Pioneer CX-961 User manual

Model Service Manual CD Mechanism Module
DEH-P90DAB/EW, ES CRT2556 CXK5301
PIONEER CORPORATION 4-1, 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 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 under repair.
CONTENTS
1. CIRCUIT DESCRIPTIONS ...........................................2
2. MECHANISM DESCRIPTIONS.................................15
3. DISASSEMBLY .........................................................17

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1. CIRCUIT DESCRIPTIONS
This unit is roughly divided into the preamplifier 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 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 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 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 Vref (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

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2) Tracking error amplifier unit
This tracking error amplifier unit outputs photodetector
output E or F from pin 14 of IC201 (TA2150FN)via 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
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) = 4.84 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

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3) RF 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) ×5.43.
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 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 reproduction.
(Switching using the HSSW terminal)
Further, 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

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4) RFRP and RFCT signal circuit unit
The RFCT signal which is the difference signal between
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)
respectively 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 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 SIGNAL CIRCUIT
Fig.6:SBAD SIGNAL CIRCUIT

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6) APC circuit section
A laser diode’s 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 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
digital equalizer unit. Fig. 8 shows a block diagram of the
focus servo.
Fig.7:APC CIRCUIT
IC401 BA5811FM
FOP
IC301 TC9495FP
DAC
A/D
FOCUS
EQUALIZER
FE FEI
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

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The operation of detecting an 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 triangular 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 reaches 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 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 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 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 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 : FE HIGH PASS FILTER OUTPUT : FEHPF
HIGH PASS FILTER
STANDBY
LEVEL
F1
F1
FOCUS SERVO ON
REF LEVEL
STANDBY LEVEL : F1
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
"
IC301 TC9495FP
DAC
A/D
TRACKING
EQ
+
AT THE TIME OF LENS KICK
TE TEI TRO
M
TD
TOM
COP
CARRIAGE
EQ
+
PWM
FMO
AT THE TIME OF FEED KICK
JUMP
CONTROL
TEZI
RFRP
SD
46
47
49
53
6
16
15
12
11
25
26
42
Fig.10:TRACKING SERVO CIRCUIT BLOCK

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•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 the 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
direction of jump and the number of tracks are
determined by the command’s 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 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 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 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 number of tracks are
specified with the command. When the 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, 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 hysteresis
operation are performed for 60 ms after the jump has
been performed.
EQUALIZER
HYSTERESIS
CLOSE
GAIN UP
NORMA
L
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:LENS KICK
SD
TE
SERVO
EQUALIZER
HYSTERESIS
OPEN
CLOSE
GAIN UP
NORMAL
ON
OFF
60ms
60ms
Fig.12:CARRIAGE MOVE

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•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
holds 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 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 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
starting 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
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 servo has the following modes:
•CLV servo
This 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 as 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 (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
23 22
54
TE
SIGNAL
DIRECTION OF THE EXTERNAL SURFACE DIRECTION OF THE INTERNAL SURFACE
RFRP
SIGNAL
AFTER
TE SIGNAL
HOLD
ON TRACK ON TRACK
ON TRACK ON TRACK
Fig.13:HYSTERESIS OPERATION
Fig.16:SPINDLE SERVO CIRCUIT BLOCK

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•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, controlling
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 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 is checked
that the rotation was delayed by monitoring the FG
pulse. If the mode is switched to the stop mode at
ejection, the operation moves to the ejection operation
after the timeout time elapses.
•Stop mode
This stop mode is used at POWER ON and ejection.
The drive output is 0.
1.3 Automatic Adjustment Function
This system automates all circuit adjustments inside
CD-LSI (IC301: TC9495FP). All the adjustments are
performed every time at disk insertion or source key CD
mode selection.
The contents of each automatic adjustment are
described.
1) Automatic TE and FE offset controls
These controls 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. Besides, because this adjustment is
performed inside a digital filter, no change cannot be
found as an error offset voltage after adjustment.
2) Automatic tracking balance (T. BAL)
control
This control is used to equalize output difference
between Ech and Fch from the pickup by adjusting the
preamplifier’s internal gain. In practice, a TE waveform
is adjusted so as to become symmetric vertically for a
servo reference level.
The adjustment procedures are as follows:
(1) After focus close
(2) Turn on the spindle servo.
(3) Calculate a TE center value according to the
introduced TE signal and TE offset levels in the LSI.
(4) This center value changes the gain of the RF
amplifier so as to approach to a servo reference level.
The servo reference level is as follows:
TEI input level at servo OFF (= TE offset level) when
offset adjustment is performed
Vref level when no offset adjustment is performed
To improve adjustment accuracy, the adjustment is
repeated several times.
A/D
DETECTION OF
THE BOTTOM
VALUE
FREQUENCY
MONITOR
DIGITAL
EQUALIZER
FILTER
AVERAGING
+
DECISION
WINDOW
PWM
OUTPUT
CIRCUIT
TEBC
IC301 TC9495FP
IC201 TA2150FN
TEI
TEB TE
46
52
11 14
DETECTION OF
THE PEAK
VALUE
+
AVERAGE OF
128 SAMPLES
OFFSET
RESISTOR
DIGITAL
EQUALIZER
A/D
+
-
FEI
TEI D/A
IC301 TC9495FP
43or
46pin
Fig.17:OFFSET ADJUSTMENT
Fig.18:TRACKING BALANCE ADJUSTMENT

C X-961
3) Focus or tracking AGC
This adjustment automatically adjusts the servo loop
gain of focus or tracking AGC.
The adjustment procedures are as follows:
(1) Inject disturbance into the servo loop.
(2) Sample an error signal (FE or TE) via B. P. F at
disturbance injection.
(3) Compare the signal obtained as mentioned above
inside the LSL and the phase with disturbance.
(4) Adjust a phase difference so as to reach the target
phase value set on the microcomputer.
4) FE bias automatic adjustment
This adjustment maximizes an RFI level by optimizing
the focus point during play and adjust the level using
the RFRP level and phase difference at the disturbance
input of a focus error.
The adjustment procedures are as follows:
(1) Inject disturbance into the focus loop with a
microcomputer command. (Inside the servo LSI)
(2) Detect an RFRP signal level inside the LSI.
(3) Process the relationship between the above RFRP
signal and disturbance inside the LSI and detect the
amount and direction of focus misalignment.
(4) Substitute the detected results for the bias
adjustment item inside the servo LSI.
Besides, this adjustment repeats a series of
arrangements several times in the same manner as
auto (automatic) gain control and improves adjustment
accuracy.
SINE WAVE
GENERATION
CIRCUIT
BPF
+
AVERAGE
PHASE
COMPARATOR
DECISION
WINDOW
DIGITAL
EQUALIZER
A/D D/A
FEI,TEI
IC301 TC9495FP
43or
46
+
A/D
PEAK DETECTION
DECISION
WINDOW
DIFFERENTIAL
CALCULATION
AVERAGING
BIAS ADJUSTMENT CIRCUIT
+
DIGITAL
EQUALIZER
RFRP SIGNAL FE SIGNAL
RFRP FEI
BIAS
CIRCUIT
GENERATION OF
STEP SIGNAL
IC301 TC9495FP
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 between the RFI and
RFO.
The adjustment procedures are as follows:
(1) Calculate the PP level of RFRP from the peak and
bottom values of the RFRP level inside the servo LSI.
(2) Set such an amount of amplifier gain as a desired
RFO level by being compared with the reference level
and control the gain of the RF amplifier.
This adjustment is performed in the following timings:
Immediately before setup completion (immediately
before play)
Until focus was out of order during play and then is
recovered
6) Preamplifier stage gain adjustment
This adjustment increments 13 dB the gain of the entire
FAMP (FE, TE and RE amplifiers) according to the
setting of the GVSW terminal when there are few lens
stains or there is remarkably little reflected light of a
disk while playing the CD-RW.
The adjustment procedures are as follows:
If it is judged that the reflection of a disk is considerably
small during setup, the entire RFAMP is incremented 13
dB by switching the GVSW terminal from “H”to “L”.
Besides, if the gain is changed, redo the setup from the
first.
+
LPFPWM
PEAK
DETECTION
A/D
RFREF RFRP
BOTTOM
RFI
RFRP
RFGC
RFRP
RFGC
+
--
IC301 TC9495F
RFGO
RFO
IC201 TA2150FN
2
52
38
42
20
25
Fig.19:LOOP GAIN ADJUSTMENT
Fig.20:FE BIAS ADJUSTMENT
Fig.21:RF LEVEL ADJUSTMENT
11

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7) Adjustment initial value
All automatic adjustments are basically performed
assuming the previous adjustment value as an initial
value so long as the microcomputer power supply is
not turned off (backup is not disconnected) (there are
also several exceptions). If the backup is disconnected
and the GVSW terminal is “L”, the automatic
adjustment is performed from the initial vale instead of
the previous adjustment value.
8) Coefficient display of adjustment results
For part of the automatic adjustments (FE or TE offset,
T. BAL, F or T AGC, FE bias and RFAGC), the results can
be displayed and checked in the test mode.
The coefficient display in each automatic adjustment is
as follows:
(1) FE or TE offset
Standard value = 32 (coefficient 32 indicates that no
adjustment was necessary) and the display is
performed in a unit of approximately 46 mV.
Example: For FE offset coefficient = 35,
35 - 32 = 3 3 X 46 mV = 138 mV
The FE offset before adjustment is +138 mV.
(2) T. BAL
Standard value = 32
Coefficient = 33 to 63 ....... TE: Top side - Bottom side <
0
Coefficient = 31 to 0 ....... TE: Top side - Bottom side > 0
Every time 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 approximately 0.375 dB.
Example: For AGC coefficient = 48,
48 - 32 = 16 16 x 0.375 dB = 6 dB
The adjustment of +6dB (twice) was performed. (“A
half loop gain was used originally, the entire gain was
doubled to obtain a target value”.)
(4) FE bias
Standard value = 32, and the display is performed in a
unit of approximately 21.5 mV.
Example: For EF bias coefficient = 35,
35 - 32 = 3 3 x 21.5 mV = 64.5 MV
The FE bias alignment before adjustment results in
+64.5 mV.
(5) RF level adjustment (RFAGC)
Standard value = 32
Coefficient = 33 to 63 ....... Direction where an RF level
increases (direction where a gain increases)
Coefficient = 31 to 0 ........ Direction where an RF level
decreases (direction where a gain decreases)
Every time the coefficient moves by 1, the gain changes
by approximately 0.07 to 0.15 dB.
When the maximum gain = coefficient 63, the gain is
TYP (typical value) + 2.69 dB.
When the minimum gain = coefficient 0, the gain is TYP
- 3.93 dB.

13
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DETECTION SWITCH STATUS AT THE TIME OF LOAD EJECTION
STATUS A B C D E
SW1(S901) ON OFF OFF OFF ON
SW2(S902) OFF OFF ON ON OFF
SW3(S903) OFF OFF OFF ON OFF
SW4(CLAMP SW) OFF OFF OFF OFF ON
MECH. STATUS NO DISK CLAMP
1.4 Power Supply Loading Unit
This system power supply uses VD (8.3±0.5 V) supplied
from the mother substrate. The VD supply destination
is a 5-ch CD driver IC or 5 V regulator IC. The power
supply used inside the system is the two systems of the
above VD (drive system), and V+5 (control system).
The ON/OFF other than the loading and ejection of the
CD driver is controlled by the microcomputer with
“CONT”and the 5V ON/OFF is controlled by the
microcomputer with “CD5VON”, respectively. For the
ON/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 states (A to E) is judged using the
microcomputer A/D port. An eight/12 cm disk is judged
according to this state transition. Fig. 23 shows each
status and Fig. 24 shows the state transition.
LOP
LOM
LOADING
MOTOR
IC401
BA5811FM
M
9
10
1
2
GND 27
24
CONT 20
CDEJET 11
CD5VON 13
CDLOAD 10
8
7
6
VD
23
28
26
30
29
32
31
PGND
AGND
7 8
PREVCC VCC
FWD
REV
21
MUTE
19
GND
IC801
BA05SFP
3
1
V+5
CN701
2
4
DSCSNS 21
CLAMP SW
Mechanism Unit
S901S903 S902
Fig.22:POWER SUPPLY / LOADING SYSTEM CIRCUIT BLOCK
Fig.23:DSCSNS STATUS

14
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Fig.24:LOADING OPERATING STATE TRANSITION DIAGRAM
LOAD EJECTION OPERATING STATUS TRANSITION DIAGRAM
LOADING
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

15
C X-961
2. MECHANISM DESCRIPTIONS
-Configuration
-Loading operation
1. When a disk is inserted, the centering arm L or R
rotates, and the loading motor starts when SW1 is
switched from ON to OFF.
2. For a 12-cm disk, when the disk is carried to the
position of a dashed line, SW3 is set to ON by the
centering arm L, and the microcomputer judges the
disk to be an 12-cm one.
3. For an 8-cm disk, the disk cannot approach 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
retreated from the disk trace.
Centering Arm L
Carriage Motor
Clamp SW
Centering Guide
SW3
SW2
SW1
Centering Arm R
Mechanical Unit Lock Arm
Loading Motor
Pickup(P8)
Home SW
Core Unit
Centering Guide
Relief Arm

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C X-961
1. The centering guide is supported on the shaft at the
clamp arm rear part and the front part is energized to
the bottom.
2. For an 8-cm disk, the disk is centered at the position
where it runs against the centering guide front part as
is, and clamp operation occours.
3. For a 12-cm disk, the centering guide front is held by
the centering guide relief arm. The disk passes through
under it and is centered at the mechanical unit depth
position, and clamp operation occours.
-Clamp operation
1. 8-cm and 12-cm disks drive the detection arm at the
centered 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
operation starts.
2. A 12-cm disk completes ejection operation when
SW3 is set from OFF to ON to OFF in this order.
3. An 8-cm disk completes ejection operation when
SW2 is set from OFF to ON to OFF in this order.
Centering Guide
Detection Lever
Rack Arm
Drive Gear
Mechanical Unit Lock Lever
Mechanical Unit Lock Arm
Clamp SW
SW3
SW2
8cm
12cm
Detection Arm
Frame

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C X-961
3. DISASSEMBLY
The numeral enclosed by a circle in the drawing
indicates the order of removal.
-How to hold the mechanical unit
1. Hold the top frame and main frame.
2. Do not hold the front of the top frame tightly
because its strength is low.
-How to remove the top frame and main frame
1. Remove the four screws and four springs of the top
frame in the clamped state 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 hook of the right fulcrum part.
3. Remove the E ring of the left fulcrum and remove
the guide arm assy.
Top Frame
Clamper Arm
Assy
Guide Arm
Assy
Main Frame
Disk
Damper
Damper

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C X-961
-How to remove the loading arm assy and
spindle motor
1. Remove the E ring of the left fulcrum and remove
the springs and loading arm assy.
2. Remove the connector of the spindle motor and
remove the mounting three screws.
-How to remove the loading motor assy
1. Remove the gear cover screw and remove the gear
cover.
2. Remove the holder which was tightened together
with the gear cover.
(Note):
At assembly, tighten the holder together with the gear
cover by 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 the holder
and leaf spring.
5. Put the mechanical unit face downward, remove the
mounting screws of the loading motor assy and remove
the loading motor assy.
Loading Motor Assy
Loading Arm Assy Spindle
Motor
Gear Cover
Holder
Leaf Spring
Holder
Grease Application

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C X-961
-How to remove the carriage motor assy
1. Remove the solder of the carriage motor lead wire.
2. Remove the grease cover screw and remove the
grease cover.
3. After having removed the lead wire processing of
the motor, remove the mounting 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
Grease Application
Grease Application