LG 22LN4000 User manual

Printed in KoreaP/NO : MFL67698505 (1303-REV00)
CHASSIS : LM91N
MODEL : 22LN4000 22LN4000-TA
CAUTION
BEFORE SERVICING THE CHASSIS,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
LED TV
SERVICE MANUAL
North/Latin America http://aic.lgservice.com
Europe/Africa http://eic.lgservice.com
Asia/Oceania http://biz.lgservice.com
Internal Use Only

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Only for training and service purposes
CONTENTS
CONTENTS .............................................................................................. 2
SAFETY PRECAUTIONS ........................................................................ 3
SERVICING PRECAUTIONS ................................................................... 4
SPECIFICATION ...................................................................................... 6
ADJUSTMENT INSTRUCTION ............................................................... 7
TROUBLE SHOOTING GUIDE ............................................................... 10
BLOCK DIAGRAM ................................................................................. 18
EXPLODED VIEW .................................................................................. 19
SCHEMATIC CIRCUIT DIAGRAM ..............................................................

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Only for training and service purposes
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by in the
Schematic Diagram and Exploded View.
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 1 W), keep the resistor 10 mm 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 1 MΩ and 5.2 MΩ.
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 1.5 K / 10 watt resistor in parallel with a 0.15 uF 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
0.5 mA.
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
IMPORTANT SAFETY NOTICE
SAFETY PRECAUTIONS

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Only for training and service purposes
SERVICING PRECAUTIONS
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 conict between the
following servicing precautions and any of the safety precautions
on page 3 of this publication, always follow the safety precau-
tions. 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 explo-
sion 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 specied 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 ammable mixture.
Unless specied 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 xtures specied in this
service manual.
CAUTION: Do not connect the test xture ground strap to any
heat sink in this receiver.
Electrostatically Sensitive (ES) Devices
Some semiconductor (solid-state) devices can be damaged eas-
ily by static electricity. Such components commonly are called
Electrostatically Sensitive (ES) Devices. Examples of typical ES
devices are integrated circuits and some eld-effect transistors
and semiconductor “chip” components. The following techniques
should be used to help reduce the incidence of component dam-
age 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. Alter-
natively, obtain and wear a commercially available discharg-
ing 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 expo-
sure 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 sol-
der removal devices not classied as “anti-static” can generate
electrical charges sufcient to damage ES devices.
5. Do not use freon-propelled chemicals. These can generate
electrical charges sufcient 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 elec-
trically 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 mate-
rial to the chassis or circuit assembly into which the device will
be installed.
CAUTION: Be sure no power is applied to the chassis or cir-
cuit, and observe all other safety precautions.
8. Minimize bodily motions when handling unpackaged replace-
ment ES devices. (Otherwise harmless motion such as the
brushing together of your clothes fabric or the lifting of your
foot from a carpeted oor can generate static electricity suf-
cient to damage an ES device.)
General Soldering Guidelines
1. Use a grounded-tip, low-wattage soldering iron and appropri-
ate 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 1.25 cm) 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 circuit
board 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 ows onto and around both the compo-
nent 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.

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Only for training and service purposes
IC Remove/Replacement
Some chassis circuit boards have slotted holes (oblong) through
which the IC leads are inserted and then bent at against the cir-
cuit 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 remain-
ing 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 pos-
sible 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 when-
ever 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 connec-
tions).
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 con-
nected 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.

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Only for training and service purposes
SPECIFICATION
NOTE : Specifications and others are subject to change without notice for improvement .
1. Application range
This spec sheet is applied to the 22” LED TV used LM91N
chassis.
2. Requirement for Test
Each part is tested as below without special appointment.
1) Temperature: 25 °C ± 5 °C(77 °F ± 9 °F), CST: 40 °C ± 5 °C
2) Relative Humidity: 65 % ± 10 %
3) Power Voltage
: Standard input voltage (AC 100-240 V~, 50/60 Hz)
* 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 5 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
4. General Specification
No. Item Specication Remarks
1. Market NON EU
2. Broadcasting system PAL B/G/DK,/I,
NTSC-M
3. Available Channel
(Revision 21: 10.12.08)
BAND PAL NTSC China(DK) Australia(BG)
VHF/UHF C1~C69 2~78 VHF/UHF C1~C62 C1~C75
CATV S1~S41 1~71 CATV S1~S41 S2~S44
4. Receiving system Upper Heterodyne
5. CVBS Input (1EA) PAL, SECAM, NTSC 4 System(Rear) :PAL50, SECAM, NTSC, PAL60
6. RGB Input RGB-PC Analog (D-SUB 15Pin)
7. Audio Input (1EA) CVBS L/R Input

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Only for training and service purposes
ADJUSTMENT INSTRUCTION
1. Application Range
This document is applied to LD93Q chassis 22” LED TV which
is manufactured in TV Factory or is produced on the basis of
this data.
2. Designation
(1) The adjustment is according to the order which is designated
and which must be followed, according to the plan which
can be changed only on agreeing.
(2) Power adjustment : Free Voltage.
(3) Magnetic Field Condition: Nil.
(4) Input signal Unit: Product Specification Standard.
(5) Reserve after operation : Above 5 Minutes (Heat Run)
Temperature : at 25 °C ± 5 °C
Relative humidity : 65 ± 10 %
Input voltage : 100 - 240V~, 50 / 60 Hz
(6) Adjustment equipments : Color Analyzer (CA-210 or
CA-110), Pattern Generator (MSPG-925L or Equivalent),
DDC Adjustment Jig equipment, Service remote control
3. Adjustment items
3.1. PCB assembly adjustment items
3.1.1. Input Tool-Option, Area Option
- Option adjustment following BOM (Tool Option, Area Option)
(1) Required Equipments
: Remote control for adjustment
(2) Profile: Must be changed the option value because being
different with some setting value Depend on module
maker, inch and market.
(3) Adjustment method
The input methods are same as other chassis. (Use
IN-START key on the Adjust Remote control.)
1) Push the IN-START key in the Adjust R/C.
2) Input the Option Number that was specified in the BOM,
into the Shipping area.
3) Select “Tool Option/ Area Option” by using ▲/▼(CH+/-)
key, and press the number key(0~9) consecutively
Ex) if the value of Tool Option1 is 7, input the data using
number key “7” (If not changed the option, the input
menu can differ from the model spec.)
* Refer to Job Expression of each main chassis ass'y
(EBTxxxxxxxx) for Option value
* Before PCB check, you have to change the Tool option,
Area Option and have to AC off/on (Plug out and in)
(If missing this process, set can operate abnormally)
* Never push the IN-STOP key after completing the
function inspection.
3.2. S/W program download
(1) Profile : This is for downloading the s/w to the flash
memory of IC603.
(2) Equipment
1) PC
2) MTK_tool program
3) Download jig
4) USB
(3) Connection structure
(4) Connection condition
1) IC name and circuit number : Flash Memory and IC603
2) Tact time : about 2min
3.3. Download method 1
3.3.1. Preliminary steps
(1) Connect the download jig to 4pin jack (P303)
(2) Connect the PC to USB jack
Case1 : Software version up
1. After downloading S/W by USB , TV set will reboot
automatically.
2. Push “In-stop” key.
3. Push “Power on” key.
4. Function inspection
5. After function inspection, Push “In-stop” key.
Case2 : Function check at the assembly line
1. When TV set is entering on the assembly line, Push
“In-stop” key at rst.
2. Push “Power on” key for turning it on.
→ If you push “Power on” key, TV set will recover
channel information by itself.
3. After function inspection, Push “In-stop” key.
OG<6K# # # OJG# # # P5575D#
Pdlq# # # Y4133# # # XWW# # # # [#
DGF0QJ# # # HGLG0QJ/#QJ# # # # # # #
#
#
#
=

Wrro#Rswlrq# # # # # # # # # # # # 54;7#

Duhd#Rswlrq################4#
PC Main
B/D
Download jig
4pin harness

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Only for training and service purposes
3.3.2. Download steps
(1) Execute ‘ISP Tool’ program in PC, then a main window will
be opened
(2) Click the Config and Change speed
(MT8223, Using Port, 115200, 4ms)
(3) Click the connect button and confirm
(4) Read and write bin file
Click “(1) Browse” tab, and then load download file (XXXX.
bin) by clicking and open.
(5).Click “Upgrade” tab and set as below
(6) After downloading, AC Power OFF and ON.
3.4. Download method 2
1) Connection USB memory for upgrade.(File name : Mx42A_
PMN_xxxx.bin or Mx42A_PTN_xxxx.bin)
2) Press the IN START key.
3) Select the ‘Upg Fw’ menu
4) Press the ► key and wait
5) If the progressive bar 100% will be completed
- Notice: Do not plug out USB during upgrading.
4. Check EDID and Write HDCP key
- This model is no need to write. EDID data is in Program source
4.1. EDID data
kG



HKNGZZZDKP 


OG<6T# # # OJG# # # P5575D#
Pdlq# # # 僚Y4133# # # XWW# # # # 7#
DGF0RN# # # HGLG0RN/# # RN# # #
#
Wrro#Rswlrq# # # # # # # # # # # # # # # # # 54;7#
Duhd#Rswlrq####################4#
V|vwhp#frqwuro4#
V|vwhp#frqwuro5#
Srzhu#Rii#Klvwru|#
Xsj#Iz#
No. Item content 16bit Data
1 Manufacturer ID GSM 1E6D
2 Product ID Analog : 22984 59C8
3 Year 2012 16
4 Version Analog : 1 1
5 Revision Analog : 3 3
6 Model Name 2D HD LG TV

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Only for training and service purposes
(1) RGB EDID Data
1) All data are HEXA
2) Adjustable Data :
**: week
***: year ex) when year 2008: input “12”
****: CHECK SUM (deferent along week, year)
5. Check of White Balance
RGB_Gains are fixed data for each model.
Insert D-sub jack (I2C) which is connected with PC
for White Balance or equivalent device.
→ Total Assembly line should be check whether the
color coordinate(x, y) data Refer to below table
were meet or not.
5.1. Required Equipment
■ Remote controller for checking W/B
■ Color Analyzer : CA-210
■ CH: 14 (LCD MNT, Normal) → 22LN4000
■ PC (for communication through RGB)
■ Pattern Generator (MSPG-925FS series)
5.2. Connecting diagram of equipment for
measuring(For Automatic Adjustment)
(Method 1, using IIC, You connect RGB Cable)
(Standard color coordinate and temperature when using the
CA210 equipment)
RGB_Gains are fixed data for each model
* When doing Adjustment, Please make circumstance as below.
* W/B condition
- Ambient Humidity : 20 % ~ 80 %
- Ambient Temperature : 25 ± 5 °C
6. Function Check
6.1. Check display and sound
■ Check input and Signal items. (cf. work instructions)
1. TV
2. AV (CVBS)
3. RGB (PC : 1366 x 768 @ 60hz)(Display only)
4. HDMI
7. Preset CH writes condition
(1) AC on time on only one after assembled automatically
(2) CH recover on SVC OSD manually
Color
Temperature
Cool 13,000k °K x = 0.269 (±0.03)
y = 0.273 (±0.03)
<Test Signal>
RF/AV
Inner pattern
(216gray, 85IRE)
Medium 9,300k °K x = 0.285 (±0.03)
y = 0.293 (±0.03)
Warm 6,500k °K X=0.313 (±0.03)
Y=0.329 (±0.03)
Luminance
(cd/m2)
Cool Min: 150 Typ : 200 <Test Signal>
(Full white,
100IRE)
Medium Min: 150 Typ : 200
Warm Min: 150 Typ : 200
System Control 2
EDID Download ►
Channel Recover ►
UTT Reset ►

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Only for training and service purposes
TROUBLE SHOOTING
1. NO POWER-Main PCBA
pGhG
vG}vs{hnlG X`U[}
GG qr^WWf
NO POWER
pGZUZ}G G j^^Xf
jGG G ]WWG
YES
NO
YES
NO
YES
check open or short at Line.
or change Adapter.
check the Lines of IC701,
If there is any problem at Line,
Change IC701
NO
Check Line short or open between
IC600 and X600,
Change IC600 or change X600
1
2
4
pG\}GGj^X]f
GXUX}G Gj^Z^f
3
YES
check the Lines of IC704,IC706
If there is any problem at Line,
Change IC704,IC706.
NO
Insert F/W
GZUZ}G GXYG G wXYWf
GGGS
pGWG GYGG wXYWf
Change control
Or check Line short or open of P120
5
GGGGG XXGG wXYWS
GGGfG
6
NO
YES
change IR board
Or check Line short or open of P120
NO
4
]WW

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Only for training and service purposes
2. No raster (Power LED blue, black screen)
pGX`U[}G Gqr^WWf
NO RASTER
(Screen is not displayed)
Insert the F/W back
or REPLACE LCD MODULE
pGXUX}G G s^WXf
pGZUZ}G G s^XYf
pGXUY\}G GYGG pj^WYf
pGYU\}G G YGG pj^WZf
YES
NO
YES
NO
YES
Check Line short or open between
IV701/IC704 and IC600,
If there is any problem at Line,
Change IC701/IC704 or change IC600
NO check open or short at Line and waf er
between IC702,IC703 and IC600.
If there is any problem at Line,
Change IC702,IC703 or IC600
1
2
GZ}GGXGG pj_WXf
YES
It is not over 3V at 1pin of IC801.
Change Q801.
Or check Line short or open between
R803 and 95pin of IC600.
Change IC 600.
4
3
NO
check open or short at Line.
or change Adapter
pGXY}G GXGG wXWXf
If is not under 1.5V at R744,
change Q702 or check open and short
of Line among Q703 and Q702.
If is under 10.8V at L710,
Check open and short
Of line between L710 and P101.
6NO
wGGs}kzGGf
s}kzGGGf
NO
If LVDS cable isn’t insulted enough,
Insult LVDS cable until locking hook.
If LVDS cable have damage,
Change LVDS cable
5
YES
YES

- 12 - LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.
Only for training and service purposes
3. Abnormal/No screen (All input)-Main PCBA
wGGs}kzGGf
s}kzGGGf
Abnormal/No screen
(all input)
jGG GG
GG wYWXG OjaXWSXXSYYSYZ
kaG_S`SXYSXZSX\SX]SX_SX`SYWS
YXSY\SY]SY^SY_SY`SZWP
YES
NO
YES
NO
YES
If LVDS cable isn’t insulted enough,
Insult LVDS cable until locking hook.
If LVDS cable have damage,
Change LVDS cable
1
Change module
WAVEFORMS
3
pGXY}G GXGG wXWXf
If is not under 1.5V at R744,
change Q702 or check open and short
of Line among Q703 and Q702.
If is under 10.8V at L710,
Check open and short
Of line between L710 and P101.
2
3NO Check open and short
Of line between Q703 and P101.
Or Check LVDS cable have damage.
Another is change IC600.
_S`SXYSXZSX\SX]SX_SX`SYWSYXS
Y\SY]SY^SY_SY`SZWwG G wYWX
OkGsP
XWSXXSYYSYZwG G wYWX
OjGP

- 13 - LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.
Only for training and service purposes
4. Abnormal screen (TV)-Main PCBA
wGGymG Gf
Abnormal screen (TV)
YES
NO
NO
insult RF cable tight and then
Cable nut screw tight.
1
Change Main PCBA
WAVEFORMS
pG\}GG\GG {|[WXf
2
pGpYjG G
hG]S^G G {|[WXf
3
4pGpmG G G]^
S]_GGG pj]WWf
NO
NO
3
^wGG {|[WXG OzjsP ]wGG {|[WXG OzkhP
4
]^SG]_G G pj]WW
If 4.9V is not at plus pin of L705, check
It is over 3V at 2pin of IC706,
if it is not, Check Line between IC706
and IC600 is open or short.
Another is change IC706
Check Line between TU401 and IC600
is open or short, Another is change
IC600 or TU401
Check Line between TU401 and IC600
is open or short, Another is change
IC600 or TU401

- 14 - LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.
Only for training and service purposes
5. Abnormal screen (AV)-Main PCBA
wGGh}GGf
Abnormal screen (AV)
YES
NO
NO
Insult AV cable tight
1
Change IC600
WAVEFORMS
pGpG GG
GG Gf
Change Timing to 480I, 576I
Or change format CVBS
2
pGG Gy]\X
3Check Line between JK101 and IC600
is open or short, Another is
change AV cable
NO
YES
YES
y]\XGOj}izP
3

- 15 - LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.
Only for training and service purposes
6. No sound (all source )-Main PCBA
k GGGw\WXG G f
NO sound (All source)
YES
NO
YES
NO
YES
Connect wire between P501 and speaker.
1
Change speaker and wire
pGX`U[}G GYSZ[S[WS[[
G pj\WYG f
If 8V is not plus at L703, check
of JK700 is open.
If is not Check Line between L703
and IC502 is open or short.
.Another is change IC502
2
NO
pGZUZ}G G XZSY^G G pj\WYf
If 3V is not plus 13,27pin of IC502,
check It is over 3V at L501,L504,
if it is not, Check Line between L712
and IC502 is open or short.
Another is change IC701,IC502
NO
3
4
YES
pGpYjG G G
YZSY[G G pj\WYf
Check Line between IC502 and IC600
is open or short, Another is change
IC502 or IC600.
NO
5
pGpYzGG G
y\XWSy\XXSy\XYSy\XZf
6
Check Line between IC501 and IC600
is open or short, Another is change
IC502 or IC600.
YES
pGGGG w\WXf
Check Line between IC502 and P501
is open or short. And then check resistance
of speaker is under 4ohm.
Another is change IC502
NO
4
YZGG pj\WY Y[GG pj\WY
5
y\XZOzkvP y\XXO~zP y\XYOzjrP
5
y\XWOtjsrP
6
XGG w\WXOhG P

- 16 - LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.
Only for training and service purposes
7. Abnormal sound (TV)-Main PCBA
wGGymG Gf
Abnormal sound (TV)
YES
NO
NO
insult RF cable tight and then
Cable nut screw tight.
1
Change Main PCBA
WAVEFORMS
pG\}GG\GG {|[WXf
If 4.9V is not at plus pin of L706, check
It is over 3V at 2pin of IC706,
if it is not, Check Line between IC706
and IC600 is open or short.
Another is change IC706
2
pGpYjG G
hG]S^G G {|[WXf
3Check Line between TU401 and IC600
is open or short, Another is change
IC600 or TU401
4pGpmG G G]^
S]_GGG pj]WWf
Check Line between TU401 and IC600
is open or short, Another is change
IC600 or TU401
NO
NO
3
^wGG {|[WXG OzjsP ]wGG {|[WXG OzkhP
4
]^S]_G GG pj]W[

- 17 - LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.
Only for training and service purposes
8. Abnormal sound (AV)-Main PCBA
wGGh}GGf
Abnormal sound (AV)
YES
NO Insult AV cable tight
1
Change IC600
WAVEFORMS
pGG Gj]__Sj]_`
2Check Line between JK101 and IC600
is open or short, Another is
change AV cable
NO
YES
j]__Sj]_`G OGP
2

- 18 - LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.
Only for training and service purposes
19V 19V_amp
DC/DC 3.3V Stand by
5v_tuner
1
9
V
_
a
m
p
3
.
3
V
S
t
a
n
d
b
y
5
v
_
t
u
n
e
r
`
TMDS/HDMI RX
VIF De- mode Decoder
saw filter
ADC Audio
processor
Scalar
Video
processor LVDS TX
System
EEPROM
ADC
Speaker
Amp(5W)
LCD
module
Flash
video
ADC
audio
saw filter
OSD/LUT
Crystal
IRLED
Touch
SIF De- mode
LDO 2.5v_SDR
MCU
64M SDRAM
CVBS
RF
3.3v_AVCC
1.1V_VCCK
1.25v_AVDD
LVDS
1366X768 60hz
76M hz
24M hz
MT8223L
DC/DC DC/DC DC/DC
LDO
Adapter
BJT
12v_module
Burst up(22”) 24V
BLOCK DIAGRAM

- 19 - LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.
Only for training and service purposes
A2 A31
900
200
400
540
910
120
122
300
510
502 511
501
800
LV1
EXPLODED VIEW
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These
parts are identified by in the Schematic Diagram and EXPLODED VIEW.
It is essential that these special safety parts should be replaced with the same components as
recommended in this manual to prevent X-RADIATION, Shock, Fire, or other Hazards.
Do not modify the original design without permission of manufacturer.
IMPORTANT SAFETY NOTICE

APCPCWM_4828539:WP_GLOBAL_PFWP_GLOBAL_PF
APCPCWM_4828539:WP_GLOBAL_PFWP_GLOBAL_PF
Copyright © 2013 LG Electronics. Inc. All rights reserved.
Only for training and service purposes
LGE Internal Use Only