LG LM-K3960A Service manual

3CD CHANGER
KARAOKE SYSTEM

SERVICE MANUAL

MODEL: LM-K3960A, LMS-K3960V

SERVICE MANUAL MODEL: LM-K3960A, LMS-K3960V

CAUTION

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

- 1-1 -

[CONTENTS]

❍ SECTION 1. GENERAL

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

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

• SPECIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-5

❍ SECTION 2. ELECTRICAL SECTION

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

• INTERNAL BLOCK DIAGRAM of ICs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13

• BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19

• SCHEMATIC DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21

• WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-35

• PRINTED CIRCUIT DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-37

❍ SECTION 3. DVD PART ELECTRICAL

• DVD ELECTRICAL TROUBLESHOOTIHG GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1

• DVD SCHEMATIC DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-15

• DVD PRINTED CIRCUIT DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-23

❍ SECTION 4. EXPLODED VIEWS

• CABINET AND MAIN FRAME SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1

• TAPE DECK MECHANISM (A/R & A/S : RIGHT A/R DECK) . . . . . . . . . . . . . . . . . . . . . . . . . .4-3

• TAPE DECK MECHANISM (A/R & A/S : LEFT A/S DECK) . . . . . . . . . . . . . . . . . . . . . . . . . . .4-5

• CD MECHANISM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7

❍ SECTION 5. SPEAKER PART

• SPEAKER PART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-1

❍ SECTION 6. REPLACEMENT PARTS LIST

• REPLACEMENT PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-1

- 1-2 -

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

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 cotton
swab should be used, taking care not to distort this.

6) Never attempt to disassemble the pick-up.
Spring by 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 let
contact fingers or other exposed skin.

Magnet

How to hold the pick-up

Conductive Sheet

Cotton swab

Pressure

Pressure

- 1-3 -

■ 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 of 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 (1M Ω)

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.

CLEARING MALFUNCTION

You can reset your unit to initial status if malfunction occur(button malfunction, display, etc.).
Using a pointed good conductor(such as driver), simply short the RESET jump wire on the inside of
the volume knob for more than 3 seconds.
If you reset your unit, you must reenter all its settings(stations, clock, timer)

NOTE: 1.To operate the RESET jump wire, pull the volume rotary knob and release it.

2. If you wish to operate the RESET jump wire, it is necessary to unplug the power cord.

Resistor
(1 Mohm)

Conductive
Sheet

Resistor
(1 Mohm)

Armband

RESET jump wire

VOLUME

VOLUME KNOB

DOWN

UP

- 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 sur-

face 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 -

❏ SPECIFICATIONS

General

Power supply Refer to the main label.
Power consumption 70 W (LM-K3960Q/LM-KW3960Q/LM-K3860Q model)

50 W (LM-K3565Q model)
30 W (LM-K3365Q model)

Net Weight 6.5 kg
External dimensions (W x H x D) 272 X 322 X 354 mm

Tuner/Amplifier

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 (Mono/Stereo)
Frequency Response 140 - 10000 Hz

AM Tuning Range 522 - 1620 kHz or 520 - 1720 kHz

Intermediate Frequency 450 kHz
Signal to Noise Ratio 30 dB

Frequency Response 140 - 1800 Hz

Output Power LM-K3960Q/LM-KW3960Q model - 130 W + 130 W (4 , THD 10 %)

LM-K3860Q model - 100 W + 100 W (4 Ω , THD 10 %)
LM-K3565Q model - 50 W + 50 W (4 Ω , THD 10 %)

LM-K3365Q model - 30 W + 30 W (4 Ω , THD 10 %)
T.H.D 0.5 %
Frequency Response 140 - 20000 Hz
Signal-to-noise ratio 75 dB

DVD/VCD/CD player

Frequency response (audio) 40 - 20000 Hz
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
Video output 1.0 V (p-p), 75 Ω
S-video output (Y) 1.0 V (p-p), 75 Ω

(C) 0.3 V (p-p), 75 Ω
Component Video output (Y) 1.0 V (p-p), 75 Ω

(Pb)/(Pr) 0.7 V (p-p), 75 Ω

Speakers

Speaker Name Front Speaker (L/R)
Type Bass Reflex 2Way 3Speaker (LMS-K3960V/LMS-KW3960V/LMS-K3860V)

Bass Reflex 2Way 2Speaker (LMS-K3565V/LMS-K3365V)
Impedance 4
Frequency Response 55 - 20000 Hz
Sound Pressure Level 86 dB/W (1m)
Rated Input Power 130 W (LMS-K3960V/LMS-KW3960V)

100 W (LMS-K3860V)

50 W (LMS-K3565V)

30 W (LMS-K3365V)
Max. Input Power 260 W (LMS-K3960V/LMS-KW3960V)

200 W (LMS-K3860V)

100 W (LMS-K3565V)

60 W (LMS-K3365V)
Net Dimensions (W x H x D) 214 X 386 X 318 mm (LMS-K3960V/LMS-KW3960V/LMS-K3860V)

229 X 224 X 286 mm (LMS-K3565V/LMS-K3365V)
Net Weight 6.3 kg (LMS-K3960V/LMS-KW3960V/LMS-K3860V)

4.2 kg (LMS-K3565V)

3.8 kg (LMS-K3365V)

Cassette tape player

Tape Speed 3000 ± 3 % (MTT-111.

NORMAL-SPEED)

Wow Flutter 0.25 %

(TT -111, JIS-WTD)
F.F/REW. Time 120 sec (C-60)
Frequency Response 250 - 8000 Hz
Signal to Noise Ratio 43 dB
Channel Separation 50 dB (P/B)/45 dB (R/P)
Erase Ratio 55 dB (MTT-5511)

Ω

Ω

- 1-6 -

- 2-1 -

SECTION 2. ELECTRICAL SECTION

❏ ELECTRICAL TROUBLESHOOTING GUIDE

P7904 6PIN P-SENS check

Refer to SMPS

Troubleshooting

Check if IC101 KIA7042
input is over 5V

Check if IC101 KIA7042

input is over 4.3V

IC101 KIA7042
relevant parts check

relevant parts

replacement

normal

IC101 KIA7042?

IC100 78KO/KF2 1 PIN
Power Check

normal

YES

NO

NO

NO NO

YES

YES

YES

YES

■ MICOM PART CHECK I

- 2-2 -

Q102 BASE PIN

0.6V HIGH check

Q102 COLLECTOR

0.6V LOW check

Check if IC101

KIA7042 output

power is over 4.3V

relevant parts check

relevant parts

replacement

normal

relevant parts

replacement

relevant parts check

normal

IC 103 8PIN IC 100 19,20,59
PIN 5V check

X101:32.768KHz
X100:9.8304MHz operation
status check

normal

P7904 5PIN 5.6V check

Refer to SMPS

Troubleshooting

Output 5V operation check
D101 1SR35

relevant parts check

normal

relevant parts

replacement

D101 1SR35 both terminal
power check

Q101 EMITTER 5V check
and COLLECTO

NO

NO

NO

NO

NO

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

■ MICOM PART CHECK II

- 2-3 -

IC100 78KOKF2 22,24

PIN Check

22 PIN DATA MICOM power 5V check

Refer to MICOM

Troubleshooting

relevant parts

replacement

relevant parts check

normal

Refer to SMPS

Troubleshooting

P7302 assembly check

Each PIN power check

normal

relevant parts

replacement

normal

P7904 1,2,3 power check

F1+, F2 both terminal: 3.7V and
above VKK: power is over 26V

P7302 connection status
check and power check
F+,F2- both termainal: 3.7V
or above VKK:26V or above
power check

IC301 PT6324 Power check
50 PIN VKK:-26V 9.52
PIN +5V

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

NO

NO

NO

NO

NO

NO

■ IC103 KS4CD21CS CHECK

■ FLD DISPLAY CHECK

- 2-4 -

IC100 ➞ IC301 DATA
Communication check
PIN PIN
75 PIN ➞ 3PIN STB
76 PIN ➞ 2PIN DO
77 PIN ➞ 4PIN DI
78 PIN ➞ 1PIN CLK

If 5V defective D3191SR35
input and output power check

relevant parts check

76 PIN ➞ DATA input check

relevant parts check

relevant parts

replacement

normal

relevant parts

replacement

normal

FLT light on

normal

IC100
75 PIN ➞ STB
77 PIN ➞ 4PIN DI
78 PIN ➞ 1PIN CLK
Data output check

YES

YES

YES

YES

YES

YES

YES

YES

NO

NO

NO

NO

- 2-5 -

P7905 9PIN 3.3V check

X601 12.288MHz operation
check

IC604 PS9829
86 PIN CLK input check

IC100 78KOKF2
21 ➞ PWM_CLK
22 ➞ PWM_DATA
23 ➞ PWM_REST
output check

IC604 PS9829 DATA input
check
78 PIN ➞ DATA
79 PIN ➞ CLK
96 PIN ➞ REST

PWM MODULATOR output
check
FL:75(+)74(-)FR:71(+)70(-)
SW:68(+)67(-)CEN:62(+)61
(-) SL:59(+)58(-)SR:52(+)51(-)

normal

IC604 PS9829 VDD PIN
Power check
(3.10.22.29.39.47.56.65.72.

87. 94)

Refer to SMPS

Troubleshooting

relevant parts check X604

12.288MHz

normal

R668(470Ω) output check

normal

LINE resistance check
DATA:R671 CLK:R670
RST:R665

normal

DVD ASS`Y PS9829 commu­nication status check(P7403)

IC604 PS9829 DATA input check

normal

IC604 PS9829 parts check

relevant parts

replacement

relevant parts

replacement

relevant parts

replacement

Refer to DVD

Troubleshooting

Check each line

resistance check

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

NO

NO

NO

NO

NO

NO

NO

NO

NO

NO

NO

■ PWM ALTERATION PART CHECK

- 2-6 -

P7905 3 PIN+12 13.14.15
PIN 32V

Each IC700,701,702,703

34.29.26.21 PIN input power
check

Each IC 700.701.702.703

1.36.17.18.19 PIN +12V
input power check

PWM MODULATOR input
power check Each IC

4.6.14.16 PIN

POWER IC 700.701.702.703

34.29.27.20 PIN output
check

Output LINE COIL check

normal

Refer to SMPS

Troubleshooting

Each LINE resistance output
power check
IC700:R702.701.726.727.724
IC701:R730.729.750.753.752
IC702:R756.755.768.771.770
IC703:R774.773.794.797.796

relevant parts

replacement

YES

YES

YES

YES

YES

YES

NO

NO

NO

■ POWER AMP PART CHECK

- 2-7 -

Check whether JK800
contacts or not

IC200
(BU4052)4,11PI
N input waveform check

IC200
(BU4052)3,13PIN output
waveform check

IC801 (MC4580)
2,6PIN input waveform check

normal

IC200 (BU4052)16PINVDD,
8PIN VSS power check

u-COM (IC301)83PIN,84PIN
Communication check

Refer to SMPS

Troubleshooting

relevant parts

replacement

IC801 (MC4580)4PIN
VSS,8PIN VDD power check

relevant parts

replacement

YES

YES

YES

YES

YES

YES

NO

NO

NO

NO

■ AUX FUNCTION

- 2-8 -

Tuner module (TU601)

operation check

TUNER MODUEL power
check (2PIN 9Vcheck)

IC200 (BU4052)16PIN-

VDD,8PIN VSS power check

relevant parts

replacement

relevant parts

replacement

IC200 (BU4052)16PIN­VDD,8PIN VSS power check

relevant parts

replacement

IC200 (BU4052)16PIN­VDD,8PIN VSS power check

relevant parts

replacement

IC801(MC4580)4PIN
VSS,8PIN VDD power check

IC200(BU4052)1,
12PIN input waveform check

IC200 (BU4052)3,13PIN
output waveform check
IC601(BU4052)2,15PIN
input waveform check

IC801 (MC4580)2,6PIN input
waveform check.

normal

TAPE PCB ASS`Y

IC801 (MC4580)2,6PIN input
check

normal

IC200(BU4052)2,1
5PIN input waveform check

IC200 (BU4052)3,13PIN
output check IC601(BU4052)
2,15PIN input waveform
check

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

NO

NO

NO

NO

NO

■ TUNER FUNCTION CHECK

■ TAPE FUNCTION CHECK

- 2-9 -

P2707:4 PIN ➞ 12V

IC201 (HA12237)16 PIN 12V
input waveform check

IC201:5.26 PIN
Signal Output check

IC20114 PIN MUTE

operation check

normal

Refer to SMPS

Troubleshooting

DECK HEAD input check

DECK HEAD input IC201

32.39 PIN check

HEAD WIRE or
Mecha replacement

relevant parts

replacement

relevant parts

replacement

relevant parts check

normal

IC202 10 PIN HIGH operation

check

relevant parts check

normal

YES

YES

YES

YES

YES

YES

YES

YES

YES

NO

NO

NO

NO

NO

NO

■ TAPE PLAY PART CHECK

- 2-10 -

IC604 PS9829 #49,#52 PWM
output check

Refer to PWM modulation
part

Q601 Collector waveform check

Board to Board cantact check

IC203 8 PIN +12V check

relevant parts check

normal

Q205(D1304)
BASE HIGH check

IC202 4 PIN HIGH operation
check

Refer to SMPS

Troubleshooting

relevant parts

replacement

relevant parts

replacement

normal

P7207 #2.#4 output check

P2707 #5.#7 input check

IC203 MC4580 #1,#7 check

IC201 7.24 PIN REC input
check

IC201 10.21 PIN output
check

L203 2.3 PIN oscillation check

P2203 5.3 PIN input check
8 PIN ERASE input check

normal

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

YES

NO

NO

NO

NO

NO

NO

NO

NO

■ TAPE REC PART CHECK

- 2-11 -

Check the fuse F901

Check the DC V of C905.
If DC V is over 400V

Check the DC V Of
C981,C945. If DC V is 6.1V

OK

Chcek the DC VOf
C950,C951 If DC V is in
35V,-35V

Chcek the DC V Of C909,
C903,C921 If DC V is in
14~19V and it is steady.

Replace the fuse

Check BD901, LF901,902

Check IC901 ,902 Replace IC 901,902

Check short of P9702 line

Check short of P9701 line

Check short of P9701,P9702

line

*MAIN PART

YES

NO

YES

YES

YES

YES

YES

NO

NO NO

NO

NO

■ SMPS POWER CIRCUIT

- 2-12 -

Check the PIN6 OF P9702
If DC V is over 5.6V

OK

Check power circuit Trouble
shooting

*P-SENS PART

Check the PIN3 OF P9702
If DC V is over -28V ±2

OK

Check power circuit
Trouble shooting

*VKK PART

YES

YES

NO

NO

- 2-13 -

❏ INTERNAL BLOCK DIAGRAM of ICs

• TAS5142

BLOCK DIAGRAM