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Nakamichi -- 481 -

1. 04150 Main P C B U S A amp Canada C112 212 0B09242A Mica Capacitor 47 50V J R140 164 0B05641A Carbon Resistor ERD 25T J 411 416 R437 0B09049A Fail Safe Type Resistor 22 ERD 14F 4 SW301 0807316 Record Switch BA04149A Main P C B Japan 113 213 0B09262A PP Capacitor 3000 50V 240 264 417 418 R438
2. 04150 Main P C B Ass y U S A amp Canada C111 211 0801836 Electrolytic Capacitor 47 10v R140 164 0805641A Carbon Resistor 47K ERD 25T J 0401 403 0806013 Transistor 28A733 R436 0809314 Carbon Resistor 5 1K ERD 25T J 0B07318A Push Switch A306 A 1 pce BA04149A Main P C B Ass y Japan C112 212 0 09242 Mica Capacitor 47 50v J 240 264 411 416 R437 0B09384A Fail Safe Type Resistor 27 ERD 14F J 0B08675A Pin Jack A304 1 04151 P C B Ass y 220V Class 2 C113 213 0809262 PP Capacitor 3000P 50V J R141 143 0B05626A Carbon Resistor 150 ERD 25T J 418 419 R438 443 08018574 Carbon Resistor 1K ERD 25T J 0808676 Heat Sink A304 1 pce BA04152A Main P C B Ass y UK amp Australia 114 214 0B01913A Mylar Capacitor 1800P 50V J 241 243 423 424 465 471 0808680 Heat Sink A 1 pce 04153 Main P C B Ass y Others C115 116 0B01412A Electrolytic Capacitor 10u 16V R142 242 0B05509A
3. Australia UK amp Others 0C08164G Pressure Roller 0J03663C Switch Cover U S A Canada 1 02 0 081898 Supply Tape Guide Japan 220V Class 2 amp 03 CAOBO614A Supply Pressure Roller Arm Ass y Australia 01 0 00042 E Ring 1 5mm 0M03946A Voltage Selector Lock Plate C 1 102 0 08024 Washer 2mm Others 0E00788A BT Screw M2x8 Philips Pan Head 10 0M03551B Pass Label 1 11 0M03794A Voltage Label 100V Japan 1 F03 CA08079B Take up Pressure Roller Ass y 1 0 03796 Voltage Label 220V 220V 1 Serial No A30604799 Class 2 0M03797A Voltage Label 240V UK 8 1 0C08164G Pressure Roller Australia 0 08181 Take up Tape Guide OMO3955A Voltage Label 120V 220 240V 1 CA08073B Take up Pressure Roller Arm Others Ass y 0M04097B Fuse Caution Label U S A amp 1 0 00042 E Ring 1 5mm Canada 0 08024 Washer 2mm 13 0B07092U Voltage Selector Others 0E00788A BT Screw M2x8 Philips Pan Head Fig 9 12 0M03844B Power Label UK 0F01071A Free up Belt 79 Take up Pressure Roller Ass y Serial Nos A30601001 A30604798 SDNF Labe 220V Class 2 SEV Label 220V Class 2 Serial Number Plate Nakamichi Label Japan Screw M2 6x8 Philips Binding Head Bronze 0M04055A t 0M03865A 0M04069B t 0M03798A 0 00714
4. rm Leh gt gt Head MEX m Reh pao ri 680K Em i TT II II Level Meter fen AL Playback Nu tay bac dem 25 T Rch lt 0 CP hi G RI63 2 2K REC t18 6V 2 Headphone Y C418 0 066 R490 no QU Descripti Schematic Ref Number Record Play CONTROL SWITCH P C B 0606 1460 Sweo S 173 1 5 Sweor bo P Puo O xa 2 00 e 9 605 i Notes 1 Diode is 15553 15953 or 151555 unless otherwise specified Fig 14 3 1 Serial No A30605220 2 Resistor and capacitor marked with show typical value 4 z a n m s t E E g LAMP PC B Li LAMP PC B R MAIN mm ques 150 o 100 58 CIS3 560 LINE INPUT Rch vRIO2 RI27 R426 22K MUT FQ cgo T amp TV aay 01020 kasi i 66 LINE OUTPUT gr oh 2 Rch 0406 p ol HY Record Head M
5. LO Schematic 0 00839 0 00876 NW NFP _ AA c 0 3 I l 23 a 0 08060 0 00142 0 00879 0 00838 0 00846 0 00895 48 Description Stopper Ring 2 5mm BT Screw M2 6x8 Philips Height Adjustment Nut Washer 2 6mm BT Screw M2x15 Philips P pan Stopper Ring 4 BT Screw M3x8 Philips Paan Earth Lug 3mm Head Head mm Head 04 14 Fig 9 11 2 Serial Nos 33 Ln 02 206 34 LO 46 35 25101104 l 1 27 26 25101 24 A30601001 A30605380 9 12 Rear Panel Ass y 001 Schematic Ref No HA03913A 0E00507A Nut Hex 0J03644A Chobert Rivet Rear Panel Ass y U S A amp Canada Rear Panel Ass y Japan Rear Panel Ass y 220V Class 2 Rear Panel Ass y Australia Rear Panel Ass y UK Rear Panel Ass y Others HA03912A HA03914A HA03915A HA03916A HA03917A Depends on the versions CA08117B Reel Motor Ass y s da 0C08218A 0C08063F Reel Motor Reel Motor Pulley 0B08533A Power Cord U S A Canada amp 1 Others Power Cord Japan
6. 36 8 1 55 7 244 36 8 2 Control Switch P C B ASS y be patada 36 8 3 Switch P G B ASSY 404044440 hu Qhasa Sh aa aduana lasa asa qas 36 8 4 Control PCB ASSY ia 36 8 5 Auto Shut off P C B ASSY memes ene eee nennen 36 8 6 Lamp PCB L ASS PA noce 36 8 7 Lamp P C B RASSY Lelli ia 36 8 8 HC 37 9 Mechanism Ass y and Parts List 41 9 1 515 eL 41 9 2 Front Panel Ass yY AQT pea 41 9 3 Synthesis Mechanism Ass y A02 41 9 4 Meter Escutcheon Ass y B01 42 9 5 Control Switch Holder Ass y 802 43 9 6 Headphone Jack Ass y 03 43 9 7 Mechanism Ass y 481 B04 Lia 44 9 8 Chassis Assy 805 e A wanita tie epe la ddr 45 9 9 Flywheel Holder Ass y 01 sese 45 9 10 Sub Mechanism Chassis Ass y C02 46 9 11 Main Mechanism Chassis A
7. bees oA 9 2 Note Diode is 15553 unless otherwise specified Fig 8 8 2 Seriial Nos A30601001 430605219 40 8 9 MECHANISM ASS Y AND PARTS LIST 9 1 Synthesis 0H03768A 0H03769B 0J03564A 0H03794B 0 04066 03872 03907 906 Fig 9 1 Synthesis Top Cover Bottom Cover Leg T H Volume Knob Power Switch Joint Bar Front Panel Ass y Cassette Case Cover Ass y Synthesis Mechanism Ass y U S A amp Canada Synthesis Mechanism Ass y Japan Synthesis Mechanism Ass y 220V Class 2 HA03910A HA03911A 0 03781 0M04101A 0 00858 0 00736 0 00857 0 00865 Synthesis Mechanism Ass y Australia Synthesis Mechanism Ass y UK Synthesis Mechanism Ass y Others Cushion Caution Labe BT Screw M4x6 Philips Binding Head Black Chromate Washer 4mm Black Chromate BT Screw M3x6 Philips Binding Head BT Screw M3x10 Philips Bindinc Head 9 2 Front Panel Ass y A01 O4 02 Fig 9 3 41 9 4 Meter Escutcheon Ass y B01 03905 0H03809A 03873 03874 03875 0H03744A 0H03745A 0J04094A 0 04081 0404082A 0J04098A HA03907A HA03906A HA 03909A 03910 03911 03851
8. Bias Oscillation Frequency and Erase Current External 0 1 2 Resistor in series to Erase Head Record Amplifier 21 kHz 20 dB to INPUT Equalizer Jacks Bias Trap Record Head Height Adjustment 400 Hz 0 to INPUT Jacks Record Head Azimuth 15 kHz 20 dB to INPUT Alignment Jacks Record Level Calibration and Recording Bias Current Adjustment 400 Hz 0 d8 and 15 kHz 20 dB to INPUT Jacks VTVM and Frequency Counter across the 0 1 Q Resistor VTVM to CNS 1 CN5 3 on the Main P C B VTVM to TP102 TP202 Same as above VTVM to TP102 TP202 and OUTPUT Jacks Distortion Meter to OUTPUT Jacks Record Pause Tae SW ZX Ec SW 70 us Dolby NR SW OUT MPX SW OUT Same as above Seme as above Record Playback SW SX SW 70 us Dolby NR SW OUT MPX SW OUT Same as above Record Playback Tape SW EX SX ZX Eq SW 120 us EX 70 us SX ZX D olby NR SW OUT MPX SW OUT 1 Adjust T301 to obtain 105 kHz on the frequency counter 2 Check the erase current by the VTVM Erase current will be in a range of 310 mA to 400 mA typically approx 350 mA If erase current is not sufficient increase it by shorting R310 or R311 3 After completion of the erase current adjustment re check the bies oscillation frequency Main P C B 7301 R310 R311 Remove the bias cut jumper from
9. 2 Ore leg ANS aD qui 2 14 Agito 395 3201 A do 8 4 gt lie a 90 09 ag gt gt 0 n o 5 _ 29 Midi 1 l Ole 208 Goth 4 RBIS 23 f j 540 ADS 03 4 sl PEE 5 1 5 1 o o 20 aD So L__ E 37 Serial A30605220 Fig 8 8 1 3 un erwiSe speci ed I Note Schematic Ref No Schematic Ref No Schematic Ref No Schematic Ref No Description Part No Part No Description Part No Description Description Schematic Sch ti E
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11. Pause 24V Il Reel Motor Governor Motor 225 a414 Q415 0417 FF REW R P SW DC Elimination of Tope Loosening REW 0409 8462 Capsion Motor b Krew e M 0409 One Counter L L 512 0428 0429 Shut off Transistors 9424 0425 0423 Q426 Shut off Sensor 4 d TEASE 24V Supply nn 52 for Controlling Circults 9 Shut off Detector 0427 E Power Mute x Q432 Q433 V Toke up Reel Fig 13 2 14 SCHEMATIC DIAGRAMS Dolby B Type Integrated Circuit Output Amp Limiter Noise Reduction Amp Variable Resistor Output A V Inverting Input Output B Non inverting Input B 4 5 V Non Inverting Input B Fig 14 2 Operational Amp 4558 LAMP PCS LI LAMP Gea ner SWITCH 5 sx 1 103 560P K H RN hd say LINE INPUT 2 1 RISI 7m 16201 Lch LINE OUTPUT Rch 0215 8216 R284 C219 L202 a 5 bare i n c220 5 R283 250048 lt I
12. PO 39 1 2W Fig 2 2 5 Bias Osc Circuit 11 2 3 Mechanism Control Circuits 2 3 1 Outline 1 Control Button Operation Record Rewind Stop Play and Fast Forward Buttons consist of a 5 way switch and are interlocked each other When one button is pressed it is mechanically locked in the ON state and other buttons are mechanically released Stop Button is of momentary type and acts to release other buttons mechanically But it is not used to control circuits electrically Pause Button is independent from others and is of push on and push off type Note that if two or more buttons are pressed simultaneously these buttons are locked in the ON state Under the normal con trol button operation only Record and Play Buttons are pressed simultaneously to set the N 481 in RECORD mode In this case both Record and Play Buttons are locked in the ON state and RECORD mode is set The N 481 is designed so as not to occur erroneous operation even if two or more buttons are pressed simultaneously Further to prevent from abnormal tape tension loosening of tape etc the N 481 changes its mode by passing through momentary STOP mode automatically for ex ample when PLAYBACK mode is commanded while FF mode or REW mode is commanded while FF mode 2 Auto Shut off Function Refer to Fig 2 3 1 basic circuit diagram During FF REW or PLAY PLAYBACK or RECORD Mechanically releases ach Switch TOP eo E for
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14. 21 5 1 Mechanism Control Cam Adjustment _ 21 5 2 Tape Speed Adjustment 22 5 3 Record Head and Playback Head Tilt Adjustment 23 5 4 Head Base Stroke Adjustment 3 24 5 5 Tape Guides Adjustment and Erase Head Stroke Adjustment 25 5 6 Erase Head Height and Tilt Adjustment 26 5 7 Playback Head and Record Head Height Adjustment and Azimuth Alignment 27 5 8 Record Head Stroke Adjustment 28 5 9 Tape Travelling Adjustment sss 29 5 10 Record Switch Linkage Adjustment 29 5 11 Flywheel Holder Adjustment 30 5 12 Eject Wire Adjustment 30 5 13 P 30 6 Parts Location for Electrical Adjustment 31 7 Electrical Adjustments and Measurements 32 7 1 Adjustment and Measurement Instructions 32 7 2 Playback Frequency Response Adjustment 0 35 7 3 Check on Dolby NR COUI Reg aca ak see ded iR Das 35 8 Mounting Diagrams and Parts List 3
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16. qIAWMV 2 9 33 aT 1 COLHA ip Bazi pera KNIT S yop 5219 che 3 n gU o_o io aa Z OM 221 1740000 p 7 26bH z gt Fir E 583 8579 828 8 OMO 263 DL z MQ t oro i MEE tes 23 o82 O8 2 5 ini Ca Lr EH Ae 000 2 cM TU z em cus yo t I gl zZ MCI 05 01 dell n i E I SL 44 oes 0 zr e E 312253 e L E 55 AMI ND RE 7 bv a 7 a ETE Ea ECL 1 M x x en TT N 55449 or SENS tt E OM leo Quum l 555 28 pci 4 Lap u S z 8 vee nas i ELO 201 444954 2168 pa es 22545 AMG ad vods n usi 55 52 SI x ta Poli a o o MOI LE i 811 lia 8 GANG AM NZZ 0268 7 1 m feu IS 93177 bo 0 5 eno ol uad Me nm v aim ES 1 wr 08 F 241
17. 55 13 Block Diagrams AEDEM 57 13 1 Amplifier tasu he dee ar ala aspis b deuda ids 57 13 2 Mechanism Controll uil 58 14 Schematic Diagrams uses A RAT 59 15 Specifications dene ERE Red RR SI aaa RELA 62 1 GENERAL 1 1 Control Functions Nakamichi 481 control functions are shown below o Za c 6 69 9 e 6 Fig 1 1 Front View Nakarrechi 481 Cassone Ouch lt Fig 1 2 Rear View 1 Power Switch 14 Pause Button 2 Cassette Lid 15 Fast Forward Button 3 Eject Button 16 Play Button 4 Tape Counter 17 Stop Button 5 Counter Reset Button 18 Rewind Button 6 Input Level Control Left Channel 19 Record Button 7 Peak Level Meters 20 Headphone Jack 8 Input Level Control Right Channel 21 Input Jacks 9 Dolby NR Switch 22 Output Jacks 10 Eq Switch 23 Remote Control Socket 11 MPX Filter Switch 24 Voltage Selector Switch 12 Tape Selector Switches 25 Power Cord 13 Tape Memory Switch 1 2 Voltage Selector Voltage selector is installed on the rear panel for other versions of the Nakamichi 481 This voltage selector can select either 120 V or 220 240 V at customer s disposal 2 PRINCIPLE OF OPERATION 2 1 Mechanisms 2 1 1 Headblock Refer to Fig 2 1 1 Headblock Nakamichi 481 Headblock provides more stabilized tape travel A
18. Record Head Stroke Adjustment Assemble Head Mount Base Ass y Record Head Mounting Gauge M 9048 5 5 Tape Guides Adjustment and Erase Head Stroke Adjustment Remove Head Mount Base Ass y Refer to Figs 5 8 and 59 1 b c d e 2 Supply Tape Guide Height Adjustment Load an EH Stroke Check Gauge M 9042 M 9051 in the N 481 Set the N 481 in play mode Slide the Supply Tape Guide Check Bar down against the supply tape guide thus check can be made on supply tape guide height If the supply tape guide is misaligned the Supply Tape Guide Check Bar will not come into the supply tape guide If such is noted turn to adjust the height adjustment nut A till the Supply Tape Guide Check Bar is accepted by the supply tape guide If the above are insured set the N 481 in pause mode then in play mode to see whether adjustments are appropriately made If not b through e will have to be repeated till satisfactory results are obtained Take up Tape Guide Height Adjustment Load an EH Stroke Check Gauge M 9042 M 9051 in the N 481 Fig 5 8 Tape Guide Check Bar Supply Stroke indicator b c d e 3 9 Note Set the N 481 in play mode Slide the Take up Tape Guide Check Bar down against the take up tape guide thus check can be made on take up tape guide height If the take up tape guide is misaligned the Take up Ta
19. 5640 Carbon Resistor 180K ERD 25T J 203 204 0109 110 0BO6100A Transistor 25 945 430 433 C421 0809368 Electrolytic Capacitor 22u 25V BP 1 pce R111 211 0B05623A Carbon Resistor 1 2K ERD 25T J R125 225 0B05615A Carbon Resistor 22K ERD 25T J 209 210 440 441 0 00857 BT Screw M3x6 Philips Binding Head 112 212 0B05575A Carbon Resistor 560 ERD 25T J R126 226 0805691 Carbon Resistor 390 ERD 25T J ZD101 201 0 06191 Zener Diode 2 7 448 468 Power Supply 2 pcs R113 213 0805641 Carbon Resistor 47K ERD 25T J R127 130 0B01683A Carbon Resistor ERD 25T J 0104 105 OBO61814A Silicon Diode 15553 472 473 0 00612 Screw M3x6 Philips Pan Head 2A C101 201 0B09137A Electrolytic Capacitor 22u 16 LN 227 230 204 205 475 485 1C401 0 06237 Regulator 24 uA7824 2 pes C102 202 0809376 Electrolytic Capacitor 22 25V LN R128 129 0BO1888A Carbon Resistor 10K ERD 25TJ 105 205 0807237 Semi fixed Volume 50K 486 487 0401 0806183 Diode Bridge 88151 Nut Hex 2 pcs 103 203 0B09283A Ceramic Capacitor 220P 50V 228 229 R154 159 0801889 Carbon Resistor 100K ERD 25T J 488 490 D402 0B06181A Silicon Diode 15553 105 205 0B05885A Electrolytic Capacitor 100 10V R132 232 0805621 Carbon Resistor 120K ERD 25T J 254 259 492 R309 0B09339A Fail Safe Type Resistor 3 3 RSF 25S J 106 206 0805832 Myl
20. 680K H em se Erase Head 0418 Playback Head L Reh C418 0 056 R490 100K Headphone On Shut off Sensor a Rec Protector CONTROL 8 09 CONTROL SWITCH P C B 0805 10509 100 O 0606 iy SOV E TI T Notes 1 Diode 15553 15953 151555 unless otherwise specified 4 T Fig 14 3 2 Serial Nos A30601001 A30605219 2 Resistor and capacitor marked with show typical value 4 61 250 9 U S A CANADA amp JAPAN o 040 220V CLASS 2 5 9 CN 3 avt AC BRN owt Switch Chart i Schematic Description Ref Number Record Play 5930 MPX Sw302 Dolby NR 2 Sx EX Eq
21. c d Playback Head Height Adjustment and Azimuth Alignment Connect a VTVM to the Output Jacks Load 1 kHz Track Alignment Tape DA09007A then set the N 481 in play mode Turn the PH Height Gear until the output of both channels becomes minimum Load 15 kHz Azimuth Tape 09004 then set the N 481 in play mode Turn the PH Azimuth Alignment Screw until the output of both channels becomes maximum Repeat b through e 1 2 times Record Head Height Adjustment and Azimuth Alignment Connect a VTVM to the Output Jacks Load a Reference SX Tape DA09025A Set the Eq and Tape Switches of the N 481 to 70 ps and SX positions then set the N 481 in record and play mode Feed in 400 Hz 0 dB then turn the RH Height Gear until the output of both channels becomes maximum Feed in 15 kHz 20 dB then turn the RH Azimuth Alignment Screw until the output of both channels becomes maximum Height Adjustment PH Azimuth e Repeat c and d 1 2 times f After completion of both adjustment and alignment feed in 400 Hz 0 dB and record it to the same portion of both A and B sides of the tape g Immerse the recorded tape in a magnetized develop ing solution In turn check to insure that the recording head tracks across the center are separated with a distance of 0 55 to 0 75 mm typically 0 65 mm as illustrated in Fig 5 13 Note Liquid for tape magnetized development solution MA
22. 1 2 3 Remove Sub Mechanism Chassis 55 referring to item 3 17 Remove F12 Reel Hub Heads then disassemble F13 Reel Hub B Assemblies F14 Reel Hub Take up Ass y F15 Reel Hub Supply Ass y F16 Back Tension Ass y and F17 Back Tension Spring Remove F18 then disassemble F19 Idler Ass y 3 24 Cam Drive Gear and Control Refer to Fig 3 7 1 Remove Sub Mechanism Chassis Ass y referring to item 3 17 2 Remove F20 then disassemble F21 Cam Drive Gear 3 Remove 222 then disassemble F23 Counter Load Arm Ass y 4 Remove F24 then disassemble F25 Control Cam 3 22 Head Mount Base Ass y Refer to Fig 3 8 1 Referto Fig 3 5 Remove Cassette Case Ass y refer ring to item 3 14 2 Remove F01 then disassemble 202 Head Mount Base Ass y 3 23 Pressure Roller Ass y and Erase Head Refer to Fig 3 8 1 Remove Head Mount Base Ass y referring to item 3 22 Remove F03 and a washer then disassemble F04 Supply Pressure Roller Ass y 3 Remove 205 then disassemble 206 Erase Head 4 Remove F07 and a washer then disassemble F08 Take up Pressure Roller Ass y 2 3 24 Playback Head Ass y and Record Head Refer to Fig 3 8 1 Remove Head Mount Base Ass y referring to item 3 22 2 Turn F09 by 90 degrees by pushing it then disassemble F10 Playback Head Ass y 3 Turn Fl 1 by 90 degrees by pushing it then d
23. 17 3 6 Mechanism ASSY 00 17 3 7 1 86 aaa 17 3 8 Lamp P C B RAss y and Lamp P C B L AssSy _ 17 3 9 Main P C B ASS Y ENNET KEE enne 17 3 10 Control Switch Holder ASS Y 17 3 11 Switch P C B ASSY 17 3 12 volume P C B Ass y and Control Switch P C B Ass y 17 3 13 Rear Panel Ass y Power Transformer and Power Switch 17 3 14 Cassette Case Ass y and Cover Plate Assy _ 19 3 15 Tape CounterAsS y Luini 19 3 16 Capstan Motor Ass y Flywheel 5 20 3 17 Sub Mechanism Chassis ASS Y 20 3 18 Control Motor Ass y and Reel Motor 20 3 19 Cam Control volume 20 3 20 Reel Hub Ass y and Idler 5 20 3 21 Cam Drive Gear and Control Cam 20 3 22 Head Mount Base ASSY 20 3 23 Pressure Roller Ass y and Erase Head 20 3 24 Playback Head Ass y and Record Head Ass y __ 20 4 Measurement Instruments 21 5 Mechanical Adjustments
24. 7 Side B lene 5 Copston Belt zT Lm pc 7 7 vi Ei m d 5 fra 2 ed Capstan NS ce 147 Side A Shaft B 7 7 X 4 x NS H Capstan ve Hr EIER N f 7 FIX i Pressure lt 22 a Rolleri B Ww k gt 5 A EN LN _ gt a Pressure N a Roller A Fig 2 1 5 Double Capstan Tape Drive 2 1 4 Mechanism Control Cam Operation Refer to Fig 2 1 6 Mechanism Control Cam timing chart Function of N 481 Mechanism is done by Cam Control Cam is driven by the Control Motor The Motor operates So as to result zero in the difference of voltages between each voltage corresponding to mechanism function and each reference voltage which corresponds to each com mands of the Control Switch When the difference comes to zero then it stops In this way each function is kept properly operated For further details please see the ex planation on Logic Control Here we explain principle of its mechanical functions Cam Control System works as follows Cam Drive Gear is driven by Control Motor by means of Drive Belt Cam Drive Gear is related to the cam with which each function may be mechanically set on 1 Play Mode Press the Play Switch to make it
25. Carbon Resistor 33K ERD 25T J 425 429 R442 0B01680A Carbon Resistor 820 ERD 25T J 0 08144 Record Spring 1 Serial A30605220 187 215 R144 244 0B09263A Carbon Resistor 12K ERD 25T J 431 R453 0805621 Carbon Resistor 120K ERD 25T J 0B08569C Record Wire Holder 1 pce 215 287 R145 245 0B05575A Carbon Resistor 560 ERD 25T J 0402 406 06069 Transistor 2SB564 R454 481 0B09335A Carbon Resistor 680K ERD 25T J 0B08570A Record Spring Holder 1 C117 217 0805885 Electrolytic Capacitor 100 10 R147 185 0B01679A Carbon Resistor 100 ERD 25T J 409 428 R457 458 0B05622A Carbon Resistor 2 2K ERD 25T J 0808573 Wire Holder 1 pce C118 218 0B09191A PP Capacitor 4700P 100v G 247 285 Q404 410 0B06100A Transistor 250945 A R463 476 0801846 Carbon Resistor 4 7K ERD 25T J 0M03782A Fuse Label 250V 1 Q101 102 0 06119 Transistor 25 1844 119 219 0801804 Mylar Capacitor 3900P 50V J R148 149 1856 Carbon Resistor 8 2K ERD 25T J 412 415 R470 0B01684A Carbon Resistor 470K ERD 25T J U S A Canada Japan amp Others 201 202 C120 220 0B09240A PP Capacitor 0 033 100V G 248 249 420 421 R484 0B01683A Carbon Resistor 15K ERD 25T J 0M04082B Fuse Label T 125 250V 1 pce ZD301 0806239A Zener Diode RD20EB C121 221 0801862 Electrolytic Capacitor 22u 16 R150 151 0B093314A Fail Safe Type Resistor
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27. ou 254733 gt Play Pause Y 10x Pause Fig 2 3 10 Control Motor Drive Circuit sos prav rrmem pear fuse se pater freeman rime stor FFREM e a EZ To Z PS oe Te Ic402 6 0 1C402 5 Contrai Motor Fig 2 3 11 Timing Chart 16 2 3 8 Reel Motor Governor Refer to Fig 2 3 12 circuit diagram One end of the reel motor is connected with 12 V and the other end is a terminal for controlling During FF mode Q413 is turned ON and the reel motor is grounded Accordingly the reel motor turns in the direction of fast forwarding On the other hand during REW mode 24 V REW H is applied to the reel motor and the reel motor turns in the direction of rewinding During PLAY PLAYBACK or RECORD mode Q412 is turned OFF and the Pause position signal becomes H as a result 0417 is turned OFF and the reel motor is turned at a constan speed by the governor composed of Q414 and Q415 During PLAY PAUSE mode Q412 is turned ON and the Pause position signal becomes L therefore Q417 is turned ON 0414 is biased in the reverse direction and Q414 is cut off thus the reel motor does not turn Take up function at loading When a cassette tape is inserted and loaded Eject Switch will become open Consequently the base current is applied to Q413 through C409 and Q413 is turned ON pulse likely
28. se 58 573833 0 0 dI RW WHT 8 WHT 0 109 5 Control Switch Aes y Component Side Shut off PC B Assy Component Sida Volume Componant Side 28 Lamp R Assy Lamp PCB L Assy R ch L ch Playback Head Head Erase Head Counter Switch Component Side Component Side Level Meter Fig 12 2 56 Control Motor Record Protector Switch Contro Volume Capstan Motor Reel Motor Eject Switch 13 BLOCK DIAGRAMS 13 1 Amplifier Rec Level VR Line Input 50 Dolby NR MPX Filter Out RO Q 1 x I Record Head 8 d Test Point 100 Line Output Tape 600mV QU Heodphon Amp Headphone Output 10 Meter Col nen 2 Erase Head Level Meter Mute Rec Fig 13 1 13 2 Mechanism Control FF REW PLAY Control Motor Dri us TAN Refer ontrol Motor Driver Voltage STOP mechanically releases soch switch 1040211 2 0404 040 12 g rar 9406 0410 0407 0408 FF FF n A REW REW Rec Pulse 0403 PLAY PLAY pz VR602 Stop VR60I PRUSE vR603 PAUSE PAUSE Pon R x FC Pouse Position Datector 0412 ute PLAY REC FF REW SW Circuile pau 1 Ei 941 9420 Playt 5
29. 1 Shut off Sensor Light from lamp PL407 is projected through holes in a disc rotating synchronously with the take up reel and the intermittent flashes coming through the disc are converted into electrical signals by a phototransistor Q450 These signals are amplified into square waves and transmitted to the shut off detecting circuit in the subsequent stage When the tape end comes the take up reel and the disc stops rotating and no pulse is output from the sensor 11 Fig 2 3 2 12 V Power Source Circuit Meanwhile the Power mute L pulse is applied to the shut off circuit and shut off is activated 2 Power Switch OFF The output from the secondary winding of the power transformer ceases quickly and Q433 is turned OFF Consequently the base current flows to Q432 through R481 0432 is turned ON and the Power mute signal becomes L The Power mute L signal makes Q416 to turn ON as a result Mute signal becomes H and the amp circuit is muted At the same time shut off circuit is shut off by the Power mute L signal Fig 2 34 Timing Chart 2 Shut off Detecting Circuit and Peripheral Circuits Shut off conditions are as follows o reached tape end during PLAY PLAYBACK or RECORD FF or REW mode o mode is changed as follows from FF to REW mode or vice versa from FF to PLAY mode from RECORD mode to FF or REW mode When the mode is changed shut off is momentarily activated and the mode is changed to STOP m
30. 3 2 1 Remove Front Panel Ass y referring to item 3 4 2 Remove F07 and F08 then disassemble F09 Mechanism Ass y including 5 connectors and record switch linkage 3 7 Meter Ass y Refer to Fig 3 2 1 Remove Front Panel Ass y referring to item 3 4 2 Remove F10 Meter Ass y by releasing self interlocking pins of the Meter Ass y 3 8 Lamp P C B R Ass y and Lamp P C B L Ass y Refer to Fig 32 1 Remove Meter Ass y referring to item 3 7 2 Remove F11 Lamp P C B Ass y and F12 Lamp P C B L Ass y by releasing the self interlocking pins Fig 3 2 Fig 3 1 3 9 Main P C B Ass y Refer to Fig 3 3 1 Refer to Fig 3 2 Remove Front Panel Ass y referring to item 3 4 2 Remove 5 connectors and the wires connected by wrapping from the 205 Main P C B Ass y 3 Remove F01 202 F03 F04 and the Record Switch Linkage from the Wire Holder assembled with Record Switch then disassemble F05 Main P C B Ass y 3 10 Control Switch Holder Ass y Refer to Fig 3 3 1 Refer to Fig 3 2 Remove Meter Ass y referring to item 3 7 2 Remove F06 then disassemble F07 Control Switch Holder Ass y 3 11 Switch P C B Ass y Refer to Fig 3 3 1 Refer to Fig 3 2 Remove Front Panel Ass y referring to item 3 4 2 Remove F08 then disassemble F09 Switch P C B Ass y 3 12 Volume P C B Ass y and Control Switch P C B Ass y Refer to Fig 3 3 1 Remove Contro
31. JA03645A 0J04068B 0 040698 0808720 BAO4150B 041498 BA04151B 041528 BA041538 HA03913A HA03912A HA03914A HA03915A HA03916A HA03917A 0C08240A 0 03700 0 00502 0 00857 0 00860 0 00624 0 00178 0 00507 0 00037 4 03641 JAO3640A JA03642A JA03643A 03644 JAO3645A 0J04068B 0J04069B 0B08539A 04150 BA04149A 4151 BA04152A BA04153A HA03913A HA03912A HA03914A HA03915A Chassis Ass y U S A 8 Canada Chassis Ass y Japan Chassis Ass y 220V Class 2 Chassis Ass y Australia Chassis Ass y UK Chassis Ass y Others Serial No A30605220 Front Chassis Side Chassis Plastic Rivet Main Ass y U S A amp Canada Main P C B Ass y Japan Main Ass y 220V Class 2 Main Ass y UK amp Australia Main P C B Ass y Others Rear Panel Ass y U S A amp Canada Rear Panel Ass y Japan Rear Panel Ass y 220V Class 2 Rear Panel Ass y Australia Rear Panel Ass y UK Rear Panel Ass y Others Contact Wire Earth Mark Label Screw M3x5 Philips Pan Head BT Screw M3x6 Philips Binding Head BT Screw M3x6 Philips Binding Head Black Chromate Screw M3x10 Philips Pan Head 2A Washer 3mm Nut Hex M3 Earth Lug 8 5 Depends on the versions Chassis Ass y U S A 8 Canada Chassis Ass y Japan Chassis Ass y 220V Class 2 Chassis Ass y Australia Chassis Ass
32. Pressure Roller Take up Tape Guide Take up Pressure Roller Arm 0C08164G 0 08181 CA08073B 0 00756 Screw 4 8 Philips Binding Head Bronze 0 00042 E Ring 1 5mm 0E00860A BT Screw M3x6 Philips Binding 0C08024A Washer 2mm Head Black Chromate Screw M3x5 Philips Pan Head Screw M3x6 Philips Binding Head Bronze 0E00788A BT Screw M2x8 Philips Pan Head 0E00502A 0E00593A 49 9 13 Reel Motor Ass y E01 Fig 9 13 9 14 Control Motor Ass y E02 04 05 Fig 9 14 9 15 Head Mount Base Ass y 50 9 16 Supply Pressure Roller Ass y F02 03 9 16 9 17 Take up Pressure Roller Ass y 203 LO3 02 9 18 Head Ass y 204 9 21 Auto Shut off Ass y F07 Fig 9 21 9 22 Pneumatic Damper Ass y 208 s Fig 9 18 9 19 Cassette Case Holder L Ass y 205 Fig 9 22 9 23 P 8L Playback Head Ass y G01 Fig 9 19 9 20 Cassette Case Holder R Ass y 206 O2 Fig 9 23 9 24 R 8L Record Head Ass y G02 01 Fig 9 20 51 Schematic Ref No 08121 GA02017A 0C08158D 0 08166 0 08174 0 08175 08086790 0 00889 0 00909 0 00117 0 00853 Head Ass y E 8L Erase Head EH Hold Plate EH Hold Plate Spring Cassette Hold Spring Head Base Ass y Head Base L S
33. 71 EL e E sf I Abe Say eat Cel lt a Oa ng 8 15 1 I Sho 3 8 rig ci 12 ll LII EAS qaqa 8 ER 13 DSL 1411 11 WOO 658 MODI AS ASE eR E 22 9 NOME n Viie EARS ere e __ NW yo MM s 4 HOS 028 01 age pe 18 0618 29 1514 8 28 21 d TN ARI MO SIAMO 23 5 06 assu NZA 2 agrees US 53 21 ST d amp mue 2 Nt 55 8 67 ita oli 8 oi 4 5010 020 Sa DE ii 1021 tie 4 1 J F O s 88 lo oR gt 4 1911 216 e ALa 90 OBOE i 290 in 102 2044 6029 N rt lor AMI M PIOBESI 7 ue _ Sete xt WM oT 83 wws2fez o Mili 58 gemmas owe 5 Ae Py 2012 409 2075 4522 YOC wee 69 HOSE GELA T4 rioss 9604 598 OM Mi ee ee n e Sor uu M MEE 9018 Wiz _ 808 9024 Xi _ 8098 ri4o06t 6129 AM
34. After the tilt is adjusted in such a way as above adjust the height by loosening or tightening the Height Gear Azimuth alignment is adjusted by loosening or tightening the PH Azimuth Screw This system has been carefully designed so as to minimize in fluence each other between azimuth and height adjust ment 3 Record Head Height Adjustment and Azimuth Alignment Record head tilt adjustment can be performed in the same way as for the Playback Head Height adjustment can be adjusted while recording 400 Hz test tone by loosening or tightening RH Height Adjust ment Screw to obtain the maximum level on the both Level Meters Azimuth alignment can be adjusted while playing back 15 kHz signal by loosening or tightening RH Azimuth Alignment Screw to obtain the maximum Fig 2 1 1 Headblock level on the both Level Meters This system has also been carefully designed so as to minimize influence each other between azimuth and height adjustment 2 1 2 Erase Head Fig 2 1 3 shows the sectional view of the Erase Head Fig 2 1 4 shows the characteristics of erasing current and erasure Fig 2 1 2 Trackings It has the same characteristics with the previous type Direct Flux Erase Head but been purposely developed to minimize the size further Conventional Erase Head had its inside core narrower than its outside core while this Erase Head is equipped with an inside core wider than the outside core This
35. Capstan Flanges and Flywheel Thrust Caps are in a flat state Excessive tightening of the Thrust Screws however will give b damages on the Flywheel Assemblies to which careful attention is lt Y invited Lock 2 Return the Thrust Screws by 1 2 turn 3 Fixing the Thrust Screws with a screwdriver lock the Lock Nut 4 Apply a quantity of lock tight paint to the Thrust Screws Fig 5 18 5 12 Eject Wire Adjustment 1 Referring to Fig 5 19 1 insert a 1 5 mm spacer between the Eject Arm and Eject Stopper by turning the Eject Arm the illustrated ap 15mm direction then set N 481 in playback mode 2 With pushing the Eject by hand loosen the screw and then pull the Eject Wire in the direction of 11 the arrow until it stops as shown Fig 5 19 2 gt 3 Tighten the screw then apply a quantity of lock tight paint 9 22 11120 _ 5 13 Lubrication lt 481 is a lubrication free cassette deck except when parts are replaced M Apply the following lubricant for each replaced part gt o 1 LAUNA 100 Eject NI Capstan Shaft LR Pressure Roller Shaft Thrust Cap 2 FLOILGB TS 1 Reel Hub Shaft Thrust portion on the Capstan Shaft Fig 5 19 1 FLOIL GB TS 1 made by Kanto Chemicals Co Ltd in Japan We suggest you use the above or equivalent type unavailable please contact Ka
36. ERD 25TJ 153 253 0809379 Ceramic Capacitor 560 50V R301 302 0B05668A Carbon Resistor 82K ERD 25TJ R412 417 0B05627A Carbon Resistor 330K ERD 25T J F402 0 08698 Fuse T 500mA 250V 218 286 C154 254 0 01388 Electrolytic Capacitor 4 72 16 R303 304 0B09212A Fail Safe Type Resistor 2 2 RDF 25S J 429 452 U S A Canada amp Others R120 124 0B05620A Resistor 270K ERD 25TJ 155 255 0809279 Ceramic Capacitor 222 50VJ R305 0B01682A Carbon Resistor 6 8K ERD 25T J 455 469 F402 0 08697 Fuse T 500mA 250V 220 224 R310 0B09296A Fail Safe Type Resistor 39 RSF B J 480 489 Japan R121 221 0B09317A Metal Film Resistor 3 3K SN14K2E F Line Amp R311 0809295 Fail Safe Type Resistor 82 RSF 2B J 494 F402 8457 Fuse T 500mA 250V R122 222 0B05641A Carbon Resistor 47K ERD 25T J C301 0805583 Mylar Capacitor 0 033 50V J R414 456 0B05508A Carbon Resistor 56K ERD 25T J UK Australia amp 220V Class 2 R123 223 0809271A Carbon Resistor 6 2K ERD 25T4 9194 105 0801872 Transistor 2SC945 L C302 303 0 09191 PP Capacitor 4700 100vG R415 0B09328A Metal Film Resistor 9 1K 5 14 2 M2 08083424 Spark Killer U S A amp Canada R162 262 0B01857A Carbon Resistor 1K 25 J 107 204 C304 0801402 Electrolytic Capacitor 4 7u 25V R416 0B09340A Metal Film Resistor 15K SN14K2E F M2 0808363 Spark Killer Japan R165 265 080
37. Play mode Then the Cam begins to move from Stop position to Play position and the Play mode will be set The Head Base which is linked to the Cam and which is normally pushed against the Stop position gets released and the Head Base will slowly come out for playing To explain this function first the Head Base is latched and the Reel Motor begins to turn Then the Pressure Roller will be pushed and the Brake will be released Now the tape begins to run If you press the Pause Switch at this stage it comes to Pause mode Brake operates and the Pressure Roller moves away from the Capstan and the Reel Motor stops Play mode may be changed to Stop mode by pressing the Stop Switch and latch of the Head Base being released The Cassette Case cannot be opened because of the latched eject effect unless it is in Stop mode 2 Record Mode By pressing the Record Switch and the Pause or Play Switch it may be made to Record mode The Cam at this moment moves from Stop position to Rec position At the same time Rec Trigger Mechanism is driven and the Record Switch on the Main P C B is switched on to the Record side Further the Cam turns until it comes to the Pause or Play position On the other hand the Rec Trig ger Mechanism is released during this process When the Cam is set in Rec Pause or Rec Play position Record signals will be sent to Bias Oscillating Circuit from Logic Control Circuit to let the Bias to oscillate Press the St
38. be come lower by 2 5 V 0 4 V than in pause mode Short the both leads of capacitor C406 with a jumper wire Set the N 481 in record mode then adjust the value of R419 so that the voltage of VR601 will become higher by 1 V 0 4 0 2 V than in stop mode Note Remove the short of C406 after completion of adjustment Cam Timing Adjustment Remove the wires from the Control Motor terminals to set the motor open Without loading a cassette tape and with pressing the record protecting switch with your finger tip press the Record and Play Switches to set the N 481 in record mode Turn the Cam and bring the PY mark toward the pointer by hand Reel Motor will rotate before the PY mark reaches the pointer Adjust the value of R436 so that the voltage at the sliding contact of VR601 becomes 9 7 V 0 3 V when d e f 5 2 1 2 3 4 Daereona Reel Motor starts rotation Observe the mute signal at the Q416 collector Turn the Cam referring to above step c and check to insure that the voltage at the sliding contact of VR601 is 9 5 V 0 3 V when mute is released mute signal changes from H to L This voltage is determined by the adjustment of R436 in above step c Observe the Play Pause Position signal at the Q411 collector Turn the Cam referring to above step c and adjust the value of R432 to obtain 11 2 V 0 4 V at the sliding contact of VR601 when Play Pause Posit
39. has resulted more power sufficient enough for erasing with small power consumption approx 0 5 W though the head width is as small as 3 mm The smaller the power con sumption is the smaller will be the heat generation and this is of course another merit 2 1 3 Double Capstan Tape Drive As shown in Fig 2 1 5 the double capstan system con sists of two capstan shafts a and b connected to the two flywheels which are driven by a capstan belt Against these capstans two pressure rollers a and b are engaged to run the tape with an adequate holdback ten sion created by the double capstan and pressure rollers Since the diameter of capstan shaft a is smaller than that of capstan shaft b when two flywheels begin to turn as shown in the figure capstan a runs slightly faster than capstan b which subsequently generates holdback ten sion As you note if the diameters of the 2 capstans should be the same the generation cycles of wow and flutter will be come approximately the same as a result of which defe ctive portion will be doubly superposed and preferable portion vice versa The N 481 employs 2 capstans each having different diameter and rotations thereby avoiding 4 Erase Head Height and Tilt Adjustment Erase Head is affixed onto the Erase Head Plate which is assembled with the Head Base It is installed with three screws By turning these screws its height tilt of back ward or frontward and tilt of leftward or rig
40. i Play i t3top Me REO 2607 2 2K Fig 8 4 Fig 8 5 Note Diode 15 15553 unless otherwise specified PI ep Lip e 8 6 Lamp P C B L Ass y 8 7 Lamp P C B Ass y vIO Fig 8 2 Note Diode 15 15553 unless otherwise specified 8 3 Switch P C B Ass y 54304 T SIK Note the wires are connected to the Moin Ass y Fig 8 3 36 Fig 8 6 Schematic eel Schematic mee tH 04114 Volume P C B Ass y 04128 Auto Shut off P C B Ass y 08078458 Volume P C B 08078528 Auto Shut off P C B VR101 201 0B07298A Slide Volume OBO6100A Transistor 250945 A 0806228 Photo Transistor PH104 BA04126A Control P C B Ass y 0B06181A Silicon Diode 15553 0B01888A Carbon Resistor 10 ERD 25T J 08078498 Control P C B 0B05671A Carbon Resistor 2 2 ERD 25T J VR602 603 809059 Semi fixed Volume 0B05615A Carbon Resistor 22K ERD 25T J R606 0805698 Carbon Resistor 1 5K ERD 25T J 0B01933A Carbon Resistor 220 ERD 25T J R607 0B05622A Carbon Resistor 2 2K ERD 25T J 0B01405A Electrolytic Capacitor 1 50V 0 08552 Lamp 12V 25 BA04154A Switch P C B Ass y 04125 Lamp P C B L 55 0807861A Switch P C B VR701 801 0B07237A Semi fixed Volume 50K 08078518 Lamp P C B L VR702 802 0B07261A Semi fixed Volume 20K 0808674 Lamp VR703 803 0B07236A Semi fixed Volume 10K C130 230 0B09283A C
41. is connected to the N 481 If only Play Button is pressed playback will be carried out when the power is connected to the N 481 24V s end Memory Rewind 5 Power mute Stop Button Command New Button Commend Basic Auto Shut off Circuit 2 3 2 12 V Power Source Refer to Fig 2 3 2 circuit diagram Only 24 V DC power supply is used in the N 481 The circuit acts to produce a 12 V power source from the 24 V DC power supply Mechanism control is done by using thus produced 12 V 2 3 3 Power mute Signal Refer to Fig 2 3 3 circuit diagram and Fig 2 3 4 timing chart Power mute L signal is produced pulse likely when Power Switch is turned ON or OFF This L pulse mutes the amp circuit and also acts to shut off the shut off circuit initially 1 Power Switch ON Q433 is turned ON at every positive half cycle of the out put from the secondary winding of the power transformer When Q433 is turned ON C416 is discharged as a result the voltage of C416 can not exceed the VBE of Q432 and Q432 is in the cutoff state Therefore the Power mute L pulse is produced for a certain period of time when 24 V is built up after Power Switch is turned ON The Power mute Lsignal makes 0416 to turn ON as a re sult Mute signal becomes H and the amp circuit is muted Fig 2 33 Power mute Circuit 2 3 4 Auto Shut off Circuit Refer to Fig 2 3 5 circuit diagram and Fig 2 3 6 timing chart
42. or REW Button Q419 is turned from ON to OFF therefore a negative differentiated pulse is applied to the point A via C421 22 This negative pulse acts to turn 0424 and 0426 as a result C411 is charged up to 24 V FF or REW mode is set after passing through a certain period of STOP mode in the same manner as above 1 c Power mute L The Power mute L pulse is generated when Power 13 Switch is turned ON or OFF During the Power mute sig nal is L the voltage at the point A becomes lower than the emitter voltage of Q424 Subsequently Q424 and Q426 are turned ON C41 1 is charged up to 24 V and shut off is activated in the same manner as above b d Memory Rewind During REW mode and with Memory Rewind Switch turned ON C414 is grounded when the tape counter Pies FF Button i PLAY L 3424 0426 OFF 244 0427 OFF 9430 on 9425 NEA UO lem 4428 24V5 OFF stop PLAY Fig 2 3 7 Timing Chart comes to 999 and Q431 is turned ON pulse likely As a result Q430 is turned ON and shut off is activated resulting in STOP mode 2 3 5 Record Control Circuit Refer to Fig 2 3 8 circuit diagram RECORD mode is set by pressing Record Button then Play Button together By pressing Record Button the Krec signal becomes L Q419 is turned ON Q421 is turn ed ON and the record lamp is illuminating The
43. the dip side of the Main 2 Adjust 1104 1204 to obtain peak reading at 21 kHz on the VTVM Re solder the bias cut jumper Main P C B L104 L204 Adjust the Record Head Height Adj Screw to obtain maximum reading of L and R channels on the VTVM See Record Head Height Adjustment and Azimuth Alignment in item 5 7 Record Head Height Adj Screw Adjust the Record Head Azimuth Alignment Screw to obtain maxi mum reading of L and R channels on the VTVM See Record Head Height Adjustment and Azimuth Alignment in item 5 7 Record Head Azimuth Alignment Screw Connect VTVM to TP102 TP202 on the Main P C B Feed in 400 Hz then set the input level controls to obtain O dB on the level meters Record signals on the reference EXII tape DAQ9021A reference SX tape DA09025A or reference ZX tape DAO9037A then play it back Adjust Rec Cal VR104 8204 for EXII VR103 VR203 for SX and VR102 VR202 for ZX to the center their positions Adjust Bias VR701 VR801 for EXII VR702 VR802 for SX and VR703 VR803 for ZX to obtain maximum readings on the Feed 15 kHz 20 dB than adjust Bias VR701 801 VR702 VR802 and VR703 VR803 to obtain mV on the VTVM Feed in 400 Hz 0 dB then adjust Rec Cal VR104 VR204 VR103 VR203 and VR102 8202 to obtain 30 mV the VTVM Repeat 5 through 7 as above two or three times to obtain optimum perf
44. y UK Chassis Ass y Others Serial Nos A30601001 A30605219 Front Chassis Side Chassis Plastic Rivet Main P C B Ass y U S A 8 Canada Main P C B Ass y Japan Main P C B Ass y 220V Class 2 Main P C B Ass y UK amp Australia Main P C B Ass y Others Rear Panel Ass y U S A amp Canada Rear Panel Ass y Japan Rear Panel Ass y 220V Class 2 Rear Panel Ass y Australia Schamatic Ref No AN 45 HA03816A 03917 0 08240 0M03700A 0E00502A 0 00857 0 00860 0 00624 0 00178 OE00507A 0E00037A CA08109A 0 08013 04126 0C08219A 0C08212B 0M04077A 0E00226A 0 00843 0C08068C 0 03857 Description Rear Panel Ass y UK Rear Panel Ass y Others Contact Wire Earth Mark Label Screw M3x5 Philips Pan Head BT Screw M3x6 Philips Binding Head BT Screw M3x6 Philips Binding Head Black Chromate Screw M3x10 Philips Pan Head 2A Washer 3mm Nut Hex M3 Earth Lug 5 Depends on the versions Flywheel Holder Ass y Flywhee Holder Control P C B Ass y Capstan Motor Capstan Motor Pulley Motor Seal Screw M2 6x4 Philips Pan Head BT Screw M3x5 Philips Pan Head Thrust Screw Lock Nut dad 9 10 Sub Mechanism Chassis Ass y 02 Fig 9 10 Schematic i pron CA08165A Sub Mechanism Chassis Ass y OCO8039B Reel Hub Head 0803
45. 0B05614A Carbon Resistor 1 8K ERD 25T J 0B07318A Push Switch A306 A 1 pce 04151 Main P C B 220 Class 2 C114 214 0B01913A Mylar Capacitor 1800P 50V J R141 143 0B05626A Carbon Resistor 150K ERD 25T J 419 423 R443 465 0801857 Carbon Resistor 1K ERD 25T J 0808675 Pin Jack A304 1 pce 04152 Main P C B Assy UK amp Australia C115 116 0801412 Electrolytic Capacitor 10 16V 241 243 424 425 471 0B08676A Heat Sink A304 1 pce BA04153A Main P C B Assy Others 187 215 8142 242 0B05509A Carbon Resistor 33K ERD 25T J 429 431 R453 0B05621A Carbon Resistor 220K ERD 25T J OBO8680B Heat Sink A 1 pce Serial Nos A30601001 A30605219 216 287 8144 244 9263 Carbon Resistor 12K ERD 25T J 0402 406 Transistor 258564 R454 481 0B09335A Carbon Resistor 680K ERD 25T J 0 08144 Record Spring t pce C117 217 OBO5885A Electrolytic Capacitor 100 10V 8145 245 0B05575A Carbon Resistor 560 ERD 25T J 409 428 8457 458 0B05622A Carbon Resistor 2 2K ERD 25T J OBO8569C Record Wire Holder 1 pce PB Eq Amp C118 218 0 09191 PP Capacitor 4700P 100V G R147 185 0B01679A Carbon Resistor 100 ERD 25T J 0404 410 0 06100 Transistor 25 945 8463 476 0 01846 Carbon Resistor 4 7K ERD 25T J 0B08570A Record Spring Holder 1 pce C119 219 0801804 Mylar Capacitor 3900P 50V J 247 285 412 415 R470 0B01684A C
46. 258564 K C414 0B09333A Electrolytic Capacitor 4 7 25 LN UK amp Australia 204 206 Amp C142 242 0801862 Electrolytic Capacitor 22u 16V 0417 0B06155A Transistor 254733 P CA15 0B01272A Electrolytic Capacitor 100 25 0808348 Fuse Clip 4 pcs R105 205 0809330 Carbon Resistor 100K ERD 25TS J C145 245 0801412 Electrolytic Capacitor 10 16V Q432 0806251 Transistor 25 945 0 C416 0B01405A Electrolytic Capacitor lu UK Australia 8 220V Class 2 Noiseless 0103 203 08018784 Transistor 280945 1 C147 247 0 01272 Electrolytic Capacitor 100 25 D403 431 0B06181A Silicon Diode 15553 29 pcs C417 0801674 Electrolytic Capacitor 10 25 0E00117A Washer 2mm 1 R107 207 0B05622A Carbon Resistor 2 2K ERD 25T J 1104 105 0800068A Trap Coil 10 5mH C152 252 0 05553 Mylar Capacitor 1500P 50V J R403 407 0B01889A Carbon Resistor 100K ERD 25TJ c418 0B01676A Mylar Capacitor 0 056 50V 0 00172 Washer 3mm Toothed Lock 1 pce 308 204 205 408 413 C419 0809292 Ceramic Capacitor 0 1 50VZ 0 00788 Screw 2 8 Philips Pan Head R108 208 0805629A Carbon Resistor 2 7K ERD 25T J VR102 103 0B07237A Semi fixed Volume 50K Meter Amp 418 422 C420 422 0 09290 Ceramic Capacitor 0 017 50V Z 1 pce R109 209 0805675 Carbon Resistor 3 9K ERD 25T J 104 202 427 428 423 OE00831A BT Screw M3x10 Philips Pan Head R110 210
47. 285 0809281 Ceramic Capacitor 150P 50V K 238 282 160 260 5691 Carbon Resistor 390 ERD 25T J 493 C186 286 0809242 Mica Capacitor 47P 50V J R166 266 0B05936A Carbon Resistor 10 ERD 25T J R161 261 0B09213A Fail Safe Type Resistor 150 RDF 25S J 406 491 0805575 Carbon Resistor 560 ERO 25T J Miscellaneous C126 226 0B05530A Mylar Capacitor 6800 50V J C148 248 0801405A Electrolytic Capacitor 50V R409 464 05508 Carbon Resistor 33K ERD 2 5T J Dolby C127 227 0B05652A Mylar Capacitor 4700P 50V J C149 249 08092184 Electrolytic Capacitor 47u 16V LN R410 425 0B05615A Carbon Resistor 22K ERD 25T J 08078608 Main P C B C128 228 555 Mylar Capacitor 1000P 50V J C150 250 0B09219A Electrolytic Capacitor 6 84 16V LN 426 442 0801857 Carbon Resistor 1K ERD 25T J 1C101 201 0B06175A IC 7 C129 229 0805885 Electrolytic Capacitor 1007 10V 151 251 0B01270A Electrolytic Capacitor 1004 25V 460 466 2 pcs 102 202 0B03919B Inductor 36mH C133 233 0B01862A Electrolytic Capacitor 22u 16V 474 477 2401 0808374 Fuse 250V 1 103 203 0B03563A 19K Coil 23mH C134 135 0801780 Mylar Capacitor 50V J Bias Osc 478 479 U S A Canada amp Others 8114 214 0 01846 Carbon Resistor 4 7K ERD 25T J 234 235 483 F401 OBO8686A Fuse 1A 250V Japan R115 215 0B01888A Carbon Resis
48. 4 03627 04154 JA03616A Front Panel Ass y Front Panel Push Button Ass y C Push Button Ass y D Eject Button Ass y Green Lens Orange Lens Control Button Pad Adhesive Tape 55x6 Adhesive Tape 30x6 Adhesive Tape 70x6 Synthesis Mechanism Ass y U S A amp Canada Synthesis Mechanism Ass y Japan Synthesis Mechanism Ass y 220V Class 2 Synthesis Mechanism Ass y Australia Synthesis Mechanism Ass y UK Synthesis Mechanism Ass y Others Meter Escutcheon Ass y Control Switch Holder Ass y Switch P C B Ass y Headphone Jack Ass y 42 081358 JA03640A JA03642A JA03643A JA03644A JA03645A 0B08515A 0 00857 0 00502 0 00878 0 00867 HAQ3851A 0H03770B 0H03786A BA04110B BA04124A BA04125A 0H03785A 0H037718 Mechanism Ass y 481 Chassis Ass y U S A amp Canada Chassis Ass y Japan Chassis Ass y 220V Class 2 Chassis Ass y Australia Chassis Ass y UK Chassis Ass y Others Insu Lock BT Screw M3x6 Philips Binding Head Screw M3x5 Philips Pan Head BT Screw M4x20 Fhilips Binding Head BT Screw M4x15 Philips Binding Head Meter Escutchaon Ass y Meter Escutcheon Volume Cover Meter Ass y Lamp P C B R Ass y Lamp L Ass y Filter Cover Aluminum Seal Lame mete R LLO MA ATION omen oon 9 5 Control Switch Holder Ass y 802 9 6 Headp
49. 406 In the control motor stop condition both voltages at pins No 5 non inverting input and No 6 inverting input of IC402 1 2 are equal and the difference of both inputs is zero When a new mode is demanded the balance of both inputs is broken as a result the control motor is driven until both inputs are balanced The cam control variable resistor VR601 moves synchronously with the motor so that the voltage at the sliding contact of VR601 is changed When the voltage at the sliding contact of VR601 is changed and the input difference of the differential Record Q403 Q410 pulse Q412 Stop Q412 Q404 Q410 Q412 ed D417 ON 0411 Play Com Angle 205 o 30 Voltage ot Com Control Volume 16V 15V 13 5V Sliding Contact Mode Record Stop Fast FF REW 15 ye amplifier 1 402 1 2 becomes zero the control motor stops The following table shows the relationship between cam position and the voltage at the sliding contact of the cam control variable resistor VR601 and the state of transis tors in each mode Position on Typical Voltage at Sliding Contact of Corn Control Volume Q404 Q403 Q404 Q410 Q403 Q403 Q404 Q410 Q403 Q404 Q410 Q411 Q412 665 90 411 162 70 2 10V 7 5V I I I Pause Play eot vci UK sss 9 _ 4207 1 ij nuo REC MAY 2 Mao 406 2 22 24 tav
50. 45 1 i at iso ag es m Lal nm 2 on on CA ijo gt ToT 58 E 4553 or eg 1 lo a SEAT x 2192 55 23 r e Or AMS ze d sete lol 4 JS S t ESM 13 Ro pos X00 WU RUM II o 13 55 Y OS AMP aM sz 5 gt Bi AMO avi 85 424715 880 4 0 I A r j v e cop 5 Low JUST i 10 T pn Sg Xf gos 52 oo ul E XOS Hu Liga T Puis 9 7 WS D MA e6 7 5 finito o o Y Pe o ba 91a TUR Q s ini ta ars siti bel NOZI 57 C F mo ieri ne 2 258 dd 1 gt l 35 NOCE 69vH Sg 7 77 4 dn vu SSKA 3 sora X00 EIv amp Es 1958 5 Porra dii GLA gt _ T XOU 1098 em BUE 8 o_o e x xS i LODS amp f rito emos le annie S 2 3 25 250 TM ES e me 55 5 Lorum OA A orra 5 OLA 9 AM al AMO 055 5088 est Rioni sara Sg
51. 472 16V LN 493 Miscellaneous C127 227 0B05652A Mylar Capacitor 4700P 50V J C150 250 0 09219 Electrolytic Capacitor 6 8 16V LN R406 491 0B05575A Carbon Resistor 560 ERD 25T J 1C101 201 08061754 128 228 OBO5550A Mylar Capacitor 1000P 50V J C151 251 0801270 Electrolytic Capacitor 100 25V R409 464 0B05509A Carbon Resistor 33K ERD 25T J 08078600 Main L102 202 0803919B Inductor 36mH C129 229 OBO5885A Electrolytic Capacitor 100 10V R410 425 0B05615A Carbon Resistor 22K ERD 25T J 0B01857A Carbon Resistor 1K ERD 25T J 2 pcs 1103 203 0B03563A 19K Coil 23mH C133 233 0B01862A Electrolytic Capacitor 22u 16 Bias Osc 426 460 F401 0B08374A Fuse 1A 250V R114 214 0801846 Carbon Resistor 4 7K ERD 25TJ 134 135 0B01780A Mylar Capacitor 50V Jj 466 474 U S A Canada amp Others R115 215 0B01888A Carbon Resistor 10K ERD 25T J 234 235 0301 302 0B06100A Transistor 25945 477 478 F401 0808686 Fuse 250 Japan R116 216 0B05629A Carbon Resistor 2 7K ERD 25TJ 138 238 0809246 Mica Capacitor 150P 50V J 303 479 69 FARA 0 08275 Fuse 125 250V R117 217 0801887 Carbon Resistor 5 6K ERD 25TJ 139 239 0B09322A PP Capacitor 330P 100V T301 0806613A Osc R411 0801682 Carbon Resistor 6 8K ERD 25T J UK Australia amp 220V Class 2 118 186 0B05509A Carbon Resistor 33K
52. 5 81 looo 9j 82 n 2 3 2 33 KN s 427 ni 1 2 88 s Hi z 2 5 DI ie Teoh 37 st 8 3 a ks ope 2 990 1588 8 N 8 5 a 9 w gl e F6 08088220 ws at 4 ie S a ol q 1 Li 22 x e E P 2 4 28 Foe gt T 2 5 da dii ti Site be 111 pi CIS 2 5 4 4 5 3143 1 locu 2 gt gt 600 1062 oiko eto eglas d 111 1 1 18400197 2082 452 4 4 1 P 11 2 fo 1 41 i ge dia Ho E SE 258 18 40048 A 1 818 gt 4 5 gt N 10 gos 1 oe et st 18 lo ir ij n 51512 E gt 23 x 58 5253855 Sho 1 837 at 5 gt 8 fF n iii 5 448 1 57508 811 22151 d aa la 5 MIL __ o 844 5 T esL cal 1 it n 4 Wr o Mr e 2 581 sa 8 1 le 1 be 2 325 fox Q CS E SS Keri 6 2 E n opa giza nao 1 5 gras porn MO z 00223 122 x 9 L 2o om nol IM Boece T o 22 tuo ore H
53. 5 5 V and the VBE of Q430 Q430 is turned ON and the base current flows to 0429 Con sequently 0429 is turned ON Q428 is cut off 24 VS is shut off PLAY mode is changed to STOP mode and play lamp goes out 0430 0429 0428 R476 R474 R456 and C420 consist of a Schmitt circuit which provides hysteresis characteristics for ON OFF of Q430 Accordingly Q430 will be turned ON or OFF without chattering for the input waveform with a large time constant developed across C412 If Pause Button is pressed during PLAY mode tape stops and no pulse is transmitted from the shut off sensor but Q427 is kept ON since Q423 is turned ON during PLAY PAUSE mode therefore no charge is made at C412 and shut off is not activated When shut off is made at the tape end during PLAY mode PLAY mode is changed to STOP mode If Stop Button is further pressed Play Button will be re leased and the voltage at the point A returns to 24 V as R488 is released from grounding as a result 0425 is turned OFF and C412 is discharged quickly through D423 and R467 10 kohm Accordingly 0430 is turned OFF 0429 is turned OFF 0428 is turned ON and 24 VS is again applied preparing for the next control button opera tion 0449 Collector Sensor Output L OFF et 1554 9430 ov ON 0430 0423 ore IN dm E ES 42 ts 245 OFF ON Play Lamp Fia 2 3 68 Timina Chart Q429 258 564
54. 7237A Semi fixed Volume 430 433 C420 0809290 Ceramic Capacitor 0 01 50 Z UK Australia amp 200V Class 21 R108 208 0B05629A Carbon Resistor 2 7K ERD 25T J 104 202 Meter Amp 440 441 C421 0B09368A Electrolytic Capacitor 22 25V BP 4 pes R109 209 OBO5675A Carbon Resistor 3 9K ERD 25T J 203 204 448 468 0E00117A Washer 2mm 1 pce R110 210 OBOS640A Carbon Resistor 180K ERD 25T J R125 225 0805615 Carbon Resistor 22K ERD 25T J 0109 110 Transistor 25 945 472 473 Power Supply 0 00172 Washer 3mm Toothed Lock 1 pce 111 211 0B05623A Carbon Resistor 1 2K ERD 25T J R126 226 0B05691A Carbon Resistor 390 ERD 25T J 209 210 475 485 0 00788 BT Screw M2x8 Philips Pan Head R112 212 0B05575A Carbon Resistor 560 ERD 25T J R127 130 0B01683A Carbon Resistor 15K ERD 25T J 20101 201 0 06191 Zener Diode 2 7EB 486 487 1 401 0806237 Regulator 24V 7824 1 pce 8113 213 0 05641 Carbon Resistor 47K ERD 25T J 227 230 D104 105 0806181 Silicon Diode 15553 488 490 0401 0806183 Diode Bridge RB151 0E00831A BT Screw M3x10 Philips Pan Head C101 201 0B09137A Electrolytic Capacitor 22u 16V LN R128 129 0B01888A Carbon Resistor 10K ERD 25T J 204 205 492 D402 0806181 Silicon Diode 15553 11 pce C102 202 0B09376A Electrolytic Capacitor 224 25V LN 228 229 VR105 205 0807237 Semi fixed Volume SOK R404 446 0
55. 8 Reel Hub B Ass y CA08037A Reel Hub Take up Ass y CA08064A Reel Hub Supply Ass y Back Tension Ass y 0 08178 Back Tension Spring CAO08040A Idler Ass y 0C08127B Idler Arm Spring 08042 Brake Arm Ass y 0 08030 Brake Drive Arm 0 08029 Brake Arm Spring 0C08128A Brake Drive Arm Spring 08117 Reel Motor Ass y A08124A Control Motor Ass y 0 080538 Volume Coupler 0B07240A Volume Contro 10k B CA08041A Sub Chassis Ass y OEO00842A Stopper Ring 2mm 0E00837A Stopper Ring 3mm 0 00838 Stopper Ring 4mm 0 00859 Screw 2 6 6 Philips Binding Head 0 00226 Screw M2 6x4 Philips Pan Head Volume Nut Volume Washer 46 Schematic 9 11 Main Mechanism Chassis Ass y 03 Ref No Description C03 08171 Main Mechanism Chassis Ass y 1 Serial No A30605381 33 LTi 34 01 46 35 25101104 01 08141 Cassette Case Holder Ass y 1 y uw of 02 CA08022A Cassette Case Holder R Ass y 1 5 03 08111 Cassette Case Ass y 1 AE Me 04 0 080191 Cover Plate 1 05 0 03977 Cassette Viewer Label 1 06 CA08136A Head Mount Ass y 1 07 0 08121 Supply Pressure Roller Spring 1 08 CA08053B Supply Pressure Roller Ass y 1 o9 0C08122B Supply Pressure Roller T
56. 8 2 25 J 422 426 C403 0809286A Ceramic Capacitor 470P 50V UK Australia amp 220V Class 2 L101 201 08039198 Inductor 36mH 122 222 0805583 Mylar Capacitor 0 0335 50V J 250 251 427 430 C406 411 08093324 Electrolytic Capacitor 2 24 25 LN 0M04100B Fuse Label T 500mA 250 1 pce 101 201 0B07237A Semi fixed Volume 50K C123 223 OBO1405A Electrolytic Capacitor 1u 50v R152 252 0801857 Carbon Resistor 1K ERD 25T J 433 412 U S A Canada Japan amp Others R101 103 0B01889A Carbon Resistor 100K ERD 25TJ C124 224 0B01603A Mylar Capacitor 50 R153 253 0 09306 Fail Safe Type Resistor 68 RDF 25S J Q405 413 Transistor 250471 C407 0B09251A Electrolytic Capacitor 33g 25 0M04096B Fuse Label 500mA 250V 1 pce 201 203 C125 225 0809327 Electrolytic Capacitor 0 334 50 LN R163 263 0805622 Carbon Resistor 2 2K ERD 25TJ 0407 0806020 Transistor 25 1096 C408 0B09283A Ceramic Capacitor 220P 50V K 220V Class 2 R102 202 0B01706A Carbon Resistor 47 ERD 25TJ C137 237 0B01272A Electrolytic Capacitor 100 25 C140 240 0B05652A Mylar Capacitor 4700P 50V J 0408 0806012 Transistor 25 634 C409 0B09345A Electrolytic Capacitor 3 34 25V 0 04096 Fuse Label 500mA 250V 1 pce R104 106 0 05509 Carbon Resistor 33K ERD 25T J C141 241 0B01405A Electrolytic Capacitor 1 50V Q414 0B06252A Transistor
57. 801887 Carbon Resistor 5 6K ERD 25TJ R309 0B09339A Fail Safe Type Resistor 3 3 RSF 255 J 0 00857 BT Screw M3x6 Philips Binding Head C103 203 0809283A Ceramic Capacitor 220P 50V R132 232 0B05621A Carbon Resistor 120 ERD 25T J R154 159 0B01889A Carbon Resistor 100K ERD 25T J 447 R401 0B01888A Carbon Resistor 10K ERD 25T J 2 pos C105 205 0B05885A Electrolytic Capacitor 100 10V 133 233 0B01856A Carbon Resistor 82K ERD 25T J 254 259 R405 424 1888 Carbon Resistor 10K ERD 25T J R402 0B01684A Carbon Resistor 470K ERD 25T J 0E00612A Screw M3x6 Philips Pan Head 2A C106 206 0B05832A Mylar Capacitor 0 018 50V J R134 234 0B01857A Carbon Resistor 1K ERD 25T J 8155 255 0B09318A Metal Film Resistor 560K SN14K2E F 435 449 C306 0B01870A Electrolytic Capacitor 10000 25V 2 pcs C107 207 0B01412A Electrolytic Capacitor 104 16V R135 235 0B05698A Carbon Resistor 1 5K ERD 25TJ R156 256 0B09338A Metal Film Resistor 390K SN14K2E 450 451 C401 402 0B01412A Electrolytic Capacitor 10 16V 0 00507 Nut Hex 2 pcs C108 208 08012724 Electrolytic Capacitor 100 25V 8136 138 0B05622A Carbon Resistor 2 2 ERD 25T J R157 158 0BO1888A Carbon Resistor 10K ERD 25T J 459 461 C404 0B093364A Electrolytic Capacitor 2200 50V C109 209 0 05687 Mylar Capacitor 1200P 50V J 182 236 257 258 462 467 C405 0B09373A Electrolytic Capacitor 3300u 25V C185
58. 8086718 12P H Connector 1 14 OB08671B 15 0B08672B 3P H Connector 1 15 0B08672B 16 0808515 Insu Lock 16 0B08515A 17 0M03902A Motor Label 730 1 17 0M03902A 101 0 00834 BT Screw M3x30 Philips 1 01 0 00834 Head 102 0E00178A Washer 3mm 2 02 0 00178 103 0E00833A BT Screw M3x20 Philips Pan 3 1 03 0E00833A Head 04 0E00883A Screw M3x18 Philips Pan 5 104 0E00883A Head 105 0E00835A BT Screw M3x25 Philips 1 05 0E00835A Head Description Mechanism Ass y 481 Serial Nos A30601001 A30605380 Flywheel Holder Ass y Capstan Belt Supply Flywheel Ass y Take up Flywheel B Ass y Thrust Washer 3 1mm Thrust Washer 2 6mm Flange Thrust Cap Flange Thrust Spring Sub Mechanism Chassis Ass y Counter Belt 8 Control Motor Belt Main Mechanism Chassis Ass y Lid Arm Spring Tube 12P H Connector 3P H Connector Insu Lock Motor Label 730 BT Screw M3x30 Philips Pan eo Washer 3mm 2 BT Screw M3x20 Philips Pan 3 Head BT Screw M3x18 Philips Pan 5 Head BT Screw M3x25 Philips Pan 1 Head dee 9 8 Chassis Ass y 805 02 Fig 9 8 9 9 Flywheel Holder Ass y 01 Fig 9 9 Schematic Ref No Description JA03641A JA03640A JA03642A JA03643A JA03644A
59. 9383A Fail Safe Type Resistor 390 256 J _205 207 C305 0809254 PP Capacitor 0 068 100 R419 0805626 Carbon Resistor 150K ERD 25TJ 2 0808445 Spark Killer 220V Class 2 R183 283 0805776A Carbon Resistor 1M ERD 25T 2106 108 0B06013A Transistor 25 733 R420 421 0805671 Carbon Resistor 2 2M ERD 25T J 08082400 Spark Killer UK Australia amp Others R184 284 0B05627A Carbon Resistor 330K ERD 25T J 206 208 Logic R423 0B09214A Fail Safe Type Resistor 1 2554 1 5 0B08654A AP T Post C110 210 0B09223A Electrolytic Capacitor 1 50 LN 0101 102 0B06181A Silicon Diode 15853 R431 432 0B01681A Carbon Resistor 3 3K 25 4 2 0808681 12P T Post 201 202 1C402 0806124B RC4558D 439 445 CN3 0B08653A Post R139 146 OB01681A Carbon Resistor 3 3K ERD 25T J R434 0B05692A Carbon Resistor 68K ERD 25T J 0808656 2P T Post 239 246 0807316 Record Switch 38 Schematic
60. B08656A 2P T Post 39 canne sud w 9999 x Sa Do 9 4 0 7 ser 90 02 oH 1098 NOOI 4298 Q w n 1 58 101 4098 COMA qum AN 09 2098 1098 O AN wde t Salt 9 1 Amo 1 e 6 ep iien 4021 x X g amp 5 gt l n 095 79 Orso API Sere RAM 9 94 90 288 NOT MON 9065 t Q Q G 9 90 I OM V F FOCE SSH Fanart vee mrt e t quid f euro 9 NOI Gava o deg 500 TRAIT 90 Ae gobi 4 r dla f e WORE 6968 bi 19p sewer e 1 C418 0 086 othe T GBPH 4 MM 0688 es 524 w 9422 250945 9421 25C945 izva a 2 o f 1 t tst 1 7 1541 123 14 15759 Per f f Pe E 5 l 15 I i 1 1 1 gt S gt 212
61. During Q413 is turned ON the reel motor turns in the direction of fast forwarding and eliminates tape loosening of the cassette tape if any 1 123 2x 4 42 R 1 24 Motor n 183 i E K 4 1440 Y 1 4 T 2 Fig 2 3 12 Reel Motor Governor 481 3 REMOVAL PROCEDURES 3 1 Cassette Case Cover 55 Refer to Fig 3 1 1 Press the Eject Button to open the Cassette Case Ass y 2 Pull out F01 Cassette Case Cover Ass y upwardly 3 2 Top Cover Ass y Refer to Fig 3 1 Remove F02 and F03 then disassemble F04 Top Cover Ass y 3 3 Bottom Cover Ass y Refer to Fig 3 1 Remove F05 then disassemble F06 Bottom Cover Ass y 3 4 Front Panel 55 Refer to Fig 3 2 1 Refer to Fig 3 1 Remove Top Cover Ass y and Bottom Cover Ass y referring to items 3 2 and 3 3 2 Pull out Volume Knobs 3 Remove F02 Power Switch Joint Bar by releasing the self interlocking pin of the Power Switch Joint Bar from Power Switch and turn F02 Power Switch Joint Bar by 90 degrees either clockwise or counter clockwise then disassemble F02 Power Switch Joint Bar from the Power Switch Knob Ass y 4 Remove F03 then disassemble F04 Front Panel Ass y 3 5 Headphone Jack Ass y Refer to Fig 3 2 1 Remove Front Panel Ass y referring to item 3 4 2 Remove 205 then disassemble F06 Headphone Jack Ass y 3 6 Mechanism Ass y Refer to Fig
62. GNA SEE SOUND CRAFT a product of CBS RECORDS a division of Columbia Broad casting System Inc Danbury Conn 06810 U S A or equivalent After development clean the tape otherwise pressure rollers and heads will become dirty Typical Q65mm Fig 5 13 1 Heght 4d ustment RH Azimutn Alignment 5 8 Record Head Stroke Adjustment Refer to Figs 5 14 and 5 15 Note This adjustment will be required only to insure 5 6 7 freedom from misalignment of the record head stroke in the record head stroke check mode Check the accuracy of the record head stroke Remove Head Mount Base Ass y referring to item 3 22 Remove the record head assembly Adjustment of Record Head Mounting Gauge M 9048 DA09048A a Mount the Block B onto the Mounting Gauge Plate b Loosen the 2 screws fixing the Block A c As shown in the Fig 5 14 hold the Gauges 3 05 mm and 0 1 mm thickness between the Block A and Block B fix the Block A with screws pushing the Block A to the 2 guide pins Remove the Block B from the Mounting Gauge Plate As shown in the Fig 5 15 mount the R 8L record head assembly onto the Mounting Gauge Plate then check the location of the R 8L record head surface If record head contacts to the Block C loosen 2 pcs of screws that assembled record head and R 8L record head assembly then place the R 8L record head assembly onto the Plate Remove the R 8L record head assembly from
63. M 9039 DA09039A EH Tilt Check Gauge M 9040 DA09040A EH Stroke Check Gauge M 9042 DA09042A EH Stroke Check Gauge M 9051 DA09O51A Stroke Check Gauge M 9047 DA09047A Record Head Mounting Gauge M 9048 DA09048A Audio Analyzer T 1 00 including Distortion Wow Flutter Speed Oscillator and dB meter Notes 1 10 27 the products of Nakamichi Corporation 2 EH Stroke Check Gauge M 9042 DA09042A should be used for the Models from serial Nos A30601001 to A30604798 and EH Stroke Check Gauge M 9051 DA09051A is for the Models bearing serial Nos A30604799 and greater 5 MECHANICAL ADJUSTMENTS 5 1 Mechanism Control Cam Adjustment Before Adjustment disassemble the Front Panel Ass y then remove the Cover Plate Ass y referring to items 3 4 and 3 14 1 Offset Adjustment of Control Motor Driver Refer to Figs 5 1 and 5 2 Adjust VR602 and VR603 on the Control P C B to locate approximately at the middle of the variable range Then turn ON the Power Switch VR602 for Cam position stop VR603 for Cam position play Press the Stop Switch to set the N 481 in stop mode Adjust VR602 for stop so that the mark on the Cam corresponds to the pointer on the mechanism chassis Press the Play Switch to set the N 481 in playback mode Cam will rotate and the position marked with PY comes to the pointer Adjust VR603 for play so that the PY mark on the Cam corresponds to the pointer Repea
64. MPX SW IN 400 Hz to INPUT Jacks Distortion Meter to OUTPUT Jacks 20 T 3 kHz Speed Wow Flutter Wow Flutter Meter to dad Tape DA09006A OUTPUT Jacks 7 2 Playback Frequency Response Adjustment Fig 7 7 shows the playback equalization curve for the N 481 and Fig 7 8 is the circuit for adjustment 1 Level Adjustment for middle frequency response This adjustment will be required when playback level is not sufficient at 10 kHz PB Frequency Response Tape refer to step 7 in 7 1 Adjustment and Measurement Instructions Playback equalization level can be varied by the modifi cation of R108 R208 and R109 R209 Following are the details for level modification Total Harmonic Distortion Playback Playbac Eq SW 70 us 5 Approx 188 R108 R208 3 0 R109 R209 4 3 K R108 R208 2 7 R109 R209 3 9 Approx 188 R108 R208 2 4 R109 R209 3 6 2 Peaking Adjustment for high frequency response This adjustment will be required when playback level is not sufficient at 20 kHz PB Frequency Hesponse Tape refer to step 7 in 7 1 Adjustment and Measurement Instructions Peaking portion compensates the gap loss of the playback head Peaking level is varied by the short circuit of R112 0 0 Op
65. N 09 0081 than the IEC Standard no deterioration of frequency response or level difference will occur Any other method for instance record and playback on ferric oxide tape with putting Tape Switch on EX and Eq Switch on at 70 us When Nakamichi EX or EXII Tape is used at Tape Switch EX and Eq Switch 70us S N ratio will be improved by approximately 4 dB WTD R300 244 Fig 2 2 1 Playback Eq Circuit Playback e Head R110 92101 120 22 O 981641 fa 1101 L201 Riig 36mH 5 8211 TAA 25 1 2 560 5 gt gt 5 1 e 5 2 Output 2 1 CIBG amp 47 25 c 18 o Fig 2 2 2 System Diagram 3180us 9102 Collector 1101 Output 100 IK IOK 20K Fig 2 2 3 Time Constant 11 2 2 2 Record Equalizer Amplifier Circuit The record equalizer amplifier circuit consists of the Out put Amp incorporated in the Dolby NR IC and peripheral circuits as shown in Fig 2 2 4 VR102 VR103 and VR104 are the record calibration semi fixed volumes for ZX SX and EX tapes The output of the Output Amp is given to these volumes and the outputs from the volumes are fed back to the inverting input of the Output Amp via amplifier Q103 and a time constant changeover circuit By adjusting L104 compensation for the high frequency range is made by setting a resonance freq
66. Nakamichi Service Manual Nakamichi 481 Discrete Head Cassette Deck 5 1 General air 3 2 Principle af Operationi iii 4 2 1 Mechanisms iran aaa 4 2 1 1 HeadblOCK iii 4 2 1 2 Erase ead eredi uadit 5 2 1 3 Double Capstan Tape Drive _ 5 2 1 4 Mechanism Control Cam Operation 6 2 2 ER 7 2 2 1 Playback Eq Amp Circuit 2 7 2 2 2 Record Eq Amp Circuit 9 2 2 9 Bias Osc Circuit 9 2 3 Mechanism Control Circuits 000 10 2 391 Outline 10 2 3 2 12v Power SOUICO tle re dee 11 2 3 3 Power mute Signal 11 2 3 4 Auto Shutoff Circuit iced 11 2 3 5 Record Control Circuit 14 2 3 6 Mute Signal 14 2 3 7 Control Motor Drive Circuit 15 2 3 8 Reel Motor Governor 16 3 Removal Procedures _ 17 3 1 Cassette Case Cover ASS Y 1 17 3 2 Cover 0 17 3 3 Bottom Cover Assy renes 17 3 4 Front Panel 17 3 5 Headphone Jack 5
67. O P M ate on A 5 d M 7 M mt E 3 001 928 gt BA Pad 001 0208 e o E 03 X001 a vU age 2928 NETTE ket 4 MEX 19419 n AOS io se a gt AM 2 E rc ah 1622 408 2 3 noi Wea ly 5 Sai 95 2 ur SU pi RZ PERA ento 8 54 B gt 3 AOG 6 2 NOS GOZUA o RM Row wire 6 SOS Seed gi OIM OM c o w O wg Fog 125 5055 Y 187 20 5 5 4 ge cole Daga Fener SRL 3 004082 000 0022 029 ners oh 4 Oo ward y DN Ha NG 8 1013 1025 z vl 2 omino 9 NE E 023 5 HE reca di Was ne GE DICH Hu deri 1044 1028 07 ML 4 mase DT 58 gi 8 S D AN z 5 POL e 2 1 co a 8 017 goed gt 31 se gt an 5 234 4 peoo 1068 1 m3 2 28 14 4 1 Gf 01219096 1 gt 4919002
68. Posse Switch 20 FF Li T 2 Q402 2 255 PLAY eo 0418 PLAY 24 e 5 A T wo w K Qam SZ RECORD PAUSE 4 e 27 PAUSE Fig 2 3 1 10 mode auto shut off will be activated when the tape comes to end and FF REW or PLAY mode is changed to STOP mode Following explanation is made in regard to REW mode In the initial condition 0428 is turned ON and 24 VS is applied to the emitter of Q402 When Rewind Button is pressed it is locked in the ON state as a result Q402 is turned ON the REW signal becomes H and the N 481 is set in REW mode When tape end comes auto shut off is activated and 0428 is turned OFF as a result 24 VS is shut off 0402 is cut off and the REW signal becomes L In this way REW mode is changed to STOP mode Note that Rewind Button is still locked in the ON state When Play Button is pressed in this state REW Button is released and Q428 is turned ON as a result 24 VS is applied again Q418 is turned ON the PLAY signal becomes H and the N 481 is set in PLAY mode 3 Unattended Recording or Playback Unattended recording or playback is carried out by the use of the lock mechanism of control button therefore no special circuit is required for this purpose If Record and Play Buttons are pressed unattended re cording can be carried out when the power
69. Power Cord 220V Class 2 Power Cord Australia Power Cord UK Cord Bushing C U S A Canada Japan 220V Class 2 amp Others Cord Bushing Australia Cord Bushing 4K 4 UK Rear Panel 6P DIN Socket Power Transformer U S A amp Canada Power Transformer Japan Power Transformer 220V Class 2 Australia amp UK Power Transformer Others Bott Receptacle Plate Power Switch Holder Power Switch U S A amp Canada Power Switch Japan Power Switch 220V Class 2 0B08219B 08124 Control Motor Ass y 08080931 0 08666 0B08348A 08080370 Control Motor Contro Motor Pulley Ceramic Capacitor 0 44 50V Z Control Motor Label Motor Seal B 0 08137 0 08064 0B09292A 0M03985A 0M03988A A c ES cs 3 0B08719A 0B08351 A 03 0H03807B 04 0B08687A 0B06623A 08136 Head Mount Base Ass y 0C08028C 0 08027 0C08026D 0C08161B 0C08131C 08083 CA08137A CA08138A Head Height Adjustment Gear Head Height Adjustment Screw Azimuth Alignment Screw Spring Stopper Head Plate Spring Head Mount Base Sub Ass y P 8L Playback Head Ass y R 8L Record Head Ass y 0B06622A 0B06624A 0B06625A 06 0 01162 07 0104076 08 0B07299A 0B07301A 0B07252A 08053 Supply Pressure Roller Ass y
70. R163 263 OB05622A Carbon Resistor 2 2K ERD 25T J 0408 414 0B06012A Transistor 25A634 C409 08093454 Electrolytic Capacitor 3 34 25V BP U S A Canada Japan amp Others R102 202 0B01706A Carbon Resistor 47 ERD 25T J C140 240 0B05652A Mylar Capacitor 4700P 50V J 0432 0806251 Transistor 25 945 0 C414 0B09333A Electrolytic Capacitor 4 7u 25V LN 1 pce R104 106 0B05509A Carbon Resistor 33K ERD 25T J Rec Amp C141 241 OBO1405A Electrolytic Capacitor 1u 50V D403 429 0806181 Silicon Diode 18853 27 pes C415 0B01272A Electrolytic Capacitor 1004 25 0 040968 Fuse Label T 500mA 250V 204 206 C142 242 0B018624A Electrolytic Capacitor 224 16V R403 407 0B01889A Carbon Resistor 100K ERD 25T J C416 0B01405A Electrolytic Capacitor 1 50 220V Class 2 1 pce 8105 205 0B09330A Carbon Resistor 100K ERD 25TS J 0103 203 0B01878A Transistor 25 945 1 C145 245 0B01412A Electrolytic Capacitor 10 16V 408 413 C417 0B01674A Electrolytic Capacitor 10u 25V OMO4096A Fuse Label T 500mA 250V Noiseless 1104 105 0800068 Trap Coil 10 5mH C147 247 0801272A Electrolytic Capacitor 100425V 418 422 C418 0801676 Mylar Capacitor 0 0564 50V UK amp Australia 1 pce 8107 207 0805622 Carbon Resistor 2 2K ERD 25T J 204 205 C152 252 0B05653A Mylar Capacitor 1500P 50V J 427 428 C419 0809292 Ceramic Capacitor 0 1 50V Z 0B08349A Fuse Clip 308 VR102 103 0B0
71. T J 107 204 C301 0B05583A Mylar Capacitor 0 0334 50V J 8416 0B09340A Metal Film Resistor 15K SN14K2EF M2 0B08342A Spark Killer U S A amp Canada R123 223 0B09271A Carbon Resistor 6 2K ERD 25T J 205 207 C302 303 0B09191A PP Capacitor 4700P 100V G R419 0B05626A Carbon Resistor 150K ERD 2 5T J M2 0B08363A Spark Killer Japan R162 262 0801857 Carbon Resistor 1K ERD 25T J Q106 108 0B06013A Transistor 29A 733 C304 0801402 Electrolytic Capacitor 4 74 25V 8420 421 OBO5671A Carbon Resistor 2 2M ERD 25TJ 2 3 0B08445A Spark Killer 220V Class 2 R165 265 0B09213A Fail Safe Type Resistor 150 RDF 25S J 206 208 C305 0B09254A PP Capacitor 0 068u 100 J R423 0B09214A Fail Safe Type Resistor 1 RDF 2 5S J M2 0B08240U Spark Killer R183 283 0805776 Carbon Resistor 1M ERD 25T 4 0101 102 0B06181A Silicon Diode 15553 8431 432 0B01681A Carbon Resistor 3 3K ERD 2 5T J UK Australia 8 Others R184 284 0B05627A Carbon Resistor 330K ERD 25T J 201 202 Logic 445 CN1 5 0B08654A 4P T Post C110 210 0809223A Electrolytic Capacitor 1 SOV LN R139 146 0801681 Carbon Resistor 3 3K ERD 25T J R434 0 05692 Carbon Resistor 68K ERD 2 5T J CN2 0 08681 12P T Post C111 211 0801836 Electrolytic Capacitor 47 10V 239 246 12402 0B06124B IC RC4558D R436 0809314 Carbon Resistor 5 1K ERD 25TJ CN3 0808653 3P T Post 0401 403 0B06013A Transistor 25 733 CN4 0
72. ad Base Stroke Adjustment Record Head Stroke Check Remove Head Mount Base Ass y Tape Guides and Erase Head Stroke Adjustment Erase Head Height and Tilt Adjustment Assemble Head Mount Base Ass y Record Head Playback Head Tilt Check M 9039 M 9047 M 9040 M 9039 Head Base Stroke Check M 9047 Playback Head and Record Head Height Adjustment and Arzimuth Alignment after play mode is securely locked 5 Check to insure freedom from contact between the 6 7 8 Tilt Check Gauge Stroke Check Gauge EM Stroke Check Gauge M 9042 or M 9051 T lt Check Gauge Tilt Check Gauge Stroke Check Gauge Fig 5 4 23 Gauge and pad lifter Beacon Playback Head Lower will light when height adjustment screw P turned clockwise but Playback Head Upper when counterclockwise Adjust so that both Upper and Lower will light on even when you move the slide knob to the direction of an arrow mark and then return it to the original place Same procedures will apply to the Beacons Record Head Upper and Lower except the height adjustment screw A Set the N 481 in stop mode and fit both of the ser rated height gears Then set the N 481 again in play mode and insure all of the 4 Beacons are illuminating If not 3 through 7 will have to be repeated till satisfactory results are obtained Remove Head Mount Base
73. ar Capacitor 0 018 50V J R133 233 0B01856A Carbon Resistor 8 2K ERD 25T J R155 255 0B09318A Metal Film Resistor 560K SN14K2E F R404 446 0801887 Carbon Resistor 5 6K ERD 25T J R401 0B01888A Carbon Resistor 16K ERD 25T J C107 207 0B01412A Electrolytic Capacitor 10u 16V R134 234 0801857 Carbon Resistor ERD 25T J R156 256 0809328A Metal Film Resistor 390K SN14K2E F 447 R402 0801684 Carbon Resistor 470K ERD 25T J C108 208 0B01272A Electrolytic Capacitor 100u 25V R135 235 0805698 Carbon Resistor 1 5K ERD 25TJ R157 158 0 01888 Carbon Resistor 10K ERD 25TJ R405 424 OBO1888A Carbon Resistor 10K ERD 25TJ C306 0801870 Electrolytic Capacitor 1000 25V C109 209 0805687 Mylar Capacitor 1200P 50VJ 8136 138 0B05622A Carbon Resistor ERD 25T J 257 258 435 449 C401 402 0B01412A Electrolytic Capacitor 10 16V C185 285 0B09281A Ceramic Capacitor 150P 50V 182 236 R160 260 0805691 Carbon Resistor 290 ERD 25T J 450 451 C404 0B09336A Electrolytic Capacitor 2200 50V C186 286 0B09242A Mica Capacitor 47P 50V j 238 282 R161 261 0B09213A Fail Safe Type Resistor 150 RDF 258 J 459 461 C405 08093734 Electrolytic Capacitor 3300u 25V R166 266 05936 Carbon Resistor 10 ERD 25TJ C148 248 0B01405A Electrolytic Capacitor 1 50V 462 467 Dolby NR C126 226 0805530 Mylar Capacitor 68000 50V J C149 249 0B09218A Electrolytic Capacitor
74. arbon Resistor 470K ERD 25T J 0B08573A Wire Holder 1 pce 0101 102 08061194 Transistor 25 1844 C120 220 0B09240A PP Capacitor 0 0334 100v 8148 149 0801856 Carbon Resistor 8 2K ERD 25T J 420 421 R484 0801683A Carbon Resistor 15K ERD 25T J 0M03782A Fuse Label 1A 250V 201 202 C121 221 0B01862A Electrolytic Capacitor 22u 16V 248 249 422 426 C403 0B09286A Ceramic Capacitor 470P 50V K U S A Canada Japan amp Others 20301 0B06239A Zener Diode RD20EB C122 222 OBO5583A Mylar Capacitor 0 0334 50V J 8150 151 0B09331A Fail Safe Type Resistor 8 2 RDF 25S J 427 430 C406 411 0B09332A Electrolytic Capacitor 2 2u 25V LN 1 pce L101 201 08039198 Inductor 36mH C123 223 0B01405A Electrolytic Capacitor 1p 50V 250 251 433 412 0 040828 Fuse Label 125 250 VR101 201 0807237 Semi fixed Volume 50K C124 224 1603 Mylar Capacitor O1u 50 R152 252 0 01857 Carbon Resistor 1K ERD 25T J 0405 413 06066 Transistor 28D471 C407 0B092514 Electrolytic Capacitor 33u 25V UK Australia amp 220V Class 2 1 pce R101 103 0801889 Carbon Resistor 100K ERD 25T J C125 225 0B09327A Electrolytic Capacitor 0 334 50V LN Rt53 253 OB09306A Fail Safe Type Resistor 68 RDF 25S J Q407 0B06020A Transistor 2561096 C408 0809283 Ceramic Capacitor 220P 50V K 0 04100 Fuse Label T 500mA 250V 201 203 C137 237 0B01272A Electrolytic 100u 25V
75. ayback Head 1 kHz Track Alignment 8 MPX SW OUT Track Alignment Tape DAO9007A as above Eq SW 70 us Dolby NR SW OUT 5 Playback Head 15 kHz Azimuth Tape Azimuth Alignment DA09004A Sarne as above Same as above 4 6 Playback Level DUE Level rape VTVM to TP101 TP201 Same as above DA09005A 400 Hz Level Tape DA09005A 10 kHz PB Frequency Tape Playback Frequency DA09003A Response 15 kHz PB Frequency Tape DA09002A 20 kHz PB Frequency Tape DA09001A VTVM to OUTPUT Jacks Same as above IC i0 9 VRIOS VR205 50K Qu Li bea Out Fig 7 1 Fig 7 22 2 Meter Level 3 MPX Filtter 32 Capstan Motor Adjust VR501 to obtain 3 kHz 0 5 Governor VR501 is incorporated in the capstan motor VR501 1 Set the input level controls to maximum 2 Adjust the oscillator output to obtain 100 mV at TP101 TP201 then adjust 105 VR205 to obtain 0 dB on the level meters Main P C B VR105 VR205 Adjust input level controls to obtain 600 mV on the VTVM 2 Set the MPX Switch to IN position then adjust L103 L203 to obtain minimum reading on the VTVM minimum reading will be less than 30 dB Main P C B L103 L203 Adjust the Playback Head Height Adj Screw to obtain miminum reading of both L and R channels on the VTVM See Playback Head Height Ad
76. ccuracy of tape travel is one of the most essential factors for a device to optimize its performance Inaccurate tape travel will therefore induce deterioration exemplified by the following a vibration will be given to tape travel as a result of which flutter and modulation noise will become in creased b insufficient tape to head contact will result in level drops c tape skew will become greater and frequency re sponse will become decreased Needless to say constant tape travel must consist of smooth drive mechanism as well as of the fact that tape heads and tape guide are placed in the most appropriate positions 81 Playback Head and Record Head they are both made small in size so that the both heads are assembled in a space of the conventional Record Playback Head Erase Head is located at the place where the Record Head is located in the 7001 10001 Both Playback Head and Record Head are assembled on the Head Mount Base Take up Tape Guide and Supply Tape Guide are fixed to the Take up Pressure Roller Arm and Supply Pressure Roller Arm respectively Erase Head is placed on the Head Base All these can be separately adjusted Record Head is placed slightly backward approximately 0 15 mm away from the Playback Head Record Head is placed approximately 3 inclined leftward Shape of the Heads and its location have been carefully studied to bring about smoother contact of tape with the Heads Pad Lifter is affixed to t
77. ck Frequency Response mE mm T 2 4 Ul 20 100 IK IOK 20K Frequency Hz Fig 11 1 11 2 Record Current Frequency Response Gain dB 20 100 20K Ee Hz Fig 11 2 9 12 WIRING DIAGRAM Power Switch eo AC Input Voltage Selector AC Input Power BLE WHT Transformer Notes 1 Table of colors BLK Black BLU Blue ORN Orange GRY Gray GRN Green RED Red BRN Brown Yellow WHT White VIO Violet Colors of shield wire tube R Red W White B Black Gray Headphone Jack 4 Main Powar Switch e Component Side RN 8 AC Input di da Input 2 3 8 5 ijo CN 2 4101 1 oR a WR Power BLK l vat Transformer 4 4 ael 4094847 20 q d RW wa J Switch PCB Assy Component 148 2 gt 2020 544
78. e Arm Ass y Head Base Drive Arm Spring Record Arm Ass y Record Trigger Flip Flop Spring Pressure Roller Drive Arm Ass y Counter Reset Arm Eject Linkage Wire Eject Arm Arm Shaft Auto Shut off Ass y Counter Ass y Counter Belt A Eject Stopper Eject Stopper Spring Record Protector Damper Lock Arm Damper Arm Spring Tube Pneumatic Damper Ass y Supply Capstan Flange Ass y Take up Capstan Flange Ass y Cam Drive Gear Control Cam Counter Load Arm Spring Tube Counter Load Arm Spring Counter Load Arm Ass y Record Switch Linkage Wire Record Arm B Record Arm Spring Main Chassis Ass y Shield Plate Stopper Ring 3mm BT Screw M3x14 Philips Pan Head BT Screw M3x30 Philips Pan Head BT Screw M3x10 Philips Pan Head Washer 3 1mm Plastics E Ring 2mm 080798 0 08183 0 08182 08121 0 080868 OCOBOBOB 0 08051 0 08120 CA08027A 0C08143C 08025 0 080380 0 08112 CA08026A 0C08071D 0 081248 0C08057D 0 080788 08119 CA08020A 0C08097B 0C08067C 0C08134C 0 08119 0 08194 0C08153A CA08023A 08024 0C08186A 0C08029H 0C08152A 0 08117 08028 0 081238 0 08037 0C08116A 08072 0 08225 0E00837A 0 00832 0 00834 0 00831 0E00254A 0 00222 S me f roe S re
79. easure the differ ence between 2 and 3 Record and Playback 100 Hz Band Pass Filter Tape SW ZX Erasure 2 to INPUT and VTVM to OUTPUT Eq SW 70 us 5 Jacks Dolby NR SW IN MPX SW IN 165 Bios Cut 5 umber 16101 53 R310 39 1 2w LI 05 L205 C138 VR7OI VRBOUI EX Ex 50K C153 VR7O2 VR802 Tsx sx 20K VR7O3 VR803 zx 50 50K VR104 VR204 VRi031VR20O3 RI29 R 30 E Fig 7 4 Fig 7 5 8 Bias Oscillation Frequency and Erase Current 9 Record Amplifier Equalizer 10 Bias Trap 14 Overall Frequency Response Fig 7 6 13 Record Level Calibration and Recording Bias Current P STEP ITEM SIGNAL SOURCE OUTPUT CONNECTION Curve Filter Record and Playback Tape SW ZX Signal to Noise Ratio to INPUT AR Eq SW 70 us lacks 2 Dolby NR SW IN Jacks MPX SW IN ments Record and Playback level meters Tape SW EX SX ZX Eq SW 120 us EX 70 us SX ZX Dolby NR SW OUT
80. en 8212 or R111 R211 as illustrated in the figure 225 Short D Short IK 2K Frequency Hz Playback 100 Head 1 201 SOK VRIOL 0 Output Fig 7 7 Playback Equalization Curve 106 6206 0 018 31 1091 2091 1200P14 120 Fig 7 8 Playback Amp Feed in 400 Hz and record and play it back 2 Adjust the input level controls to obtain 396 total har monic distortion in playback mode 3 Close the input level controls then record 4 After rewound play back and check the output level difference between 2 and 3 Note The filter of IHF A curve shall be used in the measure Adjust the input level controls to obtain 0 dB on the 2 Record and play it back 3 Read the distortion meter and check to insure that the distortion is as follows 252 52 242 nd read the wow flutter meter 35 1 096 or less 1 096 or iess 0 996 or less 7 3 Check on Dolby NR Circuit Dolby NR Circuit incorporates a Dolby B Type NR IC 7 which has no adjustment point Perform the following checks and make sure that the IC operates accurately i e frequency response through is accurate Signal Source Output Connection 5 kHz to INPUT Jacks VTVM to the output side of C154 C254 on the Main P C B Record Pau
81. eramic Capacitor 220P 50 BA04124A Lamp 8 Ass y SW304 0B07314A Switch 0 6 6 4 0B08707A Flat Cable 80 1 pce 0B07850B Lamp P C B R 0B08674A Lamp BA04113A Control Switch P C B Ass y 0B07848B Control Switch D601 0B06181A Silicon Diode 15553 R608 609 0801678 Carbon Resistor 100 ERD 25T J C605 606 0801405 Electrolytic Capacitor 50V Pi601 602 0B08673A Lamp 24V 20mA 603 0B07297A Control Switch 1 pce T fe i ak x9 gt T x t 1 1 1 ju a m 7 57 n I 4 gt den ES 7 x SIS gt 8 f 8 5 1 3 7 f 1 gt I I i 15 4 1 5 i 8 gt l oF 5 1 n 1 T t pd ct sp ET ENS QUE a 51 4 4 1 AMI i o 1 9 a 4 AZIO 5 2 4l ges Age 9085 lt a3 T sos a ke ASZ FOO 9922 _ 5 p 4 41 4 95 ois 8019 et NOE 10444 2 6628 did Y ox 1 n XOU 5514 e CTS kampa zu 1628 agta 5 251 Soe Cm Ma rd cae 5 te Sg b 1523 ste w get er eon 1021 Mie 6022 1 Qn AN 819 is pra a 1278 55 88 ILV E 6013 3
82. he Playback Head so as not to let Tape Pad touch the Head to give more stabilized tape travel making it free from the influence of the Tape Pad within the Cassette Tape Thus the trouble of changes in azimuth can now be avoided at changing of cassette tape if only the Record Head azimuth is properly adjusted in advance The Fig 2 1 2 shows trackings of each head against a tape of the N 481 wherein the figure shows ideal locations at the time of designing thus the tracking in actual use will vary more or less depending upon the tape width etc 1 Adjustment of Tape Guide Height Tape Guide of the N 481 is assembled into the Take up and Supply Pressure Roller Assemblies With a spring in the stud of Mechanism Chassis Ass y Pressure Roller Ass y is tightly affixed with Tape Guide Adjustment Nut The Adjustment Nut is placed on a spring through Pres sure Roller Arm and therefore by either tightening or loosening height adjustment of the Tape Guide will become possible 2 Playback Head Height Adjustment and Azimuth Alignment Azimuth and height of Playback Head can be made in dependently and adjustment may be done separately without affecting others In order to adjust the tilt of Playback Head backwards or frontwards take off the Height Gear Stopper and take out the Height Gear and then turn the two Height Adjustment Screws After the adjustment is done place the Height Gear back and fix it with the Height Gear Stopper
83. his circuit Amplifier which is composed of Q101 and Q102 is an equalizer amplifier and its time constant is shown in Fig 2 2 3 R111 R112 L101 and C109 which consist of a peaking circuit compensate playback head gap loss and improve frequency response at high L101 and C186 compose a bias trap circuit and prevent bias leakage from playback eq amp circuit Playback eq amp gain adjustment should be performed as to obtain 100 mV at TP101 TP201 by adjusting VR101 VR201 during the course of playing back 400 Hz Level Tape DAO90054 Eq Switch 70 us 1 20 us is connected to the playback eq amp circuit and the overall time constant of playback eq amp circuit will become as follows Eq Switch 70 us 3180 us 50 Hz 70 us 2274 Hz Eq Switch 120 us 3180 us 50 Hz 120 us 1326 Hz Following table shows tapes used at each Tape Switch combined with Eq Switch SX 70us Nakamichi SX TDK SA Maxell XLII Scotch Master 70 us EX 120us Low Noise High Density including EX EXII TDK AD Maxell Scotch Master 120 us Nakamichi EX EXII It is specified in the IEC Standard that the time constant is 120 us on tapes of ferric oxide and 70 us on tapes of Cr02 However in the case of Eq Switch on N 481 when time constant at playback is changed at the same time constant at record must also be changed Therefore even though record and playback is made by the method other 22 5V L
84. hone Jack Ass y 803 Fig 9 6 Description 4 03627 Control Switch Holder Ass y JA03616A Headphone Jack Ass y 0H03793A Control Button 0J04071C Control Switch Holder 0J04072B Lamp Cover 0J04073A Control Button Shaft 0808511 Headphone Jack 0J04070A Headphone Jack Holder Jack Washer 02040740 Control Button Spring BA04113A Control Switch P C B Ass y 04114 Volume P C B Ass y 0E00857A BT Screw M3x6 Philips Binding Head 0E00502A Screw M3x5 Philips Pan Head 0 00117 Washer 2mm N 43 9 7 Mechanism Ass y 481 804 Fig 9 7 44 um WU CA08135B Mechanism Ass y 481 Serial No 30605381 08135 08109 02 0 08096 0 08096 Flywheel Holder Ass y Capstan Belt 03 CA08169A Supply Flywheel Ass y CA08113A 04 CA08107A Take up Flywheel B Ass y 107 08 0 08021 Thrust Washer 3 1mm 00080218 0 080208 0 08069 06 0 080208 07 0 08069 Thrust Washer 2 6mm Flange Thrust Cap 1 1 1 1 1 1 2 08 0C08022B Flange Thrust Spring 2 0C08022B 09 08165 Sub Mechanism Chassis Ass y 1 09 165 10 0C08098B Counter Belt B 1 10 0 08098 11 0 080998 Control Motor Belt 1 11 0 080998 12 CA08171A Mechanism Chassis Ass y 1 12 CA08140A 13 0C08151A Lid Arm Spring Tube 1 13 0C08151A 14 0
85. hrust 1 Spring 10 CA08079B Take up Pressure Roller Ass y 1 11 0C08183B Take up Pressure Roller Thrust 1 Spring 12 0 08182 Pressure Roller Drive Bar 1 13 CA08121A Head Base Ass y C 1 45 46 44101 43 Lie 14 0C08086B Head Base Roller 3 15 0 08050 Record Sensor 1 16 0 08051 Cassette Hold Arm 1 17 0 08120 Cassette Hold Arm Spring 1 18 CA08027A Head Base Drive Arm Ass y 1 19 0C08143C Head Base Drive Arm Spring 1 20 CA08025A Record Arm Ass y 1 21 0 080380 Record Trigger 1 22 0 08112 Flip Flop Spring 1 23 2 Pressure Roller Drive Arm Ass y 1 24 0C08071D Counter Reset Arm 1 25 0C08124B Eject Linkage Wire 1 26 0C08057D Eject Arm 1 B 27 0C08078B Arm Shaft 1 28 CA08119A Auto Shutt off Ass y 1 29 CA08020A Counter Ass y 1 30 0 080978 Counter Belt 1 31 0 08067 Eject Stopper 1 i 32 0 08134 Eject Stopper Spring 1 LO3 LM 33 0 08118 Record Protector i 27 26 25101 24 34 0C08194C Damper Lock Arm 1 35 0 08153 Damper Arm Spring Tube 1 36 Pneumatic Damper Ass y 1 37 CA08023A Supply Capstan Flange Ass y 1 Fig 9 11 1 Serial No A30605381 38 CA08024A Take up Capstan Flange Ass y 1 39 0 08186 Drive Gear 1 40 0 08029 Control Cam 1 41 0 08152 Counter Load Arm Spring Tube 1 42 0C08117A Counter Load Arm Spring 1 43 CA08028A Counter Load Arm Ass y 1 44 0COB123B Rec
86. htward can be adjusted separately thus the best location of Erase Head can be obtained the aforesaid occurrence and stabilizing wow and flutter characteristics S0ps Inside Core e Outside Core 1 4 Outside Core Fig 2 1 3 Sectional View of Erase Head Erasure dB 100 200 300 200 Erose Current mA o Fig 2 1 4 Characteristics of Erasing Current and Erasure As the double capstan system always creates a constant and stable holdback tension between the two capstans the condition of the tape between two capstans will not be affected by any external conditions such as irregular take up and supply torques irregular loading of cassette tape undesirable mechanism vibration and etc thus assuring the superior wow and flutter characteristics The double capstan system provides a constant holdback tension on the tape and maintains the stable pressure onto the tape against the heads The only critical factor in the double capstan system is to be considered the two capstans have to be positioned per fectly in parallel and to be precisely vertical against the head base the pressure rollers have to be evenly pressed against the capstan shafts and the head surface must be positioned perfectly vertical to the tape surface Other wise the running tape might become out of the tape guide resulting in irregular movement Copston Motor a Motor Pulley
87. ion signal changes from L to H bias oscillation will begin Upon completion of above adjustment re connect wires to the motor terminals Tape Speed Adjustment Remove the Top Cover Connect a Frequency Counter to the Output Jack Load a 3 kHz Speed Wow Flutter Tape DA09006A and play it back Referring to Fig 5 3 adjust the Tape Speed Adjustment Volume VR501 incorporated in the Capstan Motor to obtain 3 000 Hz on the Frequency Counter CCW Motor drives slowly CW Motor drives fast 4 2 lt z N 7 gt t v Ne gt lt my Fig 5 3 5 3 Record Head and Playback Head Tilt Adjustment Note On items 5 3 5 8 please refer to Fig 5 4 flow chart Refer to Figs 5 5 and 5 6 1 Load a Tilt Check Gauge M 9039 DA09039A in the N 481 Clip the grounding terminal of the Tilt Check Gauge with one end of the cord with clip and the other end to the chassis of the N 481 Remove both of the Height Gears Set the N 481 in play mode Check to insure whether the Beacons Playback Head Upper or Lower and Record Head Upper or Lower are illuminating In order not to give damages onto the head surfaces push both of slide knobs of the Gauge to the direction of arrow marks then return it to the original place to be in contact with record head and play back head surfaces 2 3 4 Record Head and Playback Head Tilt Adjustment He
88. isassemble F12 Record Head Ass y 7 11 w gt 05 FO roo t r FI rof 3 2 5 18 lt i zs x a E 202 F03 F06 4 lt riz 98 9 gt gt F16 ti 5 0 PA 5 lt ed F0o7 E dox w i F21 ros 8 ris 6 YE Ver 7 12 lt _ F22 gt Li 24 1 F23 4 FO5 34 o 4 i E go FO6 a 2 24 A lt i k Ly P f 3 da T m i 4 l lt gt 54 4 L 18 gb i p A i 4 4 2 NL 2 fi 2 Fig 3 8 Fig 3 7 20 4 MEASUREMENT INSTRUMENTS Audio Generator 20 Hz 200 kHz 2 AC Millivolt Meter with dB measures 3 Oscilloscope DC 5 MHz 4 Distortion Meter 5 Speed amp WOW Flutter Meter 6 Frequency Counter DC 1 MHz 7 Ohm Meter 8 DC Volt Meter 9 AC Volt Meter Torque Gauge DA09013A 15kHz Azimuth Tape DA09004A kHz Speed amp Wow Flutter Tape DA09006A 1 kHz Track Alignment Tape DA09007A 400 Hz Level Tape DA09005A 20 kHz PB Frequency Response Tape DA09001A 15 kHz PB Frequency Response Tape DA09002A 10 kHz PB Frequency Response Tape DA09003A Reference EXII Tape DA09021A 19 Reference SX Tape DA09025A Reference ZX Tape DA09037A Tilt check Gauge
89. justment and Azimuth Align ment in item 5 7 Playback Head Height Adjustment Screw Adjust the Playback Head Azimuth Alignment Screw to obtaln maximum reading of both L and R channels on the VTVM See Playback Head Height Adjustment and Azimuth Alignment in item 5 7 Note Repeat steps 4 and 5 one or two times to obtain optimum performance Main P C B Adjust VR 101 VR201 to obtain 100 mV on the VTVM 1 Load the 400 Hz level tape and play it back 2 Load the 10 kHz 15 kHz and 20 kHz PB Frequency Response Tapes and adjust the playback head azimuth to give maximum levels on the VTVM with each tape Short R112 R212 to obtain the following levels against 400 Hz level tape Refer to Fig 7 3 10 kHz 20 dB 2 dB to 2 dB 15 kHz 20 dB 2 dB to 3 dB 20 kHz 20 dB 2 dB 4 dB 3 Conduct step 5 Playback Head Azimuth Align ment 4 If above is not sufficient refer to Playback Frequency Response Adjustment in item 7 2 Playback Head Azimuth Alignment Screw Main R112 R212 LIO RII C107 R211 8212 VRIOI 2011 Fig 7 3 6 Playback Level 7 Playback Frequency Response Ess OUTPUT CONNECTION MODE STEP 8
90. l Switch Holder Ass y referring to item 3 10 2 Remove F10 then disassemble F11 Volume P C B Ass y 3 Remove F12 then disassemble F13 Control Button Spring 4 Remove F14 Control Button Shaft then disassemble F15 Control Buttons 5 Remove F16 then disassemble F17 Control Switch P C B Ass y 3 13 Rear Panel 55 Power Transformer and Power Switch Refer to Fig 3 4 1 Refer to Fig 3 1 Remove Top Cover Ass y and Bottom Cover Ass y referring to items 3 2 and 3 3 2 Remove F01 F02 and F03 then disassemble F04 Rear Panel Ass y 3 Remove F05 and F06 then disassemble F07 Power Transformer 4 Remove Power Switch Joint Bar by releasing the self interlocking pin of the Power Switch Joint Bar from Power Switch and 208 then disassemble F09 Power Switch Holder Ass y 5 Remove F10 then disassemble F11 Power Switch 17 481 FO5 Fig 34 18 3 14 Cassette Case 55 and Cover Plate Ass y Refer to Fig 3 5 1 Refer to Fig 3 2 Remove Mechanism Ass y referring to item 3 6 2 Press the Eject Button to open the Cassette Case 3 Remove F01 then disassemble the piston of the Pneumatic Damper Ass y 4 Remove 202 and Cassette Case Holder L Ass y then disassemble F04 Cassette Case Ass y 5 Remove F05 then disassemble F06 Cover Plate Ass y 3 15 Tape Counter Ass y Refer to Fig 3 5 1 Refer to Fig 3 2 Rem
91. l contact with capstans If such are noted the Pressure Roller Assemblies will have to be replaced Further excessively weak take up torque or strong take up torque may cause defective tape travelling The N 481 is intended to be an adjustment free Model however if the similar matters as above should be noted please replace the Reel Hub Ass y to obtain appropriate take up torque 5 10 Record Switch Linkage Adjustment 1 Set the N 481 in stop mode 2 Loosen the screw of the Record Spring Holder and shift the Record Spring Holder in order to remove the looseness of the Linkage Wire as shown in Fig 5 17 1 Then tighten the screws for fixing the Record Spring Holder In this case the Record Switch should be positioned at play side If on the record position it will be defective 3 Set the N 481 in record and pause mode Check to insure that the gap between the top of the wire and the Record Spring Holder is approx 1 mm as shown in Fig 5 1 7 2 Check that the Record Switch is in record position 4 Upon completion of the above adjustments apply a quantity of lock tight paint Fig 5 17 1 TDI m el J appro im Fig 5 17 2 5 11 Flywheel Holder Adjustment 1 Refer to Fig 5 18 Tighten the Thrust Screws until the gap between the Flywheel Assemblies and Thrust Screws becomes minimized when both of the Capstan Shafts are moved backwardly and forwardly the Thrust Springs between the
92. mode R486 100 kohm is grounded by the NOT Kf f L signal When Play Button is pressed it is locked ON and FF Button is released Although FF Button is re leased the NOT Kf f signal is kept L for a short period of time because the delay circuit C605 and R608 connected in parallel to FF Button acts to prolong the NOT k f f L signal In this period the voltage at the point A becomes approx 22 V from 23 V pulse likely as R486 and R488 are grounded by the NOT Kf f L and NOT Kplay L signals respectively Consequently 0424 and Q426 are turned ON and C411 is charged up to 24 V but C411 will be discharged after this period is over The base current to Q430 is supplied from C411 through D424 and R475 as a result Q430 and 0429 are turned ON 0428 is turned OFF and 24 VS is shut off resulting in STOP mode On the other hand since the base current to Q427 is supplied from C411 through R469 R427 is turned ON until the discharge of C411 is completed When the voltage of C411 is lower than the emitter voltage approx 4 2 V of Q430 Q430 and Q429 are cut off 0428 is turned ON and 24 VS is supplied as a result the PLAY signal becomes H 24 VS and PLAY mode is set 2 From RECORD mode to FF or REW mode When mode is changed from RECORD to FF or REW mode momentary STOP mode is automatically taken in view of the tape deck mechanism and after this is over a new mode is set When Record Button is released by pressing either FF
93. n by pres sing Play Button further the Kplay signal becomes L Q418 is turned ON the PLAY signal becomes H 24 VS and Q420 is turned ON Accordingly the base current flows to Q403 via C406 connected to the base of Q403 and Q403 is turned ON pulse likely The output of Q403 is fed to the control motor drive circuit and acts to bring the cam to the record position When 0403 returns to OFF the cam then moves to the play position and stays there thus the mechanism is set to RECORD mode Record circuit is designed to protect from the erroneous setting of RECORD mode even if wrong record button operation is made Q422 is turned ON during FF or REW mode or when the cam is set to the play or pause position i e PLAY or PLAY PAUSE mode In this case as D422 is grounded by 0422 0421 is not turned ON and the record lamp is not lit even if Record Button is further pressed Further the base of Q420 is grounded via D419 and 0422 consequently Q420 and Q403 are not turned ON and no pulse is output from Q403 to the control motor drive circuit 24VS 1T ca R 251 i ec Krec yu w gt 254733 caog 100K B 2 2 5OV LN zs 22 25V 0420 gt FAST o 2427 Ys Rag 25 945 rasi 39 DO R 0422 FAST R456 2 25 27 sin Ploy Pause a q422 Position J 25C945 B Qe T Fig 2 3 8 Record Cont
94. ns is illuminating Look down the mirror as shown by an arrow mark and slowly turn the Screw Height counterclockwise or clockwise so that the two horizontal lines of the mirror will become superposed on the line in different color of the erase head and check to insure whether Beacon 1 is illuminating Turn Screw counterclockwise or clockwise to light on Beacon 2 Excessive turning will cause the Beacon 1 to light off Adjustments of Screw Tilt will therefore be conducted till both of the Beacons 1 and 2 illuminate Turn Screw Azimuth counterclockwise or clock wise to light on Beacon 3 Excessive turning will cause either Beacon 1 or 2 to light off and therefore adjust with Screw Azimuth until all of the 3 Beacons 1 2 Fig 5 10 7 8 and 3 illuminate Check to insure whether the horizontal line on the mirror corresponds to that on the erase head If not 4 through 7 will have to be repeated till satisfactory results are obtained After completion of adjustment 3 pcs of screws shall be locked with lock tight paint Note Before use of this gauge check to insure freedom from dust or dirts or overflow in the groove of the erase head surface S Tilt Height Fig 5 11 5 7 Playback Head and Record Head Height Adjustment and Azimuth Alignment Refer to Fig 5 12 1 b c d e f 2 b
95. nto Chemicals Co Ltd 2 7 Suda cho Chiyoda ku Tokyo 101 Japan 3 Silicon Oil 3000 CST Air Damper Piston Note Excessive lubrication may cause defective damper action as gt 0 2 0 hole the end of the cylinder be filled with 4 4 2 j gt gt zm 1 L Fig 5 19 2 Moin PC B 6 PARTS LOCATION FOR ELECTRICAL ADJUSTMENT vos Meter Leve Bas Trop 205 L104 Uo Peokin L105 fs I 48 03 zx 5 204 t Record 4819 143 1 5206 Piaybock Leve lt ve622 d Pioy Steg 8203 R204 4 1 sx Control P E DEN VR7O3 ger sx 2X 24 ui VREO LEX Bios 8 Fig 6 7 ELECTRICAL ADJUSTMENTS AND MEASUREMENTS 7 1 Adiustment and Measurement Instructions Note Electrical adjustment should be performed after mechanical adjustment is completed STEP ITEM SIGNAL SOURCE OUTPUT CONNECTION MODE Tape Speed 3 kHz Speed and Wow Flutter Frequency Counter to Playback Tape DA09006A OUTPUT Jacks Eq SW 70 us Meter Level 400 Hz to INPUT Jacks TPAGT Chant Record Pause the Main P C B MPX Filter 19 kHz x 100 Hz to VTVM to OUTPUT Record Pause INPUT Jacks Jacks MPX SW QUT IN Playback Pl
96. ode in a short period of time and after this STOP mode is Over a new mode is set 0 Power mute L pulse is generated when Power Switch is turned ON or OFF 0 memory rewind function is activated Reached tape end during PLAY PLAYBACK or RECORD FF or REW mode Explanation is made for PLAY mode as an example For FF or REW mode the shut off function is the same as for PLAY mode As Play Button is locked ON mechanically 1 Accordingly 488 100 kohm is grounded through Play Button and the voltage at the point A becomes approx 23 V Since the voltage at the point A is not lower than the emitter voltage of Q424 Q424 is turned OFF and Q426 is also turned OFF Q424 and Q426 will be turned ON when the voltage at the point A is further lowered as described in subsequent b 0425 0427 0430 R470 and C412 consist of a shut off detecting circuit During PLAY mode the voltage at the point A is approx 23 V therefore Q425 is turned ON and C412 2 2 pF is charged toward 24 V through R470 Meanwhile pulses from the shut off sensor are applied to the base of Q427 through R489 and C418 and at every H cycle of the sensor output pulse Q427 is turned ON and C412 is discharged through Q427 When the tape end is detected pulses from the shut off sensor are not trans mitted and Q427 is turned OFF resulting in C412 being charged continuously When the voltage of C412 exceeds the sum of the emitter voltage approx
97. op Switch and the Cam comes back to the Stop position At the same time it will set the Record Switch on the P C B to the Play side 3 Rewind Mode By pressing the F F or Rewind Switch it comes either to F F or Rewind mode The only difference of these two modes is that one is to turn the Reel Motor reverse and the other to transmit the torque against the Reel Hub onto the take up side or to the supply side Brake is re leased at this stage and the Reel Motor begins to turn F F or 4 Pause Mode Press the Pause Switch to make it to Pause mode In changing it from Stop mode to Pause mode the Brake is first released then the Head Base is latched and again the Brake works At this stage the Reel Motor would not turn with the Pressure Roller being apart from the Capstan and the tape would remain still 2 0 4 1 1 1 4 1 4 1 1 Rewind 30 Com Angle MES REST L eee Rec Stop EE or Rew 20 7 30 Mode exu Head Touch Base Lotch Reel Motor Pressure Roller Rec Trigger i Re Eject Lotch Fig 2 1 6 Mechanism Control Cam Timing Chart 2 2 Amp Circuits 2 2 1 Playback Eq Amp Circuit Fig 2 2 1 shows the playback equalizer amp circuit Fig 2 2 2 shows its system diagram and Fig 2 2 3 shows the time constant of equalizer Playback Head is connected to the input of t
98. ord Switch Linkage Wire 1 45 0 08037 Record Arm B 1 Ref No Part No Description 46 0 08116 Record Arm Spring 2 jg 47 CA08072A Main Chassis Ass y 1 LOG 0E00222A E Ring 2mm 48 0 08225 Shield Plate 1 107 0E00839A Stopper Ring 2 5mm 49 0C08250A Supply Pressure Roller Spring B 1 108 0 00876 BT Screw M2 6x8 Philips Fan 11 01 0E00837A Stopper Ring 3mm 13 Head 92 0 00832 BT Screw M3x14 Philips 2 109 0 080608 Height Adjustment Nut 2 Head L10 0 00142 Washer 2 6mm 2 103 0E00834A BT Screw M3x30 Philips Pan 2 L11 0E00879A BT Screw M2x15 Philips Pan 1 Head Head 104 0 00831 Screw M3x10 Philips Pan 4 0E00838A Stopper Ring 4mm Head 0 00846 BT Screw 8 Philips Pan Head 105 OEQ0254A Washer 3 1mm Plastics 0 00895 Earth Lug 3mm 47 CA08140A Mechanism Chassis Ass y Serial Nos A30601001 A30605380 08141 CA08022A CA08111A 0 080191 0 03977 CA08136A 0C08121A CA08053B 0 08122 Cassette Case Holder L Ass y Cassette Case Holder R Ass y Cassette Case Ass y Cover Plate Cassette Viewer Label Head Mount Base Ass y Supply Pressure Roller Spring Supply Pressure Roller Ass y Supply Pressure Roller Thrust Spring Take up Pressure Roller Ass y Take up Pressure Roller Thrust Spring Pressure Roller Drive Bar Head Base Ass y C Head Base Roller Record Sensor Cassette Hold Arm Cassette Hold Arm Spring Head Base Driv
99. ormance After completion of above adjustment check to insure the followings Connect the VTVM to Output Jacks Feed in 400 Hz 0 dB then record signals for each tape Play it back after rewound then check to insure whether the readings on the VTVM are 600 mV level meters will indicate O dB Feed in 15 kHz 20 dB then record signals for each tape Play it back after rewound then check to insure whether the readings on the VTVM are 60 mV level meters will indicate 20 dB above is not sufficiant repeat above steps 1 through 9 until satisfactory results are obtained Check to insure whether the Total Harmonic Distortion T H D is less than 1 096 for EXII and SX tapes and 0 9 for ZX tape Rec Level EX VR104 VR204 SX VR103 VR203 ZX VR102 VR202 Bias Current EX VR701 VR801 SX VR702 VR802 ZX VR703 VR803 33 ITEM SIGNAL SOURCE OUTPUT CONNECTION ADJUSTMENT Feed in 400 Hz 0 dB and adjust input level controls to obtain 0 dB on the level meters Switch the Generator output level to 20 dB then record and play it back Feed 20 Hz to 18 kHz 20 dB then check to insure if the output levels are within 20 dB 4 dB If above is not sufficient adjust L104 L204 to obtain approx 20 dB on the VTVM Conduct step 13 Record Level Calibration and Recording Bias Current Adjustment If above is not sufficient precise re adjus
100. ove Meter Ass y referring to item 3 7 2 Remove F07 then disassemble F08 Tape Counter Ass y 19 3 16 Capstan Motor Ass y and Flywheel 55 Refer to Fig 3 6 1 Refer to Fig 3 2 Remove Mechanism Ass y referring to item 3 6 Remove F01 and 202 then disassemble F03 Fly wheel Holder Ass y and F08 Capstan Belt Remove F04 then disassemble F05 Capstan Motor Ass y Remove F06 then disassemble 207 Control P C B Ass y Remove F09 Supply Flywheel Ass y then disassemble F10 Take up Flywheel Ass y After removing both Flywheel Assemblies disassemble F11 Thrust Washer 3 mm F12 Thrust Washer 2 6 mm F13 Flange Thrust Caps and F14 Thrust Springs 3 17 Sub Mechanism Chassis Ass y Refer to Fig 3 7 1 2 Refer to Fig 3 6 Remove Flywheel Assemblies refer ring to item 3 16 Remove F10 and F02 then disassemble F03 Sub Mechanism Chassis Ass y 3 18 Control Motor Ass y and Reel Motor Ass y Refer to Fig 37 1 2 3 Remove Sub Mechanism Chassis 55 referring to item 3 17 Remove F04 then disassemble F05 Control Motor Ass y Remove F06 then disassemble F07 Reel Motor Ass y 3 19 Cam Control Volume Refer to Fig 3 7 1 2 3 Remove Sub Mechanism Chassis 55 referring to item 3 17 Remove F08 then disassemble F09 Volume Coupler Remove F10 then disassemble FI 1 Cam Control Volume 3 20 Reel Hub Ass y and Idler Ass y Refer to Fig 3 7
101. pe Guide Check Bar will not come into the take up tape guide If such is noted turn to adjust the height adjustment nut B till the Take up Tape Guide Check Bar is accepted by the take up tape guide If the above are insured set the N 481 in pause mode then in play mode to see whether adjustments are appropriately made If not b through e will have to be repeated till satisfactory results are obtained Erase Head Stroke Adjustment Load an EH Stroke Check Gauge M 9042 M 9051 in the N 481 Set the N 481 in play mode thus check can be made on erase head stroke through the EH Stroke Indicator Check to insure whether the erase head surface is aligned with red line on the EH Stroke Indicator If not adjust the erase head stroke by loosening 2 screws that assembled erase head and erase head plate After completion of adjustment 2 pcs of screws shall be locked with lock tight paint EH Stroke Check Gauge M 9042 DA09042A should be used for the Models from serial Nos A30601001 to A30604798 and EH Stroke Check Gauge M 9051 DA09051A is for the Models bearing serial Nos A30604799 and greater Tawe up Gude Check Bor 5 6 Erase Head Height and Tilt Adjustment Refer to Figs 5 10 and 5 11 1 2 3 4 5 6 Remove Head Mount Base Ass y referring to item 3 22 Load an EH Tilt Check Gauge M 9040 DA09040A in the N481 Set the N 481 in stop mode Check to insure whether one of the 3 Beaco
102. pring 2P H Connector Screw M1 7x8 Philips Pan Head Screw M2x6 Philips Pan Head Washer 2mm BT Screw M2x3 Philips Pan Head LION Wo Q A 08141 0 08073 0C08114A 0 0E00837A CA08022A 0C08133A CA08044A 0E00840A CA08119A 0C08047A 0C08206B 0 080888 0C082078 BAO4128A CA08030A 0 08058 00081028 0 08010 0 08059 0E00874A CA08137A 0C08160F GA02034A 0 081690 0B08704C 0 00886 CA08138A 0C08159G GA01050A 08087058 0 00887 Cassette Case Holder L Ass y Lid Arm A Lid Arm Spring Cassette Case Holder L Sub Ass y Stopper Ring 3mm Cassette Case Holder 5 Eject Sensor Cassette Case Holder R Sub Ass y BT Screw M2x8 Philips Pan Head Auto Shut off Ass y Shut off Pulley A Shut off Pulley B Shut off Pulley Shaft Shut off Pulley Holder Shut off P C B Ass y Pneumatic Damper Ass y Damper Piston Damper Ring Damper Plate Sylinder Stopper Ring CS Zmm P 8L Playback Head Ass y Head Plate P 8L Playback Head Pad Lifter 54 PH Connector Screw M1 7x6 5 Philips Pan Head R BL Record Head Ass y Head Plate R 8L Record Head RH Connector Screw M1 7x4 Philips Pan Head 52 RECORD ReYpiay B840ms 40ms ee 53 11 EQ RESPONSE 11 1 Playba
103. r C406 2 2 uF on the Main P C B with a jumper wire then press the Record and Play Switches Reference Voltage Reference voltage at the sliding contact of VR601 Cam Control Volume in each mode is as follows Mode Reference Voltage Typical Val Record 16 V 1 V 0 4 V 0 2 V Stop 15V 1 5 V 0 25 V 13 5 V Fast FF REW Pause 10 V Fr 25V 04V Play 7 5 V c Resistors for Adjustment Mode Ref No Typical Value Stop 8415 R416 9 1 kQ F 15 Fast FF REW 8414 56 F Pause 8454 680 R453 120 R419 150 Adjustment Procedures Press the Stop Switch to set the N 481 in stop mode Adjust the value of R415 and R416 to obtain 15 V 0 6 V at the sliding contact of VR601 Note When R415 and R416 are adjusted the re 3 b c ference voltage in Fast FF or REW mode is changed Therefore re check of the reference voltage in Fast FF or REW mode is required If the reference voltage is out of the range re adjustment of R414 according to next step 2 is necessary Set the N 481 in FF mode then adjust the value of R414 so that the voltage of VR601 will become lower by 1 5 V 50 25 V than in stop mode Press the Pause Switch to set the N 481 in pause mode Adjust the value of R454 to obtain 10 V 0 4 0 15 V at the sliding contact of VR601 Set the N 481 in playback mode then adjust the value of R453 so that the voltage of VR601 will
104. rol Circuit 2 3 6 Mute Signal Refer to Fig 2 3 9 circuit diagram When Q416 is turned ON the Mute H signal is fed to the amp circuit and the amp circuit is muted The condition that the amplifier circuit is muted are Mute 0416 0412 PLAY R P Switch Play Power mute Power mute When Power Switch is turned ON or OFF Power mute signal becomes L i e Power mute signal becomes H and 0416 is turned ON 0412 is in the pause position 0412 OFF Cam is in the play position PLAYBACK or RECORD mode 14 R P Switch When R P Switch on the Main P C B is in the record position 24 V is applied but when it is in the play position no voltage is applied The modes in which the amplifier circuit is not muted are Mute L 0416 OFF 0416 0412 ON PLAY R P Switch Play Power mute 0412 OFF PLAY R P Switch Record Power mute i e PLAYBACK mode and RECORD mode x 24 w 330K PLAY MW Power Muta TA ne Fig 2 3 8 Mute Signal Circuit 2 3 7 Control Motor Drive Circuit Refer to Fig 2 3 10 circuit diagram and Fig 2 3 11 timing chart The control motor is turned by varying amounts according to which control button is set This motor is connected to the mechanism control cam and the mechanism is set to the mode indicated by this cam The motor is driven by the differential amplifier 10402 1 2 and drivers Q405 and Q
105. se MPX SW IN Remove the Bias cut Jumper from the dip side of the Main P C B Connect a VTVM to TP101 TP201 on the Main P C B Feed in 5 kHz and adjust the input level so that the VTVM may read 100 mV 0 dB at each Test Point Remove the VTVM from TP101 TP201 and recon nect it to the output side of C154 C254 Decrease the input level 0 dB by 20 dB or 30 dB Check to insure that the level at output side of C154 C254 corresponds to the following with the Dolby NR Switch IN and OUT After completion of the adjustment reconnect the Bias cut Jumper Input Level Copocitor Output Level f 5 kHz Dolby NR OUT Dolby NR IN 20 48 20 dB 16 8 dB 1 5 48 30 30 dB 21 8 48 1 5 48 Mode 1 2 3 4 5 Difference between IN and OUT 3 2 dB 1 5 48 8 2 dB 1 5 48 8 MOUNTING DIAGRAMS AND PARTS LIST Note Mounting diagram shows a dip side view of the printed circuit board 8 1 Volume P C B 55 vROO 50K to Moin P to Moin RC B Fig 8 1 8 2 Control Switch P C B Ass y Pc 4 ee a lee 100 A r oF ESE Main P C B LET 59604 dh 84 Control P C B Ass y 8 5 Auto Shut off P C B Ass y gy ERED TRED
106. ss y 47 9 12 Rear Panel Assy DOT lana n 49 9 13 Reel Motor Ass y 01 iii i 50 9 14 Control Motor Ass y E02 50 9 15 Head Mount Base Ass y 701 50 9 16 Supply Pressure Roller Ass y F02 Hmmm 50 9 17 Take up Pressure Roller Ass y 50 9 18 Head Base Assy C FO4 ie M ER 51 9 19 Cassette Case Holder Ass y 605 51 9 20 Cassette Case Holder Ass y F06 51 9 21 Auto Shut off Ass y FOT sine dia lai aka dec Ede Rated uale da cena ae dus 51 9 22 Pneumatic Damper Ass y F08 51 9 23 P 8L Playback Head 01 51 9 24 R 8L Record Head Ass y 602 meme meme 51 10 Overall Timing Gha cec aiaiai s i iii 53 11 Eq Amp Frequency Response a oak 54 11 1 Playback Frequency Response 1 11 1 eee denas dn knob 54 11 2 Record Current Frequency 54 12 Wiring Diagrami
107. sy 5 9 Tape Travelling Adjustment The adjustment shall be made with a modified version of the current type EXII C 90 as shown in Fig 5 16 error will be made if a current type Tape Travelling Cassette DAO9011A should be used for this purpose While modifying an EXII C 90 the tape guides in the cassette housing shall be kept protected to avoid tilt Check shall be made in the following procedures 1 An EXII C 90 Tape thus modified shall be loaded onto the N 481 2 Release the back tension rotate the Supply Reel and feed out some length of tape and set the N 481 in play mode 3 In this juncture check to insure whether the tape is free from waving or slippage from the tape guide 4 When the modified EXII C 90 is played back check to insure whether the tape is freedom from waving from head surface or at pressure rollers 5 If either of waving or slippage from the tape guide should be noted adjustments of 5 3 Record Head and Playback Head Tilt Adjustment 5 4 Head Base Stroke Adjustment 5 5 Tape Guides Adjustment and Erase Head Stroke Adjustment 5 6 Erase Head Height and Tilt Adjustment 5 7 Playback Head and Record Head Height Adjustment and Azimuth Alignment 5 8 Record Head Stroke Adjustment etc will be required As a case may be the said waving or slippage may have been caused from defective supply Pressure Roller Ass y or Take up Pressure Roller Ass y without paralle
108. t above b and c 2 3 times so that the S and PY marks on the Cam correspond to the pointer accurately in stop and playback modes respectively This adjustment is required because the position adjusted by one volume will be slightly changed when the other volume is adjusted Set the N 481 in FF pause or record mode by pres sing each switch and check to insure that the pointer is in a range of F PS or mark respectively f If out of the range precise adjustment for each position according to 2 Offset Fine Adjustment of Control Motor Driver will be required b c d e 2 Offset Fine Adjustment of Control Motor Driver Adjust only if a satisfactory result is not obtained in 1 Offset Adjustment of Control Motor Driver This adjustment is made by changing the value of the fixed resistors on the Main P C B Note The value of voltage is typical value Pointer Fig 5 1 21 a b d Observation Point of Reference Voltage Observe the each voltage at the sliding contact of the Cam Control Volume VR601 10 kohm in stop fast FF or REW pause record and playback modes Note When Record and Play Switches are pressed to Set N 481 in record mode the Cam is first set to the record position in a short period of time then stays at the play position Therefore to keep the Cam at the record position following procedure is required Short the both leads of capacito
109. the Mounting Gauge Plate 005mm lmm 2 8 Q 3mm 3 05mm Block 8 9 10 11 12 13 14 15 Readjustment of Record Head Mounting Gauge M 9048 DA09048A a Mountthe Block B onto the Mounting Gauge Plate b Loosen the 2 screws fixing the Block A c As shown in the Fig 5 14 hold the Gauges 3 05 mm and either one of 0 05 0 15 0 2 0 25 0 3 or 0 35 mm thickness between the Block A and Block B fix the Block A with screw pushing the Block A to the 2 guide pins Remove the Block B from the Mounting Gauge Plate Mount the R 8L record head assembly onto the Mounting Gauge Plate As shown in the Fig 5 15 loosen the R 8L record head with 2 pcs of screws onto the record head plate As the location of the Block A is secured by the item 8 c push the record head to the directions A and B then tighten 2 pcs of screws Check to insure freedom from gap between the Block C and record head surface then tighten the 2 pcs of screws on the record head plate with lock tight paint Assemble the record head assembly to the head mount base assembly Assemble the head mount base assembly to the mechanism assembly Check the record head stroke If the above are inaccurate items 1 through 15 will have to be repeated till satisfactory results are obtained Block ass Gauge Plate Mounting Gouge Plate Re As
110. tment of step 7 Playback Frequency Response replacement of Playback Head or Record Head or check on item 5 9 Travelling Adjustment will be required Record Playback Tape SW EX SX ZX Eq SW 120 us EX 70 us SX ZX Dolby NR SW OUT MPX SW OUT 400 Hz 0 dB and 20 Hz to 18 kHz 20 48 to INPUT Jacks Overall Frequency Response Main P C B VTVM to OUTPUT Jacks 1104 1 204 the tape with bulk eraser 2 Adjust the input level controls to obtain 0 dB on the level meters and record the signals on the reference SX Record and Playback 1 kHz Band Pass Filter Tape SW SX and VTVM to OUTPUT Eq SW 70 us tape 09025 Jacks Dolby NR SW OUT Turn the cassette tape the other way round and play it MPX SW IN back Measure the difference between 2 and 3 Crosstalk 1 kHz to INPUT Jacks Erase the tape with bulk eraser Adjust L ch ch input level control to obtain 0 dB on the level meter and close R ch L ch input level control Record and play it back then meausre the R ch L ch level Channel Separation 1 kHz to INPUT Jacks Same as above Same as above Erase the tape with bulk eraser Adjust input level controls to obtain 0 dB on the level meters and record the signals on the reference ZX tape DA09037A Rewind the tape closa input level controls and then re cord again Rewind the tape play it back and then m
111. tor 10K ERD 25TJ C138 238 0809246 Mica Capacitor 150P 50V J Q301 302 0B06100A Transistor 250945 A R411 439 0B01682A Carbon Resistor 68K ERD 25TJ F401 0B08275A Fuse T 125mA 250V R116 216 0B05629A Carbon Resistor 2 7K ERD 25T J C139 239 0B09322A PP Capacitor 330P 100V J 303 R412 417 0805627 Carbon Resistor 330K ERD 2 5T J UK Australia amp 220V Class 2 R117 217 01887 Carbon Resistor 5 6K ERD 25T J C153 253 0B09379A Ceramic Capacitor 560P 50 T301 0806613 Osc Coil 429 452 F402 0808698 Fuse T 500mA 250V R118 186 Carbon Resistor 33K ERD 25T J C154 254 0B01389A Electrolytic Capacitor 4 7u 16V R301 302 0BO5668A Carbon Resistor 82K ERD 25T J 455 469 U S A Canada amp Others 218 286 R303 304 0B09212A Fail Safe Type Resistor 2 2 RDF 25S J 480 489 F402 0B08697A T 500mA 250V 8120 124 0B05620A Carbon Resistor 270K ERD 25T J Line Amp R305 0B01682A Carbon Resistor 6 8K ERD 25T J 494 Japan 220 224 R310 0809296 Fail Safe Type Resistor 39 RSF 1 2B J R414 456 0B05508A Carbon Resistor ERD 2 5T J F402 0B08457A Fuse 500 250V R121 221 0B09317A Metal Film Resistor 3 3K 5 14 2 F 0104 105 0B01872A Transistor 286945 L R311 0 0929 Fail Safe Type Resistor 82 RSF 2B J R415 0809328A Metal Film Resistor 9 1K SN14Kx2E F UK Australia amp 220V Class 2 R122 222 0805641 Carbon Resistor 476 ERD 25
112. uency at 21 2 2 3 Bias Oscillation Circuit Fig 2 2 5 shows a push pull oscillator with an oscillation frequency of 105 kHz which is constructed by capacitors C302 and C303 coupling the collectors and bases of two transistors Q301 and Q302 This is used to provide recording bias and as an erase sig nal By pressing the Record and Pause or Record and Play Buttons Play Pause position signal conducted from the Logic P C B Ass y becomes H and Q303 turns to ON Therefore 24 V is applied to the circuit as a result of which oscillation begins When the record mode is released oscillator output is damped by the discharge of C304 This prevents mag netization of the Record Head ri Fig 2 24 Record Eq Amp Circuit kHz or neighborhood L105 C138 and C139 compose a recording bias trap cir cuit 2 Output Amp 5 a gt sS 4 35 TU InY e Sasa 4 52 ee 4 5157 4 nel 35153 188 T i 9 1 Fai ne 8571 5 Epira Te y TE ON 20198 toy PN a Gu a 4 10 O 5 Ex MEME sx k 5 5 1 6 os 253 4 O 82 29 We d 5 AGE Bios Cut Jumper Lai ver vm 703 0 5 1 Lal vM 803
113. y 62 2 x gt Z 9429 n nae TT 1 20 sss 17 sar e ie oo di lex T 344 1 s 15 22y 25 vm 1 sx RECORD f K 2424 f E 1 75AT 5 f 53 2 6 Ex 5 1 2 2 5 2 za LET 85 7 7 254773 2430 ans 5 3 7 cass I soo 847 ger 296345 ner 304 fa 34 942 VF tt 2945 9 2 2 mecs thos 5 jd 22 4 1 82 H 4 dA s 47 25 z K amp 351214 3532 t 55 L ma gt Q i er ET BL 5 5 Shut off Sener 1 4 A e nun bi OM 350 Memor 3 zi gx Q x cao 525 33 Lo 9 i gt 0428 P e IHE Power 9 L E gt LAY Fig 2 3 5 Auto Shut off Circuit 12 b Mode is changed 1 From FF to REW mode or vice versa or from FF to PLAY mode Refer to Fig 2 3 7 timing chart When mode is changed from FF to REW mode or vice versa or from FF to PLAY mode momentary STOP mode is automatically taken in view of the response of the tape deck mechanism and after this is over a new mode is set The following explains in regard to the case when FF mode is changed to PLAY mode by pressing Play Button during FF mode During FF

Nakamichi -- 481 -

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