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ORDER NO.
CRT3815
CD MECHANISM MODULE(S10.5COMP2)
CX-3195
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.
Model Service CD Mechanism Service CD Mechanism
Model Manual Module
Manual Module
DEH-2900MP/XN/EW5 CRT3802 CXK5760 DEH-3900MP/XN/EW5 CRT3804 CXK5760
DEH-2920MP/XN/EW5 DEH-3990MP/XN/ID CRT3829 CXK5760
DEH-2900MPB/XN/EW5 DEH-P40MP/XU/EW5 CRT3834 CXK5760
DEH-2910MP/XN/UR DEH-P4950MP/XU/ES CRT3835 CXK5760
DEH-2950MP/XN/ES CRT3820 CXK5760 DEH-P490IB/XN/UC CRT3846 CXK5760
DEH-2950MP/XN/ES1 DEH-P4900IB/XN/UC
DEH-2990MP/XN/ID DEH-P4900IB/XN/EW5 CRT3847 CXK5760
DEH-P390MP/XU/UC CRT3816 CXK5760 DEH-P5950IB/XN/ES CRT3848 CXK5760
DEH-P3900MP/XU/UC DEH-P5950IB/XN/ES1
DEH-P4950MP/XU/ES CRT3817 CXK5760 DEH-P5990IB/XN/ID
DEH-P4950MP/XU/CN5 DEH-P590IB/XN/UC CRT3851 CXK5760
DEH-P2900MP/XU/UC CRT3823 CXK5760 DEH-P5900IB/XN/UC
DEH-P3950MP/XU/ES CRT3824 CXK5760 DEH-P6900IB/XN/EW5 CRT3852 CXK5760
DEH-P3950MP/XU/CN5 DEH-P6950IB/XN/ES CRT3853 CXK5760
DEH-P5900MP/XU/EW5 CRT3828 CXK5760 DEH-P6950IB/XN/ES1
PIONEER CORPORATION 4-1, Meguro 1-chome, Meguro-ku, Tokyo 153-8654, Japan
PIONEER ELECTRONICS (USA) 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
PIONEER CORPORATION 2006
K-ZZA. OCT. 2006 Printed in Japan
1 2 3 4
CONTENTS
1. CIRCUIT DESCRIPTIONS ............................................................................................................................... 3
2. MECHANISM DESCRIPTIONS...................................................................................................................... 20
A
3. DISASSEMBLY .............................................................................................................................................. 22
B
C
D
E
F
CX-3195
2
1 2 3 4
5 6 7 8
1. CIRCUIT DESCRIPTIONS
The recent mainstay of the CD LSI is the LSI integrating the core DSP with DAC or RF amplifier, which are generally
employed as peripheral circuits, however, PE5547A, used in this product, is an LSI integrating the afore-mentioned
A
LSI unit and microcomputer unit in one chip.
A,B,E,F Signal
PE5547A
Internal RAM
BMC
RF amplifier (1Mbit)
B
EFM CD-ROM
decoder decoder
Audio
DSP
CIRC
Digital servo
1bit DAC C
PORT I/F
V850ES core SRAM
Port control D
Analog output
Fig.1.0.1 Block diagram of CD LSI PE5547A
E
F
CX-3195
3
5 6 7 8
1 2 3 4
1.1 PREAMPLIFIER BLOCK
In the preamplifier block, the pickup output signals are processed to generate signals that are used in the subsequent
A blocks: servo, demodulator, and control blocks. Signals from the pickup are I/V converted in the pickup with the
preamplifier with built-in photo detectors, and after added with the RF amplifier, they are used to produce such signals as
RF, FE, TE, and TE zero-cross signals. The preamplifier block is built in CD LSI PE5547A (IC201), whose parts are
described individually below. Incidentally, as this LSI employs a single power supply (+ 3.3 V) specification, the reference
voltages of this LSI and the pickup are the REFO (1.65 V) for both. The REFO is an output obtained from REFOUT in the
LSI via the buffer amplifier, and is output from the pin 133 of this LSI. All measurements will be performed with this REFO
as the reference.
Caution: Be careful not to short-circuit the REFO and GND when measuring.
1.1.1 APC (Automatic Power Control) circuit
B
Since laser diodes have extremely negative temperature characteristics in optical output when driven in constant current,
it is necessary to control the current with the monitor diodes in order to keep the output constant. This is the feature of the
APC circuit. The LD current is obtained by measuring the voltage between LD1 and V3R3, and divide the value by 7.5
(ohms), which becomes about 30 mA. The voltage between LD1 and V3R3 is set to about 225 mV.
Pickup Unit CD CORE UNIT
C MD PD
5 5 143
REG 1.25V
VR 7 7 + +
- 6.5k -
LD- 15 15 1k
6.5k
2R4 x 2
4.7
+
LD+ 14 14
Vref
2R7
APN
LD +
142
- 100k
1k
D
2SA1577
150k 100k
3p
LDS
PE5547A
E Fig.1.1.1 APC
F
CX-3195
4
1 2 3 4
5 6 7 8
1.1.2 RF and RFAGC amplifiers
The output from the photo-detector (A + C) and (B + D) is provided from the RFO terminal as the RF signal (which can be
used for eye-pattern check), after it is added, amplified, and equalized inside this LSI. The low frequency component of the
A
voltage RFO is calculated as below.
RFO = (A + B + C + D) x 2
The RFO is used for the FOK generation circuit and RF offset adjustment circuit.
The RFO signal, output from the pin 122, is A/C-coupled externally, input to the pin 121, and amplified in the RFAGC
amplifier to obtain the RFAGC signal.
Also, this LSI is equipped with the RFAGC auto-adjustment function, explained below, which switches feedback gains of
the RFAGC amplifier so that the RFO output will be 1.5 V.
This RFO signal is also used for the EFM, DFCT, MIRR, and RFAGC auto-adjustment circuits.
B
CD CORE UNIT
PE5547A
121
122
RF-
AGCI
RFO
126
RF2-
125 4.7k
1.2k 22p
EQ2
123
4p
1.2k 56p
5k 5k 124
EQ1
+ + 3.55k 5.6k
-
- - 119
15.2k + AGCO
15.2k 44k 20k 11.75k
To DEFECT/A3T detection
RFOFF setup
For RFOK generation
Pickup Unit C
VREF R2
P3 +
- 61.0k
P7 +
A+C A + FEO
13 13 129
-
P9 135
VREF 10k 8.8k -
140k FE A/D
P2 + 61.0k 160k FE-
134
-
P4
B+C 6 B FEOFF setup
6 130
P8 10k 8.8k
VREF
D
Fig.1.1.2 RF/AGC/FE
E
F
CX-3195
5
5 6 7 8
1 2 3 4
1.1.3 Focus error amplifier
The photo-detector outputs (A + C) and (B + D) are passed through the differential amplifier and the error amplifier, and (A
+ C - B - D) is provided from the pin 135 as the FE signal. The low frequency component of the voltage FE is calculated as
A
below.
FE = (A + C - B - D) x 8.8k / 10k x 111k / 61k x 160k / 72k
= (A + C - B - D) x 3.5
For the FE outputs, an S-shaped curve of 1.5 Vp-p is obtained with the REFO as the reference. The cutoff frequency for
the subsequent stage amplifiers is 14.6 kHz.
1.1.4 RFOK circuit
This circuit generates the RFOK signal, which indicates the timing to close the focus loop and focus-close status during
the play mode, from the pin 70. As for the signal, "H" is output in closing the focus loop and during the play mode.
B
Additionally, the RFOK becomes "H" even in a non-pit area, since the DC level of the RFO signal is peak-held in the
subsequent digital block and compared at a certain threshold level to generate the RFOK signal. Therefore, the focus is
closed even on a mirror-surface area of a disc. This signal is also supplied to the microcomputer via the low-pass filer as
the FOK signal, which is used for protection and gain switching of the RF amplifier.
1.1.5 Tracking error amplifier
The photo-detector outputs E and F are passed through the differential amplifier and the error amplifier to obtain (E - F),
and then provided from the pin 138 as the TE signal. The low frequency component of the voltage TE is calculated as
below.
TEO = (E - F) x 63k / 112k x 160k / 160k x 181k / 45.4k x 160k / 80k
C = (E - F) x 4.48
For the TE output, TE waveform of about 1.3 Vp-p with the REFO as the reference. The cutoff frequency in the subsequent
is 21.1 kHz.
CD CORE UNIT
PE5547A
TE A/D
+ TEO
TEOFF setup 138
Pickup Unit -
+ 47p
-
80k 160k
D + TE-
137
-
P5 45.36k 161k
E E
11 11 132
P10
VREF 112k 63k +
+ TE2
- 139
45.36k -
+
- 160k 10000p
P1 160k
F 9 F 20k 60k
9 131
P6
112k 63k TEC
140
-
VREF + Inside TEC
E
Fig.1.1.3 TE
F
CX-3195
6
1 2 3 4
5 6 7 8
1.1.6 Tracking zero-cross amplifier
The tracking zero-cross signal (hereinafter referred to as TEC signal) is obtained by amplifying the TE signal by fourfold,
and used to detect the tracking-error zero-cross point. As the purpose of detecting the zero-cross point, the following two
A
points can be named:
1. To use for track-counting in the carriage move and track jump modes
2. To use for detecting the direction in which the lens moves in tracking close. (Used in the tracking brake circuit to be
explained later.)
The frequency range of the TEC signal is from 300 Hz to 20 kHz, and
TEC voltage = TE level x 4
The TEC level can be calculated at 4.62 V, which, at this level, exceeds the D range of the operational amplifier, and clips
the signal, but, because the CD LSI only uses the signal at the zero-cross point, it poses no particular problem.
1.1.7 EFM circuit B
The EFM circuit converts the RF signal into digital signals of 0 and 1. The AGCO signal output from the pin 119 is
A/C-coupled externally, input to the pin 118, and supplied to the EFM circuit.
Missing RF signal due to scratches and stains on the disc, and asymmetry of the upper and lower parts of the RF, caused
by variation in disc production, cannot be entirely eliminated in AC coupling process, the reference voltage ASY of the
EFM comparator is controlled, using the probability that 0 and 1 occur at 50%. Thus, the comparator level will always stay
around the center of the RFO signal. This reference voltage ASY is generated by passing the EFM comparator output
through the low-pass filter. The EFM signal is output from the pin 113.
PE5547A C
Vdd
ASY
114
EFM signal
RFI
118 + EFM
113
- 2k
Vdd
D
40k +
-
+
- 1.5k 7.5k
40k
E
Fig.1.1.4 EFM
F
CX-3195
7
5 6 7 8
1 2 3 4
1.2 SERVO BLOCK (PE5547A: IC201)
The servo block performs servo control such as error signal equalizing, in-focus, track jump and carriage move. The DSP
A block is the signal-processing unit, where data decoding, error correction, and compensation are performed. The FE and
TE signals, generated in the preamplifier stage, are A/D-converted, and output drive signals for the focus, tracking, and
carriage systems via the servo block. Also, the EFM signal is decoded in the signal-processing unit, and ends up in
outputting D/A-converted audio signals through the D/A converter. Furthermore, in this decoding process, the spindle
servo error signal is generated, supplied to the spindle servo block, and used to output the spindle drive signal.
Each drive signal for focus, tracking, carriage, and spindle servos (FD, TD, SD, and MD) are output as PWM3 data, and
then converted to analog data through the LPF. These drive signals, after changed to analog form, can be monitored with
the FIN, TIN, CIN, and SIN signals, respectively. Subsequently, the signals are amplified and supplied to the actuator and
motor for each signal.
B
1.2.1 Focus servo system
The main equalizer of the focus servo consists of the digital equalizer block. The figure 1.2.1 shows the block diagram of
the focus servo system.
In the focus servo system, it is necessary to move the lens within the in-focus range in order to close the focus loop. For
that purpose, the in-focus point is looked for by moving the lens up and down with the focus search voltage of triangular
signal. During this time, the rotation of the spindle motor is retained at a certain set speed by kicking the spindle motor.
The servo LSI monitors the FE and RFOK signals and automatically performs the focus-close operations at an appropriate
timing. The focus-close operation is performed when the following three conditions are satisfied at the same time:
1) The lens moves toward the disc surface.
C 2) RFOK = "H"
3) The FE signal is zero-crossed.
Consequently, the FE converges to "0" (= REFO).
When the above-mentioned conditions are met and the focus loop is closed, the FSS bit is shifted from "H" to "L," and
then, in 10 ms, the CPU of the LSI starts monitoring the RFOK signal obtained through the low-pass filter.
If the RFOK signal is determined to be "L," the CPU of the LSI takes several actions including protection.
Fig.1.2.2 shows a series of actions concerning the focus close operations. (It shows a case where the focus loop cannot
be closed.)
With the focus mode selector displaying 01 in the test mode, pressing the focus close button, allows to check the
S-shaped curve, search voltage, and actual lens behavior.
D
IC201 PE5547A IC301 BA5839FP
A+C
129
FE DIG.
B+D AMP A/D EQ
130 FOP
FD 12
PWM LENS
E CONTROL 109 6
FOM
FOCUS SEARCH 11
TRIANGULAR
WAVE GENERATOR
Fig.1.2.1 Block diagram of the focus servo system
F
CX-3195
8
1 2 3 4
5 6 7 8
Search start
A
Output from FD terminal
A blind period The broken line in the figure is assumed in the
case without focus servo.
FE controlling signals
You can ignore this for blind periods.
FSS bit of SRVSTS1 resistor B
RFOK signals
The status of focus close is judged from the statuses
of FSS and RFOK after about 10 mS.
Fig.1.2.2 Timing chart for focus close operations
C
1.2.2 Tracking servo system
The main equalizer of the tracking servo consists of the digital equalizer block. The figure 1.2.3 shows the block diagram of
the tracking servo system.
IC201 PE5547A IC301 BA5839FP
E D
132
TE DIG.
F AMP A/D EQ
131 TOP
TD 14 LENS
PWM
CONTROL 110 2
TOM
13
JUMP
PARAMETERS
E
Fig.1.2.3 Block diagram of the tracking servo system
F
CX-3195
9
5 6 7 8
1 2 3 4
(a) The track jump operation is automatically performed by the auto-sequence function inside the LSI with a command
from the CPU of the LSI. For the track jumps used in the search mode, a single track jump and four to 100 multi-track jump
are available in this system. In the test mode, out of these track jumps, 1, 32, and 32 * 3 track jumps, as well as carriage
A
move can be performed and checked in mode selection. In a track jump, the CPU of the LSI sets about half the number of
the total tracks to jump (about five tracks for a 10-track jump), and the set number of tracks are counted using the TEC
signal. By outputting the brake pulse for a certain period of time (set by the CPU of the LSI) from the time the set number
is counted, and stopping the lens, the tracking loop can be closed so that the normal play can be continued.
Also, in order to facilitate closing of the tracking loop in a track jump, the brake circuit is kept ON for 50 msec, after the
brake pulse is stopped, for increasing the tracking servo gain. The FF/REW action in the normal operation mode is
realized by performing single jumps consecutively. The speed is approximately 10 times faster than in the normal mode.
(b) Brake circuit
Since the servo loop is not closed very well in the setup mode and track jump mode, the brake circuit is used for stabilizing
B
the servo-loop close operation. The brake circuit detects the direction in which the lens moves, and outputs only the drive
signal for the direction opposite to the movement to slow down the lens, thereby stabilizing the tracking servo-loop close
operation. Additionally, the off-track direction is determined from the TEC and MIRR signals, as well as their phase
relation.
BRAKE
t2
TD
C
t1
KICK
TEC
ON
T. BRAKE
OFF
GAIN UP
EQUALIZER GAIN NORMAL
NORMAL
D
OPEN
T. SERVO
CLOSED
Fig.1.2.4 Single-track jump
E
F
CX-3195
10
1 2 3 4
5 6 7 8
TD t1
A
t2
TEC
(10 TRACK)
GAIN UP
EQUALIZER 50 mS
NORMAL
ON
T. BRAKE
OFF
OPEN
SERVO B
CLOSED
SD
t
2.9mS (4.10 TRACK JUMP)
5.8mS (32 TRACK JUMP)
Fig.1.2.5 Multi-track jump
C
LENS MOVING FORWARDS LENS MOVING BACKWARDS
(INNER TRACK TO OUTER)
TEC
TZC
(TEC "SQUARED UP" )
(INTERNAL SIGNAL )
D
MIRR
MIRR LATCHED AT
TZC EDGES
=
SWITCHING PULSE
EQUALIZER OUTPUT
(SWITCHED)
E
DRIVE DIRECTION REVERSE FORWARD
Time
Note : Equalizer output assumed to hava same phase as TEC.
Fig.1.2.6 Track brake
F
CX-3195
11
5 6 7 8
1 2 3 4
1.2.3 Carriage servo system
The carriage servo system inputs the output of the low frequency component from the tracking equalizer (information on
the lens position) to the carriage equalizer, and, after the gain is increased to a certain level, outputs the drive signal from
A
the CD of the LSI. This signal is applied to the carriage motor via the driver IC.
Specifically, since it is necessary to move the whole pickup to the FORWARD direction when the lens offset reaches a
certain level during the play mode, the equalizer gain is set to output higher voltage than the carriage motor starting
voltage at this time. In actual operations, a certain threshold level is preset in the servo LSI for the equalizer output, and
only when it exceeds the threshold level, the drive voltage will be output. This can reduce the power consumption. Also,
before the whole pickup starts moving, the equalizer output voltage may exceed the threshold level a few times, due to
such causes as eccentricity of discs. In this case, the output waveform of the drive voltage from the LSI assumes a
pulse-like form.
B
IC201 PE5547A IC301 BA5839FP
From DIG.
TRACK EQ. EQ LCOP
18
PWM SD
CONTROL 111 24 M
LCOM
17
KICK, BRAKE
REGISTERS CARRIAGE
MOTOR
C
Fig.1.2.7 Block diagram for the carriage servo block
TRACKING DRIVE
(LOW FREQUENCY)
D LENS POSITION
DRIVE ON/OFF THRESHOLD
CRG DRIVE
(INSIDE UPD63711GC)
CRG MOTOR VOLTAGE
E
CARRIAGE MOVED AT THESE POINTS
Fig.1.2.8 Waveforms of the carriage signal
F
CX-3195
12
1 2 3 4
5 6 7 8
1.2.4 Spindle servo system
In the spindle servo system, the following modes are available:
1) Kick
A
Used to accelerate the disc rotation in the setup mode.
2) Offset
a. Used in the setup mode after the kick mode, until the TBAL adjustment is completed.
b. Used during the play mode when the focus loop is unlocked, until it is locked again.
In both cases, the mode is used to keep the disc rotation approximately normal.
3) Applicable servo
CLV servo mode, used in the normal operation.
In the EFM demodulation block, by WFCK/16 sampling whether the frame sync signal and the internal frame counter
output are synchronized, a signal is created to show if they are "in-sync" or "non-sync." The status is not recognized as
asynchronous until the signal is "non-sync" for eight consecutive times; otherwise it is recognized as synchronous. In the B
applicable servo mode, the leading-in servo mode is automatically selected in the asynchronous status, and the normal
servo mode in the synchronous status.
4) Brake
Used to stop the spindle motor.
In accordance with the CPU of the LSI command, the brake voltage is sent out from the servo LSI. At this time, the EFM
waveform is monitored in the LSI, and when the longest EFM pattern exceeds a certain interval (or the rotation slows
down enough), a flag is set inside the CD of the LSI, and the CPU of the LSI switches off the brake voltage. If a flag is not
set within a certain period, the CPU of the LSI shifts the mode from the brake mode to the stop mode, and retains the
mode for a certain period of time. If the mode switches to this stop mode in the eject operation, the disc will be ejected
after the period of time mentioned above elapses. C
5) Stop
Used when the power is turned on and during the eject operation. In the stop mode, the voltage in both ends of the spindle
motor is 0 V.
6) Rough servo
Used in carriage feed (carriage move mode such as long search).
By obtaining the linear velocity from the EFM waveform, the "H" or "L" level is input to the spindle equalizer. In the test
mode, this mode is also used for grating confirmation.
D
IC201 PE5547A IC301 BA5839FP
SPEED ERROR SIGNAL
SOP
MD 16
EFM DSP DIG. PWM
BLOCK EQ
112 26 M
SIGNAL SOM
15
SPINDLE
MOTOR
PHASE ERROR SIGNAL
E
Fig.1.2.9 Block diagram of the spindle servo system
F
CX-3195
13
5 6 7 8
1 2 3 4
1.3 AUTOMATIC ADJUSTMENT FUNCTION
In this system, all the circuit adjustments are automated inside the CD of the LSI.
A All adjustments are performed whenever a disc is inserted or the CD mode is selected by pressing the source key.
Details of each adjustment will be explained below.
1.3.1 TE, FE, and RF offset auto-adjustment
In this adjustment the TE, FE, and RF amplifier offsets of the preamplifier block in POWER ON are adjusted to the
respective target values with the REFO as reference. (The target values for TE, FE, and RF offsets are 0 V, 0 V, and - 0.8
V, respectively.)
Adjusting procedure
1) The CPU of the LSI reads respective offsets through the CD of the LSI, when they are in LDOFF status.
2) The CPU of the LSI calculates the voltages for correction from the values read in 1), and substitutes the corrected
B
values to prescribed places to adjust.
1.3.2 Tracking balance (T.BAL) auto-adjustment
This adjustment equalizes the output difference of the E-ch and F-ch from the pickup by changing the amplifier gain inside
the CD of the LSI. In actual operation, adjustment is performed so that the TE waveform becomes symmetrical on each
side of the REFO.
Adjusting procedure
1) After closing the focus loop,
2) Kick the lens in the radial direction to ensure the generation of the TE waveform.
C 3) The CPU of the LSI reads the offset amount of the TE signal calculated in the LSI at the time through the CD of the LSI.
4) The CPU of the LSI determines the offset amount is 0, positive, or negative.
- When the offset amount is 0, the adjustment is completed.
- When the offset amount is positive or negative, the amp gains for E-ch and F-ch should be changed, following a certain
rule.
Then, steps 2) to 4) are repeated until the offset amount becomes 0 or the repetition reaches the limit number of times.
1.3.3 FE bias auto-adjustment
This adjustment is to maximizes the RFO level by optimizing the focus point during the play mode, utilizing the phase
difference between the 3T level waveform of the RF waveform and that of when focus error disturbance is input. This
D
adjustment is performed at the same timing as the auto-gain control, which will be described later, since disturbance is
input to the focus loop.
Adjusting procedure
1) The CPU of the LSI issues the command to introduce disturbance to the focus loop (inside the CD of the servo LSI).
2) The waver of the 3T component of the RF signal is detected in the CD of the LSI.
3) The relation between the 3T component above and the disturbance is processed inside the CD of the LSI to detect the
volume and direction of the focus offset.
4) The CPU of the LSI issues a command and reads out the detected results from the CD of the LSI.
5) The CPU of the LSI calculates the necessary correction and substitutes the result to the bias adjustment term inside
E the CD of the LSI.
Additionally, in this adjusting, a series of steps are repeated for better adjustment accuracy, the same as in the auto-gain
control.
F
CX-3195
14
1 2 3 4
5 6 7 8
1.3.4 Focus and tracking AGC
This adjustment is to automatically adjust the focus and tracking servo loop gains.
Adjusting procedure
A
1) Introduce disturbance to the servo loop.
2) The error signals (FE and TE) when disturbance is introduced are extracted through the band pass filter, to obtain the
G1 and G2 signals.
3) The CPU of the LSI reads the G1 and G2 signals through the CD of the LSI.
4) The CPU of the LSI calculates the necessary correction and performs the loop gain adjustment inside the CD of the
LSI.
For increased adjustment accuracy, the same adjustment process is repeated a few times.
1.3.5 RF level auto-adjustment (RFAGC)
This adjustment is to adjust the dispersion of the RF level (RFO), which may be caused by mechanism or disc-related B
factors, to a steady value for reliable signal transmission. The adjustment is performed by changing the amp gain between
RFO and RFAGC.
Adjusting procedure
1) The CPU of the LSI issues a command and reads out the output from the RF level detection circuit inside the CD of the
LSI.
2) From the read values, the CPU of the LSI calculates the amp gain to change the RFO level to the target.
3) The CPU of the LSI sends a command to the CD of the LSI to adjust the amp gain to the level calculated in 2).
This adjustment is performed
1) when only the focus close operation is completed during the setup mode, and C
2) immediately before the setup is completed (or when the play mode is about to start).
1.3.6 Adjustment of gains in preamplifier stage
In this adjustment, when reflected beams from the disc surface are extremely weak, such as when the lens is dirty, or a
CD-RW is played, gains in the whole RFAMP block (FE, TE, and RF amplifiers) are increased by + 6 dB or + 12 dB,
depending on the situation.
Adjusting procedure
When the system determines that the reflected beams from the disc surface are extremely weak during the setup mode,
the whole RFAMP gains will be increased by + 6 dB or + 12 dB.
D
1.3.7 Initial values in adjustment
All automatic adjustments immediately after inserting a disc are performed based on the initial values. Automatic
adjustments by source change or ACC ON are basically performed using the previous adjustment values as the initial
values.
E
F
CX-3195
15
5 6 7 8
1 2 3 4
1.3.8 Coefficient display of adjustment results
For some of the adjustments (FE and RF offset, FZD cancel, F and T gains, and RFAGC), the adjustment results can be
displayed and confirmed in the test mode.
A
The coefficient display in each auto adjustment is as follows:
1) FE and RF offset
Reference value = 32 (coefficient of 32 indicates that no adjustment is required)
The value is displayed in the unit of approximately 32 mV.
Ex. When the FE offset coefficient is 35,
35 - 32 = 3 x 32 mV = 96 mV
The correction is about +96 mV, which means the FE offset before adjustment is - 96 mV.
2) F and T gain adjustment
Reference value for focus and tracking = 20
B
The displayed coefficient / the reference value indicates the adjusted gain.
Ex. When the AGC coefficient is 40,
adjustment of 40 / 20 = 2 times (+ 6 dB) has been performed.
(It means that the original loop gain was half the target, and the whole gain was doubled to obtain the target value.)
3) RF level adjustment (RFAGC)
Reference value = 8
The coefficient of 9 to 15 indicates to increase the RF level
(for more gains).
The coefficient of 7 to 10 indicates to decrease the RF level
(for less gains).
C When the coefficient changes by 1, the gain changes by 0.7 to 1 dB.
When the coefficient is 15, the gain is the maximum at TYP + 7.9 dB.
When the coefficient is 0, the gain is the minimum at TYP - 4.6 dB.
D
E
F
CX-3195
16
1 2 3 4
5 6 7 8
1.4 POWER SUPPLY AND LOADING BLOCK
For the power supply for this system, the VD (7.5