Pioneer-CX961-tape-cdm 电路图 维修手册.pdf

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1、ModelService ManualCD Mechanism Module DEH-P90DAB/EW, ESCRT2556CXK5301 PIONEER CORPORATION4-1, Meguro 1-Chome, Meguro-ku, Tokyo 153-8654, Japan PIONEER ELECTRONICS SERVICE INC. P.O.Box 1760, Long Beach, CA 90801-1760 U.S.A. PIONEER EUROPE NV Haven 1087 Keetberglaan 1, 9120 Melsele, Belgium PIONEER E

2、LECTRONICS ASIACENTRE PTE.LTD. 253 Alexandra Road, #04-01, Singapore 159936 C PIONEER CORPORATION 2000 K-ZZA. NOV. 2000 Printed in Japan ORDER NO. CRT2503 CD MECHANISM MODULE CX-961 Service Manual - This service manual describes the operation of the CD mechanism module incorporated in models listed

3、in the table below. - When performing repairs use this manual together with the specific manual for model under repair. CONTENTS 1. CIRCUIT DESCRIPTIONS.2 2. MECHANISM DESCRIPTIONS.15 3. DISASSEMBLY .17 RadioFans.CN 收音机爱 好者资料库 2 CX-961 1. CIRCUIT DESCRIPTIONS This unit is roughly divided into the pr

4、eamplifier stage, servo unit, power supply unit and loading control unit. This LSI (large scale integrated circuit) implements eight automatic adjustments according to the combination of the preamplifier stage and servo unit used. Besides, because this system conforms to the single power supply (+5

5、V) specifications, the reference voltages of servo systems (preamplifier, servo DSP and pickup) are all Vref (2. 1 V). 1.1 Preamplifier (TA2150FN; IC201) The preamplifier processes output signal from the pickup, then generates signals to the servo unit, demodulator unit and control unit at the next

6、stage, and controls power for the pickups laser diode. The signal from the pickup is I-V converted by the preamplifier built into the pickups photodetector, then added by the RF amplifier to obtain such signals as RF, FE and TE. Reference voltage Vref (2.1 V) is output from pin 19 of this IC and 2 V

7、ref (4.2 V) is supplied as the reference voltage which determines the D range of the servo DSP A/D input. Fig.1:TA2150FN CIRCUIT RadioFans.CN 收音机爱 好者资料库 3 CX-961 2) Tracking error amplifier unit This tracking error amplifier unit outputs photodetector output E or F from pin 14 of IC201 (TA2150FN)via

8、 an amplifier and an error amplifier assuming (E - F) as a TE signal. The low frequency component of voltage TE is expressed as TE = (E - F) 300 k / 100 k 155 k / 328 k 82 k / 20 k = 5.8 times. A TE waveform of approximately 1.51 Vpp is obtained in the TE output on the basis of Vref. The cutoff freq

9、uency is 44.5 kHz or 29.4 kHz. 1) Focus error amplifier unit This focus error amplifier outputs photodetector output (A + C) or (B + D) from pin 16 of IC201 (TA2150FN) via a differential amplifier and an error amplifier assuming (A + C - B -C) as an FE signal. The low frequency component of voltage

10、FE is expressed as FE = (A + C - B - D) (150 k / 62 k) (60 k / 60 k) (12 k / 60 k) = 4.84 times. An S curve of approximately 1.45 Vpp is obtained in the FE output on the basis of Vref. The cutoff frequency is 26 kHz or 133 kHz. Fig.2:FE CIRCUIT Fig.3:TE CIRCUIT RadioFans.CN 收音机爱 好者资料库 4 CX-961 3) RF

11、 amplifier unit The head amplifier LSI, TA2150FN, adds, amplifies and equalizes photodetector output (A+C) and (B+D), then outputs RF signal to the RFI pin. (This signal enables checking eye patterns.) Low frequency element contained in RFI voltage is formulated as follows: RFI = (A + B + C + D) 5.4

12、3. RFI is used for RF Offset Control circuit. RFI signal output from Pin 28 is AC-coupled externally, and then re-input to Pin 27 and amplified by the RFAG amplifier to obtain RFO signal. As described later, TA2150FN has a built-in RFAGC function that controls the RFAGC amplifier gain so that RFO ou

13、tput stays within 1.2 0.3V p.p. range. This RFO signal is used for EFM and RFAGC control circuit and for generating RFRP and RFCT signals for track counting. Besides, the frequency characteristics of an RF equalizer are switched at double-speed reproduction. (Switching using the HSSW terminal) Furth

14、er, with RWSW the gain at the RF amplifier stage is raised by 13db, compared with that in normal operation, when the gain lowers because of stains on the lens or while playing a CDRW. Fig.4:RF CIRCUIT 5 CX-961 4) RFRP and RFCT signal circuit unit The RFCT signal which is the difference signal betwee

15、n the peak and bottom levels of the RF signal is generated through head amplifier (IC201). RFRP and RFCT can be monitored at TP203 (pin 20 of IC201 TA2150FN) and TP204 (pin 22 of IC201) respectively. The TE, RFRP and RFCT signals are compared by a hysteresis comparator inside IC301 (TC9495FP) respec

16、tively and generate track information (TEZC signal or RFZC signal). Based on this signal, the traveling speed information about a lens disk is generated and the number of tracks is counted. 5) SBAD signal circuit unit This SBAD signal circuit unit outputs photodetector output E and F from IC201 (pin

17、 15 of TA2150FN) via an addition amplifier assuming (E + F) as an SBAD signal. This SBAD signal is used as the internal decision conditions of focus ON/OFF with a focus error signal. Further, the SBAD signal is also used for detecting defects when disk scratches are passed. Fig.5:RFRP AND RFCT SIGNA

18、L CIRCUIT Fig.6:SBAD SIGNAL CIRCUIT 6 CX-961 6) APC circuit section A laser diodes driving current must be controlled so that optical output could remain constant by using a monitoring diode, because optical output has high negative characteristics that causes a heat hang-up if the laser diode were

19、driven at constant current. This is exactly where APC circuit works. LD current can be obtained by measuring voltage between LD1 and GND, which value is about 35 mA at room temperature. 1.2 Servo DSP (TC9495FP; IC301) 1) Focus servo system The main equalizer of the focus servo is comprised with a di

20、gital equalizer unit. Fig. 8 shows a block diagram of the focus servo. Fig.7:APC CIRCUIT IC401BA5811FM FOP IC301TC9495FP DAC A/D FOCUS EQUALIZER FEFEI FOO FD FOM C N O T R L O FOCUS SEARCH WAVEFORM GENERATION CIRCUIT 43 13 48 14 5 Fig.8:FOCUS SERVO CIRCUIT BLOCK 7 CX-961 The operation of detecting a

21、n adjusted focus point and turning on the focus servo is called focus search. In a focus servo system, a lens needs to move to the adjusted focus point to enable focus close. Accordingly, the adjusted focus point is detected by moving the lens up and down according to the focus search voltage of a t

22、riangular wave. Further, in the meantime, a spindle motor enters the simplified FG mode and maintains a constant speed of rotation. The focus servo turns on under the following three conditions: 1. FOK = H 2. A focus error signal exceeds a focus standby level threshold. 3. A focus error signal reach

23、es a zero cross. At this time, while the lens is fully separated from the adjusted focus point, cancel the SBAD offset and set this level to SBOFF. If the SBAD level exceeds the FOK threshold from the SBOFF standard, FOK = “H” is set. When the lens moves up and down, a focus error signal changes at

24、the adjusted focus point. However, CD-LSI removes an offset component by passing through a bypass filter after it has A/D-converted this error signal. When this FEHPE signal (LSI signal) level exceeds a focus standby high level, the servo standby state occurs because the adjusted focus point approac

25、hes. Subsequently, the FEHPF signal reaches the adjusted focus point and turns on the focus servo. The microcomputer monitors an FOON signal (Active at servo ON; L for a probe) at focus search, and starts monitoring a FOK signal in 40 ms after it has been set to Active). If it is judged that FOK is

26、not active, the microcomputer performs protection operation. Besides, when the Focus Close button is pressed with the focus mode select set to Display 01 in the test mode, a focus error, search voltage and the action of a practical lens can be checked. 2) Tracking servo system The main equalizer of

27、the tracking servo is comprised with a digital equalizer unit. Fig. 10 shows a block diagram of the tracking servo. Fig.9:FOCUS SEARCH TIMING OFFSET FOCUS SERVO ON FEI INPUT WAVEFORM : FEHIGH PASS FILTER OUTPUT : FEHPF HIGH PASS FILTER STANDBY LEVEL F1 F1 FOCUS SERVO ON REF LEVEL STANDBY LEVEL : F1

28、15.(3) FOCUS SERVO ON REF LEVEL FEHPF SBAD FOK FOON FOK LEVEL 88.1kHz 127 SAMPLE SBOFF LEVEL DEFECT(SCRATCHES) =TOK IC401 BA5811FM CARRIAGE MOTOR COM TOP IC301TC9495FP DAC A/D TRACKING EQ + AT THE TIME OF LENS KICK TETEI TRO M TD TOM COPCARRIAGE EQ + PWM FMO AT THE TIME OF FEED KICK JUMP CONTROL TEZ

29、I RFRP SD 46 47 49 53 6 16 15 12 11 25 26 42 Fig.10:TRACKING SERVO CIRCUIT BLOCK 8 CX-961 Track jump A track jump is automatically performed with a microcomputer command using the LSI auto (automatic) sequence function. This system has one to 99 lens kick modes as the track jump used at search and t

30、he carriage move used in the jump exceeding 1,000 tracks. The test mode can check the jump of lens kick modes 1, 32 and 99 and the carriage move according to the mode selection. Lens kick Jump Lens Kick jump is executed as soon as the LSI receives the Lens Kick command from the microcomputer. The di

31、rection of jump and the number of tracks are determined by the commands parameters. When the LSI receives the Lens Kick command, the jump is performed by inputting a kick pulse to the tracking EQ. The LSI controls lens traveling speed, referencing to the table held internally. By doing so, the lens

32、travels faster when there are a good number of tracks to go, while the lens traveling speed gets slower as the remaining tracks decrease. After track count has been completed, tracking close is performed. During jump, an RFRP signal is watched to perform track count and the direction of the jump is

33、detected according to the phase of RFRP or TEZI. Besides, to improve the servo feed at track jump, the tracking servo gain increase and hysteresis operation are performed for 50 ms after tracking close has been completed. The FF/REV operation in the normal mode is implemented by continuously perform

34、ing a single jump. The speed is about 10 or 20 times the normal mode. (It depends on destinations). Carriage move jump A carriage move jump is executed by issuing a carriage move command from the microcomputer. The direction of the move and the number of tracks are specified with the command. When t

35、he LSI accepts the carriage move command, the jump is performed by opening the tracking servo, applying a kick signal to the carriage equalizer and driving the carriage motor. The profile of a signal applied in this time is provided with a time constant at rise time. As the remaining tracks decrease

36、, voltage is lowered that results in slower carriage traveling speed. The servo feed at the end of the jump is improved by reducing the speed in this manner immediately before the jump terminates. Besides, to improve the servo feed at the end of the jump, the tracking servo gain increase and hystere

37、sis operation are performed for 60 ms after the jump has been performed. EQUALIZER HYSTERESIS CLOSE GAIN UP NORMAL TE RFZC (LSI INTERNAL SIGNAL PRODUCED FROM RFRP) (LSI INTERNAL SIGNAL PRODUCED FROM TEI) TEZC SERVO OPEN ON OFF 50ms THE HYSTERESIS OPERATION OF THE1-4 TRACK JUMP IS 2 ms. 50ms Fig.11:L

38、ENS KICK SD TE SERVO EQUALIZER HYSTERESIS OPEN CLOSE GAIN UP NORMAL ON OFF 60ms 60ms Fig.12:CARRIAGE MOVE 9 CX-961 Hysteresis operation Because the servo feed is deteriorated at setup and track jump, hysteresis is operated to perform a servo feed to a stable servo loop. The hysteresis operation hold

39、s a TE signal and improves the convergence of the tracking servo when a beam spot arrives at an off track. 3) Carriage servo system The carriage servo inputs the output of the low frequency component (lens position information) of the tracking equalizer to the carriage equalizer, and outputs a drive

40、 signal from the LSI after a fixed gain has been obtained. The signal further applies to the carriage motor via the driver. Specifically, because the entire pickup needs to move to the forward direction when the lens offset during play reaches a certain level, the gain of the equalizer is set so as

41、to output a higher voltage than the starting voltage of the carriage motor at that time. Besides, as a practical operation, only when a threshold level against the equalizer output is exceeded inside the servo LSI, a drive voltage is output. The threshold level is set slightly higher than the starti

42、ng voltage of the motor to reduce power consumption and stabilize operation. This drive output waveform has a pulse shape. Fig.14:CARRIAGE SERVO CIRCUIT BLOCK Fig.15:CARRIAGE SIGNAL WAVEFORM DIGITAL EQUALIZER CONTROL PMW OUTPUT CIRCUIT COP COM CRG MOTOR IC401 BA5811FM SD FMO M IC301 TC9495FP from TR

43、ACKING EQUALIZER 16 15 25 2653 TRACKING DRIVE (LOW FREQUENCY) LENS POSITION CRG MOTOR VOLTAGE DRIVE ON/OFF THRESHOLD CRG DRIVE (INSIDE TC9495FP) CRG moved at these point 4) Spindle Servo System Fig. 16 shows a block diagram of the spindle servo. The spindle servo has the following modes: CLV servo T

44、his CLV servo mode is the servo until the brake is applied to stop the disk after focus close. The spindle servo operates in this mode before tracking close and at normal reproduction. In the EFM demodulation block inside the CD-LSI, the spindle servo performs synchronous detection and operates so a

45、s be kept in a specified speed of rotation. The synchronous detection is also enabled before tracking close by using the VCO speed control of the inside of the LSI in the PLL circuit. After tracking close, the VCO speed control is muted and switched to the speed and phase control by a master clock (

46、a ceramic oscillator is used). IC401 BA5811FM IC301 TC9495FP PWM SYNCHRO- NOUS DETECTION MD DIGITAL Eq. EFM EC Brushless Motor Unit Mechanism Unit SPEEDERROR PHASEERROR FG VCO Master Clock 2322 54 TE SIGNAL DIRECTION OF THE EXTERNAL SURFACEDIRECTION OF THE INTERNAL SURFACE RFRP SIGNAL AFTER TE SIGNA

47、L HOLD ON TRACKON TRACKON TRACKON TRACK Fig.13:HYSTERESIS OPERATION Fig.16:SPINDLE SERVO CIRCUIT BLOCK 10 CX-961 Simplified FG servo mode This simplified FG servo mode is used to maintain the number of disk rotations in the state of the approximate number of regular rotations. In this mode, controll

48、ing driving voltage for the spindle motor is enabled by letting the microcomputer monitor FG signal that outputs pulses based on the number of rotations. The mode is used in the following conditions: a) Until focus close is performed from POWER ON at setup b) Until focus is out of order during play

49、and recovered later Brake mode This brake mode is used to stop the spindle motor. The brake sequence is started by issuing a CD-LSI command from the microcomputer. The LSI sets a flag on by detecting that the number of disk rotations was set to approximately one twentieth. This flag is monitored by the microcomputer to set the servo off. When no flag is set on even if a fixed time elapses, the brake mode enters the stop mode until it i