LG LMS-U5050, LMS-U5050W, LMS-U5050S, LMS-U4050, LMS-U2350 User Manual

U5050S-LMS , U5050-LMS U5050-LMSW U5050A-LM, , U4050-LMS, U4050-LMSW U4050A-LM, U2350-LMS, U2350A-LM, MODEL ,AL MAN VICE :SE R U

3CD CHANGER

HI-FI SYSTEM

SERVICE MANUAL

CAUTION

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

MODEL: LM-U2350A, LMS-U2350

LM-U4050A, LMS-U4050, LMS-U4050W

LM-U5050A, LMS-U5050, LMS-U5050W, LMS-U5050S

	[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 . . . . . . . . . . . . . . . . . . . . .		. . . . . . . . . . . . . . . . . . . . 2-10
• BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		. . . . . . . . . . . . . . . . . . . . 2-15
• SCHEMATIC DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		. . . . . . . . . . . . . . . . . . . . 2-19
• WIREING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		. . . . . . . . . . . . . . . . . . . . 2-43
• PRINTED CIRCUIT DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . .		. . . . . . . . . . . . . . . . . . . . 2-45

SECTION 3. EXPLODED VIEWS

• CABINET AND MAIN FRAME SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1

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

• TAPE DECK MECHANISM (A/R & A/S : LEFT A/S DECK) . . . . . . . . . . . . . . . . . . . . . . . . . . .3-5

• CD MECHANISM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

SECTION 4. SPEAKER PART

• SPEAKER PART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1

SECTION 5. REPLACEMENT PARTS LIST

• REPLACEMENT PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-1

- 1-1 -

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.

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 let contact 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 this.

Pressure

Magnet

Pressure

How to hold the pick-up

Cotton swab

Conductive Sheet

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.

-1-2 -

■ 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.

Armband

Resistor

(1 Mohm)

Resistor

(1 Mohm)

Conductive

Sheet

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.

VOLUME

UP	RESET jump wire
VOLUME KNOB
DOWN

- 1-3 -

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.

- 1-4 -

SPECIFICATIONS

SECTION			MODEL
	[General]	Power supply
		Power consumption
		Weight
		External dimensions (W x H x D)
	[CD]	Frequency response
		Signal-to-noise ratio
		Dynamic range
		Tuning Range
	FM	Intermediate Frequency
[Tuner]		Signal to Noise Ratio
	AM (MW)	Frequency Response
		Tuning Range
		Intermediate Frequency
		Signal to Noise Ratio
		Frequency Response
	[Amp]	Output Power
		T.H.D
		Frequency Response
		Signal-to-noise ratio
		Tape Speed
		Wow Flutter
	TAPE[ ]	F.F/REW Time
		Frequency Response
		Signal to Noise Ratio
		Channel Separation
		Erase Ratio
		Speaker Name
		Type
	Speakers[ ]	Impedance
		Frequency Response
		Sound Pressure Level
		Rated Input Power
		Max. Input Power
		Net Dimensions (W x H x D)
		Weight
		Speaker Name
		Type
	[Subwoofer]	Impedance
		Frequency Response
		Sound Pressure Level
		Rated Input Power
		Max. Input Power
		Net Dimensions (W x H x D)
		Weight

LM-U5050		LM-U4050		LM-U2350
Refer to the back panel of the unit.
	200 W			110 W

8.5 kg

280 x 370 x 400 mm

40 - 18000 Hz

75 dB

70 dB

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

10.7MHz

60/55 dB

60 - 10000 Hz

522 - 1620 kHz or 520 - 1720 kHz

450 kHz

30 dB

120 - 2000 Hz

Front : 270 W + 270 W (LM-U5050 model only)

250 W + 250 W (LM-U4050/U2350 model only) Surround : 110 W + 110 W (LM-U5050 model only) Subwoofer : 350 W (LM-U5050/U4050 model only)

0.7%

42 - 20000 Hz

80 dB

3000 ± 3 % (MTT-111. NORMAL-SPEED)

0.25 % (MTT -111, JIS-WTD)

120 sec (C-60)

125 - 8000 Hz

40 dB

50 dB (P/B)/45 dB (R/P)

55dB (MTT-5511)

Front speaker (L/R)			Surround speaker (L/R)
LMS-U5050		LMS-U4050/U2350	[LMS-U5050S]
Bass Reflex 3Way 3 Speaker			Bass Reflex 2Way 2Speaker
		6Ω	24Ω
55 - 20000 Hz			60 - 20000 Hz
	86 dB/W (1m)		86 dB/W (1m)
270 W		250 W	110 W
540 W		500 W	220 W
250 X		300 X 415 mm	187 X 258 X 415 mm
		9.3 kg	4.3 kg

Subwoofer (LMS-U5050W/U4050W)

1 Way 1 Speaker

6Ω

45 - 15000 Hz

84 dB/W (1m)

350 W

700 W

279 X 320 X 415 mm

10.0 kg

- 1-5 -

- 1-6 -

SECTION 2. ELECTRICAL

ELECTRICAL TROUBLESHOOTING GUIDE

■ SMPS POWER CIRCUIT

P-SENS PART

SMPS ASSY CN902 7PIN 5.1V CHECK

YES NO

MAIN PCB CN710 7PIN 5.1V CHECK

NO

YES

MAIN PCB CN304 5PIN 5.1VCHECK

YES

FRONT PN302 36PIN 5.1VCHECK

YES

FRONT IC306(RESET IC)

STATE CHECK

SMPS TROUBLESHOOTING CONSULT

CN710 CONNECTION STATE CHECK

MAIN PCB PATTERN CUTTING AND

SHORT CHECK

	NO
				IC306 INPUTVOLTAGE4V,
YES
				OUTPUTVOLTAGE.2.1VSTATECHECK

U-COM IC304 26PIN 5VCHECK		IC306 KIA7042 CHANGE

VKK CHECK

CN710 10PIN DC -33V CHECK

NO

YES

IC304 51PIN VOLTAGE CHECK

SMPS TROUBLESHOOTING CONSULT

- 2-1 -

MICOM (IC301) CHECK

"P-SENS" CHECK

YES	NO
	P-SENS TROUBLESHOOTING CONSULT

"RESET" IC304 11 PIN CHECK (HIGH LOW HIGH)

YES NO

IC304 VDD(17,46,72,90) PIN VOLTAGE

CHECK

YES NO

X301 VIBRATION SIGNAL CHECK

NO

YES

IC301 CHANGE

Q303 STATE CHECK

TR "Q303" CHANGE

PN302 35 PIN +5.6V(MI) CHECK

MAIN CN710 6 PIN CHECK

X301 CHANGE

SMPS TROUBLESHOOTING CONSULT

P-CTRL CHECK

PN302 33 PIN "P-CTRL" CHECK (HIGH)

YES NO

CN710 5 PIN CHECK

NO

YES

SMPS TROUBLESHOOTING CONSULT

MICOM IC304 STATE CHECK

SMPS + MAIN BORD-TO-BORD CHECK

- 2-2 -

MUTING TROUBLESHOOTING (MUTE STATE)

Q752(A102) BASE "HIGH"

YES NO

Q701, Q751(D1302) BASE "HIGH"

CHECK

NO

YES

EXPEND IC(IC305) 5PIN HIGH STATE CHECK

YES

Q752(A102)STATE CHECK

YES

Q752(A102) FAULTY IS CHANGE

YES

EACH PART TR CHANGE

MUTE

EXPEND IC(IC305/501/502) STATE

16 PIN VDD VOLTAGE CHECK

YES		NO
					D332/D553/D551(1SS133) CHECK
3 "EXP-CLK" CHECK					YES	NO			D332/D553/D551(1SS133)
									CHANGE
YES		NO
					MICOM (IC304) 4/84/85 PIN
					CHECK(CLK1/2/3)
2 "EXP-DATA" CHECK						NO
					YES				PCB PATTERN CHECK
YES		NO
					MICOM (IC304) 3 PIN CHECK
						NO
4 PIN ~ 15 PIN EACH PORT STATE
					YES				PCB PATTERN CHECK
CHECK
YES		NO
					EXPEND IC FAULTY IS CHANGE

EXPEND IC OK

- 2-3 -

SPECIFIC FUNCTION MODE HAS NO SOUND (NJW1190) IC601

IC201 INPUT CHECK(HEAD

INPUT)"A"DECK 32,39 "B"DECK 34,37

YES

NO

DECK HEAD WIRE

CONNECTION STATE CHECK

IC201 OUTPUT CHECK(5,26 PIN)

YES

NO

IC502 10PIN(PB MUTE) STATE

STATE CHECK

NO

IC601 3,36PIN INPUT SIGNAL CHECK

YES

1)

YES

NO

IC502 4PIN(REC SW) "HIGH"

IC502 4PIN(REC SW) "LOW"

CHECK

STATE REC

IC601 17,22 PIN OUTPUT SIGNAL

YES

CHECK

YES

NO

IC601(NJW1190)

Q212 (C) "HIGH" CHECK

TROUBLESHOOTING CONSULT

DECK OUTPUT

YES

Q213 (C) "LOW" CHECK

YES

1)

IC502 2 PIN/3 PIN

IC502 13 PIN "REC-BAIS" HIGH

CHECK(DATA/CL

CHECK

YES

YES

L203(4.7MH) COIL VIBRATION

IC502 16 PIN VDD CHECK

SIGNAL CHECK

YES

YES

IC601 7 /32 INPUT REC'

SIGNAL CHECK

IC502 EXPEND IC CHANGE

- 2-4 -

AUX

YES

JK601 SIGNALINPUT CHECK

YES

IC601 5,34 PIN SIGNALINPUTCHECK

YES NO

IC601 17,22 PIN OUTPUT SIGNAL

CHECK

NO

YES

AUX OUTPUT

CD

YES

CN709 1,3PIN SIGNALCHECK CD TROUBLESHOOTINGCONSULT

YES

IC601 4,35PIN SIGNALINPUTCHECK

YES NO

IC601 17,22 PIN OUTPUT SIGNAL

CHECK

YES NO

CD OUTPUT

MAIN PCB PATTERN CHECK

IC601(NJW1190)

TROUBLESHOOTING CONSULT

MAIN PCB PATTERN CHECK

IC601(NJW1190)

TROUBLESHOOTING CONSULT

- 2-5 -

TUNER

YES

TU101 3 /5 SIGNAL CHECK

YES NO

IC601 2,37 PIN SIGNALINPUTCHECK

YES

IC601 17,22 PIN OUTPUT SIGNAL

CHECK

YES

TUNER OUTPUT

TU101 2 PIN "+9V"

VOLTAGE CHECK

TU101 6,7,8,9 PIN CHECK (PLL-CE, PLL-DI, CLK, PLL-DO)

TUNER MODULE CHANGE

MIC

YES

CN303 7 PIN "MIC-SIGNAL" CHECK

<MIC PCB>

YES NO

CN303 4 MIC-SENSE CHECK

NO

IC601 44 PIN SIGNAL CHECK(OW601 YES PN400 3 PIN "+12V"CHECK PATTERN)

			IC402 8 PIN SIGNAL INPUT CHECK
YES
			YES	NO
								MIC MUTE CHECK(Q409/ Q408)
IC601 17,22 PIN OUTPUT SIGNAL
			PN400 9 "VOL-IN"CHECK
CHECK
YES			YES	NO					TR CHANGE
			IC402 2 PIN SIGNAL INPUT CHECK
MIC OUTPUT
			YES
			PN400 10 PIN "VOL-OUT"CHECK
		- 2-6 -

IC601(NJW1190) TROUBLESHOOTING

IC601 24PIN VOLTAGE INPUT CHECK

NO

YES SMPS VOLTAGE CHECK CONSULT

IC601 19,20 SDA, SCA PULSE WAVE CHECK (VOL UP, DOWN TURN CHECK)

NO

YES

FUNCTION INPUT PORT SIGNAL CHECK(NJW1190 TROUBLESHOOTING)

YES NO

IC601 17.22 PIN WAVE OUTPUT CHECK

YES

IC601 OK

AMP MODULE TROUBLESHOOTING

IC501 9 PIN(AMP-PWR)HIGH CHECK

NO

YES

IC305 9 PIN(AMP-PWR) HIGH CHECK

YES

PN702 3 PIN "PROTECTION"CHECK

(HIGH LOW)

NO

YES

IC701 11 PIN "AMP-ON/OFF" HIGH

CHECK

YES

IC701 12 PIN "PROTECTION" LOW

CHECK

YES

IC701 3 ,20 & 5 ,18 EACH +65V &-65V

CHECK

NO

YES

IC301 10,8PIN CHECK

IC301 TROUBLESHOOTING

IC601 CHANGE

EXPEND IC TROUBLESHOOTING CONSULT

PROTECTION " HIGH" SMPS VOLTAGE AND AMP ON/ OFF STATE CHECK

AMP MODULE CHECK : MOS FET BOTH ARE READ SHORT AMP DEAD

AMP MODULE CHANGE

SMPS TROUBLESHOOTING CONSULT

- 2-7 -

IC701 9 ,14 ±9V CHECK

NO

YES		SMPS TROUBLESHOOTING CONSULT

IC701 10 , 13 INPUT SIGNAL CHECK

YES

IC701 5 ,17 OUTPUT SIGNAL CHECK

YES

OK

REC CHECK (Q252,Q202 ON :R273,R223 HIGH)

IC601 24PIN VOLTAGE INPUT CHECK

YES

IC401 EACH INPUTTUNER6,39.TAPE. 7.38.CD. 8.38.AUX.9.36 PIN SIGNAL INPUT CHECK

NO

YES

IC201 7,24 PIN INPUT CHECK

YES	NO

IC201 10.21 PIN OUTPUT CHECK

YES	NO

L203 2,3PIN CHECK

NO

YES

IC202 14 PIN STATESTATE CHECK

YES

Q213.212 STATE STATECHECK

YES

DECK CHANGE

REC INPUTCHECK CHECK

INPUT LINE CHECK

REC OUTPUTCHECK AFTER FAULTY IS ICCHANGE

IC202 4PIN STATECHECK

NO	VOLTAGE CHECK CONSULT

Q205 BASE 0.6V CHECK

NO
IC202 TROUBLESHOOTING CHECK
Q204 COLLECTOR LOW
NO	Q204 CHANGE
Q203 CHANGE

NO	L203 CHANGE

OK

- 2-8 -

DUBBING CHECK ("NORMAL OR REC"//"HIGH")

IC401 11,34 OUTCHECK

YES

IC401 EACH INPUTTUNER6,39.TAPE. 7.38.CD.8.38.AUX.9.36PIN SIGNAL

INPUT CHECK

NO

YES	REC INPUTCHECK CHECK

IC201 7,24 PIN INPUT CHECK

NO

YES		INPUT LINE CHECK

IC201 10.21PIN OUTPUT CHECK

- 2-9 -

INTERNAL BLOCK DIAGRAM of ICs

• HA12237F

BLOCK DIAGRAM

- 2-10 -