LG RAD225B Service Manual

MODEL: RAD225B (RAS225B)SERVICE MANUAL

Internal Use Only

Website http://biz.lgservice.com

Mini Hi-Fi System

SERVICE MANUAL

P/NO : AFN73972629 MARCH, 2010

MODEL: RAD225B

CAUTION

BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS”
IN THIS MANUAL.

(RAS225B)

[CONTENTS]

SECTION 1. GENERAL

• SERVICING PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

• ESD PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

• SERVICE INFORMATION FOR EEPROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

•

PROGRAM DOWNLOAD GUIDE

• SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

SECTION 2. EXPLODED VIEWS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

• CABINET AND MAIN FRAME SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

• MECHANISM DECK SECTION (CDM-345) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

• SPEAKER SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

• PACKING ACCESSORY SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

SECTION 3. ELECTRICAL PART

• TROUBLESHOOTING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

• DETAILS AND WAVEFORMS ON SYSTEM TEST AND DEBUGGING . . . . . . . . . . . . . . . 3-14

• WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-18

• BLOCK DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-19

• CIRCUIT DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-21

• CIRCUIT VOLTAGE CHART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33

• PRINTED CIRCUIT DIARGAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-35

SECTION 4. REPLACEMENT PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

1-1

SECTION 1. GENERAL

SERVICING PRECAUTIONS

NOTES REGARDING HANDLING OF THE PICK-UP

1. Notes for transport and storage

1) The pick-up should always be left in its conductive bag until immediately prior to use.

2) The pick-up should never be subjected to external pressure or impact.

2. Repair notes

Storage in conductive bag

1) The pick-up incorporates a strong magnet, and so should never be brought close to magnetic materials.

2) The pick-up should always be handled correctly and carefully, taking care to avoid external pressure and
impact. If it is subjected to strong pressure or impact, the result may be an operational malfunction and/or
damage to the printed-circuit board.

3) Each and every pick-up is already individually adjusted to a high degree of precision, and for that reason
the adjustment point and installation screws should absolutely never be touched.

4) Laser beams may damage the eyes!
Absolutely never permit laser beams to enter the eyes!
Also NEVER switch ON the power to the laser output part (lens, etc.) of the pick-up if it is damaged.

NEVER look directly at the laser beam, and don’t allow
contact with fingers or other exposed skin.

5) Cleaning the lens surface
If there is dust on the lens surface, the dust should be cleaned away by using an air bush (such as used
for camera lens). The lens is held by a delicate spring. When cleaning the lens surface, therefore, a cot­ton swab should be used, taking care not to distort lens.

Drop impact

Pressure

Magnet

How to hold the pick-up

Cotton swab

Conductive Sheet

6) Never attempt to disassemble the pick-up.
Spring has excess pressure. If the lens is extremely dirty, apply isopropyl alcohol to the cotton swab.
(Do not use any other liquid cleaners, because they will damage the lens.) Take care not to use too much
of this alcohol on the swab, and do not allow the alcohol to get inside the pick-up.

1-2

Pressure

NOTES REGARDING COMPACT DISC PLAYER REPAIRS

1. Preparations

1) Compact disc players incorporate a great many ICs as well as the pick-up (laser diode). These components
are sensitive to, and easily affected by, static electricity. If such static electricity is high voltage, components
can be damaged, and for that reason components should be handled with care.

2) The pick-up is composed of many optical components and other high-precision components. Care must be
taken, therefore, to avoid repair or storage where the temperature or humidity is high, where strong magne­tism is present, or where there is excessive dust.

2. Notes for repair

1) Before replacing a component part, first disconnect the power supply lead wire from the unit

2) All equipment, measuring instruments and tools must be grounded.

3) The workbench should be covered with a conductive sheet and grounded.
When removing the laser pick-up from its conductive bag, do not place the pick-up on the bag. (This is
because there is the possibility of damage by static electricity.)

4) To prevent AC leakage, the metal part of the soldering iron should be grounded.

5) Workers should be grounded by an armband (1 MΩ)

6) Care should be taken not to permit the laser pick-up to come in contact with clothing, in order to prevent
static electricity changes in the clothing to escape from the armband.

Armband

Resistor
(1 MΩ)

Resistor
(1 MΩ)

7) The laser beam from the pick-up should NEVER be directly facing the eyes or bare skin.

Conductive
Sheet

1-3

ESD PRECAUTIONS

Electrostatically Sensitive Devices (ESD)

Some semiconductor (solid state) devices can be damaged easily by static electricity. Such components
commonly are called Electrostatically Sensitive Devices (ESD). Examples of typical ESD devices are integrated
circuits and some field-effect transistors and semiconductor chip components. The following techniques should
be used to help reduce the incidence of component damage caused by static electricity.

1. Immediately before handling any semiconductor component or semiconductor-equipped assembly, drain off
any electrostatic charge on your body by touching a known earth ground. Alternatively, obtain and wear a
commercially available discharging wrist strap device, which should be removed for potential shock reasons
prior to applying power to the unit under test.

2. After removing an electrical assembly equipped with ESD devices, place the assembly on a conductive surface
such as aluminum foil, to prevent electrostatic charge buildup or exposure of the assembly.

3. Use only a grounded-tip soldering iron to solder or unsolder ESD devices.

4. Use only an anti-static solder removal device. Some solder removal devices not classified as "anti-static" can

generate electrical charges sufficient to damage ESD devices.

5. Do not use freon-propelled chemicals. These can generate electrical charges sufficient to damage ESD
devices.

6. Do not remove a replacement ESD device from its protective package until immediately before you are
ready to install it. (Most replacement ESD devices are packaged with leads electrically shorted together by
conductive foam, aluminum foil or comparable conductive materials).

7. Immediately before removing the protective material from the leads of a replacement ESD device, touch the
protective material to the chassis or circuit assembly into which the device will by installed.

CAUTION : BE SURE NO POWER IS APPLIED TO THE CHASSIS OR CIRCUIT, AND OBSERVE ALL OTHER

SAFETY PRECAUTIONS.

8. Minimize bodily motions when handing unpackaged replacement ESD devices. (Otherwise harmless motion
such as the brushing together of your clothes fabric or the lifting of your foot from a carpeted floor can generate
static electricity sufficient to damage an ESD device).

CAUTION. GRAPHIC SYMBOLS

THE LIGHTNING FLASH WITH APROWHEAD SYMBOL. WITHIN AN EQUILATERAL TRIANGLE, IS
INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF UNINSULATED
“DANGEROUS VOLTAGE” THAT MAY BE OF SUFFICIENT MAGNITUDE TO CONSTITUTE A RISK OF
ELECTRIC SHOCK.

THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT THE
SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE
LITERATURE.

1-4

SERVICE INFORMATION FOR EEPROM

POWER ON

FLD no disc status

Remote control ‘ ’ + Front ‘STOP’

push same timing during 5s

FLD ‘OP-0….

Move to appropriate position

and make changes

with Rmc ‘skip, mode, play’ key.

Press STOP key

FLD ‘write ok’

DETECT NEW EEPROM
(OPTION EDIT SCREEN)

NAME

OPT 0
OPT 1
OPT 2
OPT 3
OPT 4
OPT 5
OPT 6
OPT 7
OPT 8
OPT 9

HEX

09
00
00
00
00
68
80
05
40
00

Remote control ‘

’ +

Front ‘STOP’ push same timing

FLD ‘E2P CLR’

Completed

1-5

PROGRAM DOWNLOAD GUIDE

1. AUDIO PROGRAM

Download program file name must be RAD125.HEX

If security program (Water Wall) is activated on your PC, you must save the file to the usb storage

device and disable the security software, then download the file to your set.

Caution: When downloading the file, you should neither unplug the usb device, change to the other

function, nor power off the device. Usb device must be unplugged when the downloading
process is completed.

ON VFD DISPLAY SCREEN

NO USB

↓← Insert usb device at usb function

READ

↓

FIRMWARE

↓

WRITE 00 .. 100

↓

UPDATED

↓

POWER OFF AUTOMATICALLY

← When completed, remove usb device.

1-6

2. CD PROGRAM

Download program file name must be HB001_DATE_00.BIN

If security program (Water Wall) is activated on your PC, you must save the file to the usb storage

device and disable the security software, then download the file to your set.

Caution: When downloading the file, you should neither unplug the usb device, change to the other

function, nor power off the device. Usb device must be unplugged when the downloading
process is completed.

ON VFD DISPLAY SCREEN

NO USB

↓← Insert usb device at usb function

READ

↓

FIRMWARE

↓

FINISH

↓

UPDATED

↓

POWER OFF AUTOMATICALLY

← When completed, remove usb device.

1-7

SPECIFICATIONS

• GENERAL

Power supply 110 ~ 240 V, 50/60 Hz

Power consumption 60 W

Net Weight 3.5 kg

External dimensions (W x H x D) 202 x 307 x 278 mm

Bus Power Supply (USB) DC 5 V 500 mA

Operating conditions Temperature 5 °C ~ 35 °C,

Operation status: Horizontal

Operating humidity 5 % ~ 85 %

Laser Semiconductor laser, wavelength 650 nm

• TUNER FM/AM [MW]

FM Tuning Range (87.5 ~ 108.0) MHz or (87.50 ~ 108.00) MHz

FM Intermediate Frequency 128 kHz

AM Tuning Range (522 ~ 1 620) kHz, (520 ~ 1 710) kHz or

(522 ~ 1 710) kHz

AM Intermediate Frequency 45 kHz

• AMPLIFIER

Output Power Front : 110 W + 110 W (4 Ω at 1 kHz, THD 10 %)

• CD

Frequency Response 40 Hz ~ 20 000 Hz

Signal-to-noise ratio 75 dB

Dynamic range 80 dB

• SPEAKERS

Front Speaker

Type 2 Way 2 Speaker

Impedance 4 Ω

Rated Input Power 110 W

Max. Input Power 220 W

Net Dimensions (W x H x D) 232 x 346 x 289 mm

Net Weight 3.3 kg

Designs and specifications are subject to change without prior notice

1-8

SECTION 2. EXPLODED VIEWS

• CABINET AND MAIN FRAME SECTION (RAD225B)

260L

A43

A42

460

460

E

USB

FRONT

261

460

CABLE2

460

460

NOTES) THE EXCLAMATION POINT WITHIN AN

EQUILATERAL TRIANGLE IS INTENDED
TO ALERT THE SERVICE PERSONNEL
TO THE PRESENCE OF IMPORTANT
SAFETY INFORMATION IN SERVICE
LITERATURE.

262

460

264

451

279

D

A47

A

C

SMPS

B

276

I

F

460

460

460

251

253

252

250

254

255L

256L

258A

258B

460

258C

257

255R

256R

A26

H

460

259

D

I

G

265

A44

A

B

460

260R

A46

E

F

H

G

460

C

300

273 274

2-1 2-2

• MECHANISM DECK SECTION (CDM-345)

A26

017

013

018

439

4

1

0

015

A02

020

432

A01

0

12A

001

002

003

010

026

431

016

A03

012

019

036

012A

432

012

037

2-3 2-4

• SPEAKER SECTION

. FRONT SPEAKER (RAS225B)

A60

2-5

• PACKING ACCESSORY SECTION

824 AM Loop Antenna

801 Instruction Ass'y

808 Battery

803 Packing

804 Bag

825 FM Wire Antenna

900 Remote Control

803 Packing

802 Box

2-6

SECTION 3. ELECTRICAL PART

AUDIO ELECTRICAL TROUBLESHOOTIHG GUIDE

1. POWER (SMPS)

No 3.7 VA

YES

Is F901 normal? Replace the F901 (Use the same fuse).

YES

Is BD901 normal? Replace BD901.

YES

Is TH902 normal? Replace TH902.

YES

Is Vcc

(10 V ~ 18 V) supplied to

IC901 Pin7?

YES

Is D922 normal? Replace D922.

YES

Is there

about 2.5 V at

IC903 Pin1?

YES

Is D923 normal? Replace D923.

NO

NO

NO

NO

Is D904 normal?

NO

Check or replace D904.

NO

NO

Replace IC903.

NO

YES

Is D921 normal? Replace D921.

YES

Is D924 normal? Replace D924.

YES

Is D925 normal? Replace D925.

YES

Power line of I/O PCB is short.

NO

NO

NO

3-1