Internal Use Only
LED TV
SERVICE MANUAL
CHASSIS : LA75M
MODEL : 32LJ550B 32LJ550B-UA
CAUTION
BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
P/NO : MFL69920608 (1702-REV00)
CONTENTS
CONTENTS ............................................................................................... 2
SAFETY PRECAUTIONS ......................................................................... 3
SERVICING PRECAUTIONS .................................................................... 4
SPECIFICATION ........................................................................................ 6
SOFTWARE UPDATE ............................................................................... 8
BLOCK DIAGRAM .................................................................................... 9
EXPLODED VIEW ................................................................................... 11
DISASSEMBLY ..................................................................................
. 12
TROUBLE SHOOTING GUIDE ................................................ APPENDIX
Copyright © LG Electronics. Inc. All rights reserved. -2- LGE Internal Use Only
Only for training and service purposes
SAFETY PRECAUTIONS
IMPORTANT SAFETY NOTICE
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by in the
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 Leakage Current Hot Check (See below Figure)
Plug the AC cord directly into the AC outlet.
An isolation Transformer should always be used during the
servicing of a receiver whose chassis is not isolated from the AC Do not use a line Isolation Transformer during this check.
power line. Use a transformer of adequate power rating as this Connect 1.5 K / 10 watt resistor in parallel with a 0.15 uF capacitor
protects the technician from accidents resulting in personal injury between a known good earth ground (Water Pipe, Conduit, etc.)
from electrical shocks. and the exposed metallic parts.
Measure the AC voltage across the resistor using AC voltmeter
It will also protect the receiver and it's components from being with 1000 ohms/volt or more sensitivity.
damaged by accidental shorts of the circuitry that may be Reverse plug the AC cord into the AC outlet and repeat AC voltage
inadvertently introduced during the service operation. measurements for each exposed metallic part. Any voltage
measured must not exceed 0.75 volt RMS which is corresponds to
If any fuse (or Fusible Resistor) in this TV receiver is blown, 0.5 mA.
replace it with the specified. In case any measurement is out of the limits specified, there is
possibility of shock hazard and the set must be checked and
When replacing a high wattage resistor (Oxide Metal Film Resistor, repaired before it is returned to the customer.
over 1 W), keep the resistor 10 mm away from PCB.
Leakage Current Hot Check circuit
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.
Copyright © LG Electronics. Inc. All rights reserved. -3- LGE Internal Use Only
Only for training and service purposes
SERVICING PRECAUTIONS
CAUTION: Before servicing receivers covered by this service 2. After removing an electrical assembly equipped with ES
manual and its supplements and addenda, read and follow the devices, place the assembly on a conductive surface such as
SAFETY PRECAUTIONS on page 3 of this publication. aluminum foil, to prevent electrostatic charge buildup or expo-
NOTE: If unforeseen circumstances create conflict between the sure of the assembly.
following servicing precautions and any of the safety precautions 3. Use only a grounded-tip soldering iron to solder or unsolder ES
on page 3 of this publication, always follow the safety precautions. devices.
Remember: Safety First. 4. Use only an anti-static type solder removal device. Some solder
removal devices not classified as “anti-static” can generate
General Servicing Precautions electrical charges sufficient to damage ES devices.
1. Always unplug the receiver AC power cord from the AC power 5. Do not use freon-propelled chemicals. These can generate
source before; electrical charges sufficient to damage ES devices.
a. Removing or reinstalling any component, circuit board mod- 6. Do not remove a replacement ES device from its protective
ule or any other receiver assembly. package until immediately before you are ready to install it.
b. Disconnecting or reconnecting any receiver electrical plug or (Most replacement ES devices are packaged with leads electri-
other electrical connection. cally shorted together by conductive foam, aluminum foil or
c. Connecting a test substitute in parallel with an electrolytic comparable conductive material).
capacitor in the receiver. 7. Immediately before removing the protective material from the
CAUTION: A wrong part substitution or incorrect polarity leads of a replacement ES device, touch the protective material
installation of electrolytic capacitors may result in an explo- to the chassis or circuit assembly into which the device will be
sion hazard. installed.
2. Test high voltage only by measuring it with an appropriate CAUTION: Be sure no power is applied to the chassis or circuit,
high voltage meter or other voltage measuring device (DVM, and observe all other safety precautions.
FETVOM, etc) equipped with a suitable high voltage probe. 8. Minimize bodily motions when handling unpackaged replace-
Do not test high voltage by "drawing an arc". ment ES devices. (Otherwise harmless motion such as the
3. Do not spray chemicals on or near this receiver or any of its brushing together of your clothes fabric or the lifting of your
assemblies. foot from a carpeted floor can generate static electricity suf-
4. Unless specified otherwise in this service manual, clean ficient to damage an ES device.)
electrical contacts only by applying the following mixture to the
contacts with a pipe cleaner, cotton-tipped stick or comparable General Soldering Guidelines
non-abrasive applicator; 10 % (by volume) Acetone and 90 % 1. Use a grounded-tip, low-wattage soldering iron and appropriate
(by volume) isopropyl alcohol (90 % - 99 % strength) tip size and shape that will maintain tip temperature within the
CAUTION: This is a flammable mixture. range or 500 °F to 600 °F.
Unless specified otherwise in this service manual, lubrication of 2. Use an appropriate gauge of RMA resin-core solder composed
contacts in not required. of 60 parts tin/40 parts lead.
5. Do not defeat any plug/socket B+ voltage interlocks with which 3. Keep the soldering iron tip clean and well tinned.
receivers covered by this service manual might be equipped. 4. Thoroughly clean the surfaces to be soldered. Use a mall wire-
6. Do not apply AC power to this instrument and/or any of its bristle (0.5 inch, or 1.25 cm) brush with a metal handle.
electrical assemblies unless all solid-state device heat sinks are Do not use freon-propelled spray-on cleaners.
correctly installed. 5. Use the following unsoldering technique
7. Always connect the test receiver ground lead to the receiver a. Allow the soldering iron tip to reach normal temperature.
chassis ground before connecting the test receiver positive (500 °F to 600 °F)
lead. b. Heat the component lead until the solder melts.
Always remove the test receiver ground lead last. c. Quickly draw the melted solder with an anti-static, suction-
8. Use with this receiver only the test fixtures specified in this type solder removal device or with solder braid.
service manual. CAUTION: Work quickly to avoid overheating the circuit
CAUTION: Do not connect the test fixture ground strap to any board printed foil.
heat sink in this receiver. 6. Use the following soldering technique.
a. Allow the soldering iron tip to reach a normal temperature
Electrostatically Sensitive (ES) Devices (500 °F to 600 °F)
Some semiconductor (solid-state) devices can be damaged eas- b. First, hold the soldering iron tip and solder the strand against
ily by static electricity. Such components commonly are called the component lead until the solder melts.
Electrostatically Sensitive (ES) Devices. Examples of typical ES c. Quickly move the soldering iron tip to the junction of the
devices are integrated circuits and some field-effect transistors component lead and the printed circuit foil, and hold it there
and semiconductor “chip” components. The following techniques only until the solder flows onto and around both the compo-
should be used to help reduce the incidence of component dam- nent lead and the foil.
age caused by static by static electricity. CAUTION: Work quickly to avoid overheating the circuit
1. Immediately before handling any semiconductor component or board printed foil.
semiconductor-equipped assembly, drain off any electrostatic d. Closely inspect the solder area and remove any excess or
charge on your body by touching a known earth ground. Alter- splashed solder with a small wire-bristle brush.
natively, obtain and wear a commercially available discharging
wrist strap device, which should be removed to prevent poten-
tial shock reasons prior to applying power to the unit under test.
Copyright © LG Electronics. Inc. All rights reserved. -4- LGE Internal Use Only
Only for training and service purposes
IC Remove/Replacement 3. Solder the connections.
Some chassis circuit boards have slotted holes (oblong) through CAUTION: Maintain original spacing between the replaced
which the IC leads are inserted and then bent flat against the cir- component and adjacent components and the circuit board to
cuit foil. When holes are the slotted type, the following technique prevent excessive component temperatures.
should be used to remove and replace the IC. When working with
boards using the familiar round hole, use the standard technique Circuit Board Foil Repair
as outlined in paragraphs 5 and 6 above. Excessive heat applied to the copper foil of any printed circuit
board will weaken the adhesive that bonds the foil to the circuit
Removal board causing the foil to separate from or "lift-off" the board. The
1. Desolder and straighten each IC lead in one operation by following guidelines and procedures should be followed whenever
gently prying up on the lead with the soldering iron tip as the this condition is encountered.
solder melts.
2. Draw away the melted solder with an anti-static suction-type At IC Connections
solder removal device (or with solder braid) before removing To repair a defective copper pattern at IC connections use the
the IC. following procedure to install a jumper wire on the copper pattern
Replacement side of the circuit board. (Use this technique only on IC connec-
1. Carefully insert the replacement IC in the circuit board. tions).
2. Carefully bend each IC lead against the circuit foil pad and
solder it. 1. Carefully remove the damaged copper pattern with a sharp
3. Clean the soldered areas with a small wire-bristle brush. knife. (Remove only as much copper as absolutely necessary).
(It is not necessary to reapply acrylic coating to the areas). 2. carefully scratch away the solder resist and acrylic coating (if
used) from the end of the remaining copper pattern.
"Small-Signal" Discrete Transistor 3. Bend a small "U" in one end of a small gauge jumper wire and
Removal/Replacement carefully crimp it around the IC pin. Solder the IC connection.
1. Remove the defective transistor by clipping its leads as close 4. Route the jumper wire along the path of the out-away copper
as possible to the component body. pattern and let it overlap the previously scraped end of the
2. Bend into a "U" shape the end of each of three leads remaining good copper pattern. Solder the overlapped area and clip off
on the circuit board. any excess jumper wire.
3. Bend into a "U" shape the replacement transistor leads.
4. Connect the replacement transistor leads to the corresponding At Other Connections
leads extending from the circuit board and crimp the "U" with Use the following technique to repair the defective copper pattern
long nose pliers to insure metal to metal contact then solder at connections other than IC Pins. This technique involves the
each connection. installation of a jumper wire on the component side of the circuit
board.
Power Output, Transistor Device
Removal/Replacement 1. Remove the defective copper pattern with a sharp knife.
1. Heat and remove all solder from around the transistor leads. Remove at least 1/4 inch of copper, to ensure that a hazardous
2. Remove the heat sink mounting screw (if so equipped). condition will not exist if the jumper wire opens.
3. Carefully remove the transistor from the heat sink of the circuit 2. Trace along the copper pattern from both sides of the pattern
board. break and locate the nearest component that is directly con-
4. Insert new transistor in the circuit board. nected to the affected copper pattern.
5. Solder each transistor lead, and clip off excess lead. 3. Connect insulated 20-gauge jumper wire from the lead of the
6. Replace heat sink. nearest component on one side of the pattern break to the lead
of the nearest component on the other side.
Diode Removal/Replacement Carefully crimp and solder the connections.
1. Remove defective diode by clipping its leads as close as pos- CAUTION: Be sure the insulated jumper wire is dressed so the
sible to diode body. it does not touch components or sharp edges.
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.
Copyright © LG Electronics. Inc. All rights reserved. -5- LGE Internal Use Only
Only for training and service purposes
SPECIFICATION
NOTE : Specifications and others are subject to change without notice for improvement.
1. Application range 3. Test method
This specification is applied to the LED TV used LA75M (1) Performance: LGE TV test method followed
chassis. (2) Demanded other specification
- Safety : CE, IEC specification
- EMC : CE, IEC
2. Test condition
Each part is tested as below without special appointment.
(1) Temperature: 25 °C ± 5 °C, CST: 40 °C ± 2 °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.
4. General Specification
No Item Specification Remark
1 Receiving system ATSC / NTSC-M, 64 & 256 QAM
2 Available Channel VHF : 02~13
UHF : 14~69
DTV : 02-69
CATV : 01~135
CADTV : 01~135
3 Input Voltage AC 100 ~ 240V@ 50/60Hz AC 120V, 50/60Hz on the label (USA)
4 Market North America
5 Aspect Ratio 16:9
6 Tuning System FS Rear gender(1EA)
7 Operating Environment Temp : 0 ~ 40 deg
Humidity : ~ 80 %
8 Storage Environment Temp. : -20 ~ 60 deg
Humidity : ~ 85%
Copyright © LG Electronics. Inc. All rights reserved. -6- LGE Internal Use Only
Only for training and service purposes
5. External Input Support Format
5.1. Component 2D input(Y, CB/PB)
No. Resolution H-freq(kHz) V-freq.(kHz) Pixel clock(MHz) Proposed
1 720*480 15.73 59.94 13.50 SDTV ,DVD 480I
2 720*480 15.75 60.00 13.5135 SDTV ,DVD 480I
3 720*480 31.47 59.94 27.00 SDTV 480P
4 720*480 31.50 60.00 27.027 SDTV 480P
5 1280*720 44.96 59.94 74.176 HDTV 720P
6 1280*720 45.00 60.00 74.25 HDTV 720P
7 1920*1080 33.72 59.94 74.176 HDTV 1080I
8 1920*1080 33.75 60.00 74.25 HDTV 1080I
9 1920*1080 67.432 59.94 148.352 HDTV 1080P
10 1920*1080 67.50 60.00 148.50 HDTV 1080P
5.2. HDMI Input (PC/DTV)
No. Resolution H-freq(kHz) V-freq.(kHz) Pixel clock(MHz) Proposed Remark
HDMI-PC DDC
1 640*350 @70Hz 31.46 70.09 25.17 EGA X
2 720*400 @70Hz 31.46 70.08 28.32 DOS O
3 640*480 @60Hz 31.46 59.94 25.17 VESA(VGA) O
4 800*600 @60Hz 37.87 60.31 40.00 VESA(SVGA) O
5 1024*768 @60Hz 48.36 60.00 65.00 VESA(XGA) O
6 1152*864 @60Hz 54.34 60.05 80.002 VESA O
7 1280*1024 @60Hz 63.98 60.02 108.0 VESA (SXGA) O FHD only
8 1360*768 @60Hz 47.71 60.01 85.50 VESA (WXGA) O
9 1920*1080 @60Hz 67.5 60.00 148.5 WUXGA(CEA 861D) O FHD only
No. Resolution H-freq(kHz) V-freq.(kHz) Pixel clock(MHz) Proposed
DTV
1 640*480 31.46 59.94 25.125 SDTV 480P
2 640*480 31.50 60.00 25.125 SDTV 480P
5 720*480 31.47 59.94 27.00 SDTV 480P
6 720*480 31.50 60.00 27.027 SDTV 480P
7 1280*720 44.96 59.94 74.176 HDTV 720P
8 1280*720 45.00 60.00 74.25 HDTV 720P
9 1920*1080 33.72 59.94 74.176 HDTV 1080I
10 1920*1080 33.75 60.00 74.25 HDTV 1080I
11 1920*1080 26.97 23.97 74.176 HDTV 1080P
12 1920*1080 27.00 24.00 74.25 HDTV 1080P
13 1920*1080 33.71 29.97 74.176 HDTV 1080P
14 1920*1080 33.75 30.00 74.25 HDTV 1080P
15 1920*1080 67.43 59.94 148.352 HDTV 1080P
16 1920*1080 67.50 60.00 148.50 HDTV 1080P
Copyright © LG Electronics. Inc. All rights reserved. -7- LGE Internal Use Only
Only for training and service purposes
SOFTWARE UPDATE
1. USB 2. NSU
(1) Insert the USB memory Stick to the USB port (This Function is needed to connect to the internet)
(2) Automatically detect the SW Version and show the below
message (1) Menu -> All Settings -> General -> About This TV
(3) Click [YES]: initiate the download and install of the update.
(2) C lick [CHEK FOR UPDATES] : system check newest
version
(4) C lick [Check Now]: move to “About This TV” page for
update
(5) TV is updating
(3) Click [DOWNLOAD AND INSTALL]
(4) TV is updating
(6) After finished the update, below Pop-up appear
(5) After finished the update, below Pop-up appear
(7) Click [Yes] : TV will be DC OFF -> ON
(8) After TV turned on, Check the updated SW Version and
Tool Option
(6) Turn OFF the TV and On. Check the updated SW Version
and Tool Option
Copyright © LG Electronics. Inc. All rights reserved. -8- LGE Internal Use Only
Only for training and service purposes
X_TAL
Copyright ©
24MHz
DDR3 2133 4Gb x16
1866
DDR3 2133 4Gb x16
DIF (+/-)
Digital Demod
Only for training and service purposes
REAR
Analog Demod
CVBS/SIF I2C EEPROM (256Kb)
OCP eMMC 5.0 (4GB)
USB1
1.5A USB
USB2 OCP
LG Electronics. Inc. All rights reserved.
SIDE 1.5A 51P(FHD)
LVDS
HDMI1 IC101 30P(HD)
(ARC)
HDMI I2S Audio AMP
HDMI2
-9-
MUX
M2R I2C (DTA-2010)
HDMI3
USB_WIFI WIFI Only
BLOCK DIAGRAM
REAR
AV/COMP CVBS/YPbPr SUB
ASSY
IR / KEY
OPTIC SPDIF OUT IR
LAN ETHERNET I2C
KEY
Sub Micom
I2C (R5F100GEAFB)
X_TAL
32.768kHz
LGE Internal Use Only
2.Power Block Diagram
Copyright © LG Electronics. Inc. All rights reserved. - 10 - LGE Internal Use Only
Only for training and service purposes
EXPLODED VIEW
IMPORTANT SAFETY NOTICE
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These
parts are identified by in the 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.
400
521
540
901
530
500
951
571
LV1
120
902
131
570
700
132
200
A10
ARC1
952
AR1
Copyright © LG Electronics. Inc. All rights reserved. - 11 - LGE Internal Use Only
Only for training and service purposes
DISASSEMBLY
Copyright © LG Electronics. Inc. All rights reserved. - 12 - LGE Internal Use Only
Only for training and service purposes
Copyright © LG Electronics. Inc. All rights reserved. - 13 - LGE Internal Use Only
Only for training and service purposes
TROUBLE SHOOTING GUIDE
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Contents of Standard Repair Process
No. Error symptom (High category) Error symptom (Mid category) Page Remarks
1 No video/Normal audio 1
2 No video/No audio 2
3 A. Video error Picture broken/ Freezing 3
4 Color error 4
Vertical/Horizontal bar, residual image,
5 5
light spot, external device color error
6 No power 6
B. Power error Off when on, off while viewing, power
7 7
auto on/off
8 No audio/Normal video 8
C. Audio error
9 Wrecked audio/discontinuation/noise 9
10 Remote control & Local switch checking 10
11 MR15 operating checking 11
12 D. Function error Wifi operating checking 12
13 Camera operating checking 13
14 External device recognition error 14
15 E. Noise Circuit noise, mechanical noise 15
16 F. Exterior error Exterior defect 16
First of all, Check whether there is SVC Bulletin in GSCS System for these model.
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Standard Repair Process
Established
Error A. Video error date
symptom
No video/ Normal audio Revised date 1/16
First of all, Check whether all of cables between board is inserted properly or not.
(Main B/D↔ Power B/D, LVDS Cable, Speaker Cable, IR B/D Cable,,,)
☞A1 ☞A18
No video Normal Y Check Back Light Y Check Power Normal Y
On Replace T-con/Main
Normal audio audio On with naked eye Board 13V etc. voltage Board or module
N
N N
Move to No
☞A18 Check Power Board 13V output Repair Power
video/No audio Board or parts
Replace Inverter
Normal Y
or module
voltage
End
N
Repair Power
Board or parts
※Precaution ☞A4 & A2
Always check & record S/W Version and White
Replace Main Board Re-enter White Balance value
Balance value before replacing the Main Board
1
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Standard Repair Process
Established
Error A. Video error date
symptom
No video/ No audio Revised date 2/16
☞A18
Check various Y Check and
Normal
No Video/ voltages of Power replace
voltage?
No audio Board (13V…) MAIN B/D
N End
Replace Power
Board and repair
parts
2
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Standard Repair Process
Established
Error A. Video error date
symptom
Picture broken/ Freezing Revised date 3/16
. By using Digital signal level meter
☞ A3
. By using Diagnostics menu on OSD
Check RF Signal level ( Setting→ Channels→ Channel Tuning→ Manual Tuning → Check the Signal )
- Signal strength (Normal : over 50%)
- Signal Quality (Normal: over 50%)
Y Check whether other equipments have problem or not.
Normal
(By connecting RF Cable at other equipment)
Signal?
→ DVD Player ,Set-Top-Box, Different maker TV etc
N
☞ A4
Check RF Cable
Normal Y Check SVC N Check Y
Connection Close
1. Reconnection Picture? S/W Version Bulletin? Tuner soldering
N
Y
N
S/W Upgrade
N Contact with signal distributor
Normal
Picture? or broadcaster (Cable or Air)
Normal N
Y Picture? Replace
Main B/D
Y
Close
Close
3
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Standard Repair Process
Established
Error A. Video error date
symptom
Color error Revised date 4/16
☞A6 ☞ A7
※ Check
Check color by input
and replace
-External Input Y Y Y
Color Link Cable Color Color
-COMPONENT Replace Main B/D Replace module
error? (LVDS) and error? error?
-AV
contact
-HDMI N N N
condition
Check error End
color input
mode
☞A8 Check
External Input/ External device Y
external
Check Test pattern Component /Cable Replace Main/T-con B/D
device and
error normal
cable
N
Request repair
for external
device/cable
N
Check external External device Y
HDMI device and /Cable Replace Main/T-con B/D
error cable normal
4
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Standard Repair Process
A. Video error Established
Error date
symptom Vertical / Horizontal bar, residual image,
light spot, external device color error Revised date 5/16
Vertical/Horizontal bar, residual image, light spot Replace
Module
☞A6
☞ A7 N
Check color condition by input Check external
Check and
-External Input Screen Y device Y Screen N Screen
-Component Normal? replace Link Replace Main/T-con B/D
normal? connection normal? normal?
-HDMI Cable
condition For LGD panel
N N Y
Y
Replace Main B/D
Replace Request repair End End
for external
☞A8 module
device
Check Test pattern
For other panel
External device screen error-Color error
Check screen
condition by input
-External Input External
Check S/W Version Check N
-Component Input Connect other external
version
-HDMI/DVI error device and cable Screen N Replace
(Check normal operation of normal? Main/T-con
Y External Input, Component, B/D
Component RGB and HDMI/DVI by
error Y
S/W Upgrade connecting Jig, pattern
Generator ,Set-top Box etc.
Request repair for
external device
Y
Connect other external
Normal N HDMI/
device and cable N
screen? DVI Screen Replace
(Check normal operation of
External Input, Component, normal? Main /T-con
Y RGB and HDMI/DVI by B/D
connecting Jig, pattern
Generator ,Set-top Box etc.
End
5
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Standard Repair Process
Established
Error B. Power error date
symptom
No power Revised date 6/16
☞A17 ☞A18
DC Power on Replace
Check Power LED Y Normal N Check Power Y
by pressing Power Key OK? Power
Logo LED On? operation? On ‘”High”
On Remote control B/D
. Stand-By: Red or Turn On
N Y
. Operating: Turn Off
Check Power cord Replace Main B/D
was inserted properly
☞A18
N Measure voltage of each output of Power B/D
Normal?
Y
Y Y
※ Normal
voltage?
Replace Main B/D
Close Normal
Check ST-BY 7.8V
Y
voltage? N
☞A18 Replace Power B/D
N
Replace Power
B/D
6
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Standard Repair Process
Established
Error B. Power error date
symptom
Off when on, off while viewing, power auto on/off Revised date 7/16
☞A19
N Y
Check A/C cord Error? Check Power Off CPU Normal? End
Replace Main B/D
Mode Abnormal
N
Y Abnormal Replace Power B/D
1
Fix A/C cord ☞A18
(If Power Off mode
is not displayed) Normal Y
Replace Main B/D
Check Power B/D voltage?
voltage
N
※ Caution
Check and fix exterior Replace Power B/D
of Power B/D Part
* Please refer to the all cases which Status Power off List Explanation
"POWEROFF_REMOTEKEY" Power off by REMOTE CONTROL
can be displayed on power off mode.
"POWEROFF_OFFTIMER" Power off by OFF TIMER
"POWEROFF_SLEEPTIMER" Power off by SLEEP TIMER
"POWEROFF_INSTOP" Power off by INSTOP KEY
"POWEROFF_AUTOOFF" Power off by AUTO OFF
Normal "POWEROFF_ONTIMER" Power off by ON TIMER
"POWEROFF_RS232C" Power off by RS232C
"POWEROFF_RESREC" Power off by Reservated Record
"POWEROFF_RECEND" Power off by End of Recording
"POWEROFF_SWDOWN" Power off by S/W Download
"POWEROFF_UNKNOWN" Power off by unknown status except listed case
"POWEROFF_ABNORMAL1" Power off by abnormal status except CPU trouble
Abnormal
"POWEROFF_CPUABNORMAL" Power off by CPU Abnormal
7
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Standard Repair Process
Established
Error C. Audio error date
symptom
No audio/ Normal video Revised date 8/16
☞A20 ☞A21+A18
Check user N Check Main B+ Y
No audio Normal
menu > Off 13V of Power
Screen normal voltage
Speaker off Board
Y N
Cancel OFF Replace Power Board and repair parts
Check N
Disconnection Replace MAIN Board End
Speaker
disconnection
Y
Replace Speaker
8
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Only for training and service purposes
Standard Repair Process
Established
Error C. Audio error date
symptom
Wrecked audio/ discontinuation/noise Revised date 9/16
→ abnormal audio/discontinuation/noise is same after “Check input signal” compared to No audio
Wrecked audio/
☞A21+A18
Check and replace
Discontinuation/ Check audio
speaker and
Noise for B+ Voltage (13V)
connector
Check input all audio
signal Y Y
Signal
-RF
normal? Wrecked audio/
-External Input Normal
signal Discontinuation/
N Replace Main B/D voltage?
Noise only
for D-TV
N
Wrecked audio/
Discontinuation/
Replace Power B/D
Noise only
for Analog
(When RF signal is not
received)
Request repair to external Wrecked audio/ Replace Main B/D End
cable/ANT provider Discontinuation/
Noise only
for External Input
(In case of N
External Input Connect and check Normal
signal error) other external audio?
Check and fix device
external device Y
Check and fix external device
9
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Only for training and service purposes
Standard Repair Process
D. Function error Established
Error date
symptom
Remote control & Local switch checking Revised date 10/16
1. Remote control(R/C) operating error Replace
Main B/D
☞A22 ☞A22 ☞A22
Check & Repair N Y Y
Check R/C itself Normal Y Normal Check B+ 13V Normal Check IR Normal
operating? Cable connection operating? Voltage? Signal?
Operation On Main B/D Output signal
Connector solder
N
Y N N
☞A18
Check R/C Operating Check & Replace Close Check 13v on Power B/D Repair/Replace
When turn off light Baterry of R/C Replace Power B/D or IR B/D
in room Replace Main B/D
(Power B/D don’t have problem)
If R/C operate, Normal Y
operating? Close
Explain the customer
cause is interference
from light in room. N
Replace R/C
10
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Standard Repair Process
D. Function error Established
Error date
symptom
Wifi operating checking Revised date 12/16
3.Wifi operating error
☞A4 ☞A24
Check the Wi-Fi Mac value N Check the Wifi wafer Normal N Replace
INSTART menu is “NG”? Voltage?
1pin Main B/D
Y
☞A24 Y
Check & Repair Close
Wifi cable
connection
☞A4
Wi-Fi Mac value N
is “NG”? Close
Y
Change the Wifi
assy
12
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Only for training and service purposes
Standard Repair Process
Established
Error D. Function error date
symptom
External device recognition error Revised date 14/16
Y Check technical
Check External Input and
Signal information Technical N
input Component Replace Main B/D
input? - Fix information information?
Recognition error
signal
- S/W Version
N Y
HDMI/
Check and fix DVI, Optical
Fix in Replace Main B/D
external device/cable Recognition error
accordance
with technical
information
14
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Only for training and service purposes
Standard Repair Process
Established
Error E. Noise date
symptom
Circuit noise, mechanical noise Revised date 15/16
Identify Check
Circuit
nose location of Replace PSU
noise
type noise
Mechanical Check location of
noise noise
※ Mechanical noise is a natural ※ When the nose is severe, replace the module
phenomenon, and apply the 1st level (For models with fix information, upgrade the
description. When the customer does not S/W or provide the description)
agree, apply the process by stage. OR
※ Describe the basis of the description ※ If there is a “Tak Tak” noise from the
in “Part related to nose” in the Owner’s cabinet, refer to the KMS fix information and
Manual. then proceed as shown in the solution manual
(For models without any fix information,
provide the description)
15
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Only for training and service purposes
Standard Repair Process
Established
Error F. Exterior defect date
symptom
Exterior defect Revised date 16/16
Zoom part with Module
Replace module
exterior damage damage
Cabinet
Replace cabinet
damage
Remote
control Replace remote control
damage
Stand
Replace stand
dent
16
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Contents of Standard Repair Process Detail Technical Manual
No. Error symptom Content Page Remarks
1 A. Video error_ No video/Normal Check LCD back light with naked eye A1
2 audio Check White Balance value A2
TUNER input signal strength checking
4 A3
method
A. Video error_ video error /Video
5 lag/stop Version checking method A4
6 Tuner Checking Part A5
A. Video error _Vertical/Horizontal bar,
7 Connection diagram A6
residual image, light spot
Check Link Cable (EPI) reconnection
8 A7
A. Video error_ Color error condition
9 Adjustment Test pattern - ADJ Key A8
10 Exchange Main Board (1) A-1/5
11 Exchange Main Board (2) A-2/5
12 Defected Type caused by T-Con/ Exchange Power Board (PSU) A-3/5
Inverter/ Module
13 Exchange Module (1) A-4/5
14 Exchange Module (2) A-5/5
Continue to the next page
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Only for training and service purposes
Contents of Standard Repair Process Detail Technical Manual
Continued from previous page
No. Error symptom Content Page Remarks
16 Check front display LED A17
B. Power error_ No power
17 Check power input Voltage & ST-BY 3.5V A18
B. Power error_Off when on, off
18 POWER OFF MODE checking method A19
while viewing
Checking method in menu when there is
19 A20
C. Audio error_ No audio/Normal no audio
video Voltage and speaker checking method
20 A21
when there is no audio
Remote control operation checking
21 A22
method
Motion Remote operation checking
22 D. Function error A23
method
23 Wifi operation checking method A24
24 Camera operation checking method A25 Not Used
25 E. Etc Tool option changing method A26
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Standard Repair Process Detail Technical Manual
Error Established
symptom A. Video error_No video/Normal audio date
Revised
Content Check LCD back light with naked eye A1
date
<32LJ550B-UA>
After turning on the power and disassembling the case, check with the naked eye,
whether you can see light from locations.
A1
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Standard Repair Process Detail Technical Manual
Error Established
symptom A. Video error_No video/Normal audio date
Revised
Content Check White Balance value A2
date
Entry
Entrymethod
method
1.1.Press
Pressthe
theADJ
ADJbutton
buttonononthe
theremote
remotecontrol
controlforforadjustment.
adjustment.
2.2.Enter
Enterinto
intoWhite
WhiteBalance
Balanceofofitem
item6.10.
3.3.After
Afterrecording
recordingthe
theR,R,G,G,B B(GAIN,
(GAIN,Cut)
Cut)value
valueofofColor
ColorTemp
Temp
(Cool/Medium/Warm),
(Cool/Medium/Warm),re-enterre-enterthe
thevalue
valueafter
afterreplacing
replacingthe
theMAIN
MAINBOARD.
BOARD.
A2
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Standard Repair Process Detail Technical Manual
Error Established
symptom A. Video error_Video error, video lag/stop date
TUNER input signal strength checking method Revised
Content date A3
All Setting Channels Channel Tuning
Manual Tuning
When the signal is strong,
use the attenuator (-10dB, -
15dB, -20dB etc.)
A3
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Standard Repair Process Detail Technical Manual
Error Established
symptom A. Video error_Video error, video lag/stop date
Version checking method Revised
Content date A4
1. Checking method for remote control for adjustment
Version
Press the IN-START with the remote
control for adjustment
A4
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Standard Repair Process Detail Technical Manual
Error Established
symptom
A. Video error_Video error, video lag/stop
date
Revised
Content TUNER checking part A5
date
Checking method:
1. Check the signal strength or check whether the screen is normal when the external device is connected.
2. After measuring each voltage from power supply, finally replace the MAIN BOARD.
A5
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Standard Repair Process Detail Technical Manual
Error A. Video error _Vertical/Horizontal bar, Established
symptom residual image, light spot date
Revised
Content Connection diagram (1) date A6
As the part connecting to the external input, check
the screen condition by signal
A6
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Only for training and service purposes
Standard Repair Process Detail Technical Manual
Error Established
symptom A. Video error_Color error date
Revised
Content Check Link Cable(VX1) reconnection condition date A7
Check the contact condition of the Link Cable, especially dust or mis insertion.
A7
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Only for training and service purposes
Standard Repair Process Detail Technical Manual
Error Established
symptom
A. Video error_Color error
date
Adjustment Test pattern - ADJ Key Revised
Content date A8
You can view 6 types of patterns using the ADJ Key
Checking item : 1. Defective pixel 2. Residual image 3. MODULE error (ADD-BAR,SCAN BAR..)
4.Video error (Classification of MODULE or Main-B/D!)
A8
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Appendix : Exchange Main Board (1)
Solder defect, CNT Broken Solder defect, CNT Broken Solder defect, CNT Broken
Solder defect, CNT Broken T-Con
T-Con Defect,
Defect,
Solder
T-Con CNT
CNT
defect,CNT
Defect, Broken
Broken
CNTBroken
Broken Abnormal Power Section
Solder defect, Short/Crack Abnormal Power Section Solder defect, Short/Crack
A - 1/5
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Appendix : Exchange Main Board (2)
Abnormal Power Section Abnormal Power Section Solder defect, Short/Crack
Solder defect, Short/Crack Fuse Open, Abnormal power section Abnormal Display
GRADATION Noise GRADATION
A - 2/5
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Appendix : Exchange Power Board (PSU)
No Light Dim Light
Dim Light Dim Light
No picture/Sound Ok
A - 3/5
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Appendix : Exchange the Module (1)
Press damage Press damage Press damage
Un-repairable Cases
In this case please exchange the module.
Crosstalk Crosstalk
A - 4/5
Copyright © 2017 LG Electronics Inc. All rights reserved. LGE Internal Use Only
Only for training and service purposes
Appendix : Exchange the Module (2)
Vertical Block Vertical Line Vertical Block
Source TAB IC Defect Source TAB IC Defect Source TAB IC Defect
Horizontal
TAB ICBlock
Horizontal Block Horizontal line
Gate Defect Gate TAB IC Defect
Gate TAB IC Defect Gate TAB IC Defect Gate TAB IC Defect
Un-repairable Cases
In this case please exchange the module.
Horizontal Block
Gate TAB IC Defect
Gate TAB IC Defect
A - 5/5
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Only for training and service purposes
Standard Repair Process Detail Technical Manual
Error Established
symptom B. Power error _No power date
Revised
Content Check front Power Indicator date A17
ST-BY condition: On or Off
Power ON condition: Turn Off
A17
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Only for training and service purposes
Standard Repair Process Detail Technical Manual
Error Established
symptom
B. Power error _No power
date
Revised
Content Check power input voltage and ST-BY 3.5V A18
date
Check the DC 13.2V.
A18
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Only for training and service purposes
Standard Repair Process Detail Technical Manual
Error
symptom B. Power error _Off when on, off whiling viewing Established
date
Revised
Content POWER OFF MODE checking method date A19
Entry method
1. Press the IN-START button of the remote
control for adjustment
2. Check the entry into adjustment item 3
A19
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Only for training and service purposes
Standard Repair Process Detail Technical Manual
Error Established
symptom C. Audio error_No audio/Normal video
date
Revised
Content Checking method in menu when there is no audio date A20
Checking method
1. Press the Setting button on the remote control
2. Select the Sound function of the Menu
3. Select the Sound Out
4. Select TV Speaker
A20
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Only for training and service purposes
Standard Repair Process Detail Technical Manual
Error Established
symptom C. Audio error_No audio/Normal video date
Voltage and speaker checking method Revised
Content date A21
when there is no audio
<32LJ550B-UA>
1 SPK_R-
2 SPK_R+
3 SPK_L-
4 SPK_L+
Checking order when there is no audio
1.Check the contact condition of or 13.2V connector of Main Board
2. Measure the 13.2V input voltage supplied from Power Board
(If there is no input voltage, remove and check the connector)
3.Connect the tester RX1 to the speaker terminal and if you hear the Chik Chik sound when you touch the
GND and output terminal, the speaker is normal.
A21
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Only for training and service purposes
Standard Repair Process Detail Technical Manual
Error Established
symptom D. Function error date
Revised
Content Remote control operation checking method date A22
< 32LJ550B-UA> P4001
1 +3.4V_WIFI
①
2 WIFI_DM
3 WIFI_DP
4 GND
5 WOL/WIFI_POWER_ON
6 +3.4V_WIFI
7 NC
8 GND
9 NC
10 NC
11 GND
12 GND
13 NC
14 NC
15 NC
16 I2C_SDA_EYE
17 I2C_SCL_EYE
② 18 GND
19 IR
20 LED_R
21 GND
Checking order to check remote control ③ 22 +3.4V_ST
23 KEY2
Checking order 24 KEY1
25 GND
1.Check IR cable condition between IR & Main board.( Check picture number① and ②)
2.Check the standby 3.5V on the terminal 22 pin (③)
3.AS checking the Pre-Amp(IR LED light) , the power is in ON condition, an Analog Tester
needle should move slowly, otherwise, it’s defective.
A22
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Standard Repair Process Detail Technical Manual
Error Established
symptom D. Function error date
Revised
Content Remote control operation checking method date A22
< 32LJ550B-UA> : WiFi AC only P4001
1 +3.4V_WIFI
① Wifi Assy Front 2 WIFI_DM
3 WIFI_DP
4 GND
5 WOL/WIFI_POWER_ON
6 +3.4V_WIFI
7 NC
8 GND
9 NC
10 NC
11 GND
② Wifi Assy Rear 12 GND
13 NC
14 NC
15 NC
16 I2C_SDA_EYE
17 I2C_SCL_EYE
③ 18 GND
19 IR
20 LED_R
② 21 GND
22 +3.4V_ST
Checking order to check WiFi 23 KEY2
24 KEY1
Checking order 25 GND
1.Check IR/Wifi cable condition between Wifi assy & Main board.
2.Check the 3.5V on the terminal
A23/A24
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Only for training and service purposes
