LG LHS-A4000WA, LHS-A4000WD, LHS-A4000C, LHS-A4000T Service Manual

DIGITAL HOME CINEMA
SYSTEM

SERVICE MANUAL

MODELS : LHS-A4000WA/LHS-A4000WD

LHS-A4000C/LHS-A4000T

MODELS : LHS-A4000WA/LHS-A4000WD/LHS-A4000C/LHS-A4000T

SERVICE MANUAL

P/NO : 3829RGP019S JULY,2005

1-1

[CONTENTS]

❍ SECTION 1.GENERAL

• ESD PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2

• SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

❍ SECTION 2. ELECTRICAL

• TROUBLESHOOTING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

• IC VOLTAGE SHEET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

• WIRNG DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

• BLOCK DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

• SCHEMATIC DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8

• PRINTED CIRCUIT DIARGAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20

❍ SECTION 3. EXPLODED VIEWS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1

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

ESD PRECAUTIONS

1-21-2

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.

SECTION 1. GENERAL

1-3

SPECIFICATIONS

Power supply Refer to the main label

Power consumption 60 W

Mass 10 kg

External dimensions (W x H x D) 246 x 430 x 420 mm

Operating conditions Temperature: 5°C to 35°C, Operation status: Horizontal

Frequency response (audio) 120 Hz to 20 kHz

Signal-to-noise ratio (audio) More than 75 dB (1 kHz, NOP, W/IHF-A & 20 kHz Filter)

Harmonic distortion (audio) 1.0 % (1 kHz, at 12W position) (20 kHz LPF/A Filter)

Surround mode Front: 60W + 60W (THD 10 %)

Center*: 60W

Surround*: 60W + 60W (8Ω at 1 kHz, THD 10 %)

Subwoofer*: 120W (4Ω at 250 Hz, THD 10 %)

FM

Tuning Range 87.5 - 108.0 MHz or 65 - 74 MHz, 87.5 - 108.0 MHz

Intermediate Frequency 10.7 MHz

Signal to Noise Ratio 60/55 dB

Frequency Response 140 -10,000 Hz

AM

Tuning Range 522 - 1611 kHz or 530 - 1610 kHz or 530 - 1720 kHz

Intermediate Frequency 450 kHz

Signal to Noise Ratio 37 dB

Frequency Response 140 - 25,000 Hz

Inputs AUX, COAXIAL, OPTICAL AUDIO

Model Satellite Speaker Center Speaker Active Subwoofer

(LHS-A4000T) (LHS-A4000C) (LHS-A4000WA/WD)

Type 2 Way 2 Speaker 2 Way 2 Speaker 1 Way 1 Speaker

Impedance 8 Ω 8 Ω 4 Ω

Frequency Response 120 - 20,000 Hz 120 - 20,000 Hz 40 - 180 Hz

Sound Pressure Level 84 dB/W (1m) 84 dB/W (1m) 82 dB/W (1m)

Rated Input Power 60 W 60 W 120 W

Max. Input Power 120 W 120 W 240 W

Net Dimensions (W x H x D) 100 x 162 x 120 mm 225 x 102 x 120 mm 246 x 430 x 420 mm

Net Weight 0.8 kg 0.9 kg 10 kg

• Designs and specifications are subject to change without notice.

2-1

TROUBLESHOOTING GUIDE

"Hello"

SECTION 2. ELECTRICAL

2-2

• AUDIO µ-COM Circuit

TURN ON "Hello"?

POWER Check or
Press the ON KEY

2-3

• IC VOLTAGE SHEET

IC201(CS42516)
PIN NO. Volt(V)

1. Power &Micom 2. DSP

IC801(PT6315)
PIN NO. V

olt(V)

5.VFD DRIVE

IC204,IC205(NJM4580M)
PIN NO. V

olt(V)

3. OP-AMP

IC202(CS493264)
PIN NO. V

olt(V)

IC501,IC502,IC503,IC504

PIN NO. Volt(V)

IC700(LC87F57C8A)
PIN NO. V

olt(V)

IC301(PS9808)
PIN NO. V

olt(V)

3
6
10
13
22
29
35
39
42
47
56
65
66
72
80
87
91
94

1.8V

1.8V

3.3V

1.8V

3.3V

3.3V

1.8V

3.3V

1.8V

3.3V

3.3V

3.3V

1.8V

3.3V

1.8V

3.3V

1.8V

3.3V

4. DAP

4
7
12
15
21
22

9
36
59

10-40V
10-40V
10-40V
10-40V
5V
5V

4.9V

4.96V

4.876V

24 4.99V 4

8

-8.19V

8.2V

1
12
23
34

2.41V

2.41V

2.41V

2.387

13
43

4.8V

4.8V