JVC-KDA77-tape-sm 维修电路原理图.pdf
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1、JVC MODEL KD-A77 A/B/C/E/J/U STEREO CASSETTE DECK No. 4186 September 1979 RadioFans.CN 收音机爱 好者资料库KD-A77A/8/C/E/J/U r-Contents Specifications . 2 Features . 3 Controls and Connections . 3 Main Parts Location . 4 Maintenance . 4 New Technique . 5 Removal of the Main Parts . 6 Main Adjustments . 1 0 Bl
2、ock Diagram . 16 Integrant Circuit . 18 Standard Schematic Diagram of KD-A 77 Amplifier circuit . 1 9 Mecha. control circuit . 20 Wiring Connection (1 ) of KD-A 7 7 . 21 Specifications Type Track system Tape speed Frequency response OVU Metal tape SA/Cr02 tape -20VU Metal tape SA/Cr02 tape * 1 *2 SF
3、/Normal tape * 3 SIN ratio Stereo cassette deck 4-track, 2-channel 1-7/8 inch/sec (4.8 cm/sec) 25-12500Hz 3dB(Typical) 25 -8000Hz 3dB(Typical) 15-20000Hz 25 -1 8000Hz 3dB(Typical) 15-20000Hz 25-1 8000Hz 3dB(Typical) 15-19000Hz 25-17000Hz 3dB(Typical) Surpases DIN 45 500 60dB (from peak level, weight
4、ed, Metal tape) The SIN is improved by 5dB at 1 kHz and by 10dB above 5kHz with ANRS on. (DIN 45 500 weighted) Effect of Super ANRS : (normal tape) Improvement of SIN : the same as with ANRS Improvement of frequency response : OVU recording; 6dB at 10kHz + 5VU recording; 12dB at 10kHz Improvement of
5、 distortion Wow and flutter Crosstalk Hormonic distortion Bias Erasure Heads No.4186 OVU recording; 3 % or less at 10kHz + 5VU recoridng; 3 % or less at 10kHz 0.04% (WRMS), 0.14% (DIN 45 500) 65dB (1 kHz) K3; 0.4%, THD: 1.0% (metal tape, 1 kHz OVU) AC bias (85kHz) AC erasure (85kHz) 3 heads SEN ALLO
6、Y head for recording, SEN ALLOY X cut type for playback and two-gap SEN ALLOY head for erasure Wiring Connection (2) of KD-A77 . 22 Enclosure Assy and Electrical Parts . 25 Enclosure Assy and Electrical Parts List . 23 Mechanical Components Parts . 26 Mechanical Components Parts List . 28 Printed Wi
7、ring Board Parts Main Amp. P.W. Board Parts . 33 Power Supply P.W. Board Parts . 34 Main Amp. P. W.B Parts List . 30 Power Supply P.W.B Parts List . 35 Other P.W.B Parts . 37 Other P. W.B Parts List . 39 Packing . Back cover Accessories . Back cover Motors Fast forward time Rewind time Semiconductor
8、s Input terminals Output terminals Power requirement Power consumption Dimensions Weight FG type DC servo motor (for Capstan) DC motor (for Reel) 85 sec. with C-60 cassette 85 sec. with C-60 cassette 1 8 ICs, 49 transistors, 59 diodes, 14 LEDs Mic jack x 2, Max. sensitivity; 0.2mV (-72dBs) Matching
9、impedance; 6000-10kO Input jack x 2, Min. input level; 80mV (-20dBs) Input impedance; 100kO Output jack x 2, Output level; 0-300mV Output impedance; 6kO Matching impedance: 50kO or more Phones jack x 1, Output level; 0-0.5mW/SO Matching impedance: 80-1 kO AC 120V, 60Hz (KD-AnCW AC 240/220/120V, 50/6
10、0Z (KD-A n A/B/E) AC 240/220/120/1 OOV, 50/60Hz (KD-A77U) 36W 17-3/4 (450 mm) W 4-3/4 (120 mm) H 12-7/16 (316mm)D 18.3 Ibs (8.3 kg) Note: * 1 . SCOTCH MET AFINE or Equivalent * 2 . TDK SA or Equivalent * 3 . MAXELL UD or Equivalent Design and specifications are subject to change without notice. -2 -
11、RadioFans.CN 收音机爱 好者资料库Features 1. 3 SA (SEN-ALLOY) heads Combined SA (SEN-ALLOY) record/play (X-cut type) heads make possible record monitoring. The erase head is a 2-gap head also made from SA (SEN-ALLOY). 2. Two-motor ID (independent Drive) mechanism This mechanism incorporates a newly developed
12、Back Tension system which gives improved tape contact with the head. 3. Self-illuminated buttons for full logic mechanical operation (excluding STOP or REC-MUTE modes.) 4. Three position Metal-Tape-Compatible tape select switch. METAL -FeCr _ SA/Cr02 NORM (Automatic switching between SA/Cr02 and NOR
13、M) 5. The REC MUTE button is at the right side of the mechanical operation buttons. KD-An A/B/C/E/J/U 6. ANRS which reduces tape hiss to an inaudible level and Super ANRS which improves linearity at high fre-quencies are incorporated. 7. MEMORY/AUTO REW switch 8. Recording equalizer switch 9. Timer
14、standby capability for automatic recording or playback using an AC timer. 10. Geared and oil-damped cassette holder. 11. New Metal-Tape-Compatible multi-peak level in-dicators (+ 9dB, + 6dB, + 3dB, -2dB, -7dB). together with back-lit VU meters with the expanded coverage from + 7VU to -20VU, make lev
15、el observa-tion easier. 12. OUTPUT volume (for LINE and HEADPHONES use) 13. Remote control terminal (for the optional remote con-trol unit -R-30E). Controls and Connections 2 3 4 5 6 10 11 12 14 15 16 17 18 19 20 21 = = = = = = = = = = r-= . . = -1. VU meters and Multi-point peak level indicators 2.
16、 INPUT LEVEL control 3. TAPE indicators 4. ANRS/Super ANRS indicators 5. Cassette holder 6. MEMORY/AUTO REW switch 7. Tape counter/counter reset button 8. EJECT button 9. TIMER STANDBY switch 10. PHONES jack 11. MIC jacks 12. INPUT SELECT switch 13. ANRS switch 14. TAPE SELECT switch 15. REC EQ swit
17、ch 1 6. OUTPUT LEVEL control n LJ 22 23 24 f r:f 1 r - I 1 7. MONITOR switch 1 8. Cassette Operation buttons REW (rewind) button FF (fast forward) button PLA Y button STOP button o REC (record) button 11 PAUSE button REC MUTE button 19. POWER switch 20. Power cord 21. Voltage select switch (KD-A 77
18、A/B/E/U) 22. REMOTE CONTROL socket 23. LINE IN (REC) terminals 24. LINE OUT (PLAY) terminals -3 -No.4186 KD-A77 A/B/C/E/J/U Main Parts Location 2 3 4 5 6 7 9 -8 1 1 1 2 1 3 (Mechanical parts) 1. Front panel assembly 1. Switch holder (U 2. DC solenoid for playback 2. Supply reel assy 3. Reel motor 3.
19、 Idler assy 4. Geared and oil-damped brake assy 4. Reel motor assy 5. Variable resistor (INPUT LEVEL control) 5. Take-up reel assy 6. Meter cover 6. Switch holder (R) 7. LED P.W. Board assy 7. Connecting wire (for play solenoid) 8. Hall element P.W. Board assy 8. Capstan 9. Power switch 9. Slide bas
20、e assy 10. Power transformer 10. Stad with pad (for back tension) 11. Remote control socket (DIN socket) 11. Erase head 12. Pin jacks assy 12. Combined SA (SEN-ALLOY) record/play heads 13. Mecha. control P.W. Board assy 13. Pinch roller assy Other mechanical parts are the same as location of model K
21、D-A6: Please refer to the service manual 0 KD-A6 A/B/C/E/J/U (No. 4179 -page 4). Maintenance To get long, trouble-free service, maintenance is important. Do not forget cleaning and demagnetizing. Cleaning After long, the heads and tape part -capstan, pinch roller, etc. -will become dirty with dust o
22、r magnetize particles. Dirty heads cause imperfect erasing or high frequency drop-off. A dirty capstan and pinch roller will cause unstable tape speed, leading to increased wow and flutter. Always keep them clean by following the procedure below. 1. Heads 1) Push the EJECT button to open the cassett
23、e holder. 2) Push up the transparent cover to remove it. 3) Use the head cleaning stick to wipe the surface where the tape comes into contact with the head. (it is effective to moisten the cotton with alcohol.) 2. Pinch roller and capstan Close the cassette holder with its transparent cover remov-ed
24、. Press the tape detection pin inside the cassette com-partment and set the deck in the playback mode. Insert the cleaning stick into the hole on the right side at the bottom of the cassette holder and clean the pinch roller and oopan. :,h , . Cleaning stick No. 4186 -4 -3. Cleaning the cabinet and
25、panel Wipe the cabinet and panel clean with a soft cloth dipped in a neutral cleaner. Do not use thinner, benzine, alcohol or other strong solvents, as these will cause damage to the surface finish of the cabient and panel. Demagnetizing The heads are made from a material resistant to magnetiza-tion
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