Toshiba-XRZ70K-tape-sm维修电路原理图.pdf

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1、RadioFans.CN 收音机爱 好者资料库 RadioFans.CN 收音机爱 好者资料库 xB-270 XR.ZTOK 14. DISASSEM BLY INSTRUCTIONS (4d x 6mm) TOP CABINET REMOVAL 1. Remove four screws tqO x 6mm) and two screws ISO x 6mm), and the top cabinet can be remov- ed from unit. (Figure 1 , 2 and 3) Figure 2 FRONT PANEL REMOVAL 1. Remove top cove

2、r. 2. Turn gear clockwise by your hand, and tray will be opened. (Figure 4) 3. Open disc holder. 4. Remove holder tray panel, while pushing tabs which f ix holder tray panel. (Figure 5) 5. Remove two screws e tSp x 6mm) securing plate. 6. Close disc holder. (Figure 6) 7. Remove three screws (3 x 6mm

3、), and three screws tsO x 8mm), and the front panel can be removed from unit. (Figure 7 and 8) .ar I Figure 4 l.-:_l : (3d x 6mm) Figure 1 t+O x 6mm) Figure 3 Tray Panel l- I ffil t . 1 I Tabs r-l Figure 6 - 18 - Figure 5 Q * liiii 6 llil ilil iliiltilililt llilllil ilil liltililt Y, Figure 8 ;:-.3M

4、 PLATE REMOVAL :,-:,etopcover. - :-:,e six screws , and bottom plate will be re- - -.=:, (Figure 9) I,il : : : ANISM ASSY REMOVAL :. : f ront panel removed. Open disc holder. .-:,e stay after removing two screws rQ (3d x (F igure 9) - gear clockwise by your hand, and tray will be ;-:.e four screws (

5、34 x 6mm) and the mecha- .- :ssy can be removed from unit. (Figure I0) Lillllt Figure 9 - 19 - Figure 10 XX ;OT NI oo o Moin Section -l Process Seclion Heod Phone Section -f F IXD Power upply I Seciion Heod Amp Section l-l Loodino) Il;r I I I I I I I I I I Lg*tt gl EJECT L_ _- Drsc Disploy Section T

6、- Key lnput Secfion DISC PU co il c .9 u o D U o l-1 NC o; lr J !t r o o -A I - o 7 3 OU (J e)i +5V tl rlfllr a 467M Adress Signol Ganerorion Sectlon E.ro. Dered/ Correcl Seclion Ddrd Ouloul Conlrol Sclion TC9r79F PLL Circurl rD 6ll5 Conlrol/Servo System Conversion T 7001 - oo07 Microcomputer SYstem

7、-l T IMP474ON SVC Circurt M8 88201 lvlicrocompuler System - 2 TM P47C4 I N olv I I e3v | _- -J FL Disploy Tube 16. BRIEF DESCRIPTION ON COMPACT DISC Conventional 30cm LP and single records are called an analogue record, whereas an entirely new playback system called a compact disc system has been de

8、veloped. Brief explanations on this are given below. 1. Disc (1 ) Compact disc (CD ) system o ln a conventional analogue record playback system, a needle is put on the groove cut in proportion to an amplitude of a signal to read out music signals by picking up vibrations which are produced by contac

9、t of the needle with the groove. o ln a compact disc system, on the other hand, a laser beam converged to nearly one micron is replaced with a needle, and is aimed at an array of pits recorded on a disc to converts variations of light reflection from the pits into digital signals. Therefore, it is n

10、ot necessary to contact with the disc to produce music signals and the digital signals thus developed are processed with signal processing circuits to reproduce an original sound. Protective Film Printed Surface (2) DISC has two sides: signal side and label side A disc is 12 cm in diameter and 1.2mm

11、 thick, and signals are recorded in its non-label side. A laser beam of nearly 800pm in the wavelength is directly hit to a disc from its transparent plastic side and reflected at an aluminium reflecting plane to generate a small digital signal, which is consisting of 1 and 0 according to the reflec

12、ting factor, with the aid of a photodiode. o Now imagine it as a TTL auto-focus camera which is a present mainstay in the camera field. The reflect- ing plane of a disc is a subject. To take out signals uninterruptely, the camera (laser beami focus is always being controlled so that the beam spot is

13、 focused and a pit array (called a track) is passed through the center of the lens by manipulating the lens back and forth, and right and left. ln order to obtain the spot about 1 gm dia. on the Al reflecting plane, scars and stains on the surface of transparent plastics are the biggest determent. F

14、urthermore, because there are important pits just beneath the printing surface separated by a thin protective film, the pits would be damaged even writing down with a pencil or ballpoint pen. Note: The diameter of a pit is as small as 0.6pm. CD System (1) What kinds of signals are recorded? Lets a l

15、ittle more think of a digital signal although this was discussed earlier a couple of times. The pack- ages of a 136 units-per-second signal series (called a frame) are delivered in succession. Analizing more this package, you can find that it is consisting of 588 bits of I or 0. Roles of these 588 b

16、its can be catego- rized into lots of rolds as a music signal which is the mainstay, as a time indication signal, as an inter-music pause signal, etc. Ref lecting Transparent Plastics -21 - xR-270 XR.ZTOK I_rrr_CK Nd.l This is usually called a music number. Each music is numbered, and it is given in

17、 the descriptions of the disc you have bought. Memorying or searching can be conducted by using this number. (This is also call- ed a TNO.) This is usually 01 to 99 except some discs starting from a number except 01 (for example, 03 or 04). This is used for subdividing one music number. ln case of c

18、lassic musics, each movement or each theme would be numbered. Some sets do not employ this numbering system due to a technical problem, but with XR-270, this system is employed to serve for memorying or finding out of a heading address o Trwrel This indicates a playback time passing since the start

19、of a track in minutes and in seconds. This is control led by a quartz, so that the time is quite precise. . A. TIME (Absolute Time) With XR-270, this time is not indicated but plays the important role inside the set. . TOC (Table of Contents) On the beginning part of a disc, allof data including the

20、 number of musics, a music length, etc. have been recorded. With XR-270, because all data are first read out to a memory, an entered datum is compared with its corresponding correct recorded information to display an error indication, for example in case of misoperation of TEN KEYs. . ERROR, CORRECT

21、ING SIGNAL, ETC. These are used in internal circuits and serve for correcting errors in which 1 and 0 are changed to 0 and 1, respectively, due to some causes, There are several kinds of signals except these signals. (2) The revolving speed of DISC is varied within the range of 500 r.p.m. to 200 rpm

22、. o The playback operation is started from the inner radius of a disc to its outer radius, but the speed of the pit array (track) being scanned beneath the focus point of the laser beam is always kept constant (con- stant linear velocity: CLV), so that the rotating speed is high at the inner radius

23、of the disc and lower as farther from the center of the disc. After listening to a music at the inner radius, you could find that the revolving speed is sharply changed if you listen to a music at the outer radius. o While XR-Z7O employs a constant linear velocity system, conventional analogue recor

24、ds employ a con stant revolving speed system. ln the compact disc, the rotation is controlled by a control signal obtained from the disc to keep the linear velocity constant. (3) Performance is uniform and yet superb . As you know, transmission of a digital signal is almost not degraded provided tha

25、t the signal is properly processed. No degradation of a signal during transmission from a recording site to your playback system is the key feature of a digital audio disc (CD system). o A flow of audio signals which are varied every moment is sampled at the rate of as high as 44,100 times and the s

26、ampled data are represented in terms of 65,536 kinds of data called 16 bit data. With this CD system XR-ZTO,signals from a recording site are first converted into digital data of 16-bits (21 6 = 65,536) and then transmitted to your compact disc playback system, o The frequency response is almost fla

27、t over the range of 4 Hz to 20 kHz. With an analogue transmission peaks or dips appear at some locations, so that it is very difficult to obtain a flat characteristic such as with XR-270. o The dynamic range is over 90 dB. Noises are almost not the least heard. In an analog system, signal levels to

28、be handled are limited due to increased distortion caused by amplitude limit depending upon character- istic of circuits and components and frequency band limit, but a 16bit digital signals are not subject to these limitations, achieving the dynamic range as wide as over 90 dB. (For the SN ratio too

29、. the same can be determined.) -22 - what is the reason why the wow and flutter figure is smaller than the measuring limit? lt is thatsignals read out of a disc are first sotred in a memory and then fed in turn to a D/A converter (A circuit for converting a digital signal to an analogue signal) at a

30、 precisely-fixed tempo controlled with a quartz osci- lator to reproduce original sounds. Critical Angle Prism Collimeter Lens Polarized Prism 1/4 Wavelength Plate Focus Servo Coil (Auto Focus) Objective Lens Tracking Servo Coil (Auto) 17. CAUTIONS ON REPLACEMENT OF PICK- UP When removing the laser

31、pick-up, temporarily connect (solder) the terminals to which red and black leads have been connected to protect the laser pick-up from damage which would be caused during removal work of the pick-up. Disconnect the connector and leads after completion of soldering. Do not touch the terminals on the

32、pick-up by your hand. when mounting a new laser pick-up, first connect the connector and leads and then remove short-circuit spring on the P.C. Board (Refer to Fig. 14 and 15). When mounting the laser pick-up, the terminals (red and black) of which were soldered in the step l. above, first connect t

33、he connector and leads before unsoldering the terminals (red and black). (Refer to Fig. 15) * Use a soldering iron grounded (or iron less leakage). * cover the working bench with a conductive mat which is also grounded. Before proceeding job. always touch the conductive mat or ground lead with your

34、both hand to discharge electric charges developed on your body. 4-Divided Photo Diodes -23- ,U Figure 12 Solder or short-circuit these two terminals before disconnecting the connector leads. The Figure 13 term i nals short-ci rcu ited. Figure 14 Figure 15 Remove the shorting spring after connection

35、of Shorting spring (to short-circuit the terminals) the connector and leads have been completed. Shorting spring RANKS OF PICK.UP The pickups are divided into two rank groups, B and C. and one of ranks is indicated on a label put on a side of the pickup as shown. When a new pickup having the same ra

36、nk as one of the pickup to be replaced is replaced, no addi- tional resistor replacement is required. However, when the pickup has a different rank, one resistor must be changed as tabulated below, depending on the rank of the pickup to be replaced. -Symbol No. Rank R124R 123 BUse 12K ohmRemove cRem

37、oveUse 4.7K ohm .4 0- Yo I I + -rfr-.- K .i YO lndication Label Ran k -24- xR-270 XR-Z7OK 18. ADJUSTMENTS Rr24$Rr23 _?, rr- Q to I dnr HEAD AMP P.C.BOARD DAC P.C.BOARD J-tz u fAra E 68, ,9l:l er :- lrorrol looo ol co J-7 J-4 - loooool e t-12 0206 f,-_l rp-z l-i-.1 Q2l I E !) lt llllJ-e ll llr I I I

38、liller*sse o - En; Il., EIU R373 Q209 Q208 | ! 1., - 1., . 1., . Q2t2 J -27 J-26 J-t2 J-t r Q20 5 T c Q504 n LJ o50 5 n L- Q50 r n Q502 MAIN P.C.BOARD Figure 16 -25- xR-270 XR.ZTOK Measurement Jigs 1. Laser Power Checker 2. Oscilloscope 3. PU Alignment Jig 4. Tester 5. AC millivoltmeter 8. Oscillato

39、r 6. Error Checker 9. Test Disc StepMeasurement ltem Measurement Refererrce Value Disc Operation Button Test Point Adjustrnent Point Test/ Setup Note 1 Laser Power Adjustment Light output 300lrW Not loaded Power ON Pick-up actuator ( Lens) R128 F igure 17 and 18 Disconnect pin 6 J8 on Mecha. P.C. Bo

40、ard and short- circuit pin 6 and of 7 2 Focus Offset Adjustment DC 0 t0.1 v Not loaded Power ON J-8 pin 8R1 18 F igure 19 3 Pick-up Height Ad justment r0.1v DC 0 DC 0 r0.1v TYPE A PLAYJ-7 pin 4 Pick-u p Lower side F igure 20 4 Pick-up Tangential D irection Adjustment Jitter meter min. TYPE A PLAY 42

41、12 Pin 41 Pick-u p Lower side F igure 21 5 PU Radial Direc- tion Adjustment AC voltage min. TYPE A PLAY TP-2 pin 1 0209 pin 10 Pick-up Lower side F igure 22 6 Servo Control Adjustment Correction factor (1 sec) 300 v 1200 TYPE A PLAY Main P.C. Board J-27, J-26, J-9 Mecha. P.C. Board J-9 R120 F igure

42、23 7Repeat steps 4 via 6. Servo Circuit Adjustment SterMeasurement ltem Measurement Reference Value Disc Operation Button Test Point Adjustment Point Test/ Setup Note 1 Focus Gain Ad justment AC 50mV RMS TYPEPAUSE Main P.C. Board TP-1 R358 Figure 24 and 25 2 Tracking Gain Adjustment AC 50mV RMS TYPE

43、PLAY Main P.C. Board TP-2 R373 F igure 26 and 27 Analog Circuit Adjustment StepMeasurement ltem Measurement Reference Value Disc Operation Button Test Point Adjustment Point TesV Setup Note 1 DC Offset Adjustment DC OV +50mV TYPEPAUSE Dac P.C. Board TP.R, TP.L R809 R81 1 Figure 28 -26- Laser Power A

44、djustment 1. Disconnect pin of J8 on Mecha. P.C. Board, and short-circuitpin and O. 2. Turn power on with disc not loaded. 3. Couple laser power checker probe to actuator (lens) section of pick-up; 4. Adjust R128 so that laser power checker indicates 300prW. ORG DRI VER ,/6 MECHANISM P.C. BOARD Figu

45、re 17 Figure 18 Focus Offset Adjustment l. Connect pin of J-8 on Mecha. P.C. Board to circuit tester or oscilloscope. 2. Turn power on with disk not loaded. 3. Adjust R118 until 0V t0.lV DC is obtained. MECHANISM P.C. BOARD 3oopW NOT LOAD- ED J-8 6prr.re RltS - GNDT 1 - 0-+-1 -+0+1-+2 in this sequen

46、ce when the unit mode is changed from STOP to PLAY with SVC switch on PU Alignment Jig placed in AUTO position. Focus Gain Adjustment 1. Connect PU Alignment Jig with TP-l on Main P.C. Board. 2. Connect AC millivoltmeter and oscillator with PU Alignment Jig. 3. Set the unit to PAUSE mode with disc l

47、oaded. 4. Set CAL/OFF switch to CAL position and ON/OFF switch to OFF position. Adjust oscillator to provide 50mV RMS output at 1 KHz when measured with AC millivoltmeter. DISCMAIN P.C. BOARD OSCI LLATOR PU ALIGNMENT JIG -_l o - -o US rOCUS OSC b lNo- oN cALGNDG EfloUT orForr 9 9 1 kHz S0mVRMS AC MI

48、LLIVOLTMET t Fiqure 24 m ) v Figure 28 -30- Figure 29 26. PARTS LIST CAUTION: The I mark, the symbol No. circled with oval in the schematic diagram and the shaded area in the parts list designate components which have special characteristics important for safety and should be replaced only with type

49、s identical to those in the original circuitorspecif ied in the parts list. Symbol No. Part No.Description o.244 o.245 0246,247, 248,249 o501 o502 o503 0504 o505 0506, 507, s08 o509 051 0 o51 1 0512,513 051 4 051 5 o51 6 o51 7 o518,519 0520 o531 0604 o605 0607 0608,609 061 0 061 1 o801 o802 o803 o804 0805 0806, 807 o808 o809 o81 0 o81 1 o81 2 o81 3 o81 4 0815,816 o901 o902 A631 7460 46534060 A6048370 80470942 22117295 22117355 80475722 804831 81 4631 7460 A