LG GCE-8240B User manual

3
INTRODUCTION
FEATURES
1. General
1) Enhanced IDE interface.
2) Internal 5.25 inch, halfheight CD-R/RW Drive.
3) 8 Mbytes buffer memory.
4) Audio CD like tray loading of a disc without using a caddy.
5) Power loading and power ejecting of a disc. The disc can also be ejected manually.
6) Supports Power saving mode and Sleep mode.
7) Vertical and Horizontal operation.
8) ExacLink Function.
2. Supported disc formats
1) Reads and writes data in each CD-ROM, CD-ROMXA, CD-I FMV, Video CD, and CD-EXTRA
2) Reads data in Photo CD (Single and Multi session).
3) Reads and writes standard CD-DA.
4) Reads and writes CD-R discs conforming to “Orange Book Part 2”.
5) Reads and writes CD-RW discs conforming to “Orange Book Parts 3”.
3. Supported write method
1) Disc at once (DAO), Session at once (SAO), Track at once (TAO), Variable packet, Fixed packet, and
Multi-session.
4. Performance
1) Random 110 ms average access time.
2) CD-R Record speed : 8X, 12X, 16X, 16-24X Z CLV.
3) CD-RW Record speed : 2X, 4X, 10X.
4) CD-ROM : Max 6,000 KB/s(Max 40x) Sustained Transfer rate.
5) Supports real time error correction and real time layered error correction at each speed.
6) PIO Mode 4, Multi DMA Mode 2 .
7) Multimedia MPC-3 Spec compliant.
8) Support CD-TEXT read/write.
5. Audio
1) Output 16 bit digital data over ATA interface.
2) 8 Times Digital Filter for CD Audio
3) Software Volume Control
4) Equipped with audio line output and headphone jack for audio CD playback.
5) Front panel Volume Control for Headphone Output.
This service manual provides a variety of service
information.
It contains the mechanical structure of the CD-
R/RW Drive and the electronic circuits in
schematic form. This CD-R/RW Drive was
manufactured and assembled under our strict
quality control standards and meets or exceeds
industry specifications and standards.
This CD-R/RW drive is an internal drive unit
designed for use with IBM PC, HP Vectra, or
compatible computer. It can write as much as 700
Mbytes of digital data into CD-R/RW disc, and can
read as much as 650 Mbytes of digital data stored
in a CD-ROM, CD-R and CD-RW disc.
This CD-R/RW Drive can easily meet the
upcoming MPC level 3 specification, and its
Enhanced Intelligent Device Electronics (E-IDE)
and ATAPI interface allows Plug and play
integration in the majority of today’s PCs without
the need of an additional interface card.

4
SPECIFICATIONS
1. SYSTEM REQUIREMENTS
-CPU: IBM Compatible Pentium 350MHZ (or faster)
(For 24X Write speed, 500MHz or faster recommended.)
-64MB Memory or greater
2. SUPPORTING OPERATING SYSTEM
3. GENERAL
1) Host Interface.......................................................................................................................ATAPI compliant
2) Read Function
• Acceptable discs ...............................................................CD-ROM Mode1 (basic format), CD-ROM XA
CD-Audio
Mixed Mode (Audio and Data Combined)
Photo-CD (Single and Multi-Session)
CD-I FMV, Video CD
CD-Plus/CD-Extra,
CD-R (Conforming to “Orange Book Part2”)
CD-RW (Conforming to “Orange Book Part3”)
3) Write function
• Applied Format..................................................................CD-ROM Mode-1
CD-ROM XA
CD-Audio
Mixed Mode (Audio and Data Combined)
Video CD, CD-I FMV
CD-Plus/CD-Extra
• Writing Method..................................................................Disc at once(DAO)
Session at once(SAO)
Track at once(TAO)
Variable packet writing
Fixed packet writing
Multi-session
4) Cache memory (R/W) .........................................................8 Mbyte
5) Disc diameter ......................................................................12 cm /8 cm
6) Data capacity (Yellow-Book)
• User Data/Block ................................................................2,048 bytes/block (Mode 1 & Mode 2 Form 1)
2,336 bytes/block (Mode 2)
2,328 bytes/block (Mode 2 Form 2)
2,352 bytes/block (CD-DA)
7) Rotational Speed
CD-Audio.............................................................................8x~24x(CAV) Approx.3,600 r/min
DAE speed ..........................................................................18x~40x(CAV) Approx.8,400 r/min
CD-RW data ........................................................................14x~32x(CAV) Approx.6,500 r/min
CD-ROM/CD-R data............................................................18x~40x(CAV) Approx.8,400 r/min
8) MTBF
• 125,000 POH at an operating duty of 10% at room temperature.
• DOS 3.1 or Higher
• Windows 95/98/2000/ME/XP
• OS/2 Warp (Ver 3.0)
• Solaris Ver 2.4 or higher
• Linux Slackware Ver 2.3
• Windows NT 4.0 or later

5
4. DRIVE PERFORMANCE
1) Data Transfer Rate
* Sustained Data Transfer Rate ..........................................300 Kbytes/s (2x)
600 Kbytes/s (4x)
1,200 Kbytes/s (8x)
1,800Kbytes/s(12x)
2,400Kbytes/s(16x)
3,600 Kbytes/s(24X)
2,700 to 6,000 Kbytes/s 18 to 40x CAV
* Burst Data Transfer Rate (ATAPI) ....................................16.67 Mbytes/s (PIO Mode 4)
16.67 Mbytes/s (MULTI-DMA Mode 2)
2) Average Access Time
Random Access ..................................................................110 ms Typical (Max.40X) : INCLUDING LATENCY
3) Data Buffer Capacity ...........................................................8 Mbytes
5. POWER REQUIREMENTS
1) Voltage
+5 V DC with +5% tolerance, less than 100 mVp-p Ripple voltage
+12 V DC with +5% tolerance, less than 100 mVp-p Ripple voltage
2) Current
• Hold Track State ...............................................................+5V DC 1.4A, +12V DC 0.5A (Typical)
• Seeking & Spin up ............................................................+5V DC 1.4A, +12V DC 0.9A (Typical)
6. AUDIO PERFORMANCE
* GCE-8240B FUNCTION TABLE
Item Typical Limit Test Signal Test Condition Note
Output Level 0.7 Vrms + 10 % 1KHz 0 dB No Filter at 47 kΩ
S/N 85 dB 75 dB 1KHz 0 dB with IHF-A + 20KHz LPF at 47kΩ
THD 0.08 % 0.1 % 1KHz 0 dB with IHF-A + 20KHz LPF at 47kΩ
Channel 65 dB 60 dB 1KHz 0 dB with IHF-A + 20KHz LPF at 47kΩ
Separation
Frequency + 2dB
Response
AUDIO OUT
+3 dB 20Hz~20KHz 0 dB No Filter at 47 kΩ
Funtion GCE-8240B
•CD-R Writing speed 8x/12x/16x/16x-24x ZCLV Data writing
•CD-RW Writing speed 2x/4x/10x Data writing
•CD-ROM Reading speed 40x Data transfer
MODEL

LOCATION OF CUSTOMER CONTROLS
6
1. Disc tray
This is the tray for the disc. Place the disc on the
ejected disc tray, then lightly push the tray (or
push the eject button) and the CD will be loaded.
NOTE: Don’t pull out or push in the disc tray
forcibly. This might cause damage to the loading
section of the drive.
2. Stop/Eject button
This button is pressed to open the CD tray.
This button works only when power is supplied to
the drive.
If an Audio CD is playing, pressing this button will
stop it, and pressing it again will open the tray.
3. Emergency Eject Hole
Insert a paper clip here to eject the Disc tray
manually or when there is no power.
4. Volume control
This is used to adjust the output volume of the
headphone jack. It can’t be used to adjust the
output volume for the audio output connectors on
the rear panel.
NOTE : Turn the volume down before turning on
the power. Sudden loud noises can damage your
hearing.
5. Headphone jack
This jack is for connecting headphones or mini-
speakers.
6. Drive activity indicators
Two colored LEDs are used to indicate the
operation of CD-R/RW Drive.
(1) Read
The orange color is displayed when the spindle
motor begins the Spin up operation: accessing
data, reading data, playing Audio, and up loading
tray.
(2) Write
The green color is flashed during disc writing
sessions.
READ
READ
WRITE
WRITE
Headphone Jack
Volume
Control Drive Activity Indicators
Stop/Eject Button
Disc Tray
Emergency Eject Hole
Front Panel

7
1. Power Connector
Connects to the power supply (5-and 12-V DC) of
the host computer.
NOTE : Be careful to connect with the proper
polarity. Connecting the wrong way may damage
the system (and is not guaranteed). Usually this
connector can only be attached one-way.
2. IDE Interface Connector
Connect to the IDE (Integrated Device
Electronics) Interface using a 40-pin flat IDE
cable.
NOTE : Do not connect or disconnect the cable
when the power is on, as this could cause a short
circuit and damage the system. Always turn the
power OFF when connecting or disconnecting the
cable.
3. Jumper Connector
This jumper determines whether the drive is
configured as a master or slave. Changing the
master-slave configuration takes effect after
power-on reset.
4. Analog Audio Output Connector
Provides output to a sound card (analog signal).
Generally you need this to play a regular audio
CD.
5. Digital Audio Output Connector
Provides output to a sound card (digital signal).
Digital Audio Output
Connector
Jumper Connector
Analog Audio Output Connector IDE Interface Connector
Power Connector
Rear Panel

1. CABINET and CIRCUIT BOARD
DISASSEMBLY
1-1. Bottom Chassis
A. Release 4 screws (A) and remove the Bottom Chassis
in the direction of arrow (1). (See Fig.1-1)
1-2. Front Bezel Assy
A. Insert and press a rod in the Emergency Eject
Hole and then the CD Tray will open in the direction
of arrow (2).
B. Remove the Tray Door in the direction of arrow
(3) by pushing the stoppers forward.
C. Release 3 stoppers and remove the Front Bezel Assy.
1-3. Cabinet and Main Circuit Board
A. Remove the Cabinet in the direction of arrow (4).
(See Fig. 1-3)
B. Release 2 hooks (a) and remove the CD Tray
drawing forward.
C. Remove the Main Circuit Board in the direction of
arrow (5).
D. At this time, be careful not to damage the 4
connectors, are positioned at right side, of the Main
Circuit Board.
2. MECHANISM ASSY DISASSEMBLY
2-1. Pick-up Unit
A. Release screws (B).
B. Separate the Pick-up Unit in the direction of arrow (6).
(4)
(5)
Main
Circuit Board
Hooks (a)
Cabinet
(A)
(A) (A)
(A)
(1)
Bottom Chassis
(2)
(3)
Tray Door
CD Tray
Front Bezel Assy
Emergency Eject Hole
Stoppers
Fig. 1-1
Fig. 1-2
DISASSEMBLY
8
Fig. 1-3
Mechanism Assy
Pick-up Unit
(B) (B)
(6)
Fig. 2-1

2-2. Pick-up
A. Release 2 screws (C) and remove the Pick-up.
Pick-up Unit
Pick-up
(C)
(C)
Fig. 2-2
9

ATIP Absolute Time in Pre-groove. With an additional modulation of the “Wobble”, the “Groove” contains a time
code information.
Wobble The pre-groove in the Disc is not a perfect spiral but is wobbled.
With : – A typical amplitude of 30 nm
– A spatial peried of 54~64 µm
CW Continuous Wave. The laser light output is at a constant level.
DOW Direct Over-Write. The action in which new information is recored over previously recorded information in
CD-RW disc.
Overwrite The action in which new information is recorded over previously recorded information.
(Pre-)Groove The guidance track in which clocking and time code information is stored by means of an FM
modulated wobble.
Land Land is characterized in the following way:
When radial signals are concerned,land is defined as the area between the grooves.
When HF signal are concerned,land is defined as the area between the marks(pits) in tangential
direction.
Hybrid Disc A Multisession disc of which the first Session is mastered. On a hybrid disc, recorded and
mastered information may co-exist.
Mastered Information,stored as pits on the disc during the manufacturing process of the disc.
Information (when making the master)
OPC Optimum Power Control. Procedure is determined optimum recording power according to CD-
R/RW Media in recording start step.
ROPC Running OPC. The purpose is to continuously adjust the writing power to the optimum power
that is required.
When the optimum power may change because of changed conditions of disc and change in
operating temperature.
Jitter The 16 value of the time variation between leading and trailing edges of a specific (I3 … I11) pit
or land as measured by Time Interval Analysis.
Deviation The difference between a fixed value of Pit length and Land length.
TOC Table Of Contents : in the Lead-in Area the subcode Q-channel contains information about the
Tracks on the disc.
Packet A method of writing data on a CD in small increments.
Writing Two kinds of packets can be written : Fixed-length and Variable-length.
Write The shape of the HF write signal used to modulate the power of the laser.
Strategy The Write Strategy must be used for recordings necessary for disc measurements.
Information Wobble, ATIP, Disc Identification, Write Power, Speed Range OPC Parameters, etc are
Area recorded in the Information area of CD-RW Disc
Finalization The action in which (partially) unrecorded or logically erased tracks are finished and the Lead-in
and/or Lead-out areas are recorded or overwritten with the appropriate TOC subcode.
Logical Erase
A method to remove information from a disc area by overwriting it with an EFM signal containing
mode 0 subcode
A logically erased area is equivalent to an unrecorded
Physical Erase The action in which previously recorded information is erased by overwriting with a CW laser
output.
After a Physical Erase action, the erased area on the CD-RW disc is in the unrecorded state
again.
Session
An area on the disc consisting of a Lead-in area, a Program area, a lead-out area.
Multi session A session that contains or can contain more than one session composed Lead-in and Lead-out
GLOSSARY
14

The differences of CD-R/CD-RW discs and General CD-ROM
1. Recording Layer
Recordable CD has a wobbled pre-groove on the surface of disc for laser beam to follow track.
2. Disc Specification
Read-only Disc
CD-R and CD-RW Disc
3~11T
1.6um
0.4~0.5 um
(Pit)Groove
Land
Track pitch(p)
Radial Direction
Iw
A
O
a
a
Groove
Land
Radial Error Signal
The Groove wobble
Average center
Actual center
CD-ROM CD-R CD-RW
Standard Yellow Book Orange Book II Orange Book III
Record Not available Write once Re-writable
I 11/Itop > 0.6 > 0.6 0.55 > M11> 0.70
(HF Modulation)
Write Laser Power(mW) 10-30 mW 6-25 mW
Read Laser Power(mW) < 0.5 mW < 0.7 mW < 1.0 mW
Jitter < 35 nsec < 35 nsec < 35 nsec
Reflectivity (Rtop) 70 % 65 % 15 % ~ 25 %
15
CD-ROM (READ-ONLY DISC) a=30nm

16
3. Disc Materials
1) CD-ROM disc
Laser Beam Groove
Substrate
(Polycarbonate)
Organic Dye Layer
Reflective Layer
Protective Layer
Label Printing
2) CD-R disc
Pigment Reflective Layer Color
Phtalocyanine Gold/Silver Yellow/White
Cyanine Gold/Silver Dark Green/Bright Green
Azo Gold/Silver Dark Blue
• It is composed of Silver _ colored aluminum plate and Reflective layer.
• Groove (Pit) of aluminum plate make a track.
• Laser wavelength : 780 nm, Laser Power (Read): 0.5mW
• Signal is detected by the
difference of reflective beam
intensity between “pit” and
“Land” on the disc.
• It is so-called WORM (Write Once Read Many) CD.
• It is composed of polycarbonate layer, Organic dye layer, Reflective layer, and Protective
layer.Gold/Silver Reflective layer is used to enhance the reflectivity
• According to the kinds of Organic dye layer, it is divided by Green CD, Gold CD, Blue CD.
• Laser Wavelength : 780 nm, Laser Power (read) : 1.2 mW
• Recording Power : 8x(9~30mW), 12x(12~38mW), 16x(14~44mW), 24x(18~50mW)
• When some part of dye layer is exposed to laser heat, it’s color changs black.Therefore, writing and
reading is enabled by the difference of reflectivity between changed part and unchanged part.
• Polycarbonate layer has Pre_Groove which make a Track.
Laser Beam
Pit
Substrate
(Polycarbonate)
Reflective Layer
Protective Layer
Label Printing

17
3) CD-RW Disc
4. Reading process of Optical Disc
Laser Beam Groove
Substrate
(Polycarbonate)
Reflective Layer
Dielectric Layer(TL)
Dielectric Layer(UL)
Protective Layer
Label Printing
•It is composed of polycarbonate layer, alloy(silver, arsenic) layer, aluminum reflectivity layer, protective layer.
•An crystalized alloy layer is transformed into noncrystalized by the laser heat. Therefore, writing and reading
is enabled by the difference of reflectivity.
•It is possible to overwrite about 1000 times.
•Laser Wavelength : 780 nm, Laser Power (Read) : 1.0mW
•Recording Power : Erase (4~18mW), Write (15~40mW)
•When disc rewriting, new data is overwritten previously recorded data.
•Polycarbonate layer has a Pre-Groove which make a track.
Lens H
D
Beam
Spot
Focusing
Lens
Laser Spot
at Constant
Read Intensity
Reflected
Light
Signal
Laser Spot
Position
(Time)
Previously Recorded Marks
Groove Land Mirror
I3Itop
I11 IGILI0
Numerical aperture: NA=nsin θ ,
n: Refractive index
Focus depth : H=
λ /NA
laser spot diameter : D=
λ /NA
2
θ

18
5. Writing Process of CD-R Disc
a b c d e f g
a
b
c
d
e
f
g
Incident
Laser
Power (Read) (Read)
(Write)
Laser Spot
Position
(Time)
a b c d e f g Laser Spot
Position
(Time)
Laser
Spot
Recorded
Mark
Reflected
Light
Signal
Reflected
Light
Signal
Below "ORP"–Mark Too Short
At Optimum Record Power ("ORP")
Above "ORP" –Mark Too Long
Time
6. Writing process of CD-RW Disc
Write Power
Erase Power
Read Power
Groove
Crystal Amorphous
Amorphous
Recorded state
(lower reflectivity)
Melting/
quenching
Heating/
gradual cooling
Crystal phase
Erased state
(higher reflectivity)

7. Organization of the PCA, PMA and Lead-in Area
1) Layout of CD-ROM disc
19
Center hole Clamping and Label Area Information Area
Lead-in Area
Lead-in Area
Diameter 15 mm
Diameter 46 mm
Diameter 120 mm
Program Area
Read Only Disc
Lead-out Area
Program Area Lead-out Area
Center hole Clamping and Label Area Information Area
PCA PMA
Test Area Count Area
Diameter 15 mm
Diameter 45 mm
Diameter 120 mm
Unrecorded Disc
Tsl-00:35:65 Tsl-00:15:05 Tsl-00:13:25 Tsl 99:59:74
00:00:00
in out
Test Area : for performing OPC procedures.
Count Area : to find the usable area immediately in T.A
Tsl : start time of the Lead-in Area, as encoded in ATIP
PMA : Program Memory Area
Disc Center
Disc Center
2) Layout of CD-R/RW disc

20
8. Function of PCA and PMA area
1) PCA (Power Calibration Area)
•PCA area is used to determine the correct Laser Power for a disc.
–Method 1 : PCA area is divided by a track.
–Method 2 : The previous Calibration value is referred.
–Method 3 : ROPC is used to determine Laser Power value automatically in data writing.
•CD-R Disc can write maximum 99 Tracks but CD-RW Disc can write unlimited tracks because it has a rewritable
function.
2) PMA (Program Memory Area)
•It has a track information (track No, track Start/End time) of every track before writing completed.
–PMA area has the last written point and the next writable point of a disc.
–In case of CD to CD copy, some writer may not write PMA area.
* When Disc is Finalized,
PMA information is transferred to the Lead_In area so that general Driver can read it.
* Because PCA and PMA area exist before Lead-In area, General CD Player or CD-ROM Drive can’t read
these areas.
9. OPC and ROPC
1) OPC (Optimum Power Control)
•This is the first step of writing process, because CD writer has its own laser power value and media have different
writing characteristics,
–This is determined by the Writing characteristic, speed, temperature, and humidity.
–Laser wavelength is determined by the environmental temperature (775~795nm) and Optical Laser Power is
determined by the test and retry.
•Asymmetry and optimum writing Power
–EFM signal Asymmetry is determined by the writing power.
Therefore, Optical Power which has the same value to the preset power value can be estimated by measuring
HF signal Asymmetry on the PCA area.
•Measurement of Asymmetry
* Parameter setting (Beta) : Using AC coupled HF signal before equalization
Beta = (A1+A2)/(A1-A2)
Time P << Po Time P = Po
HF Signal
A1
0
A2
Time P >> Po

2) ROPC (Running Optimum Power Control)
•Variable primary factor of Optimum Power
–Change of Power sensitivity on the Disc. (limited to 0.05 *Po)
–Wavelength shift of the laser diode due to the operating temperature change.
–Change of the Spot aberration due to the Disc skew,
Substrate thickness, Defocus.
–Change of Disc or Optics conditions due to the long term OPC
==> It is necessary to adjust continuously to obtain the Optimum Power.
•Principle of Running OPC
–To meet the factors mentioned above,
a horizontal _ direction movement of a curve is uesd.
–Beta = f(B-level) = constant on the Recorded Disc
–Procedure of ROPC
a. Reference B-level is determined during OPC Procedure.
b. During Recording, B-level value is controlled to have a close
Reference B-level value.
c. Normalization of B-level is used to eliminate the effect of reflectivity fluctuation.
==> The reflected B-level value is normalized by the disc reflectivity itself.
21
CD-R/RW Media
Write Strategy
Determination
PCA Test Area
Program Area
PMA Area
Lead-In Area
Lead-out Area
OPC
PCA Count Area
ROPC
* Recording Capacity of CD-R/RW (74Minute Recording media)
•(2048 Byte/Sector) X (75 Sector/Second) X (60 Second/Minute) X 74 Minute
= 681,984,000 Bytes = 682 Mbytes
•But the actual recording capacity is about 650 Mbytes. (according to the ISO 9660 standard, approximately
30 Mbytes are used to make directory structure and volume names.)
Incident recording pulse
Reflected recording pulse
Sampled timing B
11T
Sample B-level (Write Power)
Level B
Sampled at timing B
Pwo decided by OPC
Recording Power
Level Bwith Pwo
normalized to recording power
Sample Disc Reflectivity
(Read power)
10. Writing Process of DISC

INTERNAL STRUCTURE OF THE PICK-UP
1. KRS-310B Circuit Diagram
22
1
2
3
4
5
6
7
1
2
3
4
5
1
2
3
4
5
6
7
8
9
10
11
12 13
14
15
16
17
18
19
20
21
22
23
24
14
13
12
11
10
9
8
10
9
8
7
6
R3
VR1
VR2
R2
C5
C3
C6
LD
A
11
C
C4
R4
R1
L1
R6
R7
C7
R8
C10 C9 C8
Vcc
2 Axis Actuator
IC1
PDIC
IC2 FPDIC
C1
R9
R11
R12
R10
C2
GND
G
D
C
E
RF
SW
GND
H
A
B
F
Vc
NC
GND
GNDGND
VccVc
BinOUT
PDIN
VOUT
VCC
VREF
VCC
GND
IOUT
IINR
IOUT
IIN2
GND
IIN3
GND
RFREQ
RAMP
GND
ENABLE
GND
OSCEN
WEN3
VCC
WEN2
GND
GND
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
6
5
4
3
2
1FCS +
FCS -
TRK +
TRK -
-
G
D
C
E
RF SUM
SW
PDGND
PDVC
F
B
A
H
PDVCC
FPDO
FPDVCC
FPDGND
FPDVC
LDVCC
LDVCC
VRDC
VWDC1
VWDC2
LDGND
LDGND
WE1
WE2
OSCEN
33
34
ENBL
MODAMP
IC3
LD
Driver

2. Signal detection of the P/U
1) Focus Error Signal ==> (A+C)-(B+D)
This signal is generated in RF IC (IC401 : CXA2638R) and controls the pick-up’s up and down to focus on
Disc.
2) Tracking Error Signal (DPP Method) ==> {(A+D)-(B+C)}- k x {(F+H)-(E+G)}
This signal is generated in RF IC (IC401 : CXA2638R) and controls the pick-up’s left and right shift to find
to track on Disc.
3) RF Signal ==> (A+B+C+D)
This signal is converted to DATA signal in DSP IC (IC201 : OTI-9797).
23
Pick-Up module
Photo Diode Tracking
Focusing
Infrared Iaser
k[(F+H) - (E+G)]
(A+D) - (B+C)
(A+D) - (B+C) - k[(F+H) - (E+G)]
Offset
TE
Tp
Sub2
Main
Tp/2 Sub1
Track Center
F,E
D,C
A,B
H,G

DESCRIPTION OF CIRCUIT
1. ALPC (Automatic Laser Power Control) Circuit
1-1. ALPC Loop Circuit
24
RFPDG
FPDO
AUX
FVREF
WFPDSH
HOLDSW
WLDON
WR/RE
WGATE
WR/RE
WGATE EFM1
EFM2
R321
C4
R322
R427
R426
C454
C443
R447
D401
GND
R19
VWDC
WREF
HOLDTC
ODREF
APCCSW
R18
R408
C432
VWDCN
APCCSW
WREFSE
S3.
B
B
R14
25.8K
R15
25.8K
GND
GND
A
A
R12
R10
5K
R6
20K
R3
R4
20K
20K
R8
20K
10K
GND
GND
C3
SCLK
DACS
WREFSE
C445
R252
R247
R429
SHOUT
RFPDSH
20dB/26dB
3.3V
R422
R423 IC403
IC205
IC301 MICOM
IC201
OTI-9797
C456
C455
MPXOUT
(testmode)
MPXOUT
(testmode)
VRDCN
VRDC
VRDC
R16
R17
R410
C433
R11
10K
GND
GND
RREFSE
R9
5K
R1
20K
R2
20K A:OFF
B:ON
A:OFF
L:B.HOLD
H:A.SAMPLE
B:ON
RREF
WREF
ODREF
SHOUT
WRITEG WFPDG
DAC
DAC
DAC
GNDTyp.
10mV/step
sbit
GND
GND
Typ.
10mV/step
8 bit
Typ.
10mV/step
7 bit
H:RREF
R13
R5
R7
20K
(Read)
(Write)
20K
25.8K
GND
L:OPEN
H:OPEN
L:WREF
RLDON
ERCNT
8
GND
C1
96
94
97
98
25
19
22
100
32
99
62
1
31
45
48
3
5
6
7
166
188
180
183
184
60
6564
24
92
90
91 17
16
15
5
4
18
13
95
PN401
P/U
TC7W08FV
IC401 CXA2638R
FPDVC
FPDO
VRDC
26
VWDC
27
VWDC2
30
WE1
31
WE2
x1
S/H
S/H
Gain
adj.
IC402
DAC
x1
S/H

1-2. ALPC(Automatic Laser Power Control) Circuit Operation
This circuit consists of Feedback Loop to maintain light output of the Laser Diode(FPDO).
Feedback signal, output voltage from PD(Photo Detector) of P/U, is used monitor the light power of
Laser Diode.
1) Read Loop
RREF(Read Reference Voltage) of IC401(CXA2638R) Pin 96, which is from DAC(IC403) Pin 18, is the
reference level of the Read Loop part of this ALPC Circuit.
• When Playback
VRDC(Pin 97) signal of IC401(CXA2638R) is output to P/U through Gain Control S/W and drives
Laser Diode during play back.
This S/W Ciruit is designed to reduce transition time from CD-RW writing mode to playback mode.
• When writing mode
- CD-R
Three Laser Power Levels, Read, Write, and Overwrite, are used to write on CD-R disc, and Read
Level is used to monitor the output laser power.
For stabilizing read loop, the S/H signal(RFPDSH), which sample and hold the Read Level of laser
power in the CD-R writing mode, is input through Pin 32 of IC401(CXA2638R).
- CD-RW
Three Laser Power Levels, Read, Erase and Write, are used to write on CD-RW disc, and Erase
Level is used, during CD-RW writing, to monitor output laser power.
It is not VRDC but VWDC that is the output signal of the control loop performed by Erase level.
2) Write Loop
For stabilizing write Loop, the S/H signal(WFPDSH), which sample and hold the Erase Level of laser
power in the CD-RW writing mode, is input through Pin 31 of IC401(CXA2638R).
Output voltage of Write Loop, VWDC(Pin 93 of IC401(CXA2638R)), is protected by the high limit diode
applied to P/U.
25

2. RF Amplifier Circuit
Block Diagram
26
FE FE
A,B,C,D
E,F,G,H
RFSUM
PDIC
VC GND Vcc
CXA2638R (IC401) IC201
OTI9797
Pick up
KRS-310B
Gain Amp
16 15
8 7
9
14
6
17
10
7
59 197
8 9
10 87
2 3 4 5
Offset adj
R1 R2
R3
R4
R6R5
R403
C417
R404 Vref
Main S/H Gain adj Offset adj
CEM CEO CEP
TE
CE
198 204
TE
58
EQRFP
C223
EFM
163
ATFG
WOBBLE
132
Limit
Gain Amp.
Side S/H
SPPO
4((F+H)-(E+G))
MPP 2(A+D)-(B+C))
DVC
Gain adj
Gain adj
Offset adj
LPF (40KHz)
Gain adj
offset adj
Limit GCA HPF HPF AGC BPF AGC Slice
circuit
HPF
EQ HPF
63
65
67
x0.25 x5 x3.2 71
38