LG HT306SF User manual

P/NO : AFN75272761 FEBRUARY, 2011
DVD HOME CINEMA SYSTEM
SERVICE MANUAL
MODEL: HT306SF
(HT306SF, SH36SF-S, SH36SU-W)
CAUTION
BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS”
IN THIS MANUAL.
Website http://biz.lgservice.com
Internal Use Only
MODEL: HT306SF(HT306SF, SH36SF-S, SH36SU-W)SERVICE MANUAL

1-1
CONTENTS
SECTION 1 ........SUMMARY
SECTION 2 ........ELECTRICAL
SECTION 3 ........CABINET & MAIN CHASSIS
SECTION 4 ........MECHANISM (DP-15T)
SECTION 5 ........REPLACEMENT PARTS LIST

1-2
SECTION 1
SUMMARY
CONTENTS
SERVICING PRECAUTIONS .......................................................................................................................... 1-3
ESD PRECAUTIONS ....................................................................................................................................... 1-5
SERVICE INFORMATION FOR EEPROM .................................................................................................... 1-6
HOW TO UPDATE DVD & AUDIO MICOM PROGRAMS ........................................................................... 1-7
SPECIFICATIONS............................................................................................................................................ 1-8

1-3
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 cot-
ton swab should be used, taking care not to distort lens.
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.
Storage in conductive bag Drop impact
NEVER look directly at the laser beam, and don’t allow
contact with fingers or other exposed skin.
Magnet
How to hold the pick-up
Conductive Sheet
Cotton swab
Pressure
Pressure

1-4
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 magnet-
ism 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.
Resistor
(1 M Ω)Conductive
Sheet
Resistor
(1 M Ω)
Armband

1-5
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.

1-6
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
Change will be applied when power
OFF-->ON.
NAME
OPT 1
OPT 2
OPT 3
OPT 4
OPT 5
OPT 6
OPT 7
OPT 8
OPT 9
OPT A
HEX
F1
00
D0
29
00
81
A0
30
50
08
DETECT NEW EEPROM
(OPTION EDIT SCREEN)
▲
▲
▲
▲

1-7
HOW TO UPDATE DVD & AUDIO MICOM PROGRAMS
1. The Whole Sequence
1) DVD program download.
2) Power cord out −> in.
3) Audio micom program download.
4) Remote control Pause key ‘
|| ’ + ‘1472’ for input options.
5) Enter into the system information for check the version, options and check sum.
6) Power off −> on.
Attention:
After DVD program download, never input options and check the version before power cord out.
2. How to enter into System Information
1) Enter into SETUP menu in NO Disc.
2) Put on cursor [Highlight] 16:9 wide option of TV aspect in SETUP menu.
3) Press follow key in continuous using remote control.
1 −> 3 −> 9 −> 7 −> 1 −> 3 −> 9 −> ENTER
3. How to update program
3-1. How to update MTK DVD program
1) Change the filename to download as “LG_(MODEL NAME).ROM”.
[Both Upper and Lower case In filename is possible]
Ex.) HT306: “LG_HT306.ROM”
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 control.
5) Remove and reconnect the power cable when it changes to logo screen from upgrade information.
Then the upgrade process is completed.
3-2. How to update AUDIO MICOM program
1) Change the filename to download as “(MODEL NAME)_(Version).HEX”. Only upper cases are permitted.
Ex.) HT306: "HT306_0809262.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 upgradeprocess will be started with the upgrade information.
4) If the upgrade process is complete, the set will be power off automatically with “Complete” message.

1-8
SPECIFICATIONS
• GENERAL
Power requirements Refer to main label
Power consumption Refer to main label
Dimensions (W x H x D) Approx. 365 x 58.5 x 307 mm without foot
Net Weight (Approx.) 2.44 kg
Operating temperature 5 °C to 35 °C (41 °F to 95 °F)
Operating humidity 5 % to 90 %
• OUTPUTS
VIDEO OUT 1.0 V (p-p), 75 Ω, sync negative, RCA jack x 1
COMPONENT VIDEO OUT (Y) 1.0 V (p-p), 75 Ω, sync negative, RCA jack x 1
(Pb)/(Pr) 0.7 V (p-p), 75 Ω, RCA jack x 2
HDMI OUT (video/audio) 19 pin (Type A, HDMI™ Connector)
ANALOG AUDIO IN 2.0 Vrms (1 kHz, 0 dB), 600 Ω, RCA jack (L, R) x 1
PORT. IN 0.5 Vrms (3.5 mm stereo jack)
• SYSTEM
Laser Semiconductor laser, wavelength: 650 nm
Signal system Standard NTSC/PAL color TV system
Frequency response 20 Hz to 20 kHz (48 kHz, 96 kHz, 192 kHz sampling)
Signal-to-noise ratio More than 80 dB
Harmonic distortion 0.05 % at 1 W
Dynamic range More than 85 dB
Bus Power Supply (USB) DC 5 V 500 mA
• AMPLIFIER
Stereo mode 45 W + 45 W (3 Ωat 1 kHz)
Surround mode Front 45 W + 45 W (3 Ωat 1 kHz)
Center 45 W (3 Ωat 1 kHz)
Surround 45 W + 45 W (3 Ωat 1 kHz)
Subwoofer 105 W (4 Ωat 60 Hz)
• TUNER
FM Tuning Range 87.5 to 108.0 MHz or 87.50 to 108.00 MHz
• FRONT SPEAKER (LEFT/ RIGHT)
Type 1 Way 1 Speaker
Impedance Rated 3 Ω
Input Power 45 W
Max. Input Power 90 W
Net Dimensions (W x H x D) 97 x 110 x 80 mm
Net Weight 0.39 kg
• REAR SPEAKER (LEFT/ RIGHT)
Type 1 Way 1 Speaker
Impedance Rated 3 Ω
Input Power 45 W
Max. Input Power 90 W
Net Dimensions (W x H x D) 97 x 110 x 80 mm
Net Weight 0.39 kg
• CENTER SPEAKER
Type 1 Way 1 Speaker
Impedance Rated 3 Ω
Input Power 45 W
Max. Input Power 90 W
Net Dimensions (W x H x D) 97 x 110 x 80 mm
Net Weight 0.39 kg
• SUBWOOFER
Type 1 Way 1 Speaker
Impedance Rated 4 Ω
Input Power 105 W
Max. Input Power 210 W
Net Dimensions (W x H x D) 157 x 325 x 250 mm
Net Weight 3.5 kg

2-1
SECTION 2
ELECTRICAL
CONTENTS
ELECTRICAL TROUBLESHOOTING GUIDE............................................................................................... 2-2
1. POWER SUPPLY CIRCUIT.................................................................................................................... 2-2
2. FRONT CIRCUIT (1/2)............................................................................................................................ 2-3
3. FRONT CIRCUIT (2/2)............................................................................................................................ 2-4
4. SYSTEM OPERATION FLOW................................................................................................................ 2-5
5. TEST & DEBUG FLOW .......................................................................................................................... 2-6
6. AMP PROTECTION.............................................................................................................................. 2-12
7. AUDIO μ-COM CIRCUIT(DVD & AMP) ................................................................................................ 2-13
DETAILS AND WAVEFORMS ON SYSTEM TEST AND DEBUGGING.................................................. 2-14
1. SYSTEM 27 MHZ CLOCK, RESET, FLASH R/W SIGNAL.................................................................. 2-14
2. SDRAM CLOCK.................................................................................................................................... 2-15
3. TRAY OPEN/CLOSE SIGNAL.............................................................................................................. 2-16
4. SLED CONTROL RELATED SIGNAL (NO DISC CONDITION) .......................................................... 2-17
5. LENS CONTROL RELATED SIGNAL (NO DISC CONDITION) .......................................................... 2-18
6. LASER POWER CONTROL RELATED SIGNAL (NO DISC CONDITION) ......................................... 2-18
7. DISC TYPE JUDGEMENT WAVEFORMS ........................................................................................... 2-19
8. FOCUS ON WAVEFORMS................................................................................................................... 2-21
9. SPINDLE CONTROL WAVEFORMS (NO DISC CONDITION)............................................................ 2-22
10. TRACKING CONTROL RELATED SIGNAL (SYSTEM CHECKING)................................................... 2-23
11. MT1389MH VIDEO OUTPUT WAVEFORMS....................................................................................... 2-24
12. DVD & AMP WAVEFORMS MT1389MH.............................................................................................. 2-25
WIRING DIAGRAM ........................................................................................................................................ 2-27
BLOCK DIAGRAMS ...................................................................................................................................... 2-29
CIRCUIT DIAGRAMS .................................................................................................................................... 2-33
1. SMPS CIRCUIT DIAGRAM .................................................................................................................. 2-33
2. MAIN & AMP - 1 CIRCUIT DIAGRAM.................................................................................................. 2-35
3. MAIN & AMP - 2 CIRCUIT DIAGRAM.................................................................................................. 2-37
4. FRONT & POWER KEY CIRCUIT DIAGRAM...................................................................................... 2-39
5. FRONT JACK CIRCUIT DIAGRAM ...................................................................................................... 2-41
CIRCUIT VOLTAGE CHART ........................................................................................................................ 2-43
PRINTED CIRCUIT BOARD DIAGRAMS.................................................................................................... 2-47
1. MAIN & AMP P.C. BOARD................................................................................................................... 2-47
2. SMPS P.C. BOARD .............................................................................................................................. 2-51
3. FRONT P.C. BOARD............................................................................................................................ 2-53
4. POWER KEY P.C. BOARD .................................................................................................................. 2-53
5. FRONT JACK P.C. BOARD.................................................................................................................. 2-53

2-2
ELECTRICAL TROUBLESHOOTING GUIDE
1. POWER SUPPLY CIRCUIT
YES
Check power supply circuit.
Check tracking servo circuit.
Check audio circuit.
NO
NO
NO
Is power on?
YES
Does it play?
YES
Does it output
audio?
YES
YES
Turn power on.
INSERT POWER CORD.
OK

2-3
ELECTRICAL TROUBLESHOOTING GUIDE
1
2
2. FRONT CIRCUIT (1/2)
Reconnect it.
NO
YES
YES
NO Check if
PN301 is ok?
Refer to SMPS part.
NO
YES
Check if the front
power is ok?
YES
Is the Digitron on
correctly?
Check pattern and resoldering
NO
NO
Check if
DIS301 is ok?
YES
Check if the remote
control is ok?
YES
Check if all
buttons are ok?
POWER ON.
Front B/D ok.
NO

2-4
ELECTRICAL TROUBLESHOOTING GUIDE
3. FRONT CIRCUIT (2/2)
1
Refer to power(SMPS).
NO
Replace R346~R349, R352, R370.
NO
Check if the
power part of the
front is ok?
YES
Check if
R346~R349, R352, R370
ok?
YES
Refer to MICOM circuit.
2
Refer to power(SMPS).
NO
Check if the
power part of the front
is ok?
YES
Refer to MICOM circuit.
NO
Check if the remote
control waveform of PN301
pin5 is ok?
YES
Check RM circuit
NO
Check if RC301
voltage is ok(3.3 V)?
YES
Resolder or Replace RC301.

2-5
ELECTRICAL TROUBLESHOOTING GUIDE
4. SYSTEM OPERATION FLOW
YES
YES
YES
Tray closed?
1. Initializes SERVO, DSP & RISC registers.
2. Write RISC code to SDRAM.
3. Reset RISC.
Show LOGO.
Tray close to closed position.
SLED at inner
side?
Recieve
OPEN/ CLOSE
Key?
Receive
CLOSE Key?
SLED moves to inner position.
1. Judge whether have disc and disc type.
2. Jump to related disc reading procedure.
1. Execute Pressed Key & IR Key.
2. System operation routine loop.
NO
NO
NO
NO
YES
1. Stop Playback & Open Tray.
2. Display tray open message & LOGO.
POWER ON.
YES
YES

2-6
ELECTRICAL TROUBLESHOOTING GUIDE
5. TEST & DEBUG FLOW
Check the POWER PART.
NO
Check the POWER PART.
NO
YES
Check the
AC voltage Power PCBA (110 V
or 220 V).
Check the regulators or diode.
NO
1. Check 27 MHz system clock.
2. Check system reset circuit.
3. Check FLASH R/W enable signal PRD,
RWR.
4. Check FLASH Memory related circuit.
NO
Replace FLASH.
NO
YES
Are the
DC Voltage outputs OK? (12 V, 3.3 V,
5 V, 7 V, 34 V).
YES
Are 3.3 V and
5 V DC outputs normal on main
PCBA?
YES
YES
Update
FLASH successfully?
YES
Switch on the Power PCBA.
TEST.
A

2-7
ELECTRICAL TROUBLESHOOTING GUIDE
NO
Check connection lines
between FLASH & MT1389MH
and the FLASH access time
whether is suitable or not.
NO
YES
YES
YES
YES
Check AV cable
connection to TV set.
YES
YES
YES
Flash
Memory operates
properly?
Check connection lines
between SDRAM(IC503) &
MT1389MH and the SDRAM
is damaged.
NO
SDRAM
works properly?
Check the related circuit of
MT1389MH IC501 pins138,
142, 144, 145.
NO
MT1389MH
VIDEO outputs
properly?
Show LOGO?
NO Check the load OPEN &
CLOSE switch.
NO
Check AV cable connection
between main PCBA and
loader. (MECHA)
YES
YES
YES
Normal
OPEN_SW,
CLOSE_SW
signal?
Check the Tray control IO pins
on MT1389MH.
NO
Normal
TROPEN & TRCLOSE
signal?
Check the Tray control MOTOR
& SERVO circuit IC400.
NO
Normal
LOAD+ & LOAD-
signal?
Does Tray
move inside when it
is not at closed
position?
Power On.
A
B

2-8
ELECTRICAL TROUBLESHOOTING GUIDE
NO Check the connection line of
M_STBY.
NO
YES
YES
YES
Check the cable connection
with MECHA.
Do not put in disc
and close tray.
YES
YES
YES
Motor
Driver M_STBY
pin is high?
Check the related circuit of
SLD.
NO
Motor
Driver M_STBY
pin is High?
Check the amp circuit on
motor driver.
NO
SLED+ and
SLED- output
properly?
Does
the SLED move to inner
side when it is at outer
position?
NO Check Focus connection on
MT1389MH and motor driver.
NO
Check cable connection with
pick-up head.
YES
YES
Proper
Focus outputs
to motor driver?
Check the amp circuit on motor
driver.
NO
Proper F+ & F-
outputs?
Optical Lens
has movements for
searching Focus?
B
C

2-9
ELECTRICAL TROUBLESHOOTING GUIDE
NO
NO
Check the laser power circuit
on MT1389MH and
connecting to power transis-
tor.(Q403, Q405).
YES
YES
YES
YES
YES
YES
Check cable connection
between transistor output and
pick-up head.
Laser off.
Check the RF connection
between AM5890 and MT1389MH.
YES
YES
DVDLD or
CDLD output
property?
Check the related circuit on
laser power transistor.
NO
NO
Collector
voltage of power transistor
is OK?(Q403, Q405)
Laser
turns on when
reading disc?
Put disc in?
Check the cable connection
between spindle and main
PCB.
YES
YES
Check the spindle control amp
circuit of motor driver.
SPNP
SPNN output
properly?
NO Check the SPINDLE related
circuit on MT1389MH.
Proper
SPINDLE signal on
MT1389MH.
Does spindle rotate?
NO Check the related circuit on
MT1389MH RF signal.
NO
NO
NO
Proper
RF signal on
MT1389MH.
Disc ID is correct?
C
D

2-10
ELECTRICAL TROUBLESHOOTING GUIDE
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.
Check the tracking control amp
circuit on motor driver.
NO NO
YES
YES
YES
Check CD_DVDCT connection
between AM5890 and
MT1389MH.
Check cable connection
on pick-up head.
YES
YES
Proper
signals on A, B, C,
D of MT1389MH.
NO
Proper
CD_DVDCT signal on
MT1389MH.
Focus on ok?
NO
Disc Playback?
NO NO
NO
NO
YES
Proper
CD_DVDCT signal on
MT1389MH.
YES
Proper
TRACK signal
on MT1389MH.
YES
T+ & T- output
properly?
Track On OK?
D
YES
E
Check RF signal waveform.

2-11
ELECTRICAL TROUBLESHOOTING GUIDE
NO Check connection between
IC602 BCK, LRCK, ADATA0.
YES
YES
Check Digital Amp circuit
(IC701, IC702).
YES
Check the related circuit of
PWM.(Check Audio out
pins28, 31, 33, 34, 37, 39, 42).
NO
NO
YES
PWM IC
received correct data
stream?
Normal
PWM IC out?(IC602).
Normal Audio
output when disc
playback?
E
TEST END.