JVC-TDW271-tape-sm维修电路原理图.pdf

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1、SERVICE MANUAL COPYRIGHT 2003 VICTOR COMPANY OF JAPAN, LIMITED No.MB061 2004/1 DOUBLE CASSETTE DECK MB061200312 TD-W271 TABLE OF CONTENTS 1PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 2

2、SPECIFIC SERVICE INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4 3DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

3、4ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13 5TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4、. . . 1-19 5 46 37 28 19 MINMAX INPUT LEVEL COUNTER RESETCOUNTER RESET STANDBY STANDBY/ON ON OFF PLAY PHONES POWER REVERSE MODE DOUBLE CASSETTE DECK REC / REC MUTE PAUSE A B SYNCHRO DUBBING DOLBY B-C NR HX PRO PLAY REC/PLAYBACK B AUTO REVERSE 3MOTOR SILENT MECHANISM AUTO REVERSE 3MOTOR SILENT MECHAN

5、ISMPLAYBACK A DOLBY NR B OFF C AUTO TAPE SELECTOR / CONTINUOUS PLAY NORM SPEEDHIGH SPEED UF - China U - Other Areas Area Suffix RadioFans.CN 收音机爱 好者资料库 1-2 (No.MB061) SPECIFICATION Design and specifications are subject to change without notice. TypeDouble cassette deck Track system4-track, 2-channel

6、 Tape speed4.8 cm/sec (1-7/8 inch/sec) (Normal) 9.5 cm/sec (3-3/4 inch/sec) (High) Frequency response (-20 dB recording) Type IV tape20-17000Hz 30-16000 Hz (3dB) Type II tape20-16000 Hz 30-15000 Hz (3dB) Type I tape20-16000 Hz 30-15000 Hz (3dB) S/N ratio58 dB (S = 315 Hz, k3 = 3%, N = A-weighted, Ty

7、pe IV tape) The S/N is improved by about 15 dB at 500 Hz and by max. 20 dB at 1kHz 10 kHz with Dolby C NR on and improved by 5 dB at 1 kHz and by 10 dB at above 5 k Hz with DOLBY B BR on. Improvement of MOL4 dB at 10 kHz with Dolby C NR on. Wow and flutter0.08% (WRMS), 0.2% (DIN/IEC) Channel separat

8、ion10 dB (1 kHz) Crosstalk60 dB (1 kHz) Harmonic distortionk3; 0.8% (Type IV tape, 315 Hz, 0 VU) HeadsDeck AMETAPARM head for playback 1 Deck BMETAPARM head for recording/playback, 2-gap ferrite head for erasure; combination head 1 MotorsElectric govemed DC motor for capstan 1 DC motor for reel 1 DC

9、 motor for mechanism drive 1 (For both decks A and B) Fast forward/rewind timeApprox. 110 sec. with C-60 cassette Input terminalsLINE IN ( 1 circuit)Input sensitivity80 mV (0 VU) Input impeadance50 k Output terminalsLINE OUT ( 1 circuit) Output level300 mV (0 VU) Output impeadance5 k PHONES 1Output

10、level0.3 mW/8 (0 VU) Matching impedance8 - 1 k Other terminalsCOMPU LINK-3/SYNCRO 2 Power requirementAC 220 V, 50 Hz Power consumptionWith power on 17 W With power standby 4.0 W Dimensions435 139 331 mm Mass5.0 kg RadioFans.CN 收音机爱 好者资料库 (No.MB061)1-3 SECTION 1 PRECAUTION 1.1Safety Precautions (1) T

11、his design of this product contains special hardware and many circuits and components specially for safety purpos- es. For continued protection, no changes should be made to the original design unless authorized in writing by the manufacturer. Replacement parts must be identical to those used in the

12、 original circuits. Services should be per- formed by qualified personnel only. (2) Alterations of the design or circuitry of the product should not be made. Any design alterations of the product should not be made. Any design alterations or additions will void the manufacturers warranty and will fu

13、rther relieve the manufacture of responsibility for personal injury or property damage resulting therefrom. (3) Many electrical and mechanical parts in the products have special safety-related characteristics. These characteris- tics are often not evident from visual inspection nor can the protectio

14、n afforded by them necessarily be obtained by us- ing replacement components rated for higher voltage, watt- age, etc. Replacement parts which have these special safety characteristics are identified in the Parts List of Ser- vice Manual. Electrical components having such features are identified by

15、shading on the schematics and by ( ) on the Parts List in the Service Manual. The use of a substitute replacement which does not have the same safety charac- teristics as the recommended replacement parts shown in the Parts List of Service Manual may create shock, fire, or other hazards. (4) The lea

16、ds in the products are routed and dressed with ties, clamps, tubings, barriers and the like to be separated from live parts, high temperature parts, moving parts and/or sharp edges for the prevention of electric shock and fire hazard. When service is required, the original lead routing and dress sho

17、uld be observed, and it should be confirmed that they have been returned to normal, after reassem- bling. (5) Leakage shock hazard testing After reassembling the product, always perform an isola- tion check on the exposed metal parts of the product (an- tenna terminals, knobs, metal cabinet, screw h

18、eads, headphone jack, control shafts, etc.) to be sure the product is safe to operate without danger of electrical shock.Do not use a line isolation transformer during this check. Plug the AC line cord directly into the AC outlet. Using a Leakage Current Tester, measure the leakage current from each

19、 exposed metal parts of the cabinet, particular- ly any exposed metal part having a return path to the chassis, to a known good earth ground. Any leakage cur- rent must not exceed 0.5mA AC (r.m.s.). Alternate check method Plug the AC line cord directly into the AC outlet. Use an AC voltmeter having,

20、 1,000 per volt or more sensitivity in the following manner. Connect a 1,500 10W resistor paralleled by a 0.15F AC-type capacitor between an ex- posed metal part and a known good earth ground. Measure the AC voltage across the resistor with the AC voltmeter. Move the resistor connection to each expo

21、sed metal part, particularly any exposed metal part having a return path to the chassis, and measure the AC voltage across the resistor. Now, reverse the plug in the AC outlet and repeat each measurement. Voltage measured any must not exceed 0.75 V AC (r.m.s.). This corresponds to 0.5 mA AC (r.m.s.)

22、. 1.2Warning (1) This equipment has been designed and manufactured to meet international safety standards. (2) It is the legal responsibility of the repairer to ensure that these safety standards are maintained. (3) Repairs must be made in accordance with the relevant safety standards. (4) It is ess

23、ential that safety critical components are replaced by approved parts. (5) If mains voltage selector is provided, check setting for local voltage. 1.3Caution Burrs formed during molding may be left over on some parts of the chassis. Therefore, pay attention to such burrs in the case of pre- forming

24、repair of this system. 1.4Critical parts for safety In regard with component parts appearing on the silk-screen printed side (parts side) of the PWB diagrams, the parts that are printed over with black such as the resistor ( ), diode ( ) and ICP ( ) or identified by the mark nearby are critical for

25、safety. When replacing them, be sure to use the parts of the same type and rating as specified by the manufacturer. (This regulation dose not Except the J and C version) Good earth ground Place this probe on each exposed metal part. AC VOLTMETER (Having 1000 ohms/volts, or more sensitivity) 1500 10W

26、 0.15 F AC TYPE 1-4 (No.MB061) SECTION 2 SPECIFIC SERVICE INSTRUCTIONS This service manual does not describe SPECIFIC SERVICE INSTRUCTIONS. (No.MB061)1-5 SECTION 3 DISASSEMBLY 3.1Enclosure section 3.1.1Removing the top cover (See Fig.1) (1) Remove four screws A retaining the top cover from both side

27、. (2) Remove two screws B retaining the top cover from the back side. (3) To remove the top cover, slide in direction of arrow and lift away (refer to Fig.1). Fig.1 3.1.2Removing the front panel assembly (See Fig.2, 3) (1) Remove the top cover as described in above. (2) Remove the three screws C ret

28、aining the front panel as- sembly from bottom side. (3) Release the front panel assembly from two pawls in the front and bottom sides and draw it to the front side. (4) Disconnect all connectors between the mechanism assem- bly, front panel assembly and main board. Fig.2 Fig.3 A A B M B Top cover C

29、Pawl CC Pawl Front panel assembly Pull 2 Pull 2 Push 1 Push up with a screwdriver, etc. 1 1-6 (No.MB061) 3.1.3Removing the mechanism assembly Although the mechanism assembly can be removed without detaching the front panel assembly, it is recommended to de- tach the front panel assembly to do the wo

30、rk with ease. (1) Remove the two screws D or two screws E from the cor- ners of the mechanism. (Fig.6) (2) Open the door and remove the mechanism assembly. (At this time, door lock arm spring and door lock arm are re- moved together with.) (3) For moving the mechanism assembly only, disconnect the f

31、ollowing wirings. a) Mechanism assembly side (Fig.5) Top side connector of the cam switch board (CN2). Connector of the motor board (CN1). (Board to board connector) b) Main board side (Fig.4) Disconnects CN802 from mecha control board, CN801 from switch/volume board and CN861 from headphone jack bo

32、ard. Disconnect wire coming from the head mount assem- bly CN811 at deck A and CN815 at deck B. Remove one screw F and remove one GND wire from mechanism control board. 3.1.4Removing the eject arm assembly (Fig.6) (1) Remove the screws G retaining the eject arm assembly and pull it out. Fig.4 Fig.5

33、Fig.6 Main board Mechanism control board CN811 CN861 CN801 CN802 CN815 From DECK A From DECK B DECK A From Mechanism control board From Headphone jack board From Switch/ Volume board L DECK B F Motor board Motor board Motor board Motor board Mechanism control board Mechanism control board Mechanism

34、control board Cam switch board Cam switch board DECK BDECK A Cam switch board Cam switch board DECK BDECK A DDGGEE (No.MB061)1-7 3.1.5Removing the mechanism holder and door assembly (Fig.7, 8) (1) Remove four screws H retaining the mechanism holder. (2) Remove the damper assembly (for easy reassembl

35、ing work). Insert an originary (-) screwdriver or the like in to the gap between the damper and the front panel to disengage the pawl, and draw the damper assembly outwards. (See Fig.7) (3) Remove the arm shaft of the cassette holder (door assem- bly) from the mechanism holder. (The door spring is e

36、n- gaged with the door side by the longer side.) (See Fig.8) (4) Remove the eject spring from lock lever and mechanism assembly. (See Fig.8) Fig.7 Fig.8 Pawl How to remove damper Cassette door Longer side Shorter side Mechanism assembly door spring eject spring Lock lever How to engage the door and

37、eject spring 1-8 (No.MB061) 3.1.6Removing the switch 3000 15 Hz High speed: Deck A,B ; 6000 30 Hz Deck A : Normal ; VR701 High ; VR702 Deck B : Normal ; VR703 High ; VR704 1. 2. Checking wow and flutter Test tape : VT712 (3 kHz) Connect a wow and flutter meter to the LINE OUT terminals. Play back th

38、e VT712 test tape. Check to see if the reading of the meter is within 0.17 % (WRMS). 1. 2. 3. Less than 0.17 % (WRMS) Checking play back torque Torque gauge : TW2111 (FWD) TW2121 (REV) Employ a torque testing cassette tape (TW2111FWD / TW2121REV) for the checking, or remove the cassette cover and us

39、e a torque gauge. 27 - 70 g cm Checking back tension Torque gauge : TW2111 (FWD) TW2121 (REV) Employ a torque testing cassette tape (TW2111FWD / TW2121REV) for the checking, play the torque gauge and read the back tension value to confirm that the back tension is 1 - 5 g cm. 1 - 5 g cm Checking FF/R

40、EW time Tape : AC-225Play back AC-225 tape in FF/REW mode, check that the FF/REW time during tape running from begin to end. Less than 120 sec REV Adj. FWD Deck B REV Adj. FWD Deck A (No.MB061)1-15 4.5Electrical adjustment procedure Play back level adjustment Test tape : VT727 (400 Hz) Play back VT7

41、27 in FWD mode, then confirm that the level at LINE OUT is -4.5 dBs 0.5 dB. Adjust VR112/VR212 and VR117/VR217 so that LINE OUT level becomes -4.5 dBs. Difference level between Lch and Rch must less than 0.5 dB at LINE OUT. Confirm that difference playback level between FWD and REV modes within 1.5

42、dB. LINE OUT -4.5 dBs 0.5 dB Phone Out -21 dB +2.5 dB -1.5 dB Deck B L : VR117 R : VR217 Deck A L : VR112 R : VR212 Check and Adjustment Checking DOLBY circuit (Rec. mode) (BIAS-CUT) Signal input: LINE IN Cal. level : 400 Hz, -8 dBs Output terminal TP : NR IC831 53 and 8 pin. DOLBY B (Rec) 1 Input s

43、ignal (Frequency, level) Output raise value, deviation value 1 kHz, Cal. - 40 dB 5 kHz, Cal. - 20 dB 1 kHz, Cal. 1 kHz, Cal. - 40 dB 5 kHz, Cal. - 20 dB 1 kHz, Cal. +5.7 dB 2 dB +3.5 dB 1.5 dB 0 dB +0.5 dB -1.0 dB +16.2 dB +3 dB -2 dB +2.9 dB 2.5 dB 0 dB 1 dB DOLBY C (Rec) Play back frequency respon

44、se adjustment Test tape : VT742 (63 Hz, 1 kHz, 12.5 kHz) Play back VT742 test tape, and adjust VR116, VR216 (deck B) and VR111, VR211 (deck A) so that deviation of 12.5 kHz to that of 1kHz is 0.5 0.5 dB (deck A) and 0 0.5 dB (deck B). Then play back VT742 test tape to confirm that deviation of 63 Hz

45、 to 1 kHz is +2 3 dB. Difference level of 12.5 kHz from 1kHz within 0.5 0.5 dB (both decks A and B) Difference level of 63 Hz from 1 kHz within +2 3 dB. Deck B L : VR116 R : VR216 Deck A L : VR111 R : VR211 Bias frequency adjustment Frequency counter TP: CN845 pin 1 Tape: Metal Mode: REC Frequency c

46、ounter input impedance: more than 470kohm (see 3.3 Location of adjustment.) Connect frequency counter to the pin 1 of CN845 and adjust L8401 so that the counter reads 95 kHz. 95 kHz 1 kHzDeck B L8401 Slave oscillation (HX PRO) adjustment DC. Voltmeter TP: CN845 Lch (pin 3 - 4) Rch (pin 3 - 5) This s

47、tep must be performed after the bias frequency adjustment. Load a metal tape and set the deck to the recording mode. Adjust L1401 and L2401 to minimize respective DC voltage of CN845 (pin 3 - 4) at Lch and (pin 3 - 5) at Rch. MinimumDeck B L : L1401 R : L2401 *2 *3 *4 *5 ItemConditionsAdjustment and

48、 ConfirmationStandard valueAdjust point Item 1-16 (No.MB061) Checking recording bias current (Value appearing here are just for reference Measuring point: Both ends of 100 ohm resistor connected to the R/P head terminal Connect 100 ohm resistor to the R/P head in series, and measure voltage at both

49、ends of the resistor to check to see if measured voltage meets the following requirements on both channels. In recording with metal tape, the bias current is 1150 uA (1.15 mA). In recording with CrO2 tape, the bias current is 700 uA (0.7 mA). In recording with normal tape, the bias current is 590 uA (0.59 mA). Reference values Metal tape:1150 uA CrO2 tape: 700 uA Normal tape:590 uA Input sensitivity level check Supply at 1kHz signal to the LINE IN terminals at -19 dBs, confirm