LG CRD-8522B Service Manual

INTRODUCTION

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.

GENERAL FEATURE

• Enhanced IDE interface	• Software Volume Control
• Internal 5.25 inch, halfheight CD-ROM Drive	• 8 Times Digital Filter for CD Audio
• Fast 75ms Average Access Time	• Built-in MODE-1 ECC/EDC
• Max 7,200KB/sec Sustained Transfer rate	• MTBF 125,000h POH (at 10% Utilization)
• Photo-CD Multisession Disc Spec compliant	• PIO Mode 4 & Multi DMA Mode 2 support
• Multimedia MPC-3 Spec compliant	• Horizontal or Vertical Mounting
• Power Tray Loading/Ejection Mechanism	• Digital audio output connector
• 3 Way Eject support	• Digital audio through ATAPI Interface
(Software, O/C Button, Emergency Eject)	• Subcode (P-W) through ATAPI Interface
• Closed Enclosure	• Spin-down Mode for energy saving
• Built-in ATAPI Interface Controller

SPECIFICATIONS

1.MODEL: CRD-8484B

1)SUPPORTED SYSTEM

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

2)SUPPORTED OS

• MS-DOS Version 3.1 or Higher	•	Solaris Ver 2.4 or Higher	•	Windows NT 4.0 or later
• Windows '95/'98/’2000	•	Linux slackware Ver 2.3	•	OS/2 Warp (Ver 3.0)

3) GENERAL PERFORMANCE

• Data Transfer Rate .........................................................................................	Sustained Data Transfer Rate
	22Times Speed (Inner side) : 3,300 kbytes/sec
	48 Times Speed (max., Outer side) : 7,200 kbytes/sec
• Data Buffer Capacity.....................................................................................................................	128 kbytes
• Access Time.......................................................................................	Random Access Time : 75 ms Typical

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) .......................................................................	75 dB (Typical at 1	KHz 0dB)
	70 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) .............................................................................	75 dB (Typical)
• Output Voltage (1kHz 0dB) 47KΩ Load	70 dB (Limit)
	0.75Vrms + 10%
• Headphone Level (1kHz 0dB) 33Ω Load...............................................................................	0.7Vrms + 20%

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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)

Rotate disc.

Focus Servo On (FEO(TP15) signal generation)

Tracking Servo On (TEO(TP14) Signal generation)

Spindle Servo On (SPO(TP25) Signal generation)

Read TOC Area (LED Flickers)

Search the Start of Data Area and then pause.

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.

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3. Troubleshooting Guide

A. LED doesn’t light.

Check Power Voltage (TP1:3.3V, TP2:12V)

Reference Voltage

[TP3:VC(2.5V) and GND.]

OK

Does “H” output in IC501 pin 170?

YES

Check and replace R105, R106, Q12 and LED701 (LED702 for NECCI).

NG

NO

Check the power input pattern.

Is the CLOCK Frequency of	NO
IC501 pin 93 , 94	A-1
33.86MHz?
YES

Check IC501.

A-1

Is the CLOCK Frequency of IC501 pin 54	NO		Check and replace X10;
33.86MHz?			33.86MHz.

YES

Check and replace IC501.

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

Do the signals appear at IC501 pin 34 , 35 ?

(Refer to Fig. B-1.)

YES

Does “H” output at IC201 pin 41 ?

YES

Is the 2.5V at IC201 pin 25 ?

YES

Do the signals appear in PN301 pin?

(Refer to Fig. B-2.)

YES

Check the PN301, and then replace the Sled Motor.

CH1

PIN34

DA0

CH2

PIN35

DA1

NO

Check IC501.

NO		Check the pattern from
		IC501 pin 107 to IC201
		pin 41 .

NO

Replace IC102.

NO

Replace IC201.

(/A)

CH1 TP4

CH2 TP5

(A)

CH3 TP6 (/B)

CH4 TP7

(B)

Fig. B-1. DA0 and DA1 Signals

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

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

Does “Low” output at IC102 pin 15 ?

YES

Is the voltage of IC102 pin 13

(LDD) 2V?

YES

NO

Replace IC501.

NO	Check Q10, C10, C32,
	R113, R114 and then
	replace IC102.

Check Pick-Up FFC, PN101.

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

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

YES

Is the 2.5V at IC201 pin 25 ?

YES

Does the focus search signal appear between F+ (TP10) and F- (TP11)?

(Refer to Fig. D-2.)

YES

	NO		Check the pattern from
			IC501 pin 157 to R42
			and then replace IC501.

NO

Replace IC102.

NO

Replace IC201.

D-1

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D-1

Check the pattern from pin 34 , 35 of IC201 to pin 1 , 4 of PN101.

OK

Check the PN101, Pick-Up

FFC.

OK

Replace the Pick-Up.

CH1

TP9

(FDO)

NG Replace PN101 or Pick-Up

FFC.

CH1

TP10(F+)

TP11(F-)

Fig. D-1. FDO Signal

Fig. D-2. Focus Search Signal

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E. Disc doesn’t rotate.

Does the signal appear at NO F+ (TP10) during focus search?

YES

Do the signal appear at NO TP15 (FEO)?

(Refer to Fig. E-2.)

YES

Does the signal appear at		NO
FEO (TP15) when the				Replace Pick-Up.
IC501 pin 144 opened?
(Refer to Fig. E-1.)
	YES
Replace IC501.

Replace IC501.

Does the signal appear at the SP0 (TP25)?

(Refer to Fig. E-3.)

YES

Do the signals appear at IC201 pin 12 (W), 13 (V), and 14 (U)?

YES

Check the pattern from IC201 pin 12 , 13 , 14 to PN201 13 , 12 , 11 .

OK

Check Spindle Motor FFC

and then replace the

Spindle Motor.

NO

Replace IC501.

NO

Replace IC201.

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CH1

CH1

TP15:

TP15:

FEO

S-Curve

Fig. E-1. S-Curve

Fig. E-2. FEO Signal

CH1

TP25:

SPO

Fig. E-3. SPO Signal

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