LG CRD-8401B, CRD-8481B Service Manual

INTRODUCTION

GENERAL FEATURE

SPECIFICATIONS

1. MODEL: CRD-8481B

1) SUPPORTED SYSTEM

• IBM Compatible 486SX or Above (With PIO mode 4 recommended)

2) SUPPORTED OS

3) GENERAL PERFORMANCE

• Data Transfer Rate .........................................................................................Sustained Data Transfer Rate

20Times Speed (Inner side) : 3,000 kbytes/sec

48 Times Speed (max., Outer side) : 7,200 kbytes/sec

• Data Buffer Capacity.....................................................................................................................128 kbytes

• Access Time ...................................................................................................Random Access Time : 75 ms

4) POWER REQUIREMENTS

• Voltage ......................................................................................................................................+5V DC +5%

+12V DC +5%

• Ripple ..................................................................................................................+5V : Less than 100mVp-p

+12V : Less than 100mVp-p

• Current .......................................................................................................................+5V : 0.9A (Maximum)

+12V : 1.5A (Maximum)

5) AUDIO PERFORMANCE

• Frequency Response.....................................................................................................20Hz~20KHz(+3dB)

• S/N Ratio (IHF-A+20 KHz LPF) .......................................................................85 dB (Typical at 1 KHz 0dB)

80 dB (Limit at 1 KHz 0dB)

• T.H.D. (IHF-A+20 KHz LPF)............................................................................0.05% (Typical at 1 KHz 0dB)

0.15% (Limit at 1 KHz 0dB)

• Channel Separation (IHF-A+20 KHz LPF).............................................................................80 dB (Typical)

70 dB (Limit)

• Output Voltage (1kHz 0dB) 47KΩ Load.................................................................................0.7Vrms +10%

• Headphone Level (1kHz 0dB) 33Ω Load...............................................................................0.7Vrms +20%

• Enhanced IDE interface

• Internal 5.25 inch, halfheight CD-ROM Drive

• Fast 75ms Average Access Time

• Max 7,200KB/sec Sustained Transfer rate

• CRD-8481B: Max 7,200 KB/sec Sustained Transfer rate

• CRD-8401B: Max 6,000 KB/sec Sustained Transfer rate

• Photo-CD Multisession Disc Spec compliant

• Multimedia MPC-3 Spec compliant

• Power Tray Loading/Ejection Mechanism

• 3 Way Eject support

(Software, O/C Button, Emergency Eject)

• Closed Enclosure

• Built-in ATAPI Interface Controller

• Software Volume Control

• 8 Times Digital Filter for CD Audio

•

Front panel Volume Control for Headphone Output

• Built-in MODE-1 ECC/EDC

• MTBF 125,000h POH (at 10% Utilization)

• PIO Mode 4 & Multi DMA Mode 2 support

• Horizontal or Vertical Mounting

• Digital audio output connector

• Digital audio through ATAPI Interface

• Subcode (P-W) through ATAPI Interface

• Spin-down Mode for energy saving

• MS-DOS Version 3.1 or Higher

• Windows '95/'98

• Solaris Ver 2.4 or Higher

• Linux slackware Ver 2.3

• Windows NT 4.0 or later

• OS/2 Warp (Ver 3.0)

This service manual provides a variety of service information. It contains the mechanical structure of the CD-ROM Drive together with mechanical adjustments and the electronic circuits in schematic

form. This CD-ROM Drive was manufactured and assembled under our strict quality control standards and meets or exceeds industry specifications and standards.

2. MODEL: CRD-8401B

1) SUPPORTED SYSTEM

• IBM Compatible 486SX or Above (With PIO mode 4 recommended)

2) SUPPORTED OS

3) GENERAL PERFORMANCE

• Data Transfer Rate .........................................................................................Sustained Data Transfer Rate

18Times Speed (Inner side) : 2,700 kbytes/sec

40 Times Speed (max., Outer side) : 6,000 kbytes/sec

• Data Buffer Capacity.....................................................................................................................128 kbytes

• Access Time ...................................................................................................Random Access Time : 75 ms

4) POWER REQUIREMENTS

• Voltage ......................................................................................................................................+5V DC +5%

+12V DC +5%

• Ripple ..................................................................................................................+5V : Less than 100mVp-p

+12V : Less than 100mVp-p

• Current .......................................................................................................................+5V : 0.9A (Maximum)

+12V : 1.5A (Maximum)

5) AUDIO PERFORMANCE

• Frequency Response.....................................................................................................20Hz~20KHz(+3dB)

• S/N Ratio (IHF-A+20 KHz LPF) .......................................................................85 dB (Typical at 1 KHz 0dB)

80 dB (Limit at 1 KHz 0dB)

• T.H.D. (IHF-A+20 KHz LPF)............................................................................0.05% (Typical at 1 KHz 0dB)

0.15% (Limit at 1 KHz 0dB)

• Channel Separation (IHF-A+20 KHz LPF).............................................................................80 dB (Typical)

70 dB (Limit)

• Output Voltage (1kHz 0dB) 47KΩ Load.................................................................................0.7Vrms +10%

• Headphone Level (1kHz 0dB) 33Ω Load...............................................................................0.7Vrms +20%

• MS-DOS Version 3.1 or Higher

• OS/2 Warp (Ver 3.0)

• Windows '95/'98

• Solaris Ver 2.4 or Higher

• Linux slackware Ver 2.3

• Windows NT 4.0 or later

LOCATION OF CUSTOMER CONTROLS

(1) Headphone Jack

3.5mm jack for monitoring the audio signal from audio CDs.

(2) Headphone Volume Control

Adjusts the headphone sound level.

(3) Disc Drawer

Accepts a CD-ROM disc on its tray.

(4) Busy Indicator

The Busy Indicator lights during initialization and dataread operations.

(5) Emergency Eject Hole

Insert a paper clip here to eject the drawer manually or when there is no power.

(6) Play/Skip Button

When an Audio CD is in the Disc Drawer, pressing this button will start playing audio CDs from the first track. If an audio CD is playing, pressing this button will skip to the next track.

(7) Open/Close/Stop Button

This button is pressed to open or close the CD tray. If an audio CD is playing, pressing this button will stop it, and pressing it

again will open the tray.

COMPACT

54 6 73

Figure 1. Front View

(1) Digital Audio Output Connector

This is a digital audio output connector or Video CD output connector. You can connect this to the digital audio system or Video CD Board.

(2) Analog Audio Output Connector

The Audio Output Connector connects to a sound card. The supplied audio cable is a SoundBlaster

type cable. If you have a different sound card, you will need to contact the sound card manufacturer to obtain the proper cable for that card.

(3) Master / Slave / CSEL Jumper

These three jumpers are used to set the CD-ROM Drive to either a Master, Slave, or CSEL drive.

(4) Interface Connector

This 40-pin connector is used to transfer and control signals between the CD-ROM Drive and your PC. Connect the 40-pin IDE cable in your PC to this connector.

(5) Power-in Connector

Attach a power cable from the computer to this connector.

Figure 2. Back View

DIGITAL ANALOG

INTERFACE POWER

DR CSM

SLA

GLG39 1

+12

GND

AUDIO AUDIO

FRONT

REAR

Figure 2. Back View

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 it outward.

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. C. Remove the Soldering of the LD- and LD+ (B) for

the Loading Motor, and then remove the Main

Circuit Board. D. At this time, be careful not to damage the 3

connectors of the Main Circuit Board.

2. MECHANISM ASSY

A. Separate the Pick-Up Unit from the Mechanism

Assy. B. Release 1 screws (C) and then remove the Pick-

Up ( ).

DISASSEMBLY

(A)

(1)

Bottom Chassis

Fig. 1-1

Fig. 1-2

Fig. 1-3

Fig. 1-4

Cabinet

(4)

Hooks (a)

(B)

Main

Circuit Board

Tray Door

(3)

Stoppers

Emergency Eject Hole

(2)

Front Bezel Assy

CD Tray

Pick-up Unit

(C)

Mechanism Assy

2. Trouble List (Circuit)

A. LED doesn’t light. B. Pick-Up doesn’t move to the inner-track. C. The Laser of Pick-Up doesn’t light. D. Pick-Up lens doesn’t move up and down. E. Disc doesn’t rotate. F. TOC isn’t read. (The LED turns on, but doesn’t flicker.) G. During Audio CD Play, LED flickers, but Speaker is silent.

TROUBLESHOOTING GUIDE

1. Initial Lead-in Operation

Reset or Power-On.

LED Flickers.

Pick-Up moves to the inner-Track.

Laser on the Pick-Up lights.

Focus Search (through moving up and down the lens of Pick-Up)

Focus Servo On (FOK Port : H, FEO(TP15) signal generation)

Rotate disc.

Tracking Servo On (TEO(TP14) Signal generation)

Spindle Servo On (MDP(TP25) Signal generation)

Read TOC Area (LED Flickers)

Search the Start of Data Area and then pause.

3. Troubleshooting Guide

A. LED doesn’t light.

Check Power Voltage (TP1:3.3V, TP2:12V, TP20:2.7V) Reference Voltage [TP3:DVC(1.35V) and GND.]

Does “H” output in IC501 pin ?

Check and replace R705, R706, Q701 and LED701 (LED703 for DELL).

Is the CLOCK Frequency of IC501 pin 33.86MHz?

Check the power input pattern.

Check IC501.

Check and replace X501; 33.86MHz, X502: 40MHz

Is the CLOCK Frequency of IC501 pin 33.86MHz?

Check and replace IC501.

YES

109

171

A-1

B. Pick-Up doesn’t move to the inner track.

Do the signals appear at IC501 pin , ? (Refer to Fig. B-1.)

Do the signals appear in PN301 pin? (Refer to Fig. B-2.)

Does “H” output at IC201 pin ?

Is the 1.35V at IC201 pin ?

Check the pattern from IC501 pin to IC201 pin

Check IC501.

Check the R190 and then replace IC102.

Check the PN301, and then replace the Sled Motor.

YES

Replace IC201.

106

CH1 PIN74 DA0

CH2 PIN73 DA1

CH1 TP4

CH2 TP5

CH3 TP6

CH4 TP7

Fig. B-1. DA0 and DA1 Signals

Fig. B-2. TP4, TP5, TP6 and TP7 Signals

Check the pattern from IC501 pin to R225 and then replace IC501.

Does “Low” or “High” output at IC102 pin ?

Is the voltage of IC102 pin (LD) 2V?

Check Pick-Up FFC, PN101.

Check Q101, C101, C102 and then replace IC102.

Check R118 and replace IC501.

YES

Does the focus search signal appear at FAO (TP9)? (Refer to Fig. D-1.)

Is the 1.35V at IC201 pin ?

Check the R190 and then replace IC102.

YES

Replace IC201.

Does the focus search signal appear between F+ (TP10) and F- (TP11)? (Refer to Fig. D-2.)

C. The Laser of Pick-Up doesn’t light.

D. The Pick-UP lens doesn’t move up and down.

D-1

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