Pioneer CX-692 Service Manual Download Page 16

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CX-692

CH2

CH1

CH3

PICKUP UNIT

IC601
TC4053BFT

VR25

4
5

12
11
10

VD9

LCDTLT

LCDBIAS

IC501
PD5511A

LCDCLK

IC605(1/2)
NJM3414AV

IC605(2/2)
NJM3414AV

Q601

IC604(2/2)
NJM3414AV

IC604(1/2)
NJM3414AV

1.5.5 LCD TILT SERVO

With the DVD playing back system, since the SKEW margin is narrow, upto

0.6[DEG.] SKEW will become the playing

back range without SKEW compensation. The LCD tilt servo will make it possible to play back upto

1.0[DEG.] SKEW.

As for the CD, since the SKEW margin is not as narrow as that of the DVD, the LCD tilt servo is not being used.

Rectangular pulses which work to compensate the radial tilt (SKEW in radial direction) are being applied to the LCD

panel carrying split-to-three electrodes. By varying the peak value of the voltage of the rectangular pulses, the

reflection factor of the LCD can be so varied to always compensate the aberration caused by SKEW to control the

voltage being applied to the three electrodes accordingly. The above controls are being made by a microcomputer.

(Fig. 17.)

The LCD panel is being incorporated inside the pickup unit, where a slight clearance is being provided between two

sheets of glass boards and the LCD panel is being sealed inside the clearance. Transparent electrodes are being

inserted between the glass substrates and the LCD panel. One end of the electrode is of a split-to-three shape in S-

form and the opposing other electrode is not being split.

While the LCD tilt servo is in operation, the amplitudes of the CH1 and CH3 will respectively become larger and

smaller. No such change will occur with the CH2.

Fig. 16

Summary of Contents for CX-692

Page 1: ...m PIONEER ELECTRONICS ASIACENTRE PTE LTD 253 Alexandra Road 04 01 Singapore 159936 C PIONEER CORPORATION 2000 K ZZS MAY 2000 Printed in Japan ORDER NO CRT2533 DVD CD MECHANISM UNIT CX 692 Service Manual This service manual describes the operation of the DVD CD mechanism incorporated in models listed in the table below When performing repairs use this manual together with the specific manual for mo...

Page 2: ...ture characteristic necessary optical power cannot be acquired when driven at a lower current level The APC circuit is a circuit to control the current levels so that the output of the monitor diode may become constant By measuring the voltage occurring between the LD and the drive transistor the LD current can be found out and such current value should be within 20 of the value indicated on the p...

Page 3: ... 3 below shows the basic movement sequence Viewing through the objective lens the layer on this side is called Layer 0 L0 and the layer on the far side is called the Layer 1 L1 Objective lens RF FE Focus standby level Focus ON Vref GND Vref A Fig 4 TEST00 B Fig 4 IO0 L0 L1 L1 L0 L0 L1 L0 L1 L0 Layer1 L1 Layer0 L0 L1 L0 A B C D E A B C D E Fig 3 ...

Page 4: ...lter output and DC holding is effected Simultaneously the focus search drive signals are output through the TESIO0 pin and the TESIO1 pin By the circuit shown in Fig 4 these signals are made to apply drive signals to the focusing servo loop which work to drive the focusing actuator to complete the layer jump FOO 19 FOJ Q401 Q402 IC402 NJM2904M IC401 67 43 18 19 IC304 BA6797FM Focus jumping circuit...

Page 5: ...C106 109 and by inputting these signals to the time difference IC IC107 PA0065AM The error signals being output from the time difference IC are amplified through the OP amplifier IC108 and the RF amplifier IC103 before being input to the servo DSP IC401 TC9461F pin41 Under normal CD settings T GAIN 9 0dB TE GAIN 0 0dB Under normal DVD settings T GAIN 9 0dB TE GAIN 6 0dB IC103 55 53 54 52 21 IC105 ...

Page 6: ...el continuously for 32mS after focus closing the servo LSI recognizes the focus closed state to raise the FOK port of the microcomputer to the H level While if the SBAD stays below the SBREF level continuously for 12mS after focus closing the servo LSI recognizes that the focus is lost to activate the resetting process Meanwhile the reference voltages for the aforementioned SBREF level and STANDBY...

Page 7: ...eing Normally focus closing is made at this point H L CLOSE OPEN STANDBY Close Inside the servo LSI Inside the servo LSI Offsetting SBREF FOK RF SBAD FOK Inside the servo LSI H L FOK 32mS Monitor R 100kΩ C 0 016µF Offsetting STANDBY Reference voltage at 2 1V ECR Reference voltage at 2 5V Reference voltage at 2 1V Fig 8 ...

Page 8: ...s to be used for jumping of 512 tracks or more as the track jumping means to use for searching Also tracking closing movements are being realized by the zero track jumping command under the lens kick mode Under the test mode 14 types of jumps namely 1 4 8 16 32 64 100 255 512 1 000 4 095 4 096 16 384 and 32760 can be used for checking by making the mode selection accordingly Under the normal mode ...

Page 9: ...s the number of remaining tracks decreases to facilitate taking in action by the servo when the jump has been finished While jumping is in progress the track counting is being made in observation of the RFRP signals Also the jumping direction is being detected by the phases of the RFRP and the TEZ1 Meanwhile when a track jumping has been finished in order to stabilize the taking in action by the s...

Page 10: ...ng so profiled to carry a time constant in their leading edges and also it is so designed that the voltage is lowered when the number of remaining tracks decreases to bring down the moving speed of the carriage Thus the speed is being lowered just before a jump is finished to facilitate taking in action by the servo when the jump has been finished Meanwhile when a track jumping has been finished i...

Page 11: ...movements work to hold the tracking error signals when the beam spot moves to off track positions thus enhancing the convergence of the tracking servo Regarding the hysteresis movements TE signals Outer peripheral direction Inner peripheral direction RFRP signals after holding TE signals Track ON Track ON Track ON Track ON Fig 12 ...

Page 12: ...arting voltage may be outputted at that time Meanwhile as the actual movements a certain threshold level for the equalizer output is being preset inside the servo DSP and the drive voltage will be outputted from the servo DSP only when the equalizer output level exceeds the threshold level The above movement works to suppress the power consumption Also depending on the eccentricity of the disc the...

Page 13: ...13 CX 692 TRACKING DRIVE LOW FREQUENCY LENS POSITION CRG MOTOR VOLTAGE CRG moved at these point CRG DRIVE INSIDE TC9461F DRIVE ON OFF THRESHOLD Fig 14 ...

Page 14: ... is a movement to shift from roughing servo to the speed phase servo The RLOCK and FLOCK being generated from the demodulator section are signals indicating the detection state of the frame sink With these signals window is being provided at each frame cycle to determine if frame sink 14T 4T exists in there With the FLOCK the frame sink detection window width is 5 as against the VCO and with the R...

Page 15: ...CD Spindle servo changeover switch 8cm 12cm spindle gain changeover switch 8cm OFF 12cm ON PWM AFC APC DMO 160 159 158 FPWM PPWM VPWM RERR IC701 PD4995A 1 2 1 2 1 2 DIGITAL EQUALIZER CD SPDL DVD SPDL IC401 TC9461F SFSY 1 M 1 M X tal EFM SIGNAL SYNC DETECT 50 IC303 NJM2904M IC352 MC33202D IC353 2 2 MC33202D 1 6 7 SPINDLE MOTOR Fig 15 ...

Page 16: ...arrying split to three electrodes By varying the peak value of the voltage of the rectangular pulses the reflection factor of the LCD can be so varied to always compensate the aberration caused by SKEW to control the voltage being applied to the three electrodes accordingly The above controls are being made by a microcomputer Fig 17 The LCD panel is being incorporated inside the pickup unit where ...

Page 17: ...hase differences are being changed SERVO DSP B1 B4 RFRP RFGC data such as of the BUS0 BUS3 TC9461F LCD drive circuit CH1 CH2 CH3 A DC Microcomputer software D AC Generates BIAS CLOCK IC501 PD5511A The amplitudes of the CH1 and CH3 are varied TEMP LCDTLT LCDBIAS LCDCLK LPF IC103 IC401 Inside the mechanism controller Fig 17 ...

Page 18: ...ction The microcomputer detects the DSP signal waveform voltage and TRP signal waveform voltage obtained at the DSP switch S851 and the TRP switch S852 by tray retraction tray extension and clamp completion and controls the Tray Motor EJ EREF 447LSB EREF 441LSB EREF 435LSB Mech standby position EREF 319LSB EREF 313LSB EREF 307LSB DISC6 voltage position EREF 189LSB EREF 183LSB EREF 177LSB DISC5 vol...

Page 19: ...y of LEDs and photo transistors above and below the Tray Each motor is driven by the driver IC305 LB1836M LB1836M is an IC which usually operated through the combination of H and L of the 4 lines l1 l2 l3 and l4 With this system l1 l3 and control is realized through a combination of H and L of the 3 lines l1 l2 and l4 Making continuous detection of the DISC waveforms during the periods A and B sho...

Page 20: ...ove the plate spring A 5 Unscrew one screw C to remove the plate spring B 6 Remove the pickup unit together with the main shaft 7 Remove the cushion from one side only to pull out the main shaft AT this time pay attention not to lose the removed cushion Removing the PCB unit B 1 Remove soldering from the linear position sensor VR301 2 Unscrew the two screws D to remove the PCB unit B Precautions w...

Page 21: ...echanism to the left end marking on the front lever This will be the first stage 5 Remove one screw G 6 Remove the flexible PCB of the motor 7 Remove the tray motor assembly Never turn the headless screw J This screw has been mounted to prevent the tray motor shaft from rattling Removing the elevation motor assembly Fig 24 1 Remove the connecting arm spring 2 Unscrew the two screws H to remove the...

Page 22: ...power 5V to the motor directly to turn the tray motor 3 Unscrew one screw A to remove the clamp spring and the clamp When doing this be careful not to lose the ball being inserted between the clamper and the clamp spring 4 Remove the flexible PCB of the spindle motor from its holder 5 Unscrew the three screws B to remove the spindle motor assembly When doing this be careful not to cut the flexible...

Page 23: ...f altogether 5 Unscrew the nine screws K and one screw L to remove the upper frame When doing this be careful since the coil spring of the duplicate insertion preventive mechanism may drop off 6 Unscrew the five screws M and one screw N to split the frame into the front half and the rear half before removing the stage mechanism Magazin lock arm Upper frame K K K K K K M L J J M M K N K K M M Front...

Page 24: ...oove on the reverse side of the magazine When the lock arm is pushed off the cam section is released but is held again by the lock arm When the magazine lock is released the sensor arm presses the MAG switch S301 Elevation Operation The drive operation is the same as the CX 652 See service manual CX 652 CRT1857 Elevation Detection When the rear lever is driven the front lever and sensor lever are ...

Page 25: ...hold positions where they do not get in the way of the tray However when the cam gear starts to turn after completion of tray dispension the clamp lever moves and the shaft of the carriage chassis is lifted by the stepped holes and the carriage chassis is drawn to the stage chassis The spindle motor then move to the disc and lifts it from the tray Fig 32 Stage chassis Tray extending arm Cam gear C...

Page 26: ...en reached At this point if some rattling space as shown in figure 33 is not provided the shaft of the stage chassis pushes on the clamp lever directly marked with No force is transmitted to the carriage chassis and rattling occurs resulting in a deterioration of the anti vibration characteristics Therefore to reduce the rattling at each section an improvement in the anti vibration characteristics...

Page 27: ...tension and Retraction Detection A Clamp When the clamp motion of the clamp lever is complete the jointed arm moves and the protruding section of the arm pushes the TRP switch S852 ON via the leaf spring B Tray retraction When the tray retracts the switch arm which operates on the same fulcrum as the tray extending arm moves and the TRP switch S852 is pushed ON by the protruding section of the arm...

Page 28: ... dispensed due to the straight section of the stopper Further since force F2 of the lower spring is set smaller that force F1 of the upper spring F1 F2 while the stoppers are being pushed apart the dispensed tray is being pushed downward at all times F F1 F2 preventing vertical rattling of the tray due to vibrations Magazine Ejection When the lever is driven beyond the lowest position of the eleva...

Page 29: ... guide shaft Feed screw thread Feed screw tip Main shaft Clamp spring Spacer Clamper HP 300 Dow Corning Fig 38 Lubrication points 1 Around the pickup assy Use HP 300 Dow Corning for all points 2 Slide section with clamp ball 3 For the other sections use the E paste Dow Corning ...

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