Dokorder-7700-tape-sm维修电路原理图.pdf

DOKORDERrnoder 77OOSERVICE MANUALsM, 1004-001977.3sEcroN 1TECHNICAL DESCRIPTION AND ADJUSTMENTPROCEDURESDbokorder, lnc.5430 ROSECRANS AVENUE, I-WNDALE, CALIF. 90260 U.S.A.r-rE Kr )JK-YO CO., r-trE).26.1 1, 3-CHON4E, NISHI-ROKUGO, OTA-KU, TOKYO, JAPANRadioFans.CN 收音机爱 好者资料库TABLE OF CONTENTS1. GENERAL DESCRIPTION 11 1 Amplifier Circuitry g1-2 Tape Transport Mechanism1-3 Power Supply Circuitry2. SERVICE DATA 221 Mechanical2-2 Electrical3. PARTS LOCATION . 3-43-1 Outer Parts3-2 lnner Parts4. REMOVAL OF OUTER PARTS 5 r4-1 Front Panel4-2 Amp Panel4-3 Top and Bottom Boards ./5. ADJUSTMENT -MECHANTCAL- . . 6-115-1 Auto Shut-off Switch5-2 Pinch Roller Drive Mechanism5-3 Reel Motor Torques5-4 Brake Mechanism5-5 Tape Speed5-6 Wow/Flutter g6. ADJUSTMENT -ELECTRTCAL- .12-206-1 Adjustable Parts Location6-2 Adjustment Procedures7. MAINTENANCE . 217 -1 Cleaning7-2 Lubrication7 3 Demagnetizing y)B. TECHNICAL DESCRIPTION .22-318-1 Solenoid Drive Circuit8-2 Capstan Drive Circuit9. SCHEMATIC DIAG RAMNoteThis Service Manual consists of three sections:Section 1: Descriptions of circuitry, operating procedures, and methods of adjustmentsand maintenance, plus technical data.Section 2: Exploded views, and parts list.Section 3: Patterns, schematics and parts lists for printed Circuit boards.vRadioFans.CN 收音机爱 好者资料库vvvv1. GENERAL DESCRIPTIONThe Dokorder Model 7700 is a -track,2-channel,2-speed tape deck equipped with 3-motor, 3-heacl and sole-noid operation facility. Designed for high dependability and electrical performance. Their features:1.1 AMPLIFIER CIRCUITRY1. The convenience features of the 7700s amplifier circuit such as the Monitor Switch. Mic AMp Circuit, Head-phone AMP Circuit and Level Meter AMP Circuit built in.2. 4-separate controls permit subtle input/output level adjustments.3 2-stepped Equalizer Switch is equipped to use for the several type of tapes. The relation between the tapes andthe position of the switch is illustrated below.1-2 TAPE TRANSPORT MECHANISM1. The convenience features of the 7700s tape transport such as the all-electronic operation buttons, pause con-trol, tape travel counter are positive, and the mechanisms themselves are rugged and dependable.2. fhe tape transport offers an Auto Stop convenience, and when the tape reaches its end in any mode (fast for-ward, rewind, play or record). a solenoid releases the locked operating control (s) to place the deck in the stopmode.3. High dependability is proven by using newly improved electronic solenoid control system that reduces thepowerconsumption and heat up in the solenoid and its control transistors.4. Especially high speecl-accuracy and surprising wow/fluttel characteristics are realized by using most advancedPLL (Phase-Locked Loop) Servo System in capstan motor drive.5. Newly designed high-torque outer-rotor eddy-current motor is used for reel drive.1-3 POWER SUPPLY CIRCUITRY1. The primary winding of the power transformer is provided two taps 100 V and 54 V. The former is used forthe reel motor drive in the fast winding mode. while the latter is used for the reel motor drive in the rec/playmode.2. On the secondary side, the transformer also offers two windinqs for 5.6 V and 14 V x 2. The former is used forilluminating the pilot lamps, while the latter is rectified and then used to power the amplifiers, solenoid, PLLcircuit and capstan motor.Equalizer SwitchType of TapeNormal (button out)Scotch #212 or equivalentsSpecial (button in)Maxell #UD-35 or equivalentsv2. SERVICE DATA2-1 MECHANICALRecord/Playback System 4 track 2 channel stereophonicTape Width Standard 1/4 inch tapeReel Size 7-inch or smallerMotor Three (one 2 speed PLL DC servomotor for capstan, two 6 pole inductionouter-rotor type for reels)Head Three (1 erase, 1 rbcord, 1 playback)Tape Speed !1 .5o/oat 19 cm/sec (7-1 l2ipsl ,!1 .5%at 9.5 cm/sec (3 3/4 ips)Wow and Flutter Playback (RMS)0.13o/oat 19 cm/sec (7 112ipsl ,0.20% at 9.5 cm/sec (3-3/4 ips)Fast Winding Time 100 sec for 7-inch reel (1800-foot tape, 60 Hz)Motor Torque Hold-back tention (playback) 85 gr 110 gr (255 t30 g.cm)Take-up torque (playback) 150 gr (450 g.cm)FFlREW hold-back tention 30 gr ( 90 g.cm)Brake Torque 600 - 800 gr (1.8 - 2.4 kg.cm)weight 35 lbsDimension 17-314 (H) X 16-718 (W) X 6 3/4 (D)2-2 ELECTRICALalvY/VEqualizationBias FrequencyFrequency Response(Playback )Frequency Response(Overa ll )One-channel RecordingSignal to Noise RatioCrosstalkChannel SeparationBias LeakageErase EficiencyDistortion (Overall)Meter Calibrationlnput MicL ineDINOutput LineDINCircuit ComplementPower ConsumptionPower RequirementHeadphone 2mW 8QNAB130 KHz +1 KHz.19 cm/sec (7 l12ipsl50 - 100 Hz l! oa, 1o1 Hz - 1 5 KHz 13 dBo 9.5 cm/sec (3 3/4 ips)50 Hz - 7.5 KHz 13 dBo 1 9 cm/sec (1-1 12 ips)Normal 30 Hz - 20 KHz t3 dB (30 - 100 Hz, 15 - 20 KHz t5 dB)Special 30 Hz - 20 KHz 13 dB (50 - 100 Hz, 15 - 20 KHz t5 dB)o 9.5 cm/sec (3-3/4 ips)Normal 35 Hz- 12KHz t3dB (35 -1 00 Hz, 1.5- 12 KHz15 dB)Special 35 Hz - 12 KHz 13 dB (35 - 100 Hz, 7.5 - 12 KHz 15 dB)TOOHzll dB, 15 KHz+5dB at 19 cm/sec (71 /2ipsl500 Hz 11 dB, 7.5 KHz +5 dB at 9.5 cm/sec (3-314 ips)Better than 50 dB (Playback) at 0 dB output levelBetter than 46 dB (Overall) at 0 dB output levelBetter than 50 dB at 1 KHzBetter than 40 dB at 1 KHzLess than -25 dBBetter than 65 dB at 1 KHzLess than 3% at 1 KHz 0 dB output level0 dB at IOOHz 0 dB output level (P.8. VR-Max)-58 dB 10 KO (load imPedance)-20 dB 220 K930 mV 80 KQOdB 47KQ260 mV 47 KS)34 transistors, 29 diodes, 5 lC,2 FET ,2 LED, 1 PUT75WU.S.A. type 117 V (60 Hz)Universal type 100 V,117V,125V,20OV,220V,24O V (50/60 Hz)Specs are subject to change withor-rt notice.v3. PARTS LOCATION3-1 OUTER PARTSvvvFront View20 Push Button, Metal, EO, Speed, Monitor, Pause SW21 Push Button, Red, Rec. SW (556-0009-00)22 Operate Button, Rec. (556-0038-80)23 Ope. Button, FF & REW (556-0037-80)24 Ope. Button, Stop (556-0035-80)25 Ope. Button, Plav (556-0036-80)26 Level Meter (141-1004-00)Back View1 Panel Assy, Deck (880-0017-00)2 Panel Assy, Amp (880-0018-00)3 Side Board 551-0018-02)4 Top Board (551-0013-90)5 Bottorn Board (551-0010-00)6 Foot Assy (880-0019-00)7 Head Cover 880-0016-00)8 Counter (143-31 02-00)9 Turn Table Assy (810-001 1-00)1O Dressing Washer, Pinch Roller (555-0050-02)11 Pinch Roller (523-0029-00)12 Tape Guide(L), Tension Arm (558-0020-00)13 Tape Guide(R), Tension Arm (558-0021-00)14 Switch, Push, Power (131-1018-80) or (131-1019-80)15 Switch. Push, EO. Select (131-1014-00)16 Switch, Push,2-station Speed & Monitor (131-10i5-00)17 Switch, Push, 2-station, Rec. (131-1017-00)18 Switch, Push, Pause 131-1016-00)19 Push Button, Metal, Power SW (556-0030-02)(556-0013-83)fiililfi1tiilltill27 Control Knob, Metal (556-0001-00)28 Jack. Mic (135-5001-00)29 Jack, Headphone 135-5002-00)30 Cup Washer (532-0021-00)60 Back Board (551-0019-03) or (551-0020-00)61 AC Cord with Plug (162-1001-00)62 Holder, F use 1135-7001-00)Fuse, 1.5 A (138-1003-00)63 Jack, 4-Pin (1 35-5008-00)64 Terminal, GND (135-1001-00)65 Socket, DIN (136-6003-00)ar3.2 INNER PARTSaFront View31 Solenoid, Brake, DC-24V 48 ohm (1 1 6-2002-00)32 Linkage, Brake (525-0025-00)33 Stopper, Brake Linkage (528-0008-00)34 Linkage, Brake Solenoid (525-0027-00)35 Bracket, Brake (533-0082-00)36 Guide, Brake Linkage (528-0009-00)37 Spring, Brake (541-0007-05)38 Solenoid, Pinch Roller Pressure, DC-24V 15 ohm(1 1 6-2003-00)39 Spring, Pressure (541-0010-01 )40 Arm, Pinch Roller Drive (525-0029-00)41 Arm, Pinch Roller (525-0032-00)42 Shaft, Pinch Roller (521-0025-05)43 Arm, Auto Shut-Off (525-OO24-O444 Switch, Micro, Auto Shut-Of f (131-3001-00)45 Bearing, Capstan 1522-OO1O-O2)46 Dressing Plate, Tape Lifter (521-0029-00)4-l Head Base Assy (830-001 1-00)48 PC Board Assy (PCM-365A), Head Connect (831-0004-00)49 Tension Arm Assy (Left) 1840-0016-00)50 Tension Arm Assy (Right) (840-0018-00)51 Pulley, Motor, No.3 (523-0031-04)52 Belt, Capstan Drive 1524-OoO7-O2l53 Belt, Counter Drive (524-0006-00)54 PC Board Assy (PCM-3978), Rec. & Pause (8210020 00)55 PC Board Assy (PCM-3954), LED (821-0019-00)56 Switch Assy, Operate (820-0016-00)57 Chassis(A), Amp. (512-001 1-83)66 Power Transformer (1 1 1-1021-00)67 Resistor, Wirewound, 1200 ohm 20W 3O2-122O-8O)Resistor, Wirewound, 600 ohm 15 W 302-6018-90)68 Resistor, Wirewound, 200 ohm 10 W 302-2018-90)Resistor, Wirewound, 150 ohm 10 W (302-1518-90)69 Motor, Reel (113-1002-00)70 Motor, Capstan (114-5001-00)71 PC Board Assy (PCM-4118), Capstan Motor (861-0003-00)72 PC Board Assy (PCM-361C), Capacitor, Reel Motor(161-1034-00 )73 PC Board Assy (PCM-417C), Control (851-0008-00)74 PC Board Assy (PCM-4138), Bias OSC (851-0009-00)75 Arm, Flywheel Support (533-0020-02)76 Flywheel 523-0030-01 )77 PC Board Assy (PCM416E), Operate SW (821-0021-O0)78 PC Board Assy (PCM4464), Amp. 1871-0012-00)79 Chassis(A), Power Supply (533-004801)Chassis (B), Power Supply (533-0049-00)80 Chassis(B), Amp. (512-00l 2-00)2-u?*-*2,4. REMO/AL OF OUTER PARTSYUv4.1 FRONT P1. Referring to Fig. 4-1. withdraw head cover Oand remove head cover posts by turning themcounterclockwise with pliers or box driver.2. Holding pinch roller stitl, turn counterclock-wise screw securing pinch roller dressingwasher and withdraw the screw together withthe dressing washer. Then extract nylon washer anO the pinch roller from the pinch rollers h aft.NOTE: When extracting the pinch roller, takecare not to lose the nYlon washer.3. Remove four screws anA securing thefront panel by turning them counterclockwise;then remove the panel itself by moving it as thearrow in the illustration shows.NOTE: When mounting the front panel, reversethe steps described above. Take note thatcup washer should be fitted on thetwo screws securing the bottom part ofthe front panel. Also, note that conduc-tive rubber washer shoutO be f ittedon the screw securing the right side of thefront panel. This is for grounding the front panel.v4-2 AMP PANEL1. Withdraw control knobs-RECORD LEVEL CONTROLS and PLAYBACK LEVEL CONTROLS.2. Remove the two screws (BS-3 X 6) above and (BS-3 X 18) below the level meters by turning them counter-clockwise. Then, remove the four screws (BS-4 X 15) that secure the amp panel.NOTE: Take care not to lose the nylon washer whenremoving the two screws above and below the levelmeters.3. When mounting the amp panel, reverse the steps described aboveNOTE: Fit and tighten the screws only after checking to see that the record indicator LEDs are correctlyfitted in the holes on the amp panel and that the level meters are also fitted correctly in the amppanel holes. Take note that the conductive rubber washer should be fitted on the screw that securesthe upper right side of the amp panel (see 4-1. 3 above)4.3 TOP AND BOTTOM BOARDS1. Remove the six black-painted screws (RS-3 X 6) that secure the top board.2. To remove the botrom board, remove the four screws RS-3 X i4) securing the two FOOT ASSYS by turningthem counterclockwise. Then remove the FOOT ASSYS themselves3. With the FOOT ASS,YS dismounted, remove the screw (RS-3 X 8) securing the bottom board at its center byturning it counterclockwise, then remove the bottom board itself4. When mounting the top and bottom boards, take care not to confuse the screws securing the top board withthose securing the bottom board; they are different in size and finish.(e)aIF-aFig.4-1v3-2 INNER PARTS*T*-vFront ViewBack Viewffiir:t:rj:. : :- -:;. :. .:.:ii.:l:;.=?:31 Solenoid, Brake, DC-24V 48 ohm (1 1 6-2002-00)32 Linkage, Brake (525-0025-00)33 Stopper, Brake Linkage (528-0008-00)34 Linkage, Brake Solenoid (525-0027-00)35 Bracket, Brake (533-0082-00)36 Guide, Brake Linkage (528-0009-00)37 Spring, Brake (541-0007-05)38 Solenoid, Pinch Roller Pressure, DC-24V 15 ohm(1 1 6-2003-00)39 Spring, Pressure (541-0010-01 )40 Arm, Pinch Roller Drive (525-0029-00)41 Arm, Pinch Roller (525-0032-00)42 ShaIt, Pinch Roller (521-0025-05)43 Arm, Auto Shut-Off 825-OO24-O4)44 Switch, Micro, Auto Shut-Off (131-3001-00)45 Bearing, Capstan 522-OO1O-O2)46 Dressing Plate, Tape Lifter (521-0029-00)4-l Head Base AssY (830-001 1-00)48 PC Board Assy (PCM-365A), Head Connect (831-0004-00)49 Tension Arm Assv (Left) (840-0016-00)50 Tension Arm Assy (Right) (840 001800)51 Pulley, Motor, No.3 (523-0031-04)52 Belt, Capstan Drive 1524-OOO7-O2)53 Belt, Counter Drive 524-0006-00)54 PC Board Assy (PCM-3978), Rec. & Pause (821-0020-00)55 PC Board Assv PCM-395,4), LED (821-00i9-00)56 Switch Assy, Operate 820-0016-00)57 Chassis(A). Amp. (512-0011-83)66 Power Transformer (1 1 1-102 1-00)67 Resistor. Wirewound, 1200 ohm 20 W 3O2-122O-8OIResistor, Wirewound, 600 ohm 15 W (302-6018-90)68 Resistor, Wlrewound, 200 ohm 10 W (302-2018-90)Resistor. Wirewound, 150 ohm 10 W (302-1518-90)69 Motor, Reel 1 1 3-1 002-00)70 Motor, CaPstan (1 14-500100)71 PC Board Assy (PCM-4118), Capstan Motor (861-0003-00)72 PC Board Assy (PCM-361C), Capacitor, Reel Motor(161-1034-00)73 PC Board Assy (PCM417C), Control 851-0008-00)74 PC Board Assv PCM-4138), Bias OSC (851-0009-00)75 Arm, Flywheel Support (533-0020-02)76 Flywheel (523-0030-0 i )77 PC Boarcl Assy (PCM-416E), Operate SW (821-0021-00)78 PC Board Assv (PCM-446Ai, Amp 871-0012-00)79 Chassis(A), Power Supplv (533-0048-01)Chassis (B), Power Supplv (533-0049-00)8o chassis (B), AmP. (512-0012-oo)v?.-u,Q9(B) I*-lre1Iu-v-5. ADJUSTMENT -MEGHANICAL-5.1 AUTO SHUT.OFF SWITCHa. SpecificationWhen the auto shut-off urrn is pushed upward,the microswitch clicks lswitches on) at thepoint of more than 8 mm (0.32 inch) outside ofthe tape travel position and clicks again (switchesoff) at the point of more than 14 mm (0.56 inch)outside of the tape travel position.b. AdjustmentAdjust the mounting position of the microswitchc. ReferenceRefer to Fig.5 1 or section 2 on page M-12.d. Special Tools and/or lnstruments requiredN onee. PreparationRemove the head cover and front panel.f. Procedure(1) Check the on/off position of the microswitch by gently moving the auto shut-off arm by hand.(2) lf the on/off position does not meet the spec, adjust the position of the microswitch by loosening twomount screws .g. Note(1) Replace the dismounted parts and check again that the auto shut-off arm moves freely through the holein the front panel and does not come into contact with head cover.(2) Load the tape and set the deck in play mode and check if the tape travels normally. Then take up the tapecompletely by setting the deck in FF or REW mode, checking that the auto shut-off arm returns to shutoff the tape travel automatically at the tape end.5.2 PINCH ROLLER DRIVE MECHANISM2.1 STROKE ADJUSTN/IENT OF THE PINCH ROLLER PRESSURE SOLENOIDa. SpecificationStroke of plunger 4 - 4.5 mm (0.16 - 0.18 inch).b. AdjustmentAdjust the stroke adjusting nut .c. ReferenceRefer to Fig.5-2 or section 2 on page M-20.d. Special Tools and/or lnstruments requiredA open end wrench (4 mm).e. PreparationRemove the front panel (including pinch roller andhead cover).Fix the auto shut-off arm ON by a piece ofsticking tape.f. Procedure(1) Push the play and stop buttons alternately several times, m