LG MDD262 User manual

KARAOKE MINI
HOME THEATER
SERVICE MANUAL
MODEL : MDD262(MDS262V)
CAUTION
BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS”
IN THIS MANUAL .
MODEL : MDD262(MDS262V)
SERVICE MANUAL
P/NO : AFN32840846 FEBRUARY, 2007
http://biz.lgservice.com

1-1
CONTENTS
SECTION 1
GENERAL
SERVICING PRECAUTIONS ......................................1-2
• NOTES REGARDING HANDLING OF THE PICK-UP
• NOTES REGARDING COMPACT DISC PLAYER REPAIRS
ESD PRECAUTIONS ...................................................1-4
LOCATION OF USERS CONTROLS.........................1-5
SPECIFICATIONS ........................................................1-7
SECTION 2
EXPLODED VIEWS
CABINET AND MAIN FRAME SECTION..................2-1
TAPE DECK MECHANISM EXPLODED VIEW ........2-3
1. TAPE DECK MECHANISM
(A/R & A/S : RIGHT A/R DECK)........................2-3
2. TAPE DECK MECHANISM
(A/R & A/S : LEFT A/S DECK) ..........................2-5
DVD MECHANISM EXPLODED VIEW ......................2-7
SPEAKER EXPLODED VIEW ....................................2-9
MODEL : MDS262V (FRONT SPEAKERS)...........2-9
PACKING ACCESSORY VIEW.................................2-13
SECTION 3
AUDIO PART ELECTRICAL
AUDIO ELECTRICAL
TROUBLESHOOTING GUIDE....................................3-1
1. POWER (SMPS) ................................................3-1
2. P-SENS...............................................................3-2
3. VKK CHECK.......................................................3-2
4. MICOM PART CHECK I ....................................3-2
5. MICOM PART CHECK II ...................................3-3
6. IC103(KS4CD21CS) CHECK............................3-4
7. FLD DISPLAY CHECK ......................................3-5
8. PWM MODULATION PART CHECK................3-6
9. POWER AMP PART CHECK............................3-7
10. AUX FUNCTION CHECK ..................................3-8
11. TUNER FUNCTION CHECK.............................3-9
12. TAPE FUNCTION CHECK ..............................3-10
13. TAPE PLAY PART CHECK..............................3-11
14. TAPE REC PART CHECK...............................3-12
INTERNAL BLOCK DIAGRAM OF ICs...................3-13
1. ES6838 ..............................................................3-13
2. HA12237F..........................................................3-14
3. PS9829B............................................................3-15
4. PT6324...............................................................3-15
5. STR-S6757IF1905 ............................................3-16
6. TAS5142.............................................................3-17
7. U1739EJ2V1UD00/KF2_E ...............................3-18
WIRING DIAGRAM ....................................................3-20
BLOCK DIAGRAM.....................................................3-22
1. SMPS BLOCK DIAGRAM...............................3-22
2. MAIN & FRONT BLOCK DIAGRAM ..............3-24
SCHEMATIC DIAGRAMS .........................................3-26
1. SMPS SCHEMATIC DIAGRAM.......................3-26
2. MAIN SCHEMATIC DIAGRAM ........................3-28
3. AMP SCHEMATIC DIAGRAM..........................3-30
4. DECK SCHEMATIC DIAGRAM .......................3-32
5. FRONT SCHEMATIC DIAGRAM.....................3-34
PRINTED CIRCUIT DIAGRAMS...............................3-36
1. MAIN P.C.BOARD............................................3-36
2. SMPS P.C.BOARD ..........................................3-40
3. FRONT P.C.BOARD ........................................3-42
SECTION 4
DVD PART ELECTRICAL
DVD ELECTRICAL
TROUBLESHOOTING GUIDE....................................4-1
1. POWER CHECK GUIDE...................................4-1
2. TEST & DEBUG FLOW.....................................4-2
3. USB PART ..........................................................4-7
WAVEFORMS ...............................................................4-8
1. WHEN POWER ON,
RESET & DATA ETC WAVEFORM ...................4-8
2. OPEN / CLOSE WAVEFORM AT POWER ON .......4-9
3. STARTING ACTION WAVEFORM IN MD DEVICE ......4-9
4. FOCUS WAVEFORM (AT CD).........................4-10
5. FOCUS WAVEFORM (AT DVD) ......................4-10
6.
AT POWER ON, SPINDLE SIGNAL AT MD DECK ........4-11
7.
AT FIRST ACTION, FOCUS SIGNAL A, B, C, D ....4-11
8. TRACKING SIGNAL..........................................4-12
9. RF WAVEFORM ................................................4-12
10. DISK TYPE JUGEMENT WAVEFORM...........4-13
SCHEMATIC DIAGRAMS .........................................4-15
1. MPEG SCHEMATIC DIAGRAM .....................4-15
2. SERVO SCHEMATIC DIAGRAM ...................4-17
3. INTERFACE SCHEMATIC DIAGRAM ...........4-19
PRINTED CIRCUIT DIAGRAM .................................4-21
DVD P.C.BOARD .................................................4-21
SECTION 5
REPLACEMENT PARTS LIST ........5-1

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 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.
SERVICING PRECAUTIONS
SECTION 1 GENERAL

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 (1MΩ)
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.

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 know 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 ARROWHEAD 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 INTENED TO
ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY
INFORMATION IN SERVICE LITERATURE.

1-5
LOCATION OF USERS CONTROLS
FRONT / BACK PANEL
1
3
4
5
6
7
89
10
11
12
13
2
18
15
19
14
17
16
MDD262 Model
MDT352 Model
20
1. NUMERIC buttons (0-9)
2. DISPLAY WINDOW
3. • ( )POWER button
• CLOCK button
• TIMER button
• DUBBING (DUBB.) / CD SYNCHRO RECORDING
(CD SYNC.) / (ST./MO.) button
4. MULTI JOG
• MANUAL TUNING
• CD SKIP
• CLOCK ADJUST
• (b-KEY CON-#) KEY CONTROL
5. HEADPHONE Jack (PHONES): ø3.5 mm
6. USB ( ) connector
7. • FUNCTION SELECT buttons
(TUNER, TAPE, KARAOKE/DVD/CD, AUX)
• EQ button
• XTS-PRO button
• USB button
• XDSS Plus button
• Volume control knob
8. PUSH EJECT position (TAPE 1)
9. PUSH EJECT position (TAPE 2)
10.• RECORD/RECORD PAUSE ( REC/ ) button
• TUN.(-/+) buttons -AUTO TUNING /
REWIND / FAST FORWARD ( ) -TAPE/
SCAN ( ) /TEMPO (-/+) buttons -CD
• PRESET (-/+) buttons / TAPE REVERSE PLAY
()button (OPTIONAL) / TAPE FORWARD PLAY
()button
• STOP ( STOP) button
11. MIC JACKS (MIC1, MIC2): ø6.3 mm : OPTIONAL
12.MIC VOLUME knob
13.Remote control sensor
14.• OPEN/CLOSE ( OP/CL) button
• DISC SKIP (D.SKIP) button
• PLAY MODE, DEMO button
• SET/CD , RDS (OPTIONAL) button
15.DISC DOOR
16.• COMPONENT VIDEO OUT
(PROGRESSIVE SCAN) (Y Pb Pr) Connector
• VIDEO OUT Connector
17.• FM/AM ANTENNA Connector
• AUXILIARY INPUT (AUX IN) connector
18.POWER CORD
19.SPEAKER Connectors (MDT352 Model)
20.SPEAKER Connectors (MDD262 Model)

1-6
1. POWER button
2. FUNCTION SELECT buttons
(TUNER/BAND, DVD/KARAOKE, AUX, USB)
3. NUMERIC buttons (0-9)
4. TAPE FUNCTION buttons
• REVERSE PLAY ( )
• PLAY ( )
• REWIND / FAST FORWARD PLAY ( )
• TAPE 1-2 SELECT buttons (1-TAPE-2)
• RECORD / RECORD PAUSE ( / )
• TAPE STOP ( )
5. SETUP button
6. • ARROW buttons ( / )
(Selects an option in the menu)
• PRESET (-/+) buttons ( )
• TUN. (-/+) buttons ( )
7. SELECT/ENTER button
8. MENU button
(Use the MENU button to display the menu screen
included on DVD video discs.)
9. STOP ( ), PAUSE( )/ STEP, PLAY ( ) buttons
10.PROG./MEMO., REPEAT, REPEAT A-B buttons
11. EQ ,XTS-Pro, SOUND / FEMALE( ),
AUDIO / MALE( ), SUBTITLE (S-TITLE),
SHADOW, CLEAR buttons
12.ECHO VOL. ( ) buttons
13.MIC VOL. ( ) buttons
14.RDS, PTY buttons - OPTIONAL
15.XDSS plus, VSM (Virtual Sound Matrix), ZOOM,
RETURN ( ) buttons
16.• MARKER, SEARCH, MUTE( ) buttons
• TEMPO (-/+)/ SCAN ( )
• KEY CON (b/#)/ SKIP ( )
17.VOLUME -/+ buttons
18.TITLE button
(Use the TITLE button to display the title screen
included on DVD video discs.)
19.DISPLAY button
20.DIMMER button
21.SLEEP button
22.DISC SKIP (D.SKIP) button
REMOTE CONTROL
PRESET
PRESET
+
+
PRESET
PRESET
-
-
SETUP
SETUP
TEMPO
TEMPO
MENU
MENU
REPEA
REPEA
T
MARKER
MARKER
SEARCH
SEARCH
REPEA
REPEA
T A-B
A-B
PROG./MEMO.
PROG./MEMO.
ZOOM
ZOOM
EQ
EQ
AUDIO
AUDIO
S-TITLE
S-TITLE
RETURN
RETURN
RDS
RDS
PTY
PTY
CLEAR
CLEAR
TITLE
TITLE
DISPLA
DISPLA
Y
SLEEP
SLEEP
DIMMER
DIMMER
AUX
AUX
DVD/
DVD/
KARAOKE
KARAOKE
POWER
POWER
/ENTER
SELECT
MUTE
MUTE
TUNER/BAND
TUNER/BAND
USB
USB
D.SKIP
D.SKIP
ST
ST
OP
OP
PLA
PLA
Y PAUSE/STEP
AUSE/STEP
ECHO VOL.
ECHO VOL.
MIC VOL.
MIC VOL.
TUN. -
TUN. -
TUN. +
TUN. +
1 -
1 -
TAPE - 2
APE - 2
SHADOW
SHADOW
KEY
KEY
CON - #
CON - #
b -
b -
XTS Pro
XTS Pro
XDSS plus
XDSS plus
VSM
VSM
SOUND
SOUND
1
6
5
4
3
2
8
9
21
20
18
16
17
19
7
10
12 13
15
11
22
14

1-7
SPECIFICATIONS
• GENERAL
Power supply Refer to the main label.
Power consumption Refer to the main label.
Net Weight 8.65kg (MDT352)
5.9kg (MDD262)
External dimensions (W x H x D)
280 X 365 X 370mm
• TUNER/AMPLIFIER
FM Tuning Range 87.5 ~ 108.0MHz or 65 ~74MHz, 87.5 ~ 108.0MHz
Intermediate Frequency 10.7MHz
Signal to Noise Ratio 60/55dB (Mono/Stereo)
Frequency Response 140 ~ 10000Hz
AM Tuning Range 522 ~ 1620kHz or 520 ~ 1720kHz
Intermediate Frequency 450kHz
Signal to Noise Ratio 30dB
Frequency Response 140 ~ 1800Hz
Output Power Front: 130W + 130W (4Ω, THD 10%)(MDD262)
100W + 100W (4Ω, THD 10%)(MDT352)
Subwoofer: 150W (3Ω, THD 10%)(MDT 352)
T.H.D 0.5%
Frequency Response 42 ~ 20000Hz
Signal-to-noise ratio 75dB
• DVD/VCD/CD PLAYER • CASSETTE TAPE PLAYER
Frequency response (audio) 40 ~ 20000Hz Tape Speed 3000 ± 3%
Signal-to-noise ratio (audio) More than 75dB (1kHz) (MTT-111.
Signal-to-noise ratio (video) More than 55dB (1kHz) NORMAL-SPEED)
Dynamic range (audio) More than 75dB Wow Flutter 0.25%
Video output 1.0V (p-p), 75Ω(MTT-111, JIS-WTD)
S-video output (Y) 1.0V (p-p), 75ΩF.F/REW. Time 120sec (C-60)
(C) 0.3V (p-p), 75ΩFrequency Response 250 ~ 8000Hz
Component Video output (Y) 1.0V (p-p), 75ΩSignal to Noise Ratio 43dB
(Pb)/(Pr) 0.7V (p-p), 75ΩChannel Separation 45dB (P/B)/45dB (R/P)
Erase Ratio 55dB (MTT-5511)
• SPEAKERS
Speaker Name Front Speaker (L/R) (MDS352V / MDS262V)
Type Bass Reflex 2Way 3Speaker
Impedance 4Ω
Frequency Response 55 ~ 20000Hz
Sound Pressure Level 82dB/W (1m)
Rated Input Power 130W
Max. Input Power 260W
Net Dimensions (W x H x D) 212 X 414 X 305mm
Net Weight 6.3kg
Speaker Name Subwoofer (MDS352W)
Type Bass Reflex 1Way 1Speaker
Impedance 3Ω
Frequency Response 50 ~ 1500Hz
Sound Pressure Level 82dB/W (1m)
Rated Input Power 180W
Max. Input Power 360W
Net Dimensions (W x H x D) 212 X 414 X 305mm
Net Weight 6.3kg

1-8
MEMO

255
256
450
450
263
262
273
455
450
H
K
A
B
E
N
N
C
F
G
J
I
A26
A40
A47
A46
266
305
267
289
456
450
264
452
458
450
450
290
290 454
450
450
A00
257
255
259
A43
A44
253
453
253
254
252
450
450
450
CABLE4
CABLE3
CABLE1
CABLE5
CN201
P9701
P9702
260
MAIN
SMPS
291
B
M
A
L
C
O
O
D
K
H
L
J
D
I
M
A41
450
CABLE2
P5701
DVD
FRONT
252
450
282
258
2-1 2-2
SECTION 2 EXPLODED VIEWS
CABINET AND MAIN FRAME SECTION

001
A00
002
037
007
006
008
016 017
018
019
020
003
009
009
A02
A01
011
013
022
025
015
023
BRASS MOTOR PULLEY MAYBE CHANGED
FOR WOW FLUTTER WHEN NECESSARY
RING FW MAYBE ADDED
FOR WOW FLUTTER WHEN NECESSARY
RING FW MAYBE ADDED
FOR WOW FLUTTER WHEN NECESSARY
2-3 2-4
TAPE DECK MECHANISM EXPLODED VIEW
1. TAPE DECK MECHANISM (A/R & A/S : RIGHT A/R DECK)

2-5 2-6
A00
RING FW MAYBE ADDED
FOR WOW FLUTTER WHEN NECESSARY
013
011
009
009
003
008
015
022
023
024
016 017
018
019
020
007
A03
2. TAPE DECK MECHANISM (A/R & A/S : LEFT A/S DECK)

2-7 2-8
416
151
159
165
164
417
166
417
167
416
177
175
172
180
417
170
419
417
418 418
169
A30
A26
181
432
431 435
430
430
438
035
021
035A
036
430
012A
012A
012A
439
025
024
030
156
155
153
173
169A
169B
169C
168
163
162
441
440
422
DVD MECHANISM EXPLODED VIEW

A80A
A80R
A80L
A80BR
A80BL
WIRE80
WIRE81
850
855 856
857
858
860
861
863
859
851
853
852
854
862
2-9 2-10
SPEAKER EXPLODED VIEW
MODEL : MDS262V (FRONT SPEAKERS)

2-11 2-12
MEMO MEMO

2-13
PACKING ACCESSORY VIEW

3-1
AUDIO ELECTRICAL TROUBLESHOOTING GUIDE
SECTION 3 AUDIO PART ELECTRICAL
1. POWER (SMPS)
POWER (SMPS)
OK
YES
YES
YES
Replace IC 901,902
Check IC901, 902
Check the fuse
F901
NONO
NO
YES
Check short of
P9701, P9702 line
Replace the fuse
Check
the DC V of C905.
If DC V is over
400V
NO Check BD901, LF901, 902
Check the
DC V of C981, C945.
If DC V is 6.1V
NO Check short of P9702 line
YES
YES
Chcek the
DC V of C950, C951
If DC V is in
35.5V
NO Check short of P9701 line
Chcek the
DC V of C909, C903,
C921 If DC V is in 14~19V
and it is steady.
YES

3-2
2. P-SENS
P-SENS
YES
YES
Check
the PIN6 of P9702
If DC V is over 5.6V
Check power circuit Trouble shooting
NO
OK
3. VKK CHECK
VKK check
YES
YES
Check
the PIN3 of P9702
If DC V is over -28V ±2 Check power circuit Trouble shooting
NO
OK
4. MICOM PART CHECK I
MICOM part check I
OK OK
YES
YES
Check P-SENS
(P7904)_PIN6.
NO Refer to
SMPS troubleshooting.
YES YES
YES
Check both
end voltage of IC101
(KIA7042).
Check
if input voltage of
IC101(KIA7042) is
over 5V.
YES
NO Check the
periphery of IC101
(KIA7042).
NO
YES
Check if IC101(KIA7042) of
output voltage is over 4.3V.
Check voltage of IC100
78KO/KF2_PIN1.
NO Replace IC101
(KIA7042).

3-3
5. MICOM PART CHECK II
MICOM part check II
X101 : 32.768kHz
X100 : 9.8304MHz
Check the operation.
Check
Q101_ emitter/collector
5V.
Check Q102_base
0.6V HIGH.
Check if IC103_PIN8 and
IC100_PIN19, 20, 59 are 5V.
NO NO
YES
YES
Check if
voltage of P7904_PIN5
is 5.6V.
NO Refer to
SMPS troubleshooting.
YES
YES
YES
OK
YES
Check
both end voltage of
D101
YES
YES
Check D101.
NO Check if output of
D101(1SR35) is 5V.
YES
YES
YES
YES
Check IC101.
Q102_collector 0.6V LOW.
OK
Check if output of IC101
(KIA7042) is over 4.3V.
OK
NO Replace IC101.
NO Replace D101.
YES
Check Q102.
OK
NO Replace Q102.

3-4
Check
IC100(78KOKF2)_
PIN 22, 24
OK
YES
YES
Refer to
micom troubleshooting
Check micom
voltage 5V.
PIN22
DATA PIN24 CLK
NONO
YES
Replace micom.
Check micom. NO
YES
OK
6. IC103(KS4CD21CS) CHECK