LG 37LB7DF User manual

LCD TV
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE CHASSIS,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
CHASSIS : LT75A
MODEL : 37LB7DF 37LB7DF-DA

Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
- 2 -
CONTENTS
CONTENTS .............................................................................................. 2
PRODUCT SAFETY ..................................................................................3
SPECIFICATION ........................................................................................6
ADJUSTMENT INSTRUCTION ...............................................................12
TROUBLE SHOOTING ............................................................................17
BLOCK DIAGRAM...................................................................................25
EXPLODED VIEW .................................................................................. 29
REPLACEMENT PARTS LIST ............................................................... 31
SVC. SHEET ...............................................................................................

Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
- 3 -
SAFETY PRECAUTIONS
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by in the
Schematic Diagram and Replacement Parts List.
It is essential that these special safety parts should be replaced with the same components as recommended in this manual to prevent
Shock, Fire, or other Hazards.
Do not modify the original design without permission of manufacturer.
General Guidance
An isolation Transformer should always be used during the
servicing of a receiver whose chassis is not isolated from the AC
power line. Use a transformer of adequate power rating as this
protects the technician from accidents resulting in personal injury
from electrical shocks.
It will also protect the receiver and it's components from being
damaged by accidental shorts of the circuitry that may be
inadvertently introduced during the service operation.
If any fuse (or Fusible Resistor) in this TV receiver is blown,
replace it with the specified.
When replacing a high wattage resistor (Oxide Metal Film Resistor,
over 1W), keep the resistor 10mm away from PCB.
Keep wires away from high voltage or high temperature parts.
Before returning the receiver to the customer,
always perform an AC leakage current check on the exposed
metallic parts of the cabinet, such as antennas, terminals, etc., to
be sure the set is safe to operate without damage of electrical
shock.
Leakage Current Cold Check(Antenna Cold Check)
With the instrument AC plug removed from AC source, connect an
electrical jumper across the two AC plug prongs. Place the AC
switch in the on position, connect one lead of ohm-meter to the AC
plug prongs tied together and touch other ohm-meter lead in turn to
each exposed metallic parts such as antenna terminals, phone
jacks, etc.
If the exposed metallic part has a return path to the chassis, the
measured resistance should be between 1MΩand 5.2MΩ.
When the exposed metal has no return path to the chassis the
reading must be infinite.
An other abnormality exists that must be corrected before the
receiver is returned to the customer.
Leakage Current Hot Check (See below Figure)
Plug the AC cord directly into the AC outlet.
Do not use a line Isolation Transformer during this check.
Connect 1.5K/10watt resistor in parallel with a 0.15uF capacitor
between a known good earth ground (Water Pipe, Conduit, etc.)
and the exposed metallic parts.
Measure the AC voltage across the resistor using AC voltmeter
with 1000 ohms/volt or more sensitivity.
Reverse plug the AC cord into the AC outlet and repeat AC voltage
measurements for each exposed metallic part. Any voltage
measured must not exceed 0.75 volt RMS which is corresponds to
0.5mA.
In case any measurement is out of the limits specified, there is
possibility of shock hazard and the set must be checked and
repaired before it is returned to the customer.
Leakage Current Hot Check circuit
1.5 Kohm/10W
To Instrument's
exposed 
METALLIC PARTS
Good Earth Ground
such as WATER PIPE,
CONDUIT etc.
AC Volt-meter
IMPORTANT SAFETY NOTICE
0.15uF

Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
- 4 -
CAUTION: Before servicing receivers covered by this service
manual and its supplements and addenda, read and follow the
SAFETY PRECAUTIONS on page 3 of this publication.
NOTE: If unforeseen circumstances create conflict between the
following servicing precautions and any of the safety precautions on
page 3 of this publication, always follow the safety precautions.
Remember: Safety First.
General Servicing Precautions
1. Always unplug the receiver AC power cord from the AC power
source before;
a. Removing or reinstalling any component, circuit board
module or any other receiver assembly.
b. Disconnecting or reconnecting any receiver electrical plug or
other electrical connection.
c. Connecting a test substitute in parallel with an electrolytic
capacitor in the receiver.
CAUTION: A wrong part substitution or incorrect polarity
installation of electrolytic capacitors may result in an
explosion hazard.
2. Test high voltage only by measuring it with an appropriate high
voltage meter or other voltage measuring device (DVM,
FETVOM, etc) equipped with a suitable high voltage probe.
Do not test high voltage by "drawing an arc".
3. Do not spray chemicals on or near this receiver or any of its
assemblies.
4. Unless specified otherwise in this service manual, clean
electrical contacts only by applying the following mixture to the
contacts with a pipe cleaner, cotton-tipped stick or comparable
non-abrasive applicator; 10% (by volume) Acetone and 90% (by
volume) isopropyl alcohol (90%-99% strength)
CAUTION: This is a flammable mixture.
Unless specified otherwise in this service manual, lubrication of
contacts in not required.
5. Do not defeat any plug/socket B+ voltage interlocks with which
receivers covered by this service manual might be equipped.
6. Do not apply AC power to this instrument and/or any of its
electrical assemblies unless all solid-state device heat sinks are
correctly installed.
7. Always connect the test receiver ground lead to the receiver
chassis ground before connecting the test receiver positive
lead.
Always remove the test receiver ground lead last.
8. Use with this receiver only the test fixtures specified in this
service manual.
CAUTION: Do not connect the test fixture ground strap to any
heat sink in this receiver.
Electrostatically Sensitive (ES) Devices
Some semiconductor (solid-state) devices can be damaged easily
by static electricity. Such components commonly are called
Electrostatically Sensitive (ES) Devices. Examples of typical ES
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 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 to
prevent potential shock reasons prior to applying power to the
unit under test.
2. After removing an electrical assembly equipped with ES
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 ES
devices.
4. Use only an anti-static type solder removal device. Some solder
removal devices not classified as "anti-static" can generate
electrical charges sufficient to damage ES devices.
5. Do not use freon-propelled chemicals. These can generate
electrical charges sufficient to damage ES devices.
6. Do not remove a replacement ES device from its protective
package until immediately before you are ready to install it.
(Most replacement ES devices are packaged with leads
electrically shorted together by conductive foam, aluminum foil
or comparable conductive material).
7. Immediately before removing the protective material from the
leads of a replacement ES device, touch the protective material
to the chassis or circuit assembly into which the device will be
installed.
CAUTION: Be sure no power is applied to the chassis or circuit,
and observe all other safety precautions.
8. Minimize bodily motions when handling unpackaged
replacement ES 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 ES device.)
General Soldering Guidelines
1. Use a grounded-tip, low-wattage soldering iron and appropriate
tip size and shape that will maintain tip temperature within the
range or 500 F to 600 F.
2. Use an appropriate gauge of RMA resin-core solder composed
of 60 parts tin/40 parts lead.
3. Keep the soldering iron tip clean and well tinned.
4. Thoroughly clean the surfaces to be soldered. Use a mall wire-
bristle (0.5 inch, or 1.25cm) brush with a metal handle.
Do not use freon-propelled spray-on cleaners.
5. Use the following unsoldering technique
a. Allow the soldering iron tip to reach normal temperature.
(500 F to 600 F)
b. Heat the component lead until the solder melts.
c. Quickly draw the melted solder with an anti-static, suction-
type solder removal device or with solder braid.
CAUTION: Work quickly to avoid overheating the
circuitboard printed foil.
6. Use the following soldering technique.
a. Allow the soldering iron tip to reach a normal temperature
(500 F to 600 F)
b. First, hold the soldering iron tip and solder the strand against
the component lead until the solder melts.
c. Quickly move the soldering iron tip to the junction of the
component lead and the printed circuit foil, and hold it there
only until the solder flows onto and around both the
component lead and the foil.
CAUTION: Work quickly to avoid overheating the circuit
board printed foil.
d. Closely inspect the solder area and remove any excess or
splashed solder with a small wire-bristle brush.
SERVICING PRECAUTIONS

Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
- 5 -
IC Remove/Replacement
Some chassis circuit boards have slotted holes (oblong) through
which the IC leads are inserted and then bent flat against the
circuit foil. When holes are the slotted type, the following technique
should be used to remove and replace the IC. When working with
boards using the familiar round hole, use the standard technique
as outlined in paragraphs 5 and 6 above.
Removal
1. Desolder and straighten each IC lead in one operation by gently
prying up on the lead with the soldering iron tip as the solder
melts.
2. Draw away the melted solder with an anti-static suction-type
solder removal device (or with solder braid) before removing the
IC.
Replacement
1. Carefully insert the replacement IC in the circuit board.
2. Carefully bend each IC lead against the circuit foil pad and
solder it.
3. Clean the soldered areas with a small wire-bristle brush.
(It is not necessary to reapply acrylic coating to the areas).
"Small-Signal" Discrete Transistor
Removal/Replacement
1. Remove the defective transistor by clipping its leads as close as
possible to the component body.
2. Bend into a "U" shape the end of each of three leads remaining
on the circuit board.
3. Bend into a "U" shape the replacement transistor leads.
4. Connect the replacement transistor leads to the corresponding
leads extending from the circuit board and crimp the "U" with
long nose pliers to insure metal to metal contact then solder
each connection.
Power Output, Transistor Device
Removal/Replacement
1. Heat and remove all solder from around the transistor leads.
2. Remove the heat sink mounting screw (if so equipped).
3. Carefully remove the transistor from the heat sink of the circuit
board.
4. Insert new transistor in the circuit board.
5. Solder each transistor lead, and clip off excess lead.
6. Replace heat sink.
Diode Removal/Replacement
1. Remove defective diode by clipping its leads as close as
possible to diode body.
2. Bend the two remaining leads perpendicular y to the circuit
board.
3. Observing diode polarity, wrap each lead of the new diode
around the corresponding lead on the circuit board.
4. Securely crimp each connection and solder it.
5. Inspect (on the circuit board copper side) the solder joints of
the two "original" leads. If they are not shiny, reheat them and if
necessary, apply additional solder.
Fuse and Conventional Resistor
Removal/Replacement
1. Clip each fuse or resistor lead at top of the circuit board hollow
stake.
2. Securely crimp the leads of replacement component around
notch at stake top.
3. Solder the connections.
CAUTION: Maintain original spacing between the replaced
component and adjacent components and the circuit board to
prevent excessive component temperatures.
Circuit Board Foil Repair
Excessive heat applied to the copper foil of any printed circuit
board will weaken the adhesive that bonds the foil to the circuit
board causing the foil to separate from or "lift-off" the board. The
following guidelines and procedures should be followed whenever
this condition is encountered.
At IC Connections
To repair a defective copper pattern at IC connections use the
following procedure to install a jumper wire on the copper pattern
side of the circuit board. (Use this technique only on IC
connections).
1. Carefully remove the damaged copper pattern with a sharp
knife. (Remove only as much copper as absolutely necessary).
2. carefully scratch away the solder resist and acrylic coating (if
used) from the end of the remaining copper pattern.
3. Bend a small "U" in one end of a small gauge jumper wire and
carefully crimp it around the IC pin. Solder the IC connection.
4. Route the jumper wire along the path of the out-away copper
pattern and let it overlap the previously scraped end of the good
copper pattern. Solder the overlapped area and clip off any
excess jumper wire.
At Other Connections
Use the following technique to repair the defective copper pattern
at connections other than IC Pins. This technique involves the
installation of a jumper wire on the component side of the circuit
board.
1. Remove the defective copper pattern with a sharp knife.
Remove at least 1/4 inch of copper, to ensure that a hazardous
condition will not exist if the jumper wire opens.
2. Trace along the copper pattern from both sides of the pattern
break and locate the nearest component that is directly
connected to the affected copper pattern.
3. Connect insulated 20-gauge jumper wire from the lead of the
nearest component on one side of the pattern break to the lead
of the nearest component on the other side.
Carefully crimp and solder the connections.
CAUTION: Be sure the insulated jumper wire is dressed so the
it does not touch components or sharp edges.

Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
- 6 -
SPECIFICATION
NOTE : Specifications and others are subject to change without notice for improvement .
4. General Specification(FHD Module)
5. General Specification : 37LB7DF(LC370WU3-SLA1)
1. Application range
This spec sheet is applied to the 42"/37" LCD TV used LT75A
chassis
2. Specification
Each part is tested as below without special appointment.
(1) Temperature : 25 ± 5°C(77 ± 9°F), CST : 40 ± 5°C
(2) Relative Humidity : 65% ± 10%
(3) Power Voltage : Standard input voltage (100-240V~,
50/60Hz)
*Standard Voltage of each products is marked by models
(4) Specification and performance of each parts are followed
each drawing and specification by part number in
accordance with BOM.
(5) The receiver must be operated for about 20 minutes prior
to the adjustment.
3. Test method
(1) Performance : LGE TV test method followed
(2) Demanded other specification
Safety : CE, IEC Specification
EMC : CE, IEC
No. Item Specification Remark
1. Display Screen Device 37/42" wide Color Display Module LCD
2. Aspect Ratio 16:9
3. LCD Module 37LB7DF : LC370WU3-SLA1
42LB7DF : LC420WU6-SLA2
4. Operating Environment Temp. : 0 ~ 40 deg LG SPEC
Humidity : 10 ~ 90 %
5. Storage Environment Temp. : -20 ~ 50 deg LG SPEC
Humidity : 10 ~ 90%
6. Input Voltage AC100 ~ 240V, 50/60Hz Maker LG
No Item Specification Unit Remark
1Display area 819.36 (H) x 460.89 (V) mm
2Outline dimension 877 (W) x 516.8 (H) x 55.5 (D) with inverter mm
3Number of Pixels 1920 (H) x 1080(V) 1Pixel=3RGB Cells
4Cell pitch 426.75um (H) x 426.75um (V) um G cell
5Color arrangement RGB stripe arrangement
6Coating Hard coating(3H), Anti-glare
7Operating Temperature 0 ~ 40 deg Altitude
Environment Humidity 10 ~ 90 % – 0 to 1400feet
8Storage Temperature -20 ~ 50 deg Altitude
Environment Humidity 10 ~ 90 % – 0 to 4000feet

Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
- 7 -
6. General specifications : 42LB7DF(LC420WU6-SLA2)
No Item Specification Unit Remark
1Display area 930.24 (H) x 523.26 (V) mm
2Outline dimension 983 (W) x 576 (H) x 51 (D) with inverter mm
3Number of Pixels 1920 (H) x 1080(V) 1Pixel=3RGB Cells
4Cell pitch 484.5um (H) x 484.5um (V) um G cell
5Color arrangement RGB stripe arrangement
6Coating Hard coating(3H), Anti-glare
7Operating Temperature 0 ~ 40 deg Altitude
Environment Humidity 10 ~ 90 % – 0 to 1400feet
8Storage Temperature -20 ~ 50 deg Altitude
Environment Humidity 10 ~ 90 % – 0 to 4000feet
7. Mechanical specification
1) 37LB7DF
No. Item Content Unit Remark
1. Product Widt(W) Length(D) Height(H) mm
Dimension Before Packing 927 280.5 692.8 mm With Stant
After Packing 1021 296 877 mm
2. Product Only SET 21.5 Kg
With BOX 25 Kg
2) 42LB7DF
No. Item Content Unit Remark
1. Product Widt(W) Length(D) Height(H) mm
Dimension Before Packing 1033.1 300 750 mm With Stant
After Packing 1119 374 858 mm
2. Product Only SET 27.5 Kg
With BOX 32.5 Kg

- 8 -
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
8. Chroma & Brightness
1) 37LB7DF
No Item Min Typ Max Unit Measurement Result Remark
1Viewing R/L 178 Viewing R/L 178
Angle<CR>10> U/D 178 Angle U/D 178
<CR>10>
2. White average 37LB7DF 400 500 - cd/m2 - 100IRE Full White Pattern (255 gray)
brightness - Picture : Dynamic (Cool)
3. Brightness uniformity 1.3 0 1.3 cd/m2
- 100IRE Full White Pattern (255 gray)
- Picture : Dynamic (Cool)
4. Color White X 0.264 0.279 0.294
- 85IRE Full White Pattern (216 gray)
Coordinate Y 0.277 0.292 0.307 - Picture : Dynamic (Cool)
Red X 0.62 0.635 0.65
Y0.33 0.345 0.36
Green X 0.27 0.285 0.3
Y0.601 0.616 0.631
Blue X 0.13 0.145 0.16
Y0.047 0.062 0.077
5. Color coordinate uniformity -0.03 Average +0.03
- 85IRE Full White Pattern (216 gray)
- Picture : Dynamic (Cool)
6. Contrast Ratio CR with
7000 : 1 10,000 : 1 - Full white(100IRE)
at dark room
PWM-Dimming - Full black(0IRE) pattern
- Picture : Dynamic (Cool)
- Input : HDMI1,2
=> CR with PWM-Dimming
CR without 650:1 1,000:1
- Input : DTV/Analog/AV/Comp/RGB/HDMI
PWM-Dimming => CR without PWM-Dimming
7. Color Temperature Medium 8300 9300 10300
- 85IRE Full White Pattern (216 gray)
Warm 5500 6500 7500 - Picture : Dynamic (Cool)
Cool 10000 11000 12000
8. Color pull in Range PAL -500 +500 Hz
NTSC -500 +500 Hz
9. Color killer Sensitivity -80 dBm

- 9 -
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
2) 42LB7DF
No Item Min Typ Max Unit Measurement Result Remark
1Viewing R/L 178 Viewing R/L 178
Angle<CR>10> U/D 178 Angle U/D 178
<CR>10>
2. White average 42LB7DF 450 550 - cd/m2 - 100IRE Full White Pattern (255 gray)
brightness - Picture : Dynamic (Cool)
3. Brightness uniformity 1.3 0 1.3 cd/m2
- 100IRE Full White Pattern (255 gray)
- Picture : Dynamic (Cool)
4. Color White X 0.276 0.279 0.282
- 85IRE Full White Pattern (216 gray)
Coordinate Y 0.289 0.292 0.295 - Picture : Dynamic (Cool)
Red X 0.637 0.640 0.643
Y0.340 0.343 0.347
Green X 0.284 0.287 0.290
Y0.610 0.613 0.616
Blue X 0.141 0.144 0.147
Y0.062 0.065 0.068
5. Color coordinate uniformity -0.03 Average +0.03
- 85IRE Full White Pattern (216 gray)
- Picture : Dynamic (Cool)
6. Contrast Ratio CR with
7000 : 1 10,000 : 1 - Full white(100IRE)
at dark room
PWM-Dimming - Full black(0IRE) pattern
- Picture : Dynamic (Cool)
- Input : HDMI1,2
=> CR with PWM-Dimming
CR without 650:1 1,000:1
- Input : DTV/Analog/AV/Comp/RGB/HDMI
PWM-Dimming => CR without PWM-Dimming
7. Color Temperature Medium 8300 9300 10300
- 85IRE Full White Pattern (216 gray)
Warm 5500 6500 7500 - Picture : Dynamic (Cool)
Cool 10000 11000 12000
8. Color pull in Range PAL -500 +500 Hz
NTSC -500 +500 Hz
9. Color killer Sensitivity -80 dBm
9. Average Brightness & Contrast measure standard specification
1) Standard Test Condition
2) Surrounding Brightness Level: dark
3) Surrounding Temperature: 25±2°C
4) Warm-up Time: 30 Min
5) Input Signal: HDMI 1920x1080p 60Hz

Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
- 10 -
10. Component Video Input (Y, PB, PR)
No Resolution H-freq(kHz) V-freq.(Hz) Pixel clock(MHz) Proposed
1720*480 15.73 59.94 13.500 SDTV, DVD 480I(525I)
2720*480 15.75 60.00 13.514 SDTV, DVD 480I(525I)
3720*480 31.47 59.94 27.000 SDTV 480P
4720*480 31.50 60.00 27.027 SDTV 480P
51280*720 44.96 59.94 74.176 HDTV 720P
61280*720 45.00 60.00 74.250 HDTV 720P
71920*1080 33.72 59.94 74.176 HDTV 1080I
81920*1080 33.75 60.00 74.250 HDTV 1080I
91920*1080 67.50 60.00 148.50 HDTV 1080P
11. RGB Input ( PC )
No Resolution H-freq(kHz) V-freq.(Hz) Pixel clock(MHz) Proposed Remarks
1. 720*400 31.468 70.08 28.32
2. 640*480 31.469 59.94 25.17 VESA 848*480 60Hz, 852*480 60Hz
37.500 75.00 31.50 => Display 640*480 60H
3800*600 37.879 60.31 40.00 VESA
46.875 75.00 49.50
4. 832*624 49.725 74.55 57.283 Macintosh
51024*768 48.363 60.00 65.00 VESA(XGA)
56.476 70.00 75.00
60.023 75.03 78.75
61280*768 47.693 59.99 80.125 WXGA
71360*768 47.649 59.94 84.625 WXGA
81366*768 47.649 59.94 84.625 WXGA
91280*1024 63.595 60.0 108.875 SXGA
10 1400*1050 65.160 60.0 122.50 SXGA
11 1920*1080 66.647 59.988 138.625 WUXGA Reduced Blanking Timing

Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
- 11 -
12. HDMI DTV
- HDMI DTV Table
13. HDMI DTV
- HDMI PC Table
No Resolution H-freq(kHz) V-freq.(kHz) Pixel clock(MHz) Propose Remarks
1. 720*480 31.47 59.94 27.00 SDTV 480P(4:3) PC mode => Display 640*480
2. 720*480 31.50 60 27.027 SDTV 480P(4:3)
3. 640*480 31.469 59.94 25.175 SDTV 480P(4:3)
4. 640*480 31.469 60.00 25.20 SDTV 480P(4:3)
5. 720*480 31.47 59.94 27.000 SDTV 480P(16:9)
6. 720*480 31.50 60.00 27.027 SDTV 480P(16:9)
7. 720*576 31.25 50.00 27.000 SDTV 576P
8. 1280*720 37.50 50.00 74.176 HDTV 720P
9. 1280*720 44.96 59.94 74.176 HDTV 720P
PC mode =>Display 1280*768 60Hz
10. 1280*720 45.00 60.00 74.250 HDTV 720P
11 1920*1080 33.72 59.94 74.176 HDTV 1080I
12 1920*1080 33.75 60.00 74.250 HDTV 1080I
13 1920*1080 28.125 50.00 74.250 HDTV 1080I 50Hz
14 1920*1080 27.000 24.00 74.250 HDTV 1080P 24Hz
15 1920*1080 56.250 50 148.500 HDTV 1080P 50Hz
16 1920*1080 67.433 59.94 148.352 HDTV 1080P
PC mode =>Display 1920*1080 60Hz
17 1920*1080 67.500 60 148.500 HDTV 1080P
No Resolution H-freq(kHz) V-freq.(kHz) Pixel clock(MHz) Propose Remarks
1. 720*400 31.468 70.08 28.32
2. 640*480 31.469 59.94 25.17 VESA DTV mode => Display 480p
37.500 75.00 31.50 848*480 60Hz, 852*480 60Hz:
Display No signal
3800*600 37.879 60.31 40.00 VESA
46.875 75.00 49.50
4. 832*624 49.725 74.55 57.283 Macintosh
51024*768 48.363 60.00 65.00 VESA(XGA)
56.476 70.00 75.00
60.023 75.03 78.75
61280*768 47.693 59.99 80.125 WXGA
71360*768 47.649 59.94 84.625 WXGA
81366*768 47.649 59.94 84.625 WXGA
91280*1024 63.595 60.0 108.875 SXGA
10 1400*1050 65.160 60.0 122.50 SXGA
11 1920*1080 66.647 59.988 138.625 WUXGA Reduced Blanking Timing
DTV mode =>1080P Display

Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
- 12 -
ADJUSTMENT INSTRUCTION
1. Application Object
These instructions are applied to all of the LCD TV, LT75A.
2. Specification
2.1 Because this is not a hot chassis, it is not necessary to
use an isolation transformer.
However, the use of isolation transformer will help to
protect test instruments.
2.2 Adjustment must be done in the correct sequence.
2.3 The adjustment must be performed at 25±5°C
temperature and 65±10% relative humidity if there is no
specified designation.
2.4 The input voltage of the receiver must be kept between
100~220V, 50/60Hz.
2.5 Before adjustment, execute Heat-Run for 30 minutes at
RF no signal.
3. EDID
* Caution
Use the proper signal cable for EDID Download
- Analog EDID : Pin3 exists
- Digital EDID : Pin3 exists
* Caution
- Never connect HDMI & D-sub Cable at the same time.
- Use the proper cables below for EDID Writing.
- Download HDMI1, HDMI2 separately because HDMI1 is
different from HDMI2.
3.1 Data
1> ANALOG(128 Byte)
2> HDMI (256 Byte)
3> HDMI2 (256 Byte)
C/S002020202020200A000E431D4B3C000x07
FD000000
202020202020200A56542047
0x06
4C00FC0000001800002186BC048520500x05
401F3870A08036261C00002186BC00350x04
8848301E0051A050211B0101010101010x03
0101C0D1406140454031006EA54B49110x02
259C4957A3B0D9EA782746010301Month/Year0x01
Serial NoProduct ID6D1E00FFFFFFFFFFFF000x00
0x0F0x0E0x0D0x0C0x0B0x0A0x090x080x070x060x050x040x030x020x010x00
C/A000000001800002188BC00378040300x07
1E005180001F4E180000218EC40055400x06
0C2031402090D00A8C9E0000218EC4800x05
252C1020161C72D0801D011E0000218E0x04
C40055286E201ED05172001D011E00000x03
218EC4405528B8201ED052BC001D01000x02
10000C036500000183070709231022200x01
1F210514041312030111024EF12103020x00
C/S012020202020200A000F431C4B32000x07
FD000000
202020202020200A56542047
0x06
4C00FC0000001C00002186BC003588480x05
301E0051A050211B1E0000218EC400450x04
2C58402D387118803A020101010101010x03
0101C0D1406140454031006EA54B49110x02
259C4957A3B0D9EA782746800301Month/Year0x01
Serial NoProduct ID6D1E00FFFFFFFFFFFF000x00
0x0F0x0E0x0D0x0C0x0B0x0A0x090x080x070x060x050x040x030x020x010x00
C/A000000001800002188BC00378040300x07
1E005180001F4E180000218EC40055400x06
0C2031402090D00A8C9E0000218EC4800x05
252C1020161C72D0801D011E0000218E0x04
C40055286E201ED05172001D011E00000x03
218EC4405528B8201ED052BC001D01000x02
20000C036500000183070709231022200x01
1F210514041312030111024EF12103020x00
C/S012020202020200A000F431C4B32000x07
FD000000
202020202020200A56542047
0x06
4C00FC0000001C00002186BC003588480x05
301E0051A050211B1E0000218EC400450x04
2C58402D387118803A020101010101010x03
0101C0D1406140454031006EA54B49110x02
259C4957A3B0D9EA782746800301Month/Year0x01
Serial NoProduct ID6D1E00FFFFFFFFFFFF000x00
0x0F0x0E0x0D0x0C0x0B0x0A0x090x080x070x060x050x040x030x020x010x00

Before AV ADC Calibration, should be select the
"Tool Option "
4. Select LCD module size and tool.
4.1 Press ADJ Key in the Adjust remocon
4.2 Select "Tool Option1" by using D/E(CH+/-) key, and
press A (ENTER).
4.3 Change "Inch" and "Tool" according to the inch of model
name
4.4 After changing the panel size, push the EXIT Key.
37LC7D 42LC7D
Tool Option1 80 84
Tool Option2 1665 1665
5. ADC Calibration
5.1 Adjustment of RF / AV / S-VIDEO
* Required Equipments
8Remote controller for adjustment.
8MSPG-925FS Pattern Generator (Which has Video
Signal: 7 Color Bar Pattern shown in Fig. 1).
=> Model: 207 / Pattern: 65
5.1.1 Method of Auto RF / AV / S-VIDEO Color Balance
(NTSC-J).
1) Input the Video Signal: 7 Color Bar signal into AV1
2) Set the PSM to Dynamic mode in the Picture menu.
[Fig.1]
3) Press IN-START key on R/C for adjustment.
[Fig.2]
4) Press the G(Vol.+) key to operate the set, then it
becomes automatically.
5) Auto-RGB OK means the adjustment is completed.
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Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only

Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
- 14 -
5.2 Adjustment of Component
*Required Equipments
8Remote controller for adjustment
8MSPG-925FS Pattern Generator. (Which has 720p/60Hz
YPbPr output Pattern shown in Fig. 2)
=> Model: 216 / Pattern: 65
5.2.1 Method of Auto Component Color Balance
1) Input the Component 720p/60Hz 7 Color Bar (MSPG-
925FS model:216, pattern:65) signal into Component.
2) Set the PSM to Dynamic mode in the Picture menu.
[Fig.1]
3) Press IN-START key on R/C for adjustment.
4) Press the G(Vol.+) key to operate the set, then it
becomes automatically.
5) Auto-RGB OK means the adjustment is completed.
5.3 Adjustment of RGB
*Required Equipments
8Remote controller for adjustment
8MSPG-925FS Pattern Generator
(Which has XGA [1024*768] 60Hz 8 color bar 100%
pattern shown in Fig. 3 )
5.3.1 Method of Auto RGB Color Balance
1) Input the PC 1024x768 @ 60Hz 7 Color Bar (MSPG-
925FS model:3, pattern:65) signal into RGB. (using
D-sub to D-sub cable)
2) Set the PSM to Dynamic mode in Picture menu.
3) Press the IN-START key on R/C for adjustment.
[Fig.3]
4) Press the G(Vol.+) key operate To set , then it
becomes automatically.
5) Auto-RGB OK means adjustment is completed

Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
- 15 -
Before adjusting White-balance , the AV ADC
should be done
7. White Balance
*Test Equipment
8 Color Analyzer (CA-210/CH.9)
=> When you adjust LCD color temperature, on Color
analyzer (CA-210), you should use Channel 9 which
is Matrix compensated (White, Red, Green, Blue
revised) by CS-1000 and adjust in accordance with
White balance adjustment coordinate which is
specified on the next..
* Color temperature standards according to CSM and Module
CSM Plasma LCD
Cool 11,000k 11,000k
Medium 9,300k 9,300k
Warm 6,500k 6,500k
* White balance adjustment coordinate and color temperature
8 PC (for communication through RS-232C) => UART
Baud rate : 115200 bps
8 l Luminance Y AV : upper 200 cd/ß≥(Typ : 350 cd/m2) =>
Applying to Cool
- Connecting picture of the measuring instrument (On
Automatic control )
Inside PATTERN is used when W/B is controlled. Connect
to auto controller or push control R/C IN-START => Enter
the mode of White-Balance, the pattern will come out.
* Auto adjustment Map(RS-232C)
*Auto-control interface and directions
1 Adjust in the place where the influx of light like floodlight
around is blocked. (illumination is less than 10ux).
2.1 In case of PDP: Measure and adjust after sticking the Color
Analyzer (CA-100+, CA-210 ) to the side of the module.
2.2 In case of LCD: Adhere closely the Color Analyzer ( CA-210
) to the module less than 10cm distance, keep it with the
surface of the Module and Color Analyzer’s Prove
vertically.(80~100°).
3 Aging time
- After aging start, keep the power on (no suspension of
power supply) and heat-run over 15 minutes.
- In case of PDP, keep white pattern using inside pattern.
- In case of LCD, using ‘no signal’ or ‘full white pattern’ or the
others, check the back light on
Communication Type LT75A
Protocol Baud Rate Data bit Stop bit Parity
115200 8 1 None
Protocol Index Cmd 1 Cmd 2 Data
Min Value Max Value
Setting R-Gain_Normal j a 00(00) 128(80)
G-Gain_Normal j b 00(00) 128(80)
B-Gain_Normal j c 00(00) 128(80)
R-Gain_Warm j d 00(00) 128(80)
G-Gain_Warm j e 00(00) 128(80)
B-Gain_Warm j f 00(00) 128(80)
R-Gain_Cool j g 00(00) 128(80)
G-Gain_Cool j h 00(00) 128(80)
B-Gain_Cool j i 00(00) 128(80)
R-Offset_Normal l j 00(00) 128(80)
G-Offset_Normal l k 00(00) 128(80)
B-Offset_Normal l l 00(00) 128(80)
R-Offset_Warm l m 00(00) 128(80)
Offset_Warm l n 00(00) 128(80)
B-Offset_Warm l o 00(00) 128(80)
R-Offset_Cool l p 00(00) 128(80)
G-Offset_Cool l q 00(00) 128(80)
B-Offset_Cool l r 00(00) 128(80)
Inside Pattern signal w b 00 W/B Adjust start
Inside Pattern signal w b 10 Inside Pattern
Inside Pattern signal w b ff W/B Adjust end

Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
- 16 -
8. Manual white Balance
One of R Gain / G Gain / B Gain should be kept on 80, and
others are controlled lowering from 80
1) Press 'power on' of the control R/C, set heat run to white by
pressing G, and heat run over 15 minutes
(Set: RS-233 Host: PC, Baud Rate: 115200bps, Download:
Cortez).
2) Zero Calibrate CA-210, and when controlling, stick the sensor
to the center of LCD module surface.
3) Double click In-start key on Controlling R/C and get in ‘white
balance’.
4) Set test-pattern on and display inside pattern. Control is
carried out on three color temperature, COOL, MEDIUM,
WARM. (Control is carried out three times,)
5) When the R/G/B GAIN is 80 on OSD, it is the FULL DYNAMIC
Range of the Module. In order to control white balance without
the saturation of FULL DYNAMIC Range and DATA, one of R
Gain / G Gain / B Gain should be kept on 80, and other two is
controlled lowering from 80.
* Color Temperature: Cool, Medium, Warm
1. When R GAIN is set to 80
- Control G GAIN and B GAIN by lowering from 80.
2. When B GAIN is set to 80
- Control R GAIN and G GAIN by lowering from 80.
3. When G GAIN is set to 80
- Control R GAIN and B GAIN by lowering from 80.
One of R Gain / G Gain / B Gain should be kept on 80, and
adjust other two lower than 80.
(When R/G/B GAIN are all 80, it is the FULL DYNAMIC
Range of Module)

Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
- 17 -
TROUBLESHOOTING

Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
- 18 -

Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
- 19 -

Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
- 20 -