Pioneer-SK900-pr-sm电路图 维修手册.pdf

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1、NEER 7-_-7-._. ORDER NO. HRT-177-0 PORTABLE STEREO FM/AM RADIO CASSETTE RECORDER KU,KC SPECI FICATIONS Continuous power output .SW+SW/FrC 18Q, 6O-15,OOOHz 5% THD.) Max. music power. 40W Itotal music power) Speaker Air-tight cabinet, 12cm (5 in.) meehanical 2 way system with passive radiator Recordin

2、g / playback frequency characteristies 50 14,OOOHz 3dBI (Normal tape) 50 15,OOOHz (3dB) (Crl tape) 5O cv 16,OOOHz (3dB) (Meta) tape) Recording I playback SIN ratio. . 59dB (Dolby NR on, Normal tape) 51dB (Dolby NR off, Normal tape) Input. AUX, PHONO, MIC (also functions as MIX MI Cl, EXT. ANT Output

3、 UNE OUT, PHON ES Subfunctions Doiby NR, Tape seleetor (MetaI/Cr02 Normal), Auto/manual reeording, Skip seareh, Music One side repeat, Automatie Timer stand-by mechanism, 6-band graphie equalizer, FM muting, Stereo microphone mixing Indieators . Red LEDs: CrOl, METAL, AUTO EDI TOR, REC, PHONOI AUX,

4、AM, FM, FM MODE, STEREO, POWE9, SKIP SEARCH (S) Green LEDs: DOLBY NR, PLAy, REW, FF, PAUSE, ONE SIDE REPEAT, MUSIC REPEAT, TAPE Others: ACCESS TUNING (two red, one green), LEVEL (stereo meter) Frequeney range FM: 88108MHz AM: 525-1,605kHz Power source. 120V AC, 60Hz; ten size 0 flash light batteries

5、 O.5V); EXT 15V DC (12cv 15V) Dimensions (W x H x D) . 655x235x 160mm (25-3/4x9-1/4x6-1/4 in.) Weight. 9.9kg (21 .8Ibs., without batteries) Note: Specifications and design are subject to change without notice. r 1-J 0 i ) 100=001 l J L r-I 70-.; (mr;) or8 3195, AustreL8 FS AUG. 1981 Printed jn Japan

6、 RadioFans.CN 收音机爱 好者资料库 :i!:;:,:,tl Kgc:n:r,; :ik:,t;tt;7;:; CONTENTS 1. PARTS LOCATION 2 2. CIRCUIT DESCRIPTION 2.1 Tuner Section . . 3 2.2 Logic Circuits . , . . 4 2.3 Block Diagram . . 13 2.4 Level Diagram . , . . 14 3. MECHANISM DESCRIPTION . . 15 4. DISASSEMBLY . , . , . . 17 5. ADJUSTM ENT 5.

7、1 Check Points of Cassette Mechanism . 21 5.2 Head Azimuth Adjustment . . . . . . . . . . 22 5.3 Record Bias Adjustment . 22 5.4 Trapping Adjustment . 23 5.5 Dolby N R Playback Adjustment . . . . . 23 5.6 Dolby N R Characteristics Adjustment . 24 5.7 Recording and Playback Level Adjustment 25 5.8 AM

8、 I F Adjustment . . . . . . . . . . . . . . . 26 CAUTION When Handling IC TC4066P, /-LPD4066C, MSM4001RS, MSM4027RS and MSM4011RS Please Observe: JC TC4066P, /-LPD4066C, MSM4001 RS, MSM4027RS and MSM4011 RS (lC2 in the pre amp unit, IC11 in the control unit, IC1-IC4, IC6 and IC8 in the logic unit),

9、are CMOS ICs of extremely low power consumption and very high input impedance. Unless handled with special care, they could be damaged by static electricity induction. These ICs are supplied with a shorting, cap (of aluminium foil) attached. When soldering, or performing other repair work, always at

10、tach this cap as shown below. Remove the cap after the repair has been completed. Also, this type IC must not be inserted in a polysWrene package for storage. Dolby and the double-D symbol are trademarks of Dolby Laboratories Licensing corporation. . Noise Reduction System manufactured under license

11、 from Dolby Laboratories Licensing Corporation, 5.9 AM Tracking Adjustment . , 26 5.10 FM I F Adjustment . . 27 5.11 FM Tracking Adjustment . . 28 5.12 FM I F Final Adjustment . . 29 5.13 FM MPX Adjustment . . 30 6. DIAL STRINGING . , . 31 7. SCHEMATIC CIRCUIT DIAGRAM . , 36 8. CONNECTION DIAGRAM .

12、. 42 9. CABINET EXPLODED VI EW . , . . 48 10. CHASSIS (1) EXPLODED VIEW . , 51 11. CHASSIS (2) EXPLODED VfEW . . . . . . . . . . 54 12. CASSETTE MECHANISM EXPLODED VIEW (TOP). . . . . . . . . . . . . . . . . . . . . . . . . . . 57 13. CASSETTE MECHANISM EXPLODED VIEW (BOTTOM) . , 60 14. PACKING METH

13、OD. . . . . . . . . . . . . . . . . . . 63 15. ELECTRICAL PARTS LIST . , . . . . . . . . . 64 1 RadioFans.CN 收音机爱 好者资料库 1. PARTS ION NOTE Far yaur Parts Stock Contra/, the fast moving items are indicated with the marks * * and *. *: GENERALL Y MOVES FASTER THAN *. This classification shall be adjust

14、ed by each distributor because it depends an model number, temperature, humidity, etc. e The it sets and resets on clock pulses at the CP terminal. Initial Condition The initial condition depends on the position of the Timer stand by switch. The following discussion assumes the switch i5 at the off

15、position. When the power switch is turned on, the 15V fed to the circuit is then differentiated by C13 and R34. The resulting voltage across R34 is regulated to 8V by zener diode ZD5. This voltage feeds into the R or CLR terminal of the PLAY, FF, REW, and PAUSE flipflop circuits, and drops the Q ter

16、minals low, establishing a stop state. As for the REC flip-flop, the voltage differentiated by C8 and a group of resistors connected to C8 feeds into the R terminal and create a stop state. ROV Q I 4 I V 5 01-0 S(-N.J-=DQ J I Q o-LJcp o-tl K Q CLR () !PAUSE! Fig.4 Q5 VDO W + TIMER STAND-SY o 0 R3.f

17、ts 023 t055 ICI _ IC2_ t;Jt;J S Q S Q PLAY FF ZD4 I 0871 R.fm I Dqt070 080 CLR Q CLR Q R Q IC3-1 IC3-2 ICI PR Q PR Q S Cl REIN PAUSE REC Fig.5 4 R Q I + . .-. 8 0302 I. PLAY Vcc Vcc O4-4- FF fiiPl REC REW R85 sR84 ICI Q22 S Olq S 1-2 NO N REC REC REC . 064 ,+ C431 Playback Mode rn REC -05Q .-0 o-a.+

18、-lS Q PlAY PlAY With the play switch turned on, Vcc feeds into the S terminal of the PLA Y flip-flop through D59, setting the 0 terminal high. The output at the 0 terminal feeds into the R terminal of the REC flip-flop through D26, resetting the o terminal. The high state at the 0 terminal of the PL

19、AY flip-flop also feeds into pin 9 of IC2, making pin 10 and pin 12 low. Because both pin 12 and 13 are low (unless the PAUSE tlip-flop is set, pin 13 is also low), pin 11 becomes high turning 019 on. Since the HP switch (head plate switeh) is at the R (rearl position, 019 then turns 017 on, which t

20、hen activates the solenoid. When 019 turns on, 1t also turns 016 on, start1ng the capstan motor. The rotation of the capstan motor advanees the head, and the HP switch moves to the F (front) position, whieh then turns 017 off and deactivates the solenoid. This eompletes the steps for the playback mo

21、de. The positive voltage at the 0 terminal of the PLAY flip-flop also turns 07 on, Iight1ng the PLAY LED(D301) and controlling other related eircuits through D4. (I) Record Mode PlAY PlAY PLAY CAPSTAN MOTOR-: ON V-,._ SOLENOID -:, HEAD PlATE SWITCH REAR , , FRONT Fig.7 Vcc 15V +8 10301PLAY 05 _ 04 f

22、iW PR 01J REC DSI r.1 TRQ ICI Jr S Cl 7 Fast-forward and Rewind Mode ESET (REC,PlAYI REC,PB, FF) ESET(RECI FF 0303 FF , i D53 066 IC2 Vcc-u o IfIoI , I 15 Q L.-;-ip Q LC 3 I I K REIN ClR FRONT REAR 035 0304 REIN QI6 +8 HEAO PlATE .:t 5WITCH T 50lENOIDr When the FF switch is closed, Vcc (8V) sets the

23、 FF flip-flop through 066, and at the same time resets the REC, PLA Y and REW flip-flops. With the F F flip-flop set, the 0 terminal be comes high and turns on 08 and 09. When 09 is turned on, current flows through 034 into the base of 012, turning 012 on. With 09 and 012 conducting, current flows f

24、rom 09 to 012 through the reel motor, rotating the reel motor in the FF direction. When 08 is turned on, the base of 010 becomes ground ed through D28. This prevents 09 and 010 from turning on at the same time -even when 013 mistakenly turns on. The capstan motor keeps rotating during the fast forwa

25、rd mode, since 016 keeps conducting due to the current flowing through the path of Q16 -D29 08 - Ground. Fig.13 The head base needs to be withdrawn du ring the fast forward mode. Because the HP switch is at the F (front) position when the head base is advanced, 017, turned on by the current flowing

26、through the path of 017 -HP switch -D30 -08 -Ground, activates the solenoid and withdraws the head base. The rewind mode works similarly. When the REW flip-flop is set, 013, 011 and 010 turn on. Current then flows from 011 through the reel motor into 010 -the direction opposite to that of the fast f

27、orward mode. The capstan motor keeps turning since 016 is turned on by the current flowing through the path of Q16 -D36 -013 -r Ground. The head base is withdrawn by the solenoid, wh ich has been activated by the current flowing through the path of 017 -HP switch -+ 035 -+ 013 -Ground. B . Timer Sta

28、ndby Circuit The timer standby switch has three positions: OFF, REC, and PLA Y. Details of each position are as fallows: OFF position -As soon as the power is turned on, a reset pulse feeds into all the flip-flops and resets them. REC position when the power is turned on, areset pulse generated by t

29、he time constant created by CS and a group of resistors connected to ca resets the REC fl i p-flop. At the same time, a set pu Ise generated by the time constant of C13 and R34 enters the S terminal. Because the time constant of C13 and R34 is far greater than that of ca and R23, the set pulse at th

30、e 5 terminallasts longer. So, as soon as the reset pulse is gone, the set pulse sets the REC flip-flop. PLAY position -The operation of the P LAY position is similar to that of the REC position. It first resets then sets. CI Editor VDD ,- -+ R 010 PLAY Dq REC R Q R Q RECI OFF IPLAY ICI ICI SI-? -115

31、 Q SQ , + C8 Vcc ICI S Q REC R60 . R5q 0305 EDITOR If the Editor switch is pressed while recording, Q14 turns on and sends a signal to other related circuits. While the editor is in operation, the LED goes on and off in a cycle of about one second. When the Editor switch is off, pin 8 of IC4 is high

32、, which makes pin 10 low, which makes pin 4 high, keeping pin 3 stable at low. When the Editor switch is turned on, pin 8 becomes low. Pin 9 is low too, at that time, because it is connected to pin 3 through R60 and R59, and C21 is fully charged. With EDITOR OUT Fig. 15 both pin 9 and pin 8 low, pin

33、 10 turns high, making pin 4 low, and thereby pin 3 high. The high state at pin 3 then turns Q15 on, and lights the LED (D305). As soon as pin 3 turns on, C21 discharges and then starts recharging in the opposite polarity. When the recharging has advanced to some extent, pin 9 becomes high and rever

34、ses the state of the other pins, turning off the LED. Because the time constant of C21 and R59 is such as to create a cycie of about one second, D305 stays on for about 0.5 second and goes off for about 0.5 second and so forth. B 14 D44 PAUSE D45 ., d ., Setting Pause REC When editor terminates, the

35、 unit has to be put in the pause mode. The following discribes how the pulse to trigger the PAUSE flipflop is generated. While in the editor mode, pin 13 of IC4 is high due to the positive voltage across R64 developed by the current trom Q14 through D41. Pin 12 is also high because of the positive v

36、oltage acorss R63 developed by the current fram Q14 through D42. When the Editor switch is pressed at first, C22 discharges through the path of R62 -+ D38 -7 D39 -7 Q14 -+ D42 -+ C22. Because both pin 12 and pin 13 are high, pin 11 is driven low. When the Editor switch shuts off, Q14 turns off. Pin

37、13 becomes OV (=Iow) since no current flows from Q14 into R64. As for pin 12, the voltage across R63 disappears, causing a current fram R62 taward R63. Since R62 is far greater than R63, voltage drop by the current mostly takes place across R62, which then brings the voltage at pin 12 to low. It con

38、tinues to be low until C22 is sufficient Iy charged to exceed the threshold voltage of IC4. As both pin 13 and pin 12 become low, pin 11 becomes high. The high state at pin 11 then brings the Q terminal of the PAUSE flip-flop high via D43. After the PAUSE flip flop is set, Q14 cannot be turned on by

39、 the Editor switch because of the reverse bias from the Q terminal through D40. This prohibits the editor mode while in the pause mode. IC3-2 PAUSE 040 043 J 01 i + ( QI4P-1IIII+-1 C P J1. IK Q R55 EDITOR D37 OUT R56 ITOR Fig. 16 Vcc-.-. Transient response Voltage drop of C22 across R62 Voltage drop

40、 across R63 Ground position -T Fig.17 When the charging of C22 advances, and the voltage at pin 12 exceeds the threshold level of IC4, pin 12 be comes high, which then makes pin 11 low, eliminating the pulse that has set the PAUSE flip-flop. The pulse width depends on the threshold level of the JC u

41、sed. However, since the PAUSE flip-flop senses the edge of the trigger pulse, varietly in pulse width is per mitted to some extent. 10 REC:!:J,0236 Charge current1 Auto Editor R242 (SK1PI R2.33 FF + REW R234 10 I PLAY TRIGGER C 2 13 D22Cl C212 JU . REW TRIGGER Fig. 19 D231 s 3 REW J $/11 PLAY AS TRI

42、GGER 022Q Fig.20 AUTO EDITOR PAUSE 10 C208 0235 EDITOR OUT The Auto Editor circuit operates only when the unit is recording. When the unit is in other modes, the positive voitage at 0236 disables the circuit. Also, if the Pause button is pressed while in the record mode, the positive voltage at D235

43、 disables the circuit. Before this circuit is set in operation, pins 8, 4, and 2 are high and pins 10,5, and 3 are low. C208 is left uncharg ed because both of the poles are low. C210 is also left uncharged because both of the poles are high. When the unit is put in the record mode O.e. without paus

44、e), pin 9 becomes low. If the Editor switch is then closed, pin 8 turns low and pin 10 turns high. This positive voltage at pin 10 starts charging C208 with the current flowing through R229 toward pin 3, and at the same time it reverses the state of the other pins, making both of the poles of C208 h

45、igh, and stopping the charging of C208. One Side Repeat R236 1+ R237 PLAY+ REC Rl R22q Fig. 18 C210 keeps charging with the current flowing from R230 toward pin 4 wh ich has just become low. The low voltage at pin 4 also brings pin 8 low through 0227 and 0225, alienating the effect of the Auto Edito

46、r switch. When the charging of C21 0 advances sufficiently to drive pin 2 high, pin 3 turns low, which then starts charging C208 with the current flowing toward pin 3. After pin 3 turns low, the voltage 8t pin 5, which has been kept high by pin 3, steys high for the time being because C208 is being

47、charged; as the charging advances, however, the voltage gradually decreases until it is finally low enough to reverse the state of pin 4 to high. When -and only when pin 4 is low, Q14 conducts and sends a signal to other related circuits. The above sequence takes about 5.5 seconds and keeps the unit in the editor mode du ring the period. 0231 1 1 The Dne Side Repeat eircuit allows the user to rewind and replay the same side of the tape after it comes to the tape end. When the unit is in the playback or record mode, pin 12 of I