LG HT905TAW User manual

MODEL: HT905TAW (HT905TAW, SH95TA-F/ S/ C/ W, W95)SERVICE MANUAL
P/NO : AFN73671966 MARCH, 2010
MODEL: HT905TAW
(HT905TAW, SH95TA-F/ S/ C/ W, W95)
Website http://biz.lgservice.com
Internal Use Only
DVD RECEIVER SYSTEM
SERVICE MANUAL

1-1
[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. .
. . . . . . . . . . . . . . . . . . . . . . . 1-6
• SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
SECTION 2. ELECTRICAL PART
• TROUBLESHOOTING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
• DETAILS AND WAVEFORMS ON SYSTEM TEST AND DEBUGGING. . . . . . . . . . . . . . . 2-20
• WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-33
• BLOCK DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-39
• CIRCUIT DIAGRAMS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-31
• CIRCUIT VOLTAGE CHART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-69
• PRINTED CIRCUIT DIARGAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-73
SECTION 3. EXPLODED VIEWS
• CABINET AND MAIN FRAME SECTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
• DECK MECHANISM EXPLODED VIEW (DP-16T) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
• PACKING ACCESSORY SECTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
• SPEAKER SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
SECTION 4. MECHANISM (DP-16T) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
SECTION 5. REPLACEMENT PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

1-2
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
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 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

1-4
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 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.

1-5
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
C9
C0
00
00
90
10
C4
40
DETECT NEW EEPROM
(OPTION EDIT SCREEN)

1-6
HOW TO UPDATE AUDIO MICOM & DVD PROGRAMS
1. How to update AUDIO MICOM program.
[Update using CD]
1. Change the filename to download as “HT905_(Version).HEX”. Only upper cases are permitted.
ex) HT905 : “HT905_0709081.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 “HT905_(Version).HEX”. Only upper cases are permitted.
ex) HT905 : “HT905_0709081.HEX”
2. Copy the file to the root folder of USB storage.
3. After Home-menu is displayed on Screen of SET, Put the USB into the SET.
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. Copy DVD program(ex: LG_HT905LD1_Version.Rom) to Root folder of CD, and burn it.
ex) P:LG_HT905LD1_0911180.Rom
2. Insert the CD to the SET, then after a while the CD tray will be opened with upgrade information on
the screen.
3. Remove the CD, and press “PLAY” key in remote controller.
4. Remove and reconnect the power cable when it changes to logo screen from upgrade information.
Then the upgrade process is completed.
[Update using USB]
1. Copy DVD program(ex: LG_HT905LD1_Version.Rom) to Root folder of the formatted USB and burn it.
ex) P:\LG_HT905LD1_0911180.Rom
2. After Home-menu is displayed on Screen of SET, Put the USB into the SET.
Then the upgrade process will be started with the upgrade information.
3. Remove the USB, press "PLAY" key of the remote controller.
4. Remove and reconnect the power cable when it changes to logo screen from upgrade information.
Then the upgrade process is completed.

1-7
GENERAL
Power requirements Refer to main label.
Power consumption Refer to main label.
Dimensions (W x H x D) 430 x 62.5 x 281 mm without foot
Net Weight (Approx.) 4.0 kg
Operating temperature 41 °F to 95 °F (5 °C to 35 °C)
Operating humidity 5 % to 90 %
Bus Power supply (USB) DC 5 V 500 mA
INPUTS/ 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 (HDMI standard, Type A), HDMI version : 1.2A
ANALOG AUDIO IN 2.0 Vrms (1 kHz, 0 dB), 600 Ω, RCA jack (L, R) x 1
DIGITAL IN (OPTICAL 1) 3 V (p-p), Optical jack x 1
PORT. IN 0.5 Vrms (3.5 mm stereo jack)
TUNER
FM Tuning Range 87.5 to 108.0 MHz or 87.50 to 108.00 MHz
AMPLIFIER
Stereo mode 180 W + 180 W (4 Ωat 1 kHz)
Surround mode
Front 180 W + 180 W (4 Ωat 1 kHz)
Center 180 W (4 Ωat 1 kHz)
Surround 180 W + 180 W (4 Ωat 1 kHz)
Subwoofer 200 W (3 Ωat 60 Hz)
WIRELESS RECEIVER
Power requirements: Refer to main label.
Power consumption: Refer to main label.
External dimensions (WxHxD): 64 x 213.6 x 252.3 mm (2.5 x 8.6 x 9.9 inches)
Net Weight: 1.2 kg (2.6 lbs)
Reception Output: 5.8 GHz
SPECIFICATIONS

1-8
SPEAKERS
Front speaker
Type 2 Way 3 speaker
Impedance Rated 4 Ω
Input Power 180 W
Max. Input power 360 W
Net Dimensions (W x H x D) 270 x 1050 x 225 mm
Net Weight 3.1 kg
Rear speaker
Type 2 Way 2 speaker
Impedance Rated 4 Ω
Input Power 180 W
Max. Input power 360 W
Net Dimensions (W x H x D) 270 x 1050 x 225 mm
Net Weight 3.0 kg
Center speaker
Type 2 Way 3 speaker
Impedance Rated 4 Ω
Input Power 180 W
Max. Input power 360 W
Net Dimensions (W x H x D) 320 x 102 x 85 mm
Net Weight 1.4 kg
Passive Subwoofer
Type 1 Way 1 speaker
Impedance Rated 3 Ω
Input Power 200 W
Max. Input power 400 W
Net Dimensions (W x H x D) 190 x 385 x 318 mm
Net Weight 5.0 kg

2-1
TROUBLESHOOTING GUIDE
1. SMPS BOARD
YES
YES
YES
YES
No power
Replace SMPS board
Connect the open line
Replace F901
Check a 3.7 V lines short
Replace PC951, PC972, IC901
Check BD901 “+” to “
- ” pin impedance
Replace PC972, IC902's components
Check around IC901’s components
(Short, Open)
Low impedance:
Replace IC901, BD901
NO
NO
NO
NO
Check the AC
line pattern
Check fuse F901
Check C976
voltage (3.9 V)
Check IC901
Vcc voltage (10 V ~ 30 V)
YES
Check SMPS second part lines short
Check main or AMP board short
NO
Check C963
voltage (5.6 V)
SECTION 2. ELECTRICAL PART

2-2
YES
YES
No sound
Replace IC961, IC901 or
SMPS board
Check no power list, AC input voltage
Check AMP module short
Replace PC951, IC901
NO
NO
Check IC961
Vcc voltage (34 V ~ 43 V)
Check C955
voltage (25 V or 36 V)

2-3
2. POWER KEY BOARD
POWER cord insert
Power key board ok
Connect 3p Harness cable
(PN301)
Check MAIN and SMPS board
Stand by LED (LD305)
turn on?
When you press
power key, “WELCOME”
display ok?
CN331, PN301 cable
connection ok?
CN331 pin2 power ok?
NO
NO
NO
NO
YES
YES
Replace LED(LD305)
Check FRONT board
YES
YES

2-4
Power on
FRONT board ok
YES
YES
Replace DIS301
Replace IC301
Check MAIN board
Check SMPS board
Replace VR301
Connect 26p FFC cable
Check MAIN board
Digitron(DIS301) ok?
YES
YES
YES
YES
YES
“WELCOME
PLEASE WAIT” Display
on VFD ok?
When you turn
the volume knob, count
is change?
NO
NO
NO
NO
NO
NO
NO
NO
CN307 cable
connection ok?
CN307 pin24, 25
signal ok?
CN306 pin4, 5, 6
power ok?
CN307 pin14, 15, 16
data signal ok?
IC301
check ok?
3-1. FRONT BOARD (HB905 / HT905)

2-5
Power on
FRONT board ok
YES
YES
Replace DIS301
Replace IC301
Check MAIN board
Check SMPS board
Replace VR301
Connect 26p FFC cable
Check MAIN board
Digitron(DIS301) ok?
YES
YES
YES
YES
YES
“WELCOME
PLEASE WAIT” Display
on VFD ok?
When you turn
the volume knob, count
is change?
NO
NO
NO
NO
NO
NO
NO
NO
CN307 cable
connection ok?
CN307 pin24, 25
signal ok?
CN306 pin4, 5, 6
power ok?
CN307 pin14, 15, 16
data signal ok?
IC301
check ok?
3-2. FRONT BOARD (HB965 / HT965)
YES
Check SMPS board
Replace LED (LD301 ~ LD304)
YES
Volume LED
(LD301 ~ LD304)
turn on?
NO NO
CN306 pin1, 2
+12 V ok?

2-6
4. NO AUDIO CHECK
NO
PORTABLE function
Check JK2U4
IC200 pin21, 22
audio L/R ok?
YES
B
YES
NO
AUX function
Check JK202
IC200 pin7, 8
audio L/R ok?
B
YES
YES
NO
OPTICAL function
C
Check JK200
IC203 pin1
audio signal ok?
YES
YES
NO
CD/DVD Disc
or USB play
Check IC500
IC201 pin6, 8, 10, 25
I2S input signal ok?
NO
Check IC500
IC500
pin156, 157, 161, 162
I2S output signal
ok?
A
YES
YES
YES

2-7
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
TUNER Function
Check Tuner (TU100)
and Antenna connec-
tion
Check Micom (IC101)
Check IC200
Check IC500 and X500
Check IC602 and
IC605
Check IC500 and X500
Check IC505
Check 22p FFC cable
and CN601 connection
Check IC201 and X200
Check IC701
Check AMP IC
output stage and JK701
IC200 audio L/R ok?
IC203 pin6
LOW signal?
IC200 pin41
I2S output signal
ok?
IC201 pin6, 8, 10
I2S input signal
ok?
IC602, IC605
audio output signal
ok?
IC200
pin42, 43, 44 I2S
clock ok?
IC505 pin7, 9, 18
I2S output signal ok?
AMP B/D
CN601 pin5, 6, 7, 8
I2S signal ok?
IC201
pin20, 21, 23, 25
I2S output signal
ok?
IC701 audio
output signal
ok?
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
B
C
A
NO
IPOD function
Check IPOD
connection or JK3P1
IPOD B/D
JK3P1 pin27, 28
audio L/R ok?
NO
NO
NO
Check 14p FFC cable
and connection
Check 26p FFC cable
and connection
Check IC203
FRONT B/D
CN307 pin10, 11
ok?
MAIN B/D CN250
pin10, 11 ok?
IC200 pin23, 24
audio signal ok?
YES
B
YES
YES
YES
YES

2-8
5. NO VIDEO CHECK
COMPONENT video out
Check IC500
YES
NO
IC206 pin2, 3, 4
video signal ok?
Check IC206
YES
NO
IC206 pin11, 12, 13
video signal ok?
Check JK202
CVBS video out
Check JK202
YES
Check Micom (IC101)
YES
Check IC205
IC205 pin4
video signal ok?
NO NO
IC205 pin1
LOW signal?
IC206 pin14
video signal ok?
IC205 pin3
video signal ok?
NO
NO
Check IC206
Check IC500
YES
YES

2-9
CVBS video out
(IPOD video)
Check JK202
YES
Check Micom (IC101)
YES
Check IC205
IC205 pin4
video signal ok?
NO NO
IC205 pin6
HIGH signal?
IC206 pin4
video signal ok?
IPOD B/D
JK3P1 pin23 video
signal OK?
MAIN B/D
IC208 pin4 ok?
FRONT B/D
CN307 pin8 ok?
IC205 pin1
video signal ok?
NO
NO
NO
NO
NO
Check IC206
Check iPod connection or
JK3P1
Check 26p FFC cable and con-
nection
Check 14p FFC cable and
connection
Check IC208
YES
YES
YES
YES
YES

2-10
6. HDMI NO AUDIO/VIDEO CHECK (with HDMI IN)
HDMI IN function
Check CN801 (or CN802) and
HDMI cable connection
CN801 or CN802
pin1, 3, 4, 6, 7, 9, 10, 12 TMDS
input signal ok?
CN801 or CN802
soldering ok?
CN803 pin1, 3, 4, 6, 7, 9, 10, 12
TMDS data signal ok?
CN803
soldering OK?
IC803 video
input signal (pin1~36)
ok?
YES
NO
YES
NO
YES
Check IC803 and X801
Resolder CN801 or CN802
Check CN803 and HDMI cable
connection
Resolder CN803
Check IC803
NO
YES
NO
YES
NO

2-11
HDMI OUT function
Check CN803 and HDMI cable
connection
Check IC803
NO
NO
YES
YES
CN803
pin1, 3, 4, 6, 7, 9, 10, 12 TMDS data
signal ok?
IC803 video
input signal (pin1~36)
ok?
Resolder CN803
Check IC803 and X801
YES
NO
NO
YES
CN803 soldering ok?
IC500 TMDS data (R843 ~ R850)
signal ok?
Check IC500