JVC KD-A77 A, Service Manual

Page 1: ...JVC MODEL KD A77 A B C E J U STEREO CASSETTE DECK No 4186 September 1979 ...

Page 2: ...VU AC bias 85kHz AC erasure 85kHz 3 heads SEN ALLOY 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 Ass y and Electrical Parts 25 Enclosure Ass y and Electrical Parts List 23 Mechanical Components Parts 26 Mechanical Components Parts List 28 Printed Wiring Board Parts Main Amp P W Board Parts 33 Power Supply P W...

Page 3: ...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 level 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 1...

Page 4: ...oller and capstan Close the cassette holder with its transparent cover remov ed 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 oop an h Cleaning stick No 4186 4 3 Cleaning the cabinet and panel Wipe the cabinet and panel ...

Page 5: ... low frequency range With ordinary core configurations playback output is subject to peaks and dips in the low frequency range as shown in Fig B This is called the contour effect this effect is caused by interference between the length of the tape to head contact area and the wavelength of the recor ding frequency With the X cut design the core is cut diagonally to enable the tape to leave the hea...

Page 6: ... the bottom cover 5 Front plate assembly 1 Remove 5 screws 3 screws on upper side and 2 screws on bottom side fastening the front plate assembly 2 Remove TAPE ANRS indicators wires socket When adjusting or replacing REC PB heads or Erase head 1 Remove the wires of the control switches from the wire clamp and 2 wire sockets after having removed the top cover 2 Remove 2 screws positioned below the c...

Page 7: ... ass y Remove the E ring Electrical parts 1 Power supply P W B parts assembly 1 Remove a pawls of P W B holder in the order of the numbers in the illustration arrow mark 2 Remove 3 screws fastening the P W Board 3 Open the P W B to upper side 2 Main amp P W B parts assembly 1 Remove 4 screws fastening the main amp P W Board on the bottom side 2 Remove 4 screws fastening the lever switches on the f...

Page 8: ... fastening the power switch 4 Power transformer Remove the 2 screws and 2 washers fastening the power transformer Removal of the mechanical assembly 1 Remove a screw fastening the arm of gear oil damper Left side of the cassette holder and Remove 2 screws fastening the gear frame ass y to Remove door brake related parts 2 Remove 5 screws fastening the mechanical bracket to the amp chassis Right 2 ...

Page 9: ...r belt Note 1 Remove the reel disc stoppers with a piece of sheet metal inserted between the reel disc and the stopper 2 Be careful not to stain the counter belt 6 Reel motor Remove the 3 screws fastening the reel motor 7 Capstan motor 1 Remove the screw fastening the rubber stopper 2 Remove its motor belt 3 Turn the motor counter clockwise and pull it for removal Note When replacing the motor che...

Page 10: ...d Pad attached to the cassette Tape Clearance A 1 After installing the specified parts in the appropriate positions A Snug screw CD gently then back off about two turns This makes the heads nearly horizontal B Snug screw gently then back off about one turn This will roughly position the tape in the center of the tape path For tightening screw use a home make screwdriver filed down to the specifica...

Page 11: ...alue and flutter the LINE OUT terminals even if conforming to the standard a Play back the VTT 656 test tape re claim may be raised Repairs are Check to see if the reading of the necessary meter is within 0 04 WRMS Ill Repair of wow flutter If wow and flutter increase check the following points If there is defect in revolving parts the wow and flutter generated will increase in proportion to the n...

Page 12: ...ncreases the signal current VR703Rtl Q L For ANRS adjustment at playback mode _ __ J Turning In the direction of the arrow Increases the ANRS gains Main P W Board VRAOl VR501 T L VR601 G L For recoridng level adjustment 0 Rl T P R Turning in the direction of the arrow in creases the recording levels 1 Front L For ANAS adjustment at recording mode Turning in the direction of the arrow increases the...

Page 13: ...ons fall within the standard range using the 1kHz signal output as a reference It is basically desirable that the 1kHz 50Hz and 12 5KHz signal outputs are the same Adjust VR502 amd VR602 for a nor mal tape VR503 and VR603 for a chrome tape VR504 and VR604 for a metal tape until the indicated deviation of the 12 5kHz signal out put from the 1kHz signal output be comes O Adjusting point VR701 801 VR...

Page 14: ... metal tape should be less than 1dB 1 VU Perform the adjustment using a normal tape level difference between recording and playback for Cr02 and metal tapes should be less than 1 5dB and that between left and right channels should also be less than 1dB Be sure to perform this adjustment following bias current and recording level adjustments Apply an output 72dBs to the MIC terminals with the recor...

Page 15: ...s level is caliblation point 14 Adjust the input signal to 34 3dB with an attenuator and then LINE OUT level become 39 3dBs 15 Adjust the VR703 for left channel and the VR803 for right channel with ANRS switch set to ON until the LINE OUT levels become 45dBs The output difference is 5 7dB with ANRS swith to ON from OFF 16 Apply 5kHz signal with the ANRS switch set to OFF Adjust an attenuator so th...

Page 16: ...h I ON t oOFF Input Se lect Super ANRS CircUit 0 MicroPhon J SWitch Y 2SC1344 n 1 E F I le AOI TATOO0351 01 1 Control Switch UlO 23 r e Multi Peak LelA I Multi Peak Level Indicator EE 2 IC912 LBI416 Output Level Control Circuit LINE OUT _ Head phone UPC4557CI Headphone Amp Record Ing Head 3 E 1 t Cl o C _ Q CC Q 3 A 9 J J co m c c ...

Page 17: ...4 I lc 3 STOP FF 14 X 2 C Brake FF FAST 1162 Solenoid 4 MErvo REW 13 Rew 5 REW PLAY IC6 3 1 M l t 6 PAUSE 11 Rec 7 F t lJSE 10 IC2 4 REW REC g To 8 GND AR Pause Pause Amp HIC2 4 Solenoid X4 Pause I 2SC f Solenoid Counter Merrory Fo Sto ReelMotor Drive HalllC IC5 2 IC6 1 IC5 1 X6 XI12SC456R3 CO L 1 C458 Xl X9 2SD468 B C fel PGlal Play Stop XIO Motor r iIC6 4 X 8 2SC 1162 B C 4 Start 011 RD62E IC5 4...

Page 18: ...C Headpone amp Top view is the same as UPC4558C IC903 LB1416 Multi peak level circuit Top view OUT 05 04 03 02 Q I11 LB 1416 3 ATTO IN IN IN Ro Vret Ro GNO Mecha control OUT NOr Vec pu INV iNPUT AM PLIf IER No I Equivalent circuit is the same as UPC4558C except R8 only Equivalent circuit OUT GNO 05 04 03 02 IC1 M54410P See the service manual of KO 85A B C E J U No 4165 page 7 No 4186 IC3 4 5 HP740...

Page 19: ...2SC 1685 S REC HEAD VGH0425 3QI OA R 1 2 CN A 3 ERASE HEAD R75 270 10 IMETAL er 0 ISUPER J ANRS from MECHA CON I CN A4 2 1 7 076 77 SL8 26URIN 075 78 SLB 26GGIN ALL VOL TAGES ARE MEASURED BY YTYM WITHOUT I NPUT SIGNAL AT STOP MODE Diode Transistor cMM0904I4 0A I 2 Automatic CrOzSelect P W B f iiiJl M_NORM UNLESS OTHERWISE SPECifiED ALL RESISTORS ARE 1 4 W t 5 CARBON FlESISTORS AND ALL CAPACITORS A...

Page 20: ...12 1 W4 J t ftRS 8ME Coorn 8L X D X I I X 12 H CN M4 4 CN M3 4 CN M2 PL3 CN MI MEMORY sw 0852301 101 STOP OFF PLAY 2SD468 B C 25C458PG 2SC458PG C_ 0 l H t I ToAmp rrg e O r F To Amp I 53 o L 022 I IOEI F Jld 77 C Ji U ____H 97 10 Nij QSPOO29 001 L _ J VM S HOLE IC PW B IH PL I I m 1606 00A 711 1J l50V lOjJ H DM603 IOEI 8 MW 9 vGP0201 005 TERMINAL P NB I TISA 98 I RESISTOR PW B 0 31 PW B L F2 KD A7...

Page 21: ... W B Ass y 21 Earth Lug Hall IC P WB tv1echa Connector P W B _A _ _ Main PW B Ass y KD AnA B C E J U Color code are shown below Slide SW PWB 1 Brown 2 Red 3 Orange 4 Yellow 5 Green 6 Blue 7 Violet 8 Grey 9 White o Black Memory Switch Timer Switch Input Level I rols Multi PEBk Indicators VU Meter L ch No 4186 ...

Page 22: ... Counter LED Indicators Hall IC PW s Socket 5pin o KD A77A 8 C E J U Back Light for arrount indicator Reel Motor Socket 7pin o Switch unit Ass y o No 4186 22 Connector Ass y for REC Head for E Head KO A77 U for KO A77 C J P S Head ...

Page 23: ...ing 1 25 VJD4339 001 Head Mark 1 26 VGM0112 001 Level Meter 2 27 35 ZCKDA7 7Y CBF Front Plate Sub Ass y 1 set 27 VJC1089 001 Front Plate 1 28 VJD4262 003 Power Escutcheon 1 29 VJD4328 001 Knob Escutcheon 1 30 VXP4031 00B Eject Knob Ass y 1 31 VKL461 3 001 Knob Bracket 1 32 VKW3001 031 Spring 1 33 VJK4106 001 Counter Lens 1 34 VJD4329 001 Lever Escutcheon 1 35 VJD4330 001 Volume Escutcheon 1 36 VJD...

Page 24: ... KO A77 AlE 6 1 OSS2325 011 BS KO A77 B 6 1 OSR0084 00 1 KO A77 U 6 1 79 OMF51 A2 R20LBS Fuse KO A77 B 6 1 80 TAZOO0509 08 Fuse Seal KO A77 B 1 81 VKZ4001 01 1 Wire Clamp 5 82 VKL 1156 001 Front Bracket 1 83 VMW4551 001 Switch P W B for Timer Memory 2 84 OSS2301 101 Slide Switch 2 85 VKL4641 001 Chassis Bracket for Power Supply P W B 2 86 OVE3A3A 054F Variable Resistor 1 87 VMW4552 001 P w B for V...

Page 25: ...Enclosure Ass y and Electrical Parts Except P W B oard parts 2 3 4 5 6 7 8 9 10 A t At KO A77A1B E B c D E KD A77U F G 25 No 4186 ...

Page 26: ...I KD A77AIBICIEIJ U 6 7 8 9 10 No_4186 26 ...

Page 27: ...27 DPSP4010ZS Screw for Power Transformer 2 128 LDSP2604R for Cassette Lid 1 129 LPSP2604Z for Timer SW P W B x 2 4 Memory SW P W B x 2 130 LPSP2605Z for Joint Bracket 1 131 LPSP2608Z for Rack Plate 1 132 LPSP3006ZS for Power Switch x 2 6 Lever Switch x 4 133 SBSB2606Z Tapping Screw for Lamp Bracket 2 134 SBSB2608Z for Button Case 4 135 SBSB3006Z for Dumper x 2 Front Plate x 2 21 Chassis Bracket x...

Page 28: ...4 31 VKL43 70 000 Slide Base Ass y 1 32 VKP4105 00B Pinch Roller Bracket Ass y 1 33 VKL43 71 001 Push Arm 1 34 VKW4139 001 Pinch Roller Spring 1 35 VYSF10l 013 Spacer 1 36 VGH0425 301 0A R P Head Ass y 1 37 VND4020 001 Head Plate RIP Head 1 38 THC037417 02 Head Plate E Head 1 39 VKH4238 001 Azimuth Screw 1 40 VKH4239 001 RIP Head Screw 1 41 VKW3001 038 Compression Spring for Azimuth 1 42 ZMM090414...

Page 29: ...000 0 12 Belt for Counter 1 94 VKL4608 00B Mecha Bracket R Ass y 1 95 VMW4555 001 P W Board 1 96 DN6835 HaIlI C 1 97 OMV5004 004 Connector 1 98 VMW4534 001 P W Board 1 99 VKZ4128 001 Special Screw 1 100 OMV5004 003 Connector 1 101 VKL4617 001 Counter Bracket 1 102 VKL461 4 001 Lock Arm 1 103 VKH4253 001 Collar 1 104 VKW4161 002 Wire 1 105 VKL461 5 001 Lock Arm Bracket 1 106 VKW3002 024 Tension Spr...

Page 30: ...6 A08 B08 Rl06 206 All Bl1 103SY 10kO 13 C04 C05 911 912 915 916 931 933 934 Rl07 207 122SY 1 2kO 2 Rl08 208 520 620 820SY 820 4 Rl09 209 113 213 104SY 100kO 12 A09 B09 301 401 302 402 512 612 Rll 0 21 0 303 403 332SY 3 3kO 5 914 R114 214 A02 B02 473SY 47kO 9 918 941 942 952 953 R115 215 152SY 1 5kO 2 R116 216 682SY 6 8kO 2 RA01 BOl A04 B04 472SY 4 7kO 7 A 1 7 B17 925 RA03 B03 222SY 2 2kO 2 RA05 B...

Page 31: ... tF 25V 2 CA08 B08 A09 B09 QEW41AA 107N 100 tF 10V 4 CA 10 B1 O A 12 B12 QEW41 EA 47 5N 4 7 tF 25V 4 CA 14 B14 924 925 QFM41 HJ 272 Mylar Capacitor 0 0027 tF 50V 4 CA15 B15 511 611 273 0 027 tF 4 CA18 B18 122 0 0012 tF 2 CA19 B19 QEB41 HM 334M Low Leak E Capacitor 0 33 tF 2 CA21 B21 QEW41 AA 476N E Capacitor 47 tF 10V 2 CA24 B24 QEW41EA 107N 100 tF 25V 2 C503 603 504 604 QFM41 HJ 1 82 Mylar Capaci...

Page 32: ...X901 902 904 908 2SC458PG C D Si Transistor 6 909 910 D903 RD6 8E C Zener Diode 1 X501 601 907 2SD468 B C Si Transistor 3 IC902 UPC4066C I C 1 X503 603 2SC458A C D Si Transistor 2 D904 905 906 907 lS2076 Si Diode 6 908 909 X905 906 2SC1685 S Si Transistor 2 XCOl 2SA84 4 C D 1 VMJ5002 003 Jack Ass y for Mic Headphone 1 Sl OSL2209 002 Lever Switch for Input Select 1 S2 OSL2309 001 for ANRS 1 S3 OSL8...

Page 33: ...3 1 X907 0 19 2 14 0 X902 0 10 0 X908 0 0 0 68 X501 601 0 0 67 0 at recording mode E C B X909 0 5 1 0 X910 0 0 68 0 X101 102 1 2 7 3 1 81 X201 202 1 37 8 6 2 15 XC01 21 21 20 3 ICA01 8 6 8 1 8 4 8 6 6 3 3 6 0 3 5 7 4 7 4 0 2 0 0 06 0 7 17 6 7 4 8 7 7 4 8 7 9 9 9 9 9 9 9 9 14 B01 IC902 6 6 6 6 6 6 6 6 12 5 0 0 1 16 0 1 16 0 0 12 5 13 1 IC901 10 5 10 5 10 5 0 10 5 10 5 10 5 21 33 No 4186 ...

Page 34: ... 1 IC91 2 o o o 2 7 2 7 o o 14 6 0 4ICJOl 9 9 9 o 9 9 9 18 E C B XGOl 0 HOl 0 0 67 X303 403 0 0 0 X14 0 28 0 64 Xll12 0 0 0 7 X15 0 0 64 0 62 X911 16 7 16 7 16 7 X12 0 0 2 Xll 0 0 74 0 73 X6 0 0 0 74 X7 0 15 3 0 74 X8 0 15 3 0 74 X701 0 1 801 4 3 0 67 X702 0 802 0 0 65 X302 8 9 402 3 8 2 X301 401 3 8 2 3 6 No 4186 34 ...

Page 35: ...tor 22n 1 2W ill 1 R43 QRD 141 J 1 03SY C Resistor 10kn 1 4W 1 R46 391 SY 390n 1 R49 562S 5 6kn 1 R51 J02 J03 683SY 68kn 3 R52 QRD146K 152 Unflammable Resistor 1 5kn ill 1 R53 QRD141 K 332SY C Resistor 3 3kn 1 R54 QRD 141 J 472SY 4 7kn 1 R55 48 471 SY 470n 2 R56 QRD146K 2R2 Unflammable Resistor 2 2n ill 1 RG11 H11 G18 H18 QRD 141 J 1 03SY C Resistor 10kn 6 18 19 R702 802 184SY 180kn 2 R703 803 154...

Page 36: ...Capacitor 470pF 50V 2 C705 S05 QEB41CM 107M Low Leak E Capacitor 100JtF 16V 2 C706 S06 QFM41 HJ 1 53 Mylar Capacitor 0 015JtF 50V 2 C707 S07 472 0 0047JtF 2 C951 QEB41 EM 476N Low Leak E Capacitor 47JtF 25V ffi 1 C953 QEW41 EA 476N E Capacitor 47JtF 1 C95S 107N 100JtF 1 CG01 H01 QCS11 HJ 201 F Ceramic Capacitor 200pF 50V 2 CG02 H02 QFM41 HJ 1 52 Mylar Capacitor 0 0015JtF 2 CG04 H04 G23 H23 QEW41 H...

Page 37: ...ICG01 HOl TATOO0351 01 I C 2 XG01 H01 303 403 2SD46B B C Si Transistor 4 DG01 H01 G02 H02 lN34A Ge Diode 10 301 401 302 402 915 917 DG03 H03 G04 H04 lS2076 Si Diode 5 913 X301 401 2SC45BA C D Si Transistor 2 X302 402 2SAB44 C D 2 D912 916 RD4 3E C Zener Diode 2 X911 2SAB44 C D Si Transistor 1 IC912 LB1416S I C 1 OMF51 A2 1 R6BS Fuse 6 2 OMV5005 004 Connector for P Head 1 OMV5005 00B for Remote Con...

Page 38: ...KD A77AIBICIEIJ U Variable resistor LED Connector LED Transistor Cr02 switch Timer and Memory switch Resistor Pin jacks No_4186 38 ...

Page 39: ...tches VMW4551 001 Switch P W Board for Timer Memory 2 QSS2301 101 Slide Switch 2 LPSP2604Z Screw 4 Variable Resistor VMW4552 001 P W Board for V R 1 QVE5A3A 054F Variable Resistor 1 Pin Jacks TAA345532 01 Circuit Board 1 TAJ331301 03 Pin Jack Ass y 1 LED VMW4553 001 P W Board for LED 1 VKS4164 001 LED Holder 1 TLR102 LED LED VMW4554 001 P W Board 1 074 75 SLB 26GGIN LED 2 076 77 SLB 26URIN LED 2 R...

Page 40: ...l KO An A B TLJOO0476 02 ANRS Seal TLJ00047 7 02 Super ANRS Seal VPZ4001 001 Serial Ticket KO An A B E J U BT20013B Guarantee Certificate KO An B TJLOO0443 01 Seal KO An B BEAB Label KO An B QZL 1002 003BS Warning Label KO An B VNC5004 001 Mark Sticker KO An B E BT2005C Warranty Card KO An C T44362 001 CSA Marker KO An C TLT000505 0 1 UL CSA Caution Label KO An C J T43758 003 Serial Ticket KO An C...