Pioneer-SK750-pr-sm电路图 维修手册.pdf

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1、c)rrloNEeR The photo shows the model SK-750. PORTABLE STEREO FM/AM RADIO CASSETTE RECORDER KU, KCsoo sK-75c! S P ECI FI CATI ONS Continuous power output. 3W+3W/FTC (3.2O, 80-15,0OOHz 1O% THD.) Max. music power. .23w (total music power) Speakers . 16cm 2-way Frequency .6sponse . Normal tape: 30Hz-14k

2、Hz CrO2 tape: 3OHz-1 SkHz Metal tape:30H2-16kHz Fre q u e n cyra n g e. .FM: 88-108MHz AM:525-1.605kH2 Input jacks . . . . MIX MlC, PHONO/AUX, EXT MlC, EXT FM ANT Output jacks. . LINE OUT. EXT SP. PHONES Power source. . 120V AC 60H2. 12V DC (6ight 1.5V D batteries). EXT 12V DC Dimensions. .588(W) x

3、297(H) x 148(D) mm 1231/aX115/aX57/ainl Weight. .7.6k9 (16.7 lbs.) without batterios sK-700 (Sublunctions) . Direct Source Selector (DSS), tap6 selector (METAL/CrOz-NORMAL), ons- touch music search. semi-automatic roc- ord muting, timer standby mechanism, FM muting, microphone mixing (lndicators) .

4、. . POWER (red LED), MIC REC (green LED), PHONO/AUX (green LED), TAPE PLAY (groen LED). FM (greon LED), AM (green LED), REC (red LED), REC PAUSE (red LED), MUSIC SEARCH (green LEO x 2), METAL green LED, CrOz (green LED), lsvel meter (5 point red LED), TUNING (grean LED), STEREO (red LEDI KU. KC sK-7

5、50 (Subfunctionsl . Diroct Source Selector DSS), Dolby NR, tape selctor METAL/C.Oz-NORMAL, auto/manual recoiding, one-touch music search. music repeat, one side rep6at, semi-automatic rcord muting, timer standby mechanism, FM muting, microphon6 mixing (lndicators) . . . . POWER red LED), Dolby NR (g

6、reen LED), MIC REC green LED), PHONO/ AUX (gieen LED). TAPE PLAY (green LED), FM (green LED), AM 9re6n LED, REC (rod LED). REC PAUSE (r6d LED), ONE SIDE REPEAT (gron LED), MUSIC REPEAT (green LED), MUSIC SEARCH green LED x 2, METAL (green LED, CrOz (green LED), Level met6r (12 points redlgreen LED x

7、 2), TUNING (green LED), STEREO (red LED) Note: Specifications and design are subject to chango without notice ORDER NO. HRT- 1 83- O plctNEEFl ELECTFICNIC CCFIPCIFIATIGIN 4 1, Mesu.o 1-chome, Mesuno_ku. Tokyo 153, Jspan PICINEEFI ELECTFIONICB CIF AMEFilCA 1925E, Oomrnquez Sc. Long Beach Calif. 9081

8、O PrcXrlI:F| ELCCTFaCNIC aEuFlOPEt N.v. Lu,thagen Haven 9. 2O3O Antwe.p, Elelgrum FlCrNClFl ELECTFICNICS AITBTFIALIA PTY. LTO. 1 78 184 Elou.da.v Road, E|.aesrde, V,cco.,a 31 95. Auscnalra FK OJAN. 1982 Printed in Japan RadioFans.CN 收音机爱 好者资料库 CONTENTS 1. PARTS LOCATION. 2. tilECHANtstvl DESCRtpTtON

9、. . . . 3. C|RCU|TDESCR|PT|ON. 4. D ISASSE IVIB LY 5. ADJUSTI4ENT. 6, DtALSTRtNGTNC .,. . 7. SCH EI/AT IC CIRCUIT DIAGRAIVI (TUNER. SK.700, SK.750) . 8. CONNECTTON D|AG RAM (1) TUNER, SK.700, SK.750) . 9. SCH EMATIC CIRCU IT DIAGRAIM sK-700 . 10. coNN ECTTON DtAGRAtul (2) (sK-700) . 1 1. SCHEIiATIC

10、CI RCUIT DIAGRAIi sK-750) . tzl e) .2 .3 .7 . t J .17 .29 .30 .32 .34 .38 .42 .46 .53 .59 .62 . . ,65 .68 .71 . . .74 . . .11 12. CONNECTTON D tAG RAr4 2) (sK.750) . 13. ELECTRICAL PARTS LIST. . . . . 14. CABINET EXPLODED VIEW, . . . 15. CHASSIS 1) EXPLODED VIEW. . 16. CHASSIS (2) EXPLODED VIEW 17.

11、18. 19. (sK.7oo) . CHASSIS (2) EXPLODED V IEW (sK- /50) . CASSETTE I,1ECHAN ISI,1 EXPLODED VIEW (roP) . . . CASSETTE I4ECHAN ISI,1 EXPLODED VIEW (BOTTOM) 20. PACKING I4 ETHOD CAUTION When Handling lC PDl004 Please Observe: lC PDlO04 (lC in the control unit) is a C-lVlOS lC of extremely low power con

12、sumption and very high input impedance. Unless handled with special care, it could be damaged by static electricity induction. This lC is supplied with a shorting, cap (of alumlnium foil) attached. When soldering, or performing other repair work, always attach this cap as shown below. Remove the cap

13、 after the repair has been completed, Also, this type of lC must not be inserted in a polystyrene package for storage. Dolby and the double-D symbol are trademarks of Dolby Laboratories Licensing corporation. Noise Reduction System manufactured under license from Dolby Laboratories Licensing Corpora

14、tion. RadioFans.CN 收音机爱 好者资料库 1. PARTS LOCATION Microphone * HPM-1 19 AF Amp Assy HWK-215(SK-700) HWK-217 (SK-750) I Power Transformer r HTT-I68 NOTE: Parts are shipped as an assembly and not as a certain unit within an assembly. Conseguently, when undertaking repairs on a unit, replace each part. N

15、OTE o For your Parts Stock Control, the fast moving items are indicated with the marks * * and *. * * : GENERALLY MOVES FASTER THAN *. This classification shall be adjusted by each distributor because it de- pends on model number, temperature, humidity, etc. . The A mark found on some component part

16、s indicates the importance of the safety factor of the part. Therefore, when replacing, be sure to use parS of identical designation. LEDMeterUnit Volume,20kA(A)(VOLUME) HWX-386(SK-750) * HCW-101 Tuner Unit HWE-167 Microphone Assy * HPM-1 19 Mechanism Control Assy HWM-127 (SK-7001 HWM-128 (SK-750) C

17、assette Mechan ism Assy HXA-810 Fis. 1 Solenoid Head (REC/PB) HXP-104 * HpB-1 16 Button Fig.2 The photo shows the Model SK-750. e HNS-522 (SK-700) HN5-556 (SK-750) RadioFans.CN 收音机爱 好者资料库 2. MECHANISM . lnitialization DESCRIPTION 1. The mechanism uses six solenoids to perform the opera- tions requir

18、ed in STOP, FF, REW, PAUSE. PLAY and REC modes. Figure 4 shows the positional relationship between the solenoid and the gears (STOP mode in this case). 2.When power is switched ON, the motor turns for a pre- determined length of time, rotating the pulleys and gear (A). 3. At the same time, the STOP

19、solenoid comes ON and pulls on lever (A) to unlock gear (B). Arm (A) rotates gear (B) a short distance (in the direction of the arrow), where it engages with gear (A). 4. When gear (B) starts turning, the cam presses on arm (B). which in turn presses on the STOP lever. 5. The STOP lever moves the lo

20、ckplate in the direction of the arrow, releasing the lever locks for PLAY, REC, FF, and R EW. 6. Where PAUSE is the mode entered, releasing the PLAY lever causes the pin on the PLAY lever to move the slider underneath the lockplate, and this releases the PAUSE lever lock. 7. After gear (B) rotates t

21、hru one full turn, since the solenoid is now OFF, it locks. Fig. 3 - Stop Sotenoid Lever ( A ) Geor (B) .-+ Com Stop Lever d v - Arm (B) Geor (A) Stop Fis.4 FAS Puttey 6 *12 Arm(A) NL r Lr-J tr t i-1 1 E A D r tl 3 Fis. 5 o Auto Stop Mechanism Geor(C) )/ FAS Switch - Motor Fig. 6 l . During PLAY, FF

22、, REW, and REC operations, the rota- tion of the reel unit causes pin (A) to press against arm (C), and the force of the spring pushes arm (D) in the 3. direction of the arrow. Pin (B) on arm (D) moves along the outer periphery of gear (C). 2. When the reel unit stops, arm (D) is freed and pin (B) i

23、s Pin(B) l. Fig.7 drawn toward the center of gear (C). The cam also brings arm (D) inward, turning the FAS switch ON. After the FAS switch has been turned on two (or more) times. the STOP solenoid turns ON and all operations are thus stopped. , Ar Pin (A o 1. PLAY Operation Pressing the PLAY button

24、starts the motor rotating, and at the same time turns the PLAY solenoid ON. The PLAY lever is pressed by arm (B), and locked by the lockplate (see Fig. 4). The PLAY lever, via arm (E) moves the head mount for- ward. lt also presses against arm (F), which causes the pinch-roller to contact the capsta

25、n shaft. Arm (F) is coupled to the TP unit thru arm (G), and the above action causes the TP unit to contact the reel unit, completing PLAY mode entry. r Fast-Forward Operation 1. Pressing the FF button starts the motor rotating, and at the same time turns the FF solenoid ON. The FF lever is pressed

26、by arm (B), and locked by the lockplate (see Fig.4). 2. The action of the FF lever causes the FF gear to contact the FR unit and reel unit. Through coupling with arms (H) and (l),it also advances the head mount to the blank (between selection) detection position. Pinch Rotter TP UNit Arm (G ) Arm (

27、F) Fis. 8 R e e I 2. 1 PLAY Lever FR Unit Geor I /- Reet Unit r, G.o,. U nit I Arm (l ) Heod Ptote Pin 1 - A r m ( H ) Fis. 9 . REW Operation 1. Pressing the REW button starts the motor rotating, and at the same time turns the REW solenoid ON. This causes the REW lever to be pressed by arm (B) and l

28、ock- ed by the lockplate (see Fig. 4). 2. The REW lever moves arm (J) coupled to the FR unit. The FR unit thus is forced into contact with the reel unit. Through coupling with arms (H) and (l), the REW lever also advances the head mount to the blank detec- tion position. REC Operation Pressing the R

29、EC button starts the motor rotating, and at the same time turns the REC solenoid ON. The REC lever is then pressed by arm (B) (see Fig.4). At the same time, the REC lever presses the PLAY lever, and both levers are engaged by the lockplate. The REC lever, via the REC arm places the REC/PB switch on

30、the AF amp unit to the REC side. All other operations are the same as the PLAY mode. o REC PAUSE Operation l . Pressing the REC PAUSE button in the STOP mode enters the RECORD and PAUSE mode. Pressing it from a REC mode turns the PAUSE solenoid ON. The follow- ing description will apply to pressing

31、it from the REC mode. 2. The PAUSE lever is pressed by arm (B) and engaged by the slider. 3. The action of the PAUSE lever, via arm (G) releases the TP unit from the reel unit, and breaks contact between the pinch-roller and capstan shaft. stopping tape travel. The auto stop pin (Fig.6, arm (C)is lo

32、cked in a depres- sed position, preventing Auto Stop from working. STOP Operation Pressing the STOP button turns the STOP solenoid ON. Mechanism operations are the same as at initialization. A Reer unit,-g( o )B u - ./.d .V REW Lever- r Arm(J)r + Heod Ptote Pin Pinch Rotter FR Unit Geor - ReeL Unit

33、Arm(H) Fis. 10 PLAY Lever Fig. 1 1 Arm (G) Fig. 12 a 1. 2. REC Lever a 1 Arm (l ) , TP Unit + Auto Stoo Pin- PAUSE Lever Switching From REC PAUSE to REC, FF, or REW Mode When the REC button is pressed from the REC PAUSE mode, the PLAY solenoid is turned ON, and the PLAY arm (Fig. 4, arm (B) presses

34、the slider at the point of the arrow. This causes the slider to move upward, releas- ing only the PAUSE lever lock and entering the REC mode. When the FF or REW switch is pressed from the REC PAUSE mode, the pause lever lock is released as des- cribed above. This time however, the FF or REW lever mo

35、ves the lockplate downward to release the REC and PLAY lever locks, entering the FF or REW mode. o EJECT Switch 0N +OFF S witc h Arm(M When the cassette is loaded, pressure on arm (K) causes arm (L) to be unlocked. Arm (L) moves in the direction of the arrow, causing arm (M) to also move in the dire

36、c- tion of the switch and turn it OFF. Switch Operations Switch 51-1 is turned ON/OFF by the STOP lever. During STOP operations it is ON. and goes OFF when operations are completed. Switch 51-2 is turned ON/OFF by the PAUSE lever. During PAUSE switching operations it is ON, and goes OFF when switchi

37、ng operations are completed. Switch 52 is turned ON/OFF by the slider. During PLAY, FF, REW, and REC switching operations it is ON, and goes OFF when switching operations are completed. PLAY Arm + PL AY Arm 1 REW nr. -1 , - Lock Ptote t. 2. REW FF F F Fig. 13 Arm(K) Fis. 14 When EJECT is pressed to

38、remove the cassette, arm (M) (Via the EJECT Lever) moves away from the switch, turning it ON. TOP L O C K P L A T E Reet Unit 1.2. o 1. 2. 3. s2 St i d e r Sw i t c h sr- 2 R EC PAU S E L e v e r S w i tc h sr- | ST 0 P L e v e r S w ttc h Fig. 15 SV/ITCH UNIT (B) 3. CIRCUIT DESCRIPTION 3.1 TUNER SE

39、CTION Ste reo B P F F M R F A Cero m i c FM Mixer FM IFT Fitte r Locol 0SC Cerqm ic AM A M M i x e r A M I F T F i L t e r l F A m p M E T E R S I G N A L + S w i t c h i n q Fig. 16 o Tuning Indicator Circuit During FM operations, tuning a station causes a rise in the voltage present at the pin 10

40、of lC1 (K84419C). Since this turns 08 ON and 01 1 OFF, current begins to flow from R65 to D8, lighting the tuning indicator. Next, moving the tuning dial pointer to a point near the station, but lower on the frequency scale will cause one of the comparators of lC3 to gate, dropping the potential at

41、the base of Q8 and turning it OFF. This causes Q1 1 to turn On and the tuning indicator will not light. lf the pointer is moved near the tuned point, but higher on the frequency scale, the opposite comparator (lC3) will gate, preventing the tuning indicator form lighting as explained above. Addition

42、ally, in a frequency area where no stations exist, or where the incoming signal is so weak that the S/N ratio is unacceptable, 08 will be OFF and 01 l will be ON. and the tuning indicator will remain extinguished. The above operations apply when FM muting is acti- vated, and they are synchronized wi

43、th muting operations. During AM operations. +B is applied to lC3 and indicator operations are in accordance with the voltage at pin 10 of K8441 9C. F M l F A m p M P X 0 ecoder Cerom ic F i l t e r F M D e t e c t o r t I n d L C n R c h F M o u t Auto/ l.4ono S w i t c h AM FER An ten no LocaL 0SC

44、o Front End The antenna input section consists of a band-pass filtered single stage RF amplifier (Ol), a base injection mixer (02), and a modified Colpitts local oscillator circuit. o lF Amp, Detector Circuit This section is contained in the FM (Attlt) tF System lC (LAl 140) and consists of the FM l

45、F amp, two double- element ceramic filters, the preamp consisting of transistor 03. Together they form a four-stage differential amplifier. KB4419C functions as an lF amplifier, limiter, and as a quandrature detector. o FM Muting Circuit Output level is detected at the meter output pin (pin 10) of K

46、B44l9C by AN6913 (lC3). When a detuned status is detected, the signal is passed through AND gates and used to activate the muting transistor (O10). o FM Multiplex Circuit The FM multiplex circuit uses a PLL multiplex lC (KP44248. r c a - r L ED D r i v e r A M I F T A M Detector F u n c t i o n Swit

47、ch 3.2 DECK CONTROL SIGNAL SECTION o Basic Operations The cassette deck mechanism uses switches (S1-1, S1-2, 52) to detect mode switching operations. Pressing the keys to switch modes turn the switches ON/OFF. The list below shows the switch-mode status. 51-1 (STOPleverswitch) . STOP 51-2 (RECPAUSEs

48、witch) . . . . PAUSE 52 (SLIDER SWITCH). . . PLAY, REC, FF, REW PLAY mode operations will be used as an example to describe the role the switches play. The relationship bet- ween the solenoid and switches at PLAY key entry is shown is Fig. 17. A . . . . PLAY key entry turns the solenoid ON, and star

49、ts the mechanism mode switching operation. B . . . . Next. 52 is turned ON, and it functions to detect the proper switching operation (PLAY mode in this case). and this turns the solenoid OF F. . Tape End Detector Circuit The cassette mechanisms tape end detector switch (FAS swtich) also comes ON at times other that at the end of the tape, so PD1004 is designed to recognize the end of the tape as the second time this switch is turned ON. The