LG DM2740, CMS2730F Schematic

DVD Micro Hi-Fi System

SERVICE MANUAL

MODEL:

DM2740

(DM2740, CMS2730F)

CAUTION

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

MODEL: DM2740 (DM2740, CMS2730F)SERVICE MANUAL

4102 ,JUNE76615056NFA : ON/P

Website http://biz.lgservice.com

Internal Use Only

CONTENTS

SECTION 1 ........ SUMMARY

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

SECTION 3 ........ ELECTRICAL

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

1-1

SECTION 1

SUMMARY

CONTENTS

SERVICING PRECAUTIONS ................................................................................................................... 1-3

ESD PRECAUTIONS .................................................................................................................................. 1-5

FIRMWARE UPGRADE ............................................................................................................................. 1-6

1. MPEG

2. AUDIO MICOM

3. TOUCH

EEPROM OPTION SETTING ................................................................................................................... 1-7

SYSTEM RESET .......................................................................................................................................... 1-7

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

1-2

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.

Storage in conductive bag

Drop impact

2. Repair notes

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.

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.

1-3

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)

Conductive Sheet

1-4

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.

1-5

FIRMWARE UPGRADE

1. MPEG

1) Copy ﬁ rmware to USB (Do not change ﬁ le name). Ex) LG_DM2740LD1_1403190.rom

2) Change function to DVD/CD by pressing input key, and wait until home menu is shown.

3) Inset USB device which includes ﬁ rmware.

4) Firmware is detected automatically and then, shows blue screen in TV.

Ö If home menu is maintained after inserting USB, press music Icon.

5) Take off the USB and press PLAY key.

6) and then, upgrading is started.

- Do not turn off the set until upgrade is ﬁ nished.

7) After ﬁ nishing ﬁ rmware upgrading, set will restart automatically.

8) Power off and on again by pressing POWER key.

2. AUDIO MICOM

1) Copy ﬁ rmware to USB (Do not change ﬁ le name).

Ex) DM2740_1403250.HEX

2) Change function to DVD/CD by pressing input key, and wait until home menu is shown.

3) Inset USB device which includes ﬁ rmware.

4) Firmware is detected automatically and then, shows blue screen in TV.

Ö If home menu is maintained after inserting USB, press music Icon.

5) Upgrading is started.

- Do not turn off the set until upgrade is ﬁ nished.

- Do not pull out the USB device using ﬁ rmware upgrading.

6) After ﬁ nishing ﬁ rmware upgrading, set will be turned off.

3. TOUCH

1) Copy ﬁ rmware to USB (Do not change ﬁ le name).

Ex) DM2740T_1402040.dld / TC390_LG_CMDM2740_140204_0.hex

2) Change function to DVD/CD by pressing input key, and wait until home menu is shown.

3) Inset USB device which includes ﬁ rmware.

4) Firmware is detected automatically and then, shows blue screen in TV.

=> If Home menu is maintained after inserting USB, press music Icon.

5) Upgrading is started.

- Do not turn off the set until upgrade is ﬁ nished.

- Do not pull out the USB device using ﬁ rmware upgrading.

6) After ﬁ nishing ﬁ rmware upgrading, set will be turned off.

1-6

EEPROM OPTION SETTING

1) Change function to DVD/CD by pressing input key, and wait until home menu is shown.

- Do not insert disc or USB at the set.

2) Press "PAUSE 1 4 7 2" in order.

3) and then, option setting menu is displayed.

You can see 10 bytes option value. Ex ) F9 00 C1 D4 00 11 90 10 E0 08

4) Move a cursor by pressing Arrow < > key.

5) Press Num key what you want to change.

6) Press "PAUSE" key to exit option setting menu.

After change option value, you need to make system reset.

SYSTEM RESET

1) Change function to DVD/CD by pressing input key, and wait until home menu is shown.

- Do not insert disc or USB at the set.

2) Go to SETUP menu by pressing SETUP button in HOME menu.

3) Move highlight at "DISPLAY -> TV Aspect -> 16:9".

4) Press "1 3 9 7 1 3 9 Enter" in order.

5) and then, system reset menu is displayed.

6) Power off and on by pressing POWER key.

1-7

SPECIFICATIONS

• GENERAL

Power requirements Refer to the main label. Power consumption Refer to the main label. Dimensions (W x H x D) (135 x 295 x 315) mm Net Weight (Approx.) 3.7 kg Operating temperature 41 °F to 95 °F (5 °C to 35 °C) Operating humidity 5 % to 90 %

• INPUTS/ OUTPUTS

VIDEO OUT 1.0 V (p-p), 75 Ω, sync negative, RCA jack x 1 HDMI OUT (video/audio): 19 pin Type A, HDMI™ Connector DIGITAL IN (OPTICAL): 3 V (p-p), Optical jack x 1 PORT. IN 0.5 Vrms (3.5 mm stereo jack)

• SYSTEM

Laser Semiconductor laser, wavelength: 650 nm Signal system Standard NTSC color TV system Frequency response 20 Hz to 20 kHz (48 kHz, 96 kHz, 192 kHz sampling) Signal-to-noise ratio More than 80 dB Harmonic distortion 0.05 % at 1 W Dynamic range More than 85 dB Bus Power Supply 5 V 1 A

• AMPLIFIER

Stereo mode 80 W + 80 W (4Ω at 1kHz)

• TUNER

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

• FRONT SPEAKER

Type 3 Way 4 speaker Impedance 4 Ω Rated Input Power 80 W Max. Input Power 160 W Dimensions (W x H x D) (126 X 295 X 315) mm Net Weight 3.5 kg

• Design and specifications ae subject to change without notice.

1-8

SECTION 2

CABINET & MAIN CHASSIS

CONTENTS

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

1. CABINET AND MAIN FRAME SECTION (DM2740) ................................................................................ 2-3

2. DECK MECHANISM SECTION (SDP-08) ................................................................................................ 2-5

3. PACKING ACCESSORY SECTION ......................................................................................................... 2-7

4. SPEAKER SECTION (CMS2730F)........................................................................................................... 2-8

2-1

2-2

445

A26

260L

260R

251

253

254

261

A47

264

263

A42

A43

A44

267

268

262

CABLE2

SMPS

FRONT

USB

470

462

265

462

252

273

B/T

A46

MAIN

464

269

A48

A52

CABLE4

291

NFC

462

464

EXPLODED VIEWS

1. CABINET AND MAIN FRAME SECTION (DM2740)

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.

300

2. DECK MECHANISM SECTION (SDP-08)

A26

011

010

037

012

023

023C

023B

3. PACKING ACCESSORY SECTION

801 Owner’s Manual

808 Battery

811 Video cable

803 Packing

823 HDMI cable

825 FM antenna

900 Remote control

804 Bag

802 Box

4. SPEAKER SECTION (CMS2730F)

A60R

A60L

SECTION 3

ELECTRICAL

CONTENTS

ONE POINT REPAIR GUIDE ............................................................................................................................ 3-2

1. NO POWER PROBLEM ......................................................................................................................... 3-2

2. SPEAKER NO AUDIO OUTPUT ............................................................................................................ 3-3

3. USB NO DETECT ................................................................................................................................... 3-4

4. NO BOOTING ......................................................................................................................................... 3-5

ELECTRICAL TROUBLESHOOTING GUIDE ................................................................................................... 3-6

1. POWER (SMPS) ..................................................................................................................................... 3-6

2. P-SENS ................................................................................................................................................... 3-6

3. VKK CHECK ........................................................................................................................................... 3-6

4. μ-COM PART CHECK-1 ......................................................................................................................... 3-7

5. μ-COM PART CHECK-2 ......................................................................................................................... 3-7

6. FLD DISPLAY CHECK ........................................................................................................................... 3-8

7. TOUCH PART CHECK ........................................................................................................................... 3-9

8. PWM MODULATION CHECK ............................................................................................................... 3-10

9. POWER AMP PART CHECK ............................................................................................................... 3-11

10. VIDEO PART CHECK ........................................................................................................................... 3-12

11. TUNER FUNCTION CHECK ................................................................................................................. 3-13

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

1. SYSTEM 27 MHz CLOCK,RESET,FLASH R/W SIGNAL .................................................................... 3-14

2. SDRAM CLOCK .................................................................................................................................... 3-16

3. VIDEO PART (100% FULL COLOR-BAR) ........................................................................................... 3-16

4. HDMI PART .......................................................................................................................................... 3-17

WIRING DIAGRAM .......................................................................................................................................... 3-19

BLOCK DIAGRAM .......................................................................................................................................... 3-21

CIRCUIT DIAGRAMS ...................................................................................................................................... 3-23

1. SMPS CIRCUIT DIAGRAM .................................................................................................................. 3-23

2. MAIN - MICOM CIRCUIT DIAGRAM .................................................................................................... 3-25

3. MAIN - MPEG CIRCUIT DIAGRAM ...................................................................................................... 3-27

4. MAIN - RF SERVO CIRCUIT DIAGRAM .............................................................................................. 3-29

5. MAIN - I/O & ADC CIRCUIT DIAGRAM ............................................................................................... 3-31

6. MAIN - PWM & AMP CIRCUIT DIAGRAM ........................................................................................... 3-33

7. FRONT VFD CIRCUIT DIAGRAM ........................................................................................................ 3-35

8. FRONT JACK CIRCUIT DIAGRAM ...................................................................................................... 3-37

CIRCUIT VOLTAGE CHART ........................................................................................................................... 3-39

1. ICs ......................................................................................................................................................... 3-39

2. CONNECTORS ..................................................................................................................................... 3-41

3. CAPACITORS ....................................................................................................................................... 3-41

PRINTED CIRCUIT BOARD DIAGRAMS ....................................................................................................... 3-43

1. SMPS P.C.BOARD ............................................................................................................................... 3-43

2. MAIN P.C.BOARD ................................................................................................................................ 3-47

3. FRONT VFD P.C.BOARD ..................................................................................................................... 3-49

4. FRONT JACK P.C.BOARD ................................................................................................................... 3-51

3-1

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