 23 8.4 FL Indicator Circuit 24 9. EXPLODED VIEW 25 10.

3、 SCHEMATIC DIAGRAM, P.C. EOARD CONNECTION DIAGRAM AND PARTS LIST 10. 1 Schematic Diagram 3l 10.2 P.C. Board Connection Diagram 35 1 0 . 3 P a r t s L i s t . . . , . . . 4 1 1 1 . P A C K | N G . . . . 4 6 ADDITIONAL SE RV ICE MANUAL I . S P E C | F | C A T | O N S . . . . . 4 7 2. CONTRAST OF MISCE

4、LLANEOUS PARTS . . . . 48 3. SCHEMATIC DIAGRAM, P.C. BOARD PATTERNS AND PARTS LIST 3. 1 Schematic Diagram 49 3.2 Switch Assembly AWS.148) 57 5. 1 8. 3 5 7 I o o 1 2 1 2 1 2 14 14 1 6 1 7 1 9 20 e RadioFans.CN 收音机爱 好者资料库 I I t r t t t t I t t T t t t t I t I 1. SPECTFTCATIONS Power Ampl if ier Sectio

5、n Continuous Power 0utput of 60watts* per chan- nel, min., at Sohms from 20Hertz to 20,000 Hertz with n0 m0re than 0.005% total harmo nic 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 output N

6、o more than 0.005% Intermodulation Distortion (50 Hertz : 7,000 Hertz = 4 : 1) continuous rated power output No more than 0.0057o 30 watts per channel power output No more than 0,005% Frequency Response . . . . . 5 Hertz to 200,000 Hertz l! OA lnput Sensitivity/lmpedance (POWER AMP lN) or,rri 1v/50

7、kilohms Speaker A, B, A+B -: : : 1*: 1o i* He*z 8 0hms) Hum and Noise (lHF, short-circuited, A network) 115d8 Preamplifier Section I nput (Sensitivity/l mpedance) PHONO 2.5mV/50 kilohms AUX,TAPE PLAY 1,2 . . . . . . 150mVl50kilohms Phono Overload Level T.H.D.0.005%, 1,000 Hertz) PHONO . . . 250mV Ou

8、tput ( Level/l mpedance) T A P E R E C I , 2 . . . . , . 1 5 0 m V PREAMP 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 Control BASS . tSdB (100H2) T R E B L E . . . . . r , l 0 d B ( 1 0 , 0 0 0 H 2 ) Subsonic F

9、ilter . 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 8 A U X , T A P E P L A Y 1 , 2 . . , . . . . 1 1 O d B Attenuator. .-20d8 FM Tuner Section PHONO (REC OUT

10、) AUX,TAPE PLAY 1,2 . . . . . . Frequency Besponse PHONO (RIAA Equalization) or, iori ,ro i ,;ou to 20000 Hertz t02dB Usable Sensitivity (lH F ) 50dB Ouieting Sensitivity MONO STEREO Signal-to-Noise Ratio MONO STEREO Distortion (at 65dBf) MONO l00Hz. l k H z . 6kHz . STEREO IOOHz. lkHz . 6kHz - Capt

11、ure Ratio. , Alternate Channel Selectivity 4 0 0 k H z . . , . . , 7 f t 8 Stereo Separation 1 k H z . . . . . . . 4 5 d 8 3 0 H 2 t o 1 5 k H 2 . . . . . . . 3 5 d B Frequency Response . . . . 2 H z t o 1 5 k H z 1 ! l o e SpuriousResponse Ratio, . . . . . . 65dB lmageResponseRatio . 65dB l F R e s

12、 p o n s e R a t i o . . . . . . 9 0 d B AMSuppressionRatio . 55dB SubcarrierProduct Ratio . . . . . . . 50dB SCARejectionRatio . 64dB Muting 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.

13、1o/o a.a7% 0.15% O.2Yo 0.15% 0.25% r.odB No more than 0.005% 10V output No more than 0.005% (10V output) 7Hz to 8o,0oo Hertz f aa Eix-3El00 I t r| r| t t t ; t t t t rl t rl t il + + AM Tuner Section Sensitivity (lHF, Ferrite antenna). . 300pV/m lHF, Ext.antenna . . . 15pV S e l e c t i v i t y . .

14、. . . 3 0 d 8 Signal-to-NoiseBatio . 50dB lmageResponseRatio . 40dB l F R e s p o n s e R a t i o . . . . . . 4 0 d B Antenna . Ferritelooostickantenna Audio Section Output ( Level/l mpedance) F M ( 1 0 0 % M o d . ) . . . . . . 6 5 0 m V l 1 k i l o h m s A M ( 3 O % M o d . ) . . . . . . 2 0 0 m V

15、 / 1 k i l o h m s Semiconductors f C s . . . . . . . . . . 1 7 F E T s . . . . . . . . 6 T r a n s i s t o r s . . . , . 7 1 D i o d e s . . . . . . . 5 8 Miscellaneous PowerRequirements . ACi20V,60Hz PowerConsumption . . 200W(ULl Dimensions .506W x164H) x 434Dmm 19-15116(W) x6-7/16 (H) x 17-1116(D

16、) in Weight (without package) 16.2k9 (351b 12oz) Furnished Parts Operatinginstructions . . . . . . . . . 1 F M T - t y p e a n t e n n a . . . . . I * Measured Dursuant to the Federal Trade Commissions Tnde Regulation rule on Power Output Claims for Amplif iers, NATE: Specifications and the design s

17、ubject to poisible modifications without notice due to improvements. t T t t r I t t r t I T r T t 2. TRONT PANEL FACILITIES c POWER SWTTCH Set this switch to ON to supply power to the receiver. There will be a short delay when it is set to ON, because the muting circuit has been actuated to suppres

18、s the unpleasant noise that is sometimes generated when the power is switched on and off . O spERrER swtrcHEs Depress the switch corresponding to the speakers con- nected to the SPEAKERS terminals (A or B) on the rear panel. You can depress both of these buttons to listen to the sound from two pairs

19、 of speaker rystems at the same time. gnlcHrNEss sELEcroR Use this switch to select the brightness of the power meter and the frequency displav. BRIGHT: When using the receiver in daylight or other DIM: bright locations. At night or in dark locations when the exist- ing brightness is too high. CI PO

20、WER METER This meter allows you to read out the rated power level on the fluorescent display tube when speakers with a nominal impedance of g ohms are connected to the speaker terminals. orel PoINTER This pointer indicates the broadcasting stations. bunnrz LocKED tNDtcAToR This indicator lights up a

21、fter the optimum tuning point has been obtained and displays that the receiving state is stabilized by the built-in quartz lock circuit. O TTU STEREO INDICATOR This indicator lights up when receiving an FM stereo program if the FM muting off switch is released. ,o SIGNAL INDICATOR This indicator lig

22、hts in sequence from left through right during 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 maximum number of indicators light. rururruc tNDtcAToR When tuning in an FM station, the optimum reception point i

23、s indicated when the center indicator lights up. When the left indicator has come on. rotate the tuning knob slightly clockwise. When the right indicator comes on, rotate the knob slightly counterclockwise- rnEouENCY DTSPLAY This indicates the frequency which is tuned. With FM reception, the letters

24、 ,FM., appear on the left of 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 is changed. 0 rururruc KNOB Use this knob to tune in to broadcasting stations. c FM MUTTNG OFF SWTTCH When this switch

25、 is released and an FM broadcast tuned in, the muting circuit is activated inside to suppress the annoying interstation noise between the broadcasting frequencies for noise-free reception. When the broadcast- ing station is far away or when receiving a station in a fringe area, set the switch to the

26、 OFF position and then tune in. lf there is a broadcasting station with a strong r- signal level on the air next to a station whose program you want to receive. you may not be able to tune in satisfactorilv because the sound will be drowned out by the stronger signals. ln cases like this, set the FM

27、 MUTING OFF switch to OFF depressed position) and tune in. The muting circuit does not work when the tuner is receiving AM broadcasts. lf tuning has been performed after the FM MUTING OFF switch has been depressed and a station selected, the quartz locked circuit is set to the OFF mode and the LOCKE

28、D indicator does not light. FUNCTTON SELECTOR Depress the function switch which corresponds to the program source. Turn the volume control down first before selecting a different function switch while the sound from one program source is being reproduced. FM: AMr Depress this switch for FM broadcast

29、s. Depress this switch for AM broadcasts. AUX: Depress this switch when listening to an audio component connected to the AUX jacks. PHONO: Depress this switch when playing a record on the turntable connected to the PHONO jacks. NATE: Only one function swirch should be deplessed at a time. volunnE co

30、NTRoL Use this control to adjust the output level to the speakers and headphones. Turn it clockwise to increase the output level . No sound will be heard if you set it to o. ( MUTING SWITCH Set this switch to the *20d8 position to attenuate the audio output by 20d8. There is no need to adjust the vo

31、lume control if you this switch when turning down the audio output temporarily and when changing over records or tapes. LOUDNESS SWITCH When listening to a performance with the volume control turned down, depress this switch and the bass and treble will be accentuated. When the volume is low, the hu

32、man ear finds it harder to hear the bass and treble than when the volume is high. The loudness switch is thus designed to compensate for this deficiency. By depressing this switch, the bass and treble come through much more strongly and the sound takes on a punch even when the volume control is turn

33、ed down, gRl-RrcE coNTRoL Use this control to balance the volume of the left and right channels. First, however, set the mode switch to MONO. lf the sound appears to be louder on the right, it means that the volume of the right channel is higher. Turn the balance control to the left and adjust. Con-

34、 versely. if the sound appears to be louder on the left, it means that the volume of the left channel is higher. Therefore, turn the balance control to the right and adjust. After adjusting. return the mode switch to STEREO. ) TAPE MONTTOR SWTTCHES Employ for tape playback or to monitor a recording

35、in progress. 1: Playback or monitoring of a tape deck connected to the TAPE l jacks. 2:, Playback or monitoring of a tape deck connected to the TAPE 2 iacks. NOTES: l. 8e sure to set the switches to the upper IOFF) position when playing records or listening to broadcasts. 2. When recording with tvvo

36、 tape decks simultaneausly. do nat operate the tape monitor I switch as this will interrupt the signat to the T,APE 2 deck. G MODE SWITCH Use 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 rig

37、ht channel signals will be mixed and repro- duced monophonically from both speaker systems. AD LOW FILTER SWITCH When this switch is set to l SHz, a 6dB/oct attenuation can be provided or f requencies below 15H2. This means that you can cancel out noise in the ultra-low frequencies which is generate

38、d by low-pitched rumble from a turntable and other forms of distortion. Although this noise cannot be heard, it can generate intermodulation distortion and damage the speakers. BASS AND TREBLE CONTROLS When turned clockwise from the OFF position, the response in the bass and treble range, respective

39、ly, is boosted. Turning counterclockwise attenuates the reSponse. At the OFF position the tone control circuit is bypassed and frequency response is flat. HEADPHONE JACK Plug the headphones into this jack when you want to listen through your stereo headphones. Release both speaker switches if you wa

40、nt to listen to the sound through your headphones only. H H H H H t I H H H t I l| I I I t t t I t I I I t I I l j 1 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 I l-ll- lhTjl -rr- | r-; r l-68-l;l I;l-, J l I l f : r e I pacNo aux 3. BLOCK DIAGRAM R F Block 7 5

41、 n O :cono o .t il i,-qilgl AUD IO U U I I N O ,T a rC HA120r ) 1 , F 0 F F S E T .J AOJ, lOW FILTgF rc PA3007-A ) 46.468 ll 1-.! :r9:i;f, .-6: - , l l l 1-a- f-*-e l-8 -O ,. .*,i 1l :, n or. !uoa sc E NT rnorcAron IuBe -F-.o SPEA(ER B a six-3aoo OUTPUT L R 5rffEO !NOlCnI0R ovaRTz locKf,o ril9rcaToR

42、 SP(.AXERS SPeAXlP rOICAIORS -*9- f-q-* rc ( PA4O06-A l 6 !5 eS 1 PFrscalla l_ 1 FM.id I _T- *F;* 1 l , r E r , I I I ; (9 PL AY P E . PLAY .A I i + t 5 . 5 v - 5 . 5 V I I I I I t I I t-POrtT StcxaL llOa.AtOA 0AtvE R CHANNL5AME A5 L CHAAIii.i t L F.AI IRAISORMR /_ - -*-1 orL s(aLE v L 4 9 p S 4. CI

43、RCUIT DESCRIPTIONS 4.1 FM TUNER Front End The FM front end of SX-3800 includes a 3 ganged tuning capacitor, a dual-gate MOS FET- equipped L-stage RF amplifier, and a modified Clapp circuit local oscillator. This oscillator is a voltage controled oscillator employing a vari-cap (variable capacitance

44、diode). When the quartz-lock system (refer to Quartz-lock system) is not in operation, a constant voltage is applied to the diode. lF Amplifier and Detector These employ 3 ICs and 3 dual-element ceramic filten. The IC (HA1201) of the first 2 stage con- stitutes a single-stage differential amplifier

45、current- limiting limiter. The IC (PA3007-A) in the third stage,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/N ratio, delay characteristics, and other parameters,

46、shows a marked improvement in comparison to the PA3001-4. Multiplex Decoder The recently developed multiplex decoder IC (PA4006-A) combines MPX decoding with muting functions in a single IC, thereby handling the functions of the more conventional MPX IC (PA1-001-A) and AF MUTING IC (PA1002-A). Disto

47、rtion ratings and SIN ratio have been further improved by incorporating a chopper type MPX decoder. The chopper type switching circuit (see Fig. 4-1) operates by switching the signal either to ground or to the through circuit, thereby eliminating the generation of unwanted noise or distortion. Furth

48、ermore, since the PA4006-A fea- tures DC direct-coupled switching with the detec- InOut Output JU1IIIUIJIJUUI . I Switchins ,is.rc-1q/ - | thL Fig.4-1 Chopper type switching circuit ouartz-Lock system The quartz-lock system featured in the SX-3800 stereo receiver is a frequency servocontrol system e

49、mploying a crystal resonator. Any displacement in the intermediate frequency (iF) is detected as a DC voltage by the discriminator (equipped with a crystal resonator), resulting in the local oscillator frequency being corrected and subsequently locked. This extremely stable frequency servo- control system thus ensures that tuned frequencies remain tuned securely for as long as required. When the IF signal appears at pin no.l?