LG MDT505 Diagram

MODEL: MDT505(MDS505V/W)SERVICE MANUAL

Internal Use Only

Website http://biz.lgservice.com

MINI HOME THEATER

SERVICE MANUAL

MODEL:

CAUTION

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

0102,SEPTEMBER21827947NFA:ON/P

MDT505 (MDS505V/W)

CONTENTS

SECTION 1 ........ GENERAL

SECTION 2 ........ CABINET & MAIN CHASSIS

SECTION 3 ........ ELECTRICAL

SECTION 4 ........ REPLACEMENT PARTS LIST

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.

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

Armband

Resistor
(1 MΩ)

Resistor
(1 MΩ)

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

DVD LOGO status

(N0 disc status)

Remote control

pause keyÖ1Ö4Ö7Ö2 in order

Press number 0~9, press character

A~F (1~6 for a while)

Use arrow key (▲/▼/◀/▶) to

move to appropriate position and

make changes

Press pause key once

DETECT NEW EEPROM
(OPTION EDIT SCREEN)

NAME

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

HEX

A5
06
85
B4
00
08
91
01
80
00

Change will be applied
when power OFFÖON

1-5

HOW TO UPDATE AUDIO MICOM & DVD PROGRAMS

1. How to update AUDIO MICOM program.

[Update using CD]

1. Change the filename to download as “MDS715_(Version).HEX”. Only upper cases are permitted.

ex) MDS715 : “MDS715_0709081.HEX”

2. Copy the file to the root folder of a CD and burn it.

3. Insert the CD to the SET, and move to the DVD function.

Then the upgrade process will be started with the upgrade information.

4. If the upgrade process is complete, the set will be rebooted with “Complete” message.

[Update using USB]

1. Change the filename to download as “MDS715_(Version).HEX”. Only upper cases are permitted.

ex) MDS715 : “MDS715_0709081.HEX”

2. Copy the file to the root folder of USB storage.

3. After Home-menu is displayed on Screen of SET, Put the USB into the SET.

Then the upgrade process will be started with the upgrade information.

4. If the upgrade process is complete, the set will be rebooted with “Complete” message.

2. How to update DVD program.

[Update using CD]

1. Copy DVD program(ex: LG_MDS715LD1_Version.Rom) to Root folder of CD, and burn it.

ex) P:LG_MDS715LD1_0911180.Rom

2. Insert the CD to the SET, then after a while the CD tray will be opened with upgrade information on

the screen.

3. Remove the CD, and press “PLAY” key in remote controller.

4. Remove and reconnect the power cable when it changes to logo screen from upgrade information.

Then the upgrade process is completed.

[Update using USB]

1. Copy DVD program(ex: LG_MDS715LD1_Version.Rom) to Root folder of the formatted USB and burn it.

ex) P:\LG_MDS715LD1_0911180.Rom

2. After Home-menu is displayed on Screen of SET, Put the USB into the SET.

Then the upgrade process will be started with the upgrade information.

3. Remove the USB, press "PLAY" key of the remote controller.

4. Remove and reconnect the power cable when it changes to logo screen from upgrade information.

Then the upgrade process is completed.

1-6

SPECIFICATIONS

• GENERAL

Power supply 110~240 V, 50/60 Hz

Power consumption Refer to main label

Dimensions (W x H x D) 273 x 333 x 339 mm without foot

Net Weight (Approx.) 5.7 kg

Operating temperature 41 °F to 95 °F (5 °C to 35 °C)

Operating humidity 5 % to 90 %

Bus Power supply (USB) DC 5V 500mA

• INPUTS/ OUTPUTS

VIDEO OUT 1.0 V (p-p), 75 Ω, sync negative, RCA jack x 1

COMPONENT VIDEO OUT (Y) 1.0 V (p-p), 75 Ω, sync negative, RCA jack x 1,

(Pb)/(Pr) 0.7 V (p-p), 75 Ω, RCA jack x 2

ANALOG AUDIO IN 0.6 Vrms, 47 kΩ, RCA jack (L, R) x 1

PORT. IN 0.5 Vrms (3.5 mm stereo jack)

• TUNER

FM Tuning Range 87.5 to 108.0 MHz or 87.50 to 108.00 MHz

AM Tuning Range 522 to 1 620 kHz, 520 to 1 710 kHz or 522 to 1 710 kHz

• AMPLIFIER

Stereo mode 150 W + 150 W (4 Ω at 1 kHz)

Surround mode

Front 150 W + 150 W (4 Ω at 1 kHz)

Center 70 W (6 Ω at 1 kHz)

Surround 70 W + 70 W (6 Ω at 1 kHz)

Subwoofer 200 W (3 Ω at 60 Hz)

1-7

• SPEAKERS
Front speaker (MDS505V)

rekaeps 2 yaW 2 epyT

4 ecnadepmI Ω

Rated Input Power 150 W

W 003 rewop tupnI .xaM

Net Dimensions(W x H x D) 240 x 387 x 336 mm

gk 5 thgieW teN

Passive Subwoofer (MDS505W)

rekaeps 1 yaW 1 epyT

3 ecnadepmI Ω

Rated Input Power 200 W

W 004 rewop tupnI .xaM

Net Dimensions(W x H x D) 261 x 331 x 409 mm

gk 5.6 thgieW teN

1-8

SECTION 2

CABINET & MAIN CHASSIS

CONTENTS

EXPLODED VIEWS..................................................................................................................................... 2-3

1. CABINET AND MAIN FRAME SECTION (MDT505) ................................................................................ 2-3

2. TAPE DECK MECHANISM SECTION ...................................................................................................... 2-5

3. DVD DECK MECHANISM SECTION (DVM-H1723) ................................................................................ 2-7

4. SPEAKER SECTION .............................................................................................................................. 2-11

5. PACKING ACCESSORY SECTION .......................................................................................................2-13

2-1

MEMO

2-2

EXPLODED VIEWS

1. CABINET AND MAIN FRAME SECTION (MDT505)

272

iPod

464

A45

251

260

259

254

255

256

261

257

252

262

A42

263L

464

261

464

258

250

270L

FRONT

271

464

269

464

464

265

264

J

E

270R

CABLE1

263R

A43

USB

P

A26

A26

A

276

A26

274

464

B

463

A

B

463

O

464

MAIN

C

D

F

464

463

273

E

G

H

P

I

275

A46

J

464

279

455

VOLUME

253

CABLE2

464

A00

278

CABLE3

SMPS

N

463

464

451

A44

277

L

L

C

D

464

F

A47

464

O

464

CABLE4

464

G

I

H

268

N

300

464

CABLE5

M

M

267A

267A

464

266

464

464

267

267

2-3 2-4

2. TAPE DECK MECHANISM SECTION (A/R & A/S : RIGHT A/R DECK)

A00

009

003

001

007

037

015

006

017

020

019

022

018

A01

023

025

011

A02

009

2-5 2-6

3. DVD DECK MECHANISM SECTION (DVM-H1723)

151

A26

153A

159

156

153

177

167

172

166

170

162

163

175

164

181

165

155

173

180

169A

169B

169C

430

012

A02

012

010

137

A01

430

012

430

035

2-7 2-8

MEMOMEMO

2-9 2-10

4. SPEAKER SECTION

4-1. FRONT SPEAKER (MDS505V)

A60

2-11

4-2. PASSIVE SUBWOOFER (MDS505W)

A90

2-12

5. PACKING ACCESSORY SECTION

808 Battery

811 RCA Cable, 1 Pin(Black)

900 Remote Control

803 Packing, Casing

824 AM Loop Antenna

825 FM Wire Antenna

801 Owner’s Manual

804 Bag

802 Box

2-13

MEMO

2-14

SECTION 3

ELECTRICAL

CONTENTS

ELECTRICAL TROUBLESHOOTING GUIDE .................................................................................... 3-2

DETAILS AND WAVEFORMS ON SYSTEM TEST AND DEBUGGING ................................ 3-16

WIRING DIAGRAM ................................................................................................................................... 3-29

BLOCK DIAGRAM .................................................................................................................................... 3-31

CIRCUIT DIAGRAMS ............................................................................................................................... 3-33

1. SMPS - POWER CIRCUIT DIAGRAM ................................................................................................. 3-33

2. MAIN - MICOM CIRCUIT DIAGRAM .................................................................................................... 3-35

3. MAIN - PWM CIRCUIT DIAGRAM ....................................................................................................... 3-37

4. MAIN - AMP CIRCUIT DIAGRAM ........................................................................................................ 3-39

5. MAIN - DECK CIRCUIT DIAGRAM ...................................................................................................... 3-41

6. MAIN - MPEG CIRCUIT DIAGRAM ..................................................................................................... 3-43

7. MAIN - SERVO CIRCUIT DIAGRAM ................................................................................................... 3-45

8. MAIN - I/O CIRCUIT DIAGRAM ........................................................................................................... 3-47

9. VFD CIRCUIT DIAGRAM ..................................................................................................................... 3-49

10. MIC & USB CIRCUIT DIAGRAM .......................................................................................................... 3-51

11. VOLUME CIRCUIT DIAGRAM ............................................................................................................. 3-53

12. IPOD CIRCUIT DIAGRAM (OPTIONAL PART) ................................................................................... 3-55

13. KARAOKE CIRCUIT DIAGRAM (OPTIONAL PART) ........................................................................... 3-57

CIRCUIT VOLTAGE CHART ................................................................................................................. 3-59

PRINTED CIRCUIT BOARD DIAGRAMS ......................................................................................... 3-61

1. MAIN P.C.BOARD ................................................................................................................................ 3-61

2. SMPS P.C.BOARD ............................................................................................................................... 3-65

3. FRONT(VFD / USB & MIC / VOLUME) P.C.BOARD ........................................................................... 3-67

4. IPOD P.C.BOARD (OPTIONAL PART) ................................................................................................ 3-69

5. KARAOKE P.C.BOARD (OPTIONAL PART) ....................................................................................... 3-69

3-1

ELECTRICAL TROUBLESHOOTING GUIDE

1. SMPS BOARD

No power.

Check the AC

line pattern.

YES

Check fuse F901.

YES

Check C978

voltage (3.9 V).

YES

Check C963

voltage (5.6 V).

YES

NO

NO

NO

NO

Connect the open line.

Replace F901.

Check BD901 “+”

to “

-

” Pin impedance .

Check 3.7 V lines short.

Replace PC972, IC902’s components.

Check SMPS second part lines short.

Check MAIN or AMP board short.

Low impedance:

Replace IC901, BD901.

Check IC901

Vcc voltage (10 V ~ 30 V).

YES

Replace SMPS board.

NO

Replace PC951, PC972, IC901.

Check around IC901’s components

(Short, Open).

3-2