LG HT924SF Service manual

Internal Use Only

Website http://biz.lgservice.com

DVD RECEIVER SYSTEM

MODEL: HT924SF (HT924SF-A2 / SH94SF-C/S/W)SERVICE MANUAL

SERVICE MANUAL

MODEL: HT924SF

P/NO : AFN70208674 APRIL, 2009

(HT924SF-A2 / SH94SF-C/S/W)

[CONTENTS]

SECTION 1. GENERAL

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

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

• SERVICE INFORMATION FOR EEPROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

•

HOW TO UPDATE AUDIO MICOM & DVD PROGRAMS. .

• SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

. . . . . . . . . . . . . . . . . . . . . . . 1-6

SECTION 2. ELECTRICAL PART

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

• DETAILS AND WAVEFORMS ON SYSTEM TEST AND DEBUGGING . . . . . . . . . . . . . . . 2-14

• WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27

• OVERALL BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-29

• CIRCUIT DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-31

• CIRCUIT VOLTAGE CHART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-53

• PRINTED CIRCUIT DIARGAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-57

SECTION 3. EXPLODED VIEWS

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

• DECK MECHANISM EXPLODED VIEW (DP-12AV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

• PACKING ACCESSORY SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

• SPEAKER SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6

SECTION 4. MECHANISM (DP-12AV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

SECTION 5. 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

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 allow
contact with 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 lens.

Drop impact

Pressure

Magnet

How to hold the pick-up

Cotton swab

Conductive Sheet

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.

1-2

Pressure

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 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 M Ω)

Resistor
(1 M Ω)

Conductive
Sheet

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

SERVICE INFORMATION FOR EEPROM

POWER ON

DVD LOGO Status (NO Disk status)

Remote control

Pause key->1->4->7->2 in order.

Press number 0~9, Press character
A~F (1~6 for a while)

Use arrow key (

) to
move to appropriate position and
make changes

Press pause key once

DETECT NEW EEPROM
(OPTION EDIT SCREEN)

NAME

OPT 1
OPT 2
OPT 3
OPT 4
OPT 5
OPT 6
OPT 7
OPT 8
OPT 9
OPT A

HEX

21

01
CC
DD

00

09

E0

24
DA

00

Change will be applied when power

OFF->ON.

1-5

HOW TO UPDATE AUDIO MICOM & DVD PROGRAMS

1. How to update AUDIO MICOM program.

[Update using CD]

1. Change the filename to download as “(MODEL NAME)_(Version).HEX”. Only upper cases are permitted.
ex) HT924SF : “HT924SF_0810010.HEX”

2. Copy the file to the root folder of a CD and burn it.

3. Insert the CD to the SET, and move to the DVD function. Then the upgrade process will be started with
the upgrade information.

4. If the upgrade process is complete, the set will be rebooted with “Complete” message.

[Update using USB]

1. Change the filename to download as “(MODEL NAME)_(Version).HEX”. Only upper cases are permitted.
ex) HT924SF : “HT924SF_0810010.HEX”

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

3. Put the USB into the SET, and move to the USB function. Then the upgrade process will be started with
the upgrade information.

4. If the upgrade process is complete, the set will be rebooted with “Complete” message.

2. How to update DVD program.

[Update using CD]

1. Rename the filename to download as “LOGO_MODELNAME.ROM” in upper cases.

HT924SF

ex)

2. Copy the file to CD, and burn it.

3. Insert the CD to the SET, then after a while the CD tray will be opened with upgrade information on the
screen.

4. Remove the CD, and press “PLAY” key in remote controller.

5. Remove and reconnect the power cable when it changes to logo screen from upgrade information.
Then the upgrade process is completed.

: “LG_

HT924SF

.ROM”

[Update using USB]

1. Rename the filename to download as “LOGO_MODELNAME.ROM” in upper cases.

HT924SF

ex)

2. Copy the file to the formatted USB, and burn it.

3. Move to the USB function, and insert the USB to the set.
The upgrade information will be shown on the screen.

4. Remove the USB, press PLAY key of the remote controller.

5. Remove and reconnect the power cable when it changes to logo screen from upgrade information. Then
the upgrade process is completed.

: “LG_

HT924SF

.ROM”

1-6

SPECIFICATIONS

GENERAL

Power supply 110~240V, 50/60Hz

Power consumption 130W

Net Weight 3.9 kg

External dimensions (W x H x D) 430 x 73 x 327 mm

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

Operating humidity 5% to 85%

Laser Semiconductor laser, wavelength 650 nm

TUNER
FM

FM Tuning Range 87.5 - 108.0 MHz

FM Intermediate Frequency 128 kHz

AM [MW]

AM Tuning Range 552 - 1,620 kHz or 520 - 1,720 kHz

AM Intermediate Frequency 450 kHz

AMPLIFIER

Stereo mode 175 W + 175 W (4 Ω at 1 kHz, THD 10 %)

Surround mode Front: 175 W + 175 W (THD 10 %)

(* Depending on the sound mode

Center*: 175 W

settings and the source, there may
be no sound output.)

Surround*: 175 W + 175 W (4 Ω at 1 kHz, THD 10 %)

Subwoofer*: 325 W (3 Ω at 30 Hz, THD 10 %)

SPEAKERS (SH94SF)

Front/Rear Speaker Center Speaker Passive Subwoofer

SH94SF-S SH94SF-C SH94SF-W

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

Impedance 4 Ω 4 Ω 3 Ω

Rated Input Power 175 W 175 W 325 W

Max. Input Power 350 W 350 W 650 W

Net Dimensions (W x H x D) 98 x 226 x 90 mm 360 x 106 x 104 mm 216 x 405 x 310 mm

Net Weight 0.8 kg 1.0 kg 5.42 kg

Designs and specifications are subject to change without prior notice.

1-7

1-8

SECTION 2. ELECTRICAL PART

TROUBLESHOOTING GUIDE

1. Power Supply Circuit

Insert power cord.

YES

Is the Digitron on correctly?

YES

Turn power on.

YES

Is power on?

YES

Does initial read work?

YES

NO

NO

NO

Check power plug and power

supply circuit.

Check power supply circuit.

Check laser circuit.

Check focus circuit.

Check disc.

Does it play?

YES

Does it output

audio?

YES

OK

NO

Check tracking servo circuit.

NO

Check audio circuit.

2-1

2. Front circuit (1/2)

Power on.

YES

Blue LED turn off?

YES YES

Is the Digitron on

correctly?

YES

Check if all

buttons are ok?

YES

NO

NO

NO

Check if

PN301 and PN302 are ok?

Check if the front

power is ok?(*1)

YES

1

NO

NO

Reconnect it.

Refer to SMPS part.

Check if the remote

control is ok?

YES

Front B/D ok.

NO

2

*1 : PN106 Pins.

PIN1 : -34 VKK, PIN2 : -28 FL+, PIN3 : -32 FL-,
PIN12 : +5.6VA, PIN13 : +5V

Check if

DIS301 is ok?

NO

Check pattern and resoldering

2-2

3. Front circuit (2/2)

1

Check if the

power part of the

front is ok?

YES

Check if

R345~R350, R149 are

ok?

YES

Refer to MICOM circuit.

2

NO

Refer to power(SMPS).

NO

Replace R345~R350, R149.

Check if the

power part of the front

is ok?

YES

Check if the remote

control waveform of PN301

pin11 is ok?

YES

Check if RC2

voltage is ok(5V)?

YES

Resolder or Replace RC2.

NO

Refer to power(SMPS).

NO

Refer to MICOM circuit.

NO

Check RM circuit

2-3

4. System operation flow

POWER ON.

1. Initializes SERVO, DSP & RISC registers.

2. Write RISC code to SDRAM.

3. Reset RISC.

Show LOGO.

YES

Tray closed?

NO

Tray close to closed position.

SLED at inner

side?

NO

SLED moves to inner position.

1. Judge whether have disc and disc type.

2. Jump to related disc reading procedure.

Recieve

OPEN/ CLOSE

Key?

YES

NO

NO

1. Execute Pressed Key & IR Key.

2. System operation routine loop.

1. Stop Playback & Open Tray.

2. Display tray open message & LOGO.

YES

Receive

CLOSE Key?

YES

2-4

5. Test & debug flow

TEST.

YES

Check the

AC voltage Power PCBA (110V

or 220V).

YES

Switch on the Power PCBA.

YES

Are the

DC Voltage outputs OK? (-34V, -28V, -32V, ±12V,

3.5V, 5.6VA, 5V, 7V).

YES

Are 3.3V and

5V DC outputs normal on main

PCBA?

YES

Update

FLASH successfully?

YES

NO

NO

NO

NO

Check the POWER PART.

Check the POWER PART.

Check the regulators or diode.

1. Check 27MHz system clock.

2. Check system reset circuit.

3. Check FLASH R/W enable signal PRD,
RWR.

4. Check FLASH Memory related circuit.

NO

A

Replace FLASH.

2-5

A

YES

Power On.

YES

Show LOGO?

YES

Does Tray

move inside when it

is not at closed

position?

NO

NO

Flash

Memory operates

properly?

YES

SDRAM

works properly?

YES

MT1389MH

VIDEO outputs

properly?

YES

Check AV cable

connection to TV set.

Normal

OPEN_SW,

CLOSE_SW

signal?

Check connection lines

NO

NO

NO

NO

between FLASH & MT1389MH
and the FLASH access time
whether is suitable or not.

Check connection lines
between SDRAM(IC503) &
MT1389MH and the SDRAM
is damaged.

Check the related circuit of
MT1389MH IC501 Pins138,
142, 144, 145.

Check the load OPEN &

CLOSE switch.

B

YES

YES

Normal

TROPEN & TRCLOSE

signal?

YES

Normal

LOAD+ & LOAD-

signal?

YES

Check AV cable connection
between main PCBA and
loader. (MECHA)

2-6

NO

Check the Tray control IO pins

on MT1389MH.

NO

Check the Tray control MOTOR

& SERVO circuit IC400.

B

YES

Does

the SLED move to inner

side when it is at outer

position?

YES

Do not put in disc

and close tray.

NO

Motor

Driver M_STBY

pin is high?

YES

Motor

Driver M_STBY

pin is High?

YES

SLED+ and

SLED- output

properly?

YES

Check the cable connection

with MECHA.

NO

NO

NO

Check the connection line of
M_STBY.

Check the related circuit of
SLD.

Check the amp circuit on
motor driver.

Optical Lens

has movements for

searching Focus?

YES

C

NO

Proper

Focus outputs

to motor driver?

YES

Proper F+ & F-

outputs?

YES

Check cable connection with

pick-up head.

2-7

NO

NO

Check Focus connection on

MT1389MH

Check the amp circuit on motor

and motor driver.

driver.

C

YES

Laser

turns on when

reading disc?

YES

Put disc in?

YES

Disc ID is correct?

NO

NO

NO

DVDLD or

CDLD output

property?

YES

Collector

voltage of power transistor

is OK?(Q403, Q405)

YES

Check cable connection

between transistor output and

pick-up head.

Laser off.

Proper

RF signal on

MT1389MH.

NO

NO

NO

Check the laser power circuit
on MT1389MH and
connecting to power
transistor.(Q403, Q405)

Check the related circuit on

laser power transistor.

Check the related circuit on

MT1389MH RF signal.

YES

Does spindle rotate?

YES

D

NO

YES

Check the RF connection

between AM5890 and MT1389MH.

Proper

SPINDLE signal on

MT1389MH.

YES

SPNP

& SPNN output

properly?

YES

Check the cable connection

between spindle and main

PCB.

2-8

NO

NO

Check the SPINDLE related

circuit on MT1389MH.

Check the spindle control amp

circuit of motor driver.

D

YES

Focus on ok?

YES

Track On OK?

YES

NO

NO

Proper

signals on A, B, C,

D of MT1389MH.

YES

Proper

CD_DVDCT signal on

MT1389MH.

YES

Check CD_DVDCT connection

between AM5890 and

MT1389MH.

Proper

CD_DVDCT signal on

MT1389MH.

YES

Proper

TRACK signal

on MT1389MH.

NO

NO

NO

NO

Check connections between

MT1389MH and pick-up head.

Check the related circuit on

MT1389MH CD_DVDCT.

Check the related circuit on

MT1389MH.

Check the TRACK connection

on MT1389MH and motor driver.

Disc Playback?

YES

E

NO

YES

T+ & T- output

properly?

YES

Check cable connection

on pick-up head.

Check RF signal waveform.

2-9

NO

Check the tracking control amp

circuit on motor driver.

E

YES

Normal Audio

output when disc

playback?

YES

TEST END.

NO

PWM IC

received correct data

stream?

YES

Normal

PWM IC out?(IC601).

YES

Check Digital Amp circuit

(IC701, IC702, IC703, IC704).

NO

NO

Check connection between
IC601 BCK, LRCK, ADATA0,
ADATA1, ADATA2(Pins19, 20,
23, 24, 25).

Check the related circuit of
PWM.(Check Audio out
Pins 54, 55, 58, 59, 61, 62, 67,
68, 70, 71, 74, 75)

2-10

6. AMP Protection

"PROTECTION" appears on the FLD.

YES

After unplug power cord, connect again.

YES

Power on.

YES

"PROTECTION"

appears continuously on the FLD.

YES

Is the IC101 pin53
"LOW" signal(0V)?

YES

Is the Q703, Q704 and

Q705 normal?

YES

Replace TI AMP IC(IC701, IC702, IC703, IC704)

NO

OK.

NO

Replace IC101.

NO

Replace the Q703, Q704 and Q705.

2-11

7. AUDIO µ-COM Circuit(DVD & AMP)

Power On.

YES

Does

CD/DVD appear at

FLD?

YES

Does

Reading appear

at FLD?

YES

Does

no Disc or Time

appear at

FLD?

YES

Check

if DVD/CD insert

is OK.

NO

NO

Does

it appear DVD Error

at FLD?

YES

Check

power part of Main

B/D.

YES

Check

oscillator of

X100.

YES

Does AV1,

TV AUDIO, AV1 OPT and

FM 87.5 appear

at FLD.

NO

NO

Refer to SMPS.

NO

Refer to oscillator circuit.

YESNO

OK

NO

Check Power.

YES

Check DVD Module.

YES

Check SMPS.

NO

Check

if IC101 Pin29

is high.

YES

Check if

IC101 Pins 14, 40, 55, 89

are high(5V).

YES

Check

if IC101 Pin58

is high.

YES

Replace IC101.

NO

NO

NO

Check IC101 Pin29

reset waveform.

Check 5V line.

Check power section

2-12

circuit.

DETAILS AND WAVEFORMS ON SYSTEM TEST AND DEBUGGING

1. SYSTEM 27MHz CLOCK,RESET,FLASH R/W SIGNAL

1)

MT1389MH

2)

MT1389MH

Power Cord in

main clock is at 27MHz(X500)

1

1

FIG 1-1

reset is high active.

2

P_CTL

DVD_RST

RESET_IN

FIG 1-2

IC501

2

3

4

IC101

IC501

3

4

2-13

3) Flash R/W enable signal during download(Downloading)

SF_DI

5

SF_DO

6

FIG 1-3

6

5

2. SDRAM CLOCK

1)

MT1389MH

SDCLK

DCLK = 93MHz, Vp-p=2.2, Vmax=2.7V

main clock is at 27MHz(X500)

7

7

FIG 2-1

2-14

3. TRAY OPEN/CLOSE SIGNAL

1) Tray open/close waveform

OPENSW

CLOSESW

OPEN

CLOSE

FIG 3-1

3) Tray open waveform

OPENSW

2) Tray close waveform

OPENSW

8

CLOSESW

9

OPEN

10

CLOSE

11

FIG 3-2

8

8

9

10

11

8

CLOSESW

OPEN

CLOSE

FIG 3-3

10

11

9

10

11

9

2-15

4. SLED CONTROL RELATED SIGNAL (NO DISC CONDITION)

SLD

M-STBY

SL+

SL-

FIG 4-1

12

13

12

14

15

13

2-16

14

15

5. LENS CONTROL RELATED SIGNAL(NO DISC CONDITION)

FOD

F+

F-

FIG 5-1

16

17

18

16

18

17

6. LASER POWER CONTROL RELATED SIGNAL(NO DISC CONDITION)

IC501

MDI1

DVDLD

CDLD

FIG 6-1

19

20

21

19

21

20

2-17

7. DISC TYPE JUDGEMENT WAVEFORMS

24

F+

PU_DET

RF

FIG 7-1 (DVD)

F+

PU_DET

22

23

24

22

23 : This signal can see using special debug program

IC501

22

23

FIG 7-2 (DVD)

RF

23

24

2-18