Lg Dm5420k User manual

KARAOKE DVD Mini Hi-Fi System

SERVICE MANUAL

MODEL: DM5420K

(DM5420K, DMS5420V)

CAUTION

BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS”

IN THIS MANUAL.

MODEL: DM5420K (DM5420K, DMS5420V)SERVICE MANUAL

P/NO : AFN75814472 JULY, 2012

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

SERVICE INFORMATION FOR EEPROM........................................................................................... 1-6

PROGRAM UPDATE GUIDE................................................................................................................... 1-7

1. HOW TO UPDATE MICOM PROGRAM

2. HOW TO UPDATE DVD(ESS) PROGRAM

SPECIFICATIONS ....................................................................................................................................... 1-9

1-2

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

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.

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 cot-

ton swab should be used, taking care not to distort lens.

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.

Storage in conductive bag Drop impact

NEVER look directly at the laser beam, and don’t allow

contact with fingers or other exposed skin.

Magnet

How to hold the pick-up

Conductive Sheet

Cotton swab

Pressure

1-3

SERVICING PRECAUTIONS

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 magnet-

ism 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.

Resistor

(1 MΩ)Conductive

Sheet

Resistor

(1 MΩ)

Armband

1-4

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

ESD PRECAUTIONS

1-6

SERVICE INFORMATION FOR EEPROM

POWER ON

Completed

DVD Setup -> Display 16:9 mode

Press Set Remote control

‘1 -> 3 -> 9 -> 7 -> 1 -> 3 -> 9 -> Enter’ Key

Press ‘POWER’ key

TV Display ‘INFORMATION FOR EEPROM’

(DVD or USB MODE)

TV Display "NO DISC" status

Press Set Remote control

‘SETUP -> ▲ -> ▼ -> ◀-> ▶’ Key

-> Select "16:9"

1-7

1. HOW TO UPDATE MICOM PROGRAM

(1) Change the ﬁle name to download as “(MODEL NAME)_(Year)_(Month)_(Date).HEX”.

Ex) DM5620_1101190.HEX

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

(3) Put the USB into the set.

Change set function to USB function.

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

TV Display "UPDATING".

(4)

If the upgrade process is complete,

the set will be rebooted with “COMPLETED” message and set auto power off.

(5) Pull out the USB storage. Press the power key.

PROGRAM UPDATE GUIDE

1-8

2. HOW TO UPDATE DVD(ESS) PROGRAM

(1) Change the ﬁle name to download as “(MODEL NAME)_(Version)_(Year)_(Month)_(Date).rom”.

Ex) LG_DM5620LD1_1101140.rom

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

(3) Put the USB into the set.

Change set function to USB function.

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

TV display "UPDATING".

(4) If the upgrade process is complete,

the set will be rebooted with “COMPLETED” message and set manual power off.

(5) Pull out the USB storage. Press the power key.

• GENERAL

Power supply Refer to main label.

Power consumption Refer to main label.

Net Weight 5.8 kg

External dimensions (W x H x D) 272 x 340 x 380 mm

Operating conditions Temperature 5 °C to 35 °C (41 °F to 95 °F)

Operation status : Horizontal

Operating humidity 5 % to 85 %

• 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,

AUX. IN 0.6 V (RCA jack x 2)

• TUNER

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

• AMPLIFIER

Output Power Front : 55 W x 2 (4 Ω)

T.H.D ≤15 %

Frequency Response 45 Hz to 20 kHz

Signal-to-noise ratio 75 dB

• DVD/CD PLAYER

Frequency response (audio) 100 Hz to 18 kHz

Signal-to-noise ratio (audio) More than 75 dB (1 kHz)

Signal-to-noise ratio (video) More than 55 dB (1 kHz)

Dynamic range (audio) More than 80 dB

• USB

USB Version USB 2.0 or USB 1.1

Bus Power Supply DC 5 V 500 mA

• FRONT SPEAKERS

Type 2 Way 2 Speaker

Impedance 4 Ω

Rated Input Power 55 W

Max. Input Power 110 W

Net Dimensions (WxHxD) 202 x 337 x 237 mm

Net Weight(1EA) 2.57 kg

1-9

SPECIFICATIONS

1-10

MEMO

SECTION 2

CABINET & MAIN CHASSIS

CONTENTS

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

1. CABINET AND MAIN FRAME SECTION (DM5420K).............................................................................. 2-3

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

3. SPEAKER SECTION ................................................................................................................................ 2-8

2-1

2-2

MEMO

EXPLODED VIEWS

1. CABINET AND MAIN FRAME SECTION (DM5420K)

VFD

300

MAIN

SMPS

KEY_L

KEY_R

457

A43

274

455

451

457

451

457

451

251

256

255

254

253

252 276

275

A26

273

A46

272

462

457

A47

455

268

458

456

455

457

456

458

271

CABLE1

A41L

A41R

296

295

USB

MIC

A48

A56

460

459

267

A41A

260

263

250

261L

261R

262L

264L

265L

265R

262R

264R

KEY

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.

2-5 2-6

MEMOMEMO

2-7

2. PACKING ACCESSORY SECTION

803T Packing

803B Packing

804 Bag

802 Box

900 Remote Control

832 Blank Disk

808 Battery

801S Song Book

811 Video Cable

827 Microphone

801 Instruction Ass'y 825 FM Wire Antenna

2-8

A60R

A60L

3. SPEAKER SECTION

•FRONT SPEAKER (DMS5420V)

SECTION 3

ELECTRICAL

CONTENTS

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

1. SMPS PART ........................................................................................................................................... 3-2

2. AUDIO ABNORMAL................................................................................................................................ 3-4

3. FUNCTION MODE AUDIO ABNORMAL ................................................................................................ 3-5

4. CD PART ................................................................................................................................................ 3-7

5. DVD READING CHECK ......................................................................................................................... 3-8

6. USB PART .............................................................................................................................................. 3-9

7. VFD DISPLAY CHECK ......................................................................................................................... 3-10

WAVEFORMS OF MAJOR CHECK POINT...................................................................................... 3-11

1. WHEN POWER ON, RESET & DATA ETC WAVEFORM ................................................................... 3-11

2. WHEN USB FUNCTION OPERATING................................................................................................. 3-11

3. STARTING ACTION WAVEFORM IN MD DEVICE (SLED HOME) .................................................... 3-12

4. FOCUS WAVEFORM ........................................................................................................................... 3-13

5. SPINDLE KICK SIGNAL ....................................................................................................................... 3-15

6. AT FIRST ACTION, FOCUS SIGNAL A, B, C, D ................................................................................. 3-16

7. RF WAVEFORM (ANALOG SCOPE) ................................................................................................... 3-16

WIRING DIAGRAM.................................................................................................................................... 3-17

BLOCK DIAGRAM .................................................................................................................................... 3-19

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

1. SMPS CIRCUIT DIAGRAM .................................................................................................................. 3-21

2. DVD MPEG/ ADC/ COMPOSITE/ USB CIRCUIT DIAGRAM............................................................... 3-23

3. S3050/ S8082/ MIC CIRCUIT DIAGRAM ............................................................................................. 3-25

4. DSP/ SPBANA/ HEADPHONE CIRCUIT DIAGRAM............................................................................ 3-27

5. AMPLIFIER CIRCUIT DIAGRAM.......................................................................................................... 3-29

6. MCU/ TUNER/ AUX CIRCUIT DIAGRAM............................................................................................. 3-31

7. VFD/ KEY/ LED CIRCUIT DIAGRAM ................................................................................................... 3-33

8. TAPE CIRCUIT DIAGRAM (OPTIONAL PART)................................................................................... 3-35

CIRCUIT VOLTAGE CHART ................................................................................................................. 3-37

1. ICs......................................................................................................................................................... 3-37

2. CAPACITORS....................................................................................................................................... 3-37

3. CONNECTORS..................................................................................................................................... 3-39

PRINTED CIRCUIT BOARD DIAGRAMS.......................................................................................... 3-41

1. SMPS P.C.BOARD ............................................................................................................................... 3-41

2. MAIN P.C.BOARD ................................................................................................................................ 3-43

3. VFD / USB P.C.BOARD........................................................................................................................ 3-47

4. KEY_L P.C.BOARD .............................................................................................................................. 3-48

5. KEY_R P.C.BOARD.............................................................................................................................. 3-48

6. MIC P.C.BOARD................................................................................................................................... 3-49

7. KEY_TOP P.C.BOARD......................................................................................................................... 3-50

3-1