Pioneer CRT2503 Service Manual Download Page 14

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CX-961

Fig.24:LOADING OPERATING STATE TRANSITION DIAGRAM

LOAD EJECTION OPERATING STATUS TRANSITION DIAGRAM

12cm

A/D

CDLOAD

CDEJET

MOTOR

STOP

LOAD

STOP

12 cm RECOGNITION CHECK

8cm

A/D

CDLOAD

CDEJET

MOTOR

STOP

LOAD

STOP

8 cm RECOGNITION CHECK

C
D

EJECT

12cm

A/D

CDLOAD

CDEJET

MOTOR

STOP

EJECT

STOP

8cm

A/D

CDLOAD

CDEJET

MOTOR

STOP

EJECT

STOP

C
D

Summary of Contents for CRT2503

Page 1: ...EER ELECTRONICS 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 in the table below When performing repairs use this manual together with the specific manual for model u...

Page 2: ...ervo 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 stage and controls power for the pickup s laser diode The signal from the pickup is I V converted by the preamplifier built into the pickup s photodetector then added by the RF amplifie...

Page 3: ...ed in the TE output on the basis of Vref The cutoff frequency 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 FE is expressed as FE A C B D 150 k 62 k 60 k 60 k 12 k 60 k 4 8...

Page 4: ...e 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 output 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 reproducti...

Page 5: ...rate 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 15 of TA2150FN via an addition amplifier assuming E F as an SBAD signal This SBAD signal is used as the internal decision...

Page 6: ...here 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 digital equalizer unit Fig 8 shows a block diagram of the focus servo Fig 7 APC CIRCUIT IC401BA5811FM FOP IC301TC9495FP DAC A D FOCUS EQUALIZER FE FEI FOO...

Page 7: ... level the servo standby state occurs because the adjusted focus point approaches 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 not active the microcomputer pe...

Page 8: ...resis operation are performed for 50 ms after tracking close has been completed The FF REV operation in the normal mode is implemented by continuously performing 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 num...

Page 9: ...CK Fig 15 CARRIAGE SIGNAL WAVEFORM DIGITAL EQUALIZER CONTROL PMW OUTPUT CIRCUIT COP COM CRG MOTOR IC401 BA5811FM SD FMO M IC301 TC9495FP from TRACKING EQUALIZER 16 15 25 26 53 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 serv...

Page 10: ...ols are used at powering on to have the TE and FE amplifiers offset value stay within the target range using Vref as a reference The target is TE FE 0 0 V respectively The adjustment procedures are as follows 1 The servo LSI reads each offset of the laser diode OFF state 2 Calculate voltage to be offset based on the value read into earlier and then assign the offset value to the given location Bes...

Page 11: ...TMENT CIRCUIT DIGITAL EQUALIZER RFRP SIGNAL FE SIGNAL RFRP FEI BIAS CIRCUIT GENERATION OF STEP SIGNAL IC301TC9495FP 42 43 5 RF level automatic adjustment RFAGC This adjustment adjusts unevenness of the signal RFO level caused by the factor of the mechanical unit and disk to a fixed value and is performed to aim at accurate signal transfer The adjustment is performed by changing the amplifier gain ...

Page 12: ... the coefficient moves by 1 misalignment changes by approximately 0 71 to 4 97 When the maximum misalignment on the positive side coefficient 63 the misalignment is TYP typical value 45 When the maximum misalignment on the negative side coefficient 0 the misalignment is TYP typical value 45 3 F or T gain adjustment Standard value Focus or tracking 32 and the display is performed in a unit of appro...

Page 13: ... OFF of the loading drive no control terminal is provided in particular but input signal CDEJET or CDLOAD functions in the same way The loading or ejection operation is controlled according to the state changes of the clamp switch on the mechanical unit and the three switches on the control unit The DSCSNS voltage changes according to the ON OFF states of these switches For this voltage each of st...

Page 14: ... 12cm A D A B C D C B A E CDLOAD CDEJET MOTOR STOP LOAD STOP 12 cm RECOGNITION CHECK 8cm A D A B C B A E CDLOAD CDEJET MOTOR STOP LOAD STOP 8 cm RECOGNITION CHECK B C D A E B C D A E EJECT 12cm A D E A B C D C CDLOAD CDEJET MOTOR STOP EJECT STOP 8cm A D E A B C B CDLOAD CDEJET MOTOR STOP EJECT STOP B C D A E B C D A E ...

Page 15: ...ch to the position of a dashed line and clamp operation occurs as is Centering arms L and R are coupled But even if only one side is pressed the arms cannot rotate beyond a fixed width as the coupling part is locked Disk centering mechanism 1 When a 12 cm disk is carried to the position shown in the drawing the centering guide relief arm rotates holds the centering guide And the centering guide is...

Page 16: ... position on the spindle and start the disk clamp operation by engaging the rack arm and drive gear 2 The mechanical unit lock lever moves to the arrow view direction and releases the coupling between the mechanical unit lock arm and frame Further it completes clamp operation at the position where the clamp SW is set to ON Ejection operation 1 The loading motor rotates backward and the ejection op...

Page 17: ...e and remove the top frame 2 After having removed the screws of the two dampers and the dampers on the right remove the main frame 3 Remount the product connector with the frame removed and eject a disk How to remove the clamper arm assy and guide arm assy 1 Remove a total of three right left and rear springs and remove the clamper arm assy 2 Remove the left spring and remove the torsion spring ho...

Page 18: ...approaching the holder to the arrow view direction and touching the tip of the motor shaft At this time screwing with the holder being pressed tight causes higher motor load this may cause a malfunction therefore tighten screws with the hand off from the holder having the holder touching to the motor spindle edge 3 Remove the solder of the motor lead wire 4 Remove the leaf spring screw and remove ...

Page 19: ...ing screw of the carriage motor assy How to remove the pickup 1 Mount the jumper pin and remove the pickup connector 2 After having removed the processing of flexible wires remove the mounting screw of the main shaft holder and remove the pickup together with the main shaft holder and the main shaft Core Unit Carriage Motor Assy Jumper Pin Pickup Grease Cover Core Unit Main Shaft Main Shaft Holder...

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