Dokorder-7700-tape-sm1维修电路图 手册.pdf
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1、DOKORDER rnoder 77OO SERVICE MANUAL sM, 1004-00 1977.3 sEcroN 1 TECHNICAL DESCRIPTION AND ADJUSTMENT PROCEDURES D bokorder, 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, JAPAN RadioFans.CN TABLE OF CONTENTS 1. GEN
2、ERAL DESCRIPTION 1 1 1 Amplifier Circuitry g 1-2 Tape Transport Mechanism 1-3 Power Supply Circuitry 2. SERVICE DATA 2 21 Mechanical 2-2 Electrical 3. PARTS LOCATION . 3-4 3-1 Outer Parts 3-2 lnner Parts 4. REMOVAL OF OUTER PARTS 5 r 4-1 Front Panel 4-2 Amp Panel 4-3 Top and Bottom Boards ./ 5. ADJU
3、STMENT -MECHANTCAL- . . 6-11 5-1 Auto Shut-off Switch 5-2 Pinch Roller Drive Mechanism 5-3 Reel Motor Torques 5-4 Brake Mechanism 5-5 Tape Speed 5-6 Wow/Flutter g 6. ADJUSTMENT -ELECTRTCAL- .12-20 6-1 Adjustable Parts Location 6-2 Adjustment Procedures 7. MAINTENANCE . 21 7 -1 Cleaning 7-2 Lubricati
4、on 7 3 Demagnetizing y) B. TECHNICAL DESCRIPTION .22-31 8-1 Solenoid Drive Circuit 8-2 Capstan Drive Circuit 9. SCHEMATIC DIAG RAM Note This Service Manual consists of three sections: Section 1: Descriptions of circuitry, operating procedures, and methods of adjustments and maintenance, plus technic
5、al data. Section 2: Exploded views, and parts list. Section 3: Patterns, schematics and parts lists for printed Circuit boards. v RadioFans.CN v v v v 1. GENERAL DESCRIPTION The Dokorder Model 7700 is a -track,2-channel,2-speed tape deck equipped with 3-motor, 3-heacl and sole- noid operation facili
6、ty. Designed for high dependability and electrical performance. Their features: 1.1 AMPLIFIER CIRCUITRY 1. 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
7、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 and the position of the switch is illustrated below. 1-2 TAPE TRANSPORT MECHANISM 1. The convenience features of the 7700s tape transport such as the a
8、ll-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 relea
9、ses the locked operating control (s) to place the deck in the stop mode. 3. High dependability is proven by using newly improved electronic solenoid control system that reduces the powerconsumption and heat up in the solenoid and its control transistors. 4. Especially high speecl-accuracy and surpri
10、sing wow/fluttel characteristics are realized by using most advanced PLL (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 CIRCUITRY 1. The primary winding of the power transformer is provide
11、d two taps 100 V and 54 V. The former is used for the reel motor drive in the fast winding mode. while the latter is used for the reel motor drive in the rec/play mode. 2. On the secondary side, the transformer also offers two windinqs for 5.6 V and 14 V x 2. The former is used for illuminating the
12、pilot lamps, while the latter is rectified and then used to power the amplifiers, solenoid, PLL circuit and capstan motor. Equalizer Switch Type of Tape Normal (button out) Scotch #212 or equivalents Special (button in) Maxell #UD-35 or equivalents v RadioFans.CN 2. SERVICE DATA 2-1 MECHANICAL Recor
13、d/Playback System 4 track 2 channel stereophonic Tape Width Standard 1/4 inch tape Reel Size 7-inch or smaller Motor Three (one 2 speed PLL DC servomotor for capstan, two 6 pole induction outer-rotor type for reels) Head Three (1 erase, 1 rbcord, 1 playback) Tape Speed !1 .5o/oat 19 cm/sec (7-1 l2ip
14、sl ,!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
15、(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 lbs Dimension 17-314 (H) X 16-718 (W) X 6 3/4 (D) 2-2 ELECTRICAL al v Y/ V Equalization Bias Frequency Frequency Response (Playback ) Frequency Response (Overa ll ) One-channel Recording Signal
16、 to Noise Ratio Crosstalk Channel Separation Bias Leakage Erase Eficiency Distortion (Overall) Meter Calibration lnput Mic L ine DIN Output Line DIN Circuit Complement Power Consumption Power Requirement Headphone 2mW 8Q NAB 130 KHz +1 KHz .19 cm/sec (7 l12ipsl 50 - 100 Hz l! oa, 1o1 Hz - 1 5 KHz 13
17、 dB o 9.5 cm/sec (3 3/4 ips) 50 Hz - 7.5 KHz 13 dB o 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
18、 KHz 13 dB (35 - 100 Hz, 7.5 - 12 KHz 15 dB) TOOHzll dB, 15 KHz+5dB at 19 cm/sec (71 /2ipsl 500 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 level Better than 46 dB (Overall) at 0 dB output level Better than 50 dB at 1 KHz Better than 40 dB at 1 KHz L
19、ess than -25 dB Better than 65 dB at 1 KHz Less than 3% at 1 KHz 0 dB output level 0 dB at IOOHz 0 dB output level (P.8. VR-Max) -58 dB 10 KO (load imPedance) -20 dB 220 K9 30 mV 80 KQ OdB 47KQ 260 mV 47 KS) 34 transistors, 29 diodes, 5 lC,2 FET ,2 LED, 1 PUT 75W U.S.A. type 117 V (60 Hz) Universal
20、type 100 V,117V,125V,20OV,220V,24O V (50/60 Hz) Specs are subject to change withor-rt notice. v RadioFans.CN 3. PARTS LOCATION 3-1 OUTER PARTS v v v Front View 20 Push Button, Metal, EO, Speed, Monitor, Pause SW 21 Push Button, Red, Rec. SW (556-0009-00) 22 Operate Button, Rec. (556-0038-80) 23 Ope.
21、 Button, FF then remove the panel itself by moving it as the arrow in the illustration shows. NOTE: When mounting the front panel, reverse the steps described above. Take note that cup washer should be fitted on the two screws securing the bottom part of the front panel. Also, note that conduc- tive
22、 rubber washer shoutO be f itted on the screw securing the right side of thefront panel. This is for grounding the front panel. v 4-2 AMP PANEL 1. 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 meter
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