LED TV
SERVICE MANUAL
CHASSIS : UAX3E
MODEL : 55UN7300PUC/UF
MODEL : 55UN7300AUD
MODEL : 55UN7300PUB
CAUTION
BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
P/NO : MFL71703804 (2002-REV01)
Any reproduction, duplication, distribution (including by way of email, facsimile or other electronic means),
publication, modification, copying or transmission of this Service Manual is STRICTLY PROHIBITED unless you
have obtained the prior written consent of the LG Electronics entity from which you received this Service Manual.
The material covered by this prohibition includes, without limitation, any text, graphics or logos in this Service
Manual.
Copyright © 2020 LG Electronics Inc. All rights reserved. Only training and service purposes.
CONTENTS
CONTENTS ............................................................................................... 2
SAFETY PRECAUTIONS ......................................................................... 3
SERVICING PRECAUTIONS .................................................................... 4
SPECIFICATION ........................................................................................ 6
SOFTWARE UPDATE .............................................................................. 9
BLOCK DIAGRAM .................................................................................. 10
EXPLODED VIEW ................................................................................... 11
ASSEMBLY / DISASSEMBLY GUIDE .................................................... 13
TROUBLE SHOOTING GUIDE ................................................. APPENDIX
-2- Copyright © LG Electronics Inc. All rights reserved.
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.
-3- Copyright © LG Electronics Inc. All rights reserved.
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.
-4- Copyright © LG Electronics Inc. All rights reserved.
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.
-5- Copyright © LG Electronics Inc. All rights reserved.
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 UAX3E (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 Market North America
2 Broadcasting system ATSC / NTSC-M, 64 & 256 QAM
3 Available Channel VHF : 02~13
UHF : 14~69
DTV : 02-69
CATV : 01~135
CADTV : 01~135
4 Receiving system Digital : ATSC, 64 & 256 QAM
Analog : NTSC-M
5 Video Input NTSC-M Rear (1EA)
6 HDMI Input UHD HDMI 1 PC / DTV format Side, Support 6Gbps
HDMI 2 PC / DTV format Side, Support 6Gbps, Support ARC
HDMI 3 PC / DTV format Rear, Support 6Gbps
HDMI 4 PC / DTV format Rear, Support 6Gbps
7 Audio Input AV Audio / DVI Audio AV and DVI use same jack ;
8 SPDIF out Optical Audio out Rear (1EA),
9 HeadPhone HeadPhone out
10 USB Input EMF, DivX HD, For SVC (download) JPEG, MP3, DivX HD
-6- Copyright © LG Electronics Inc. All rights reserved.
Only for training and service purposes.
5. External Input Support Format
5.1. HDMI Input (PC/DTV)
No. Resolution H-freq(kHz) V-freq.(kHz) Pixel clock(MHz) Proposed Remarks
HDMI-PC
1 640*350 31.46 70.09 25.17 EGA
2 720*400 31.46 70.08 28.32 DOS
3 640*480 31.46 59.94 25.17 VESA(VGA)
4 800*600 37.87 60.31 40 VESA(SVGA)
5 1024*768 48.36 60 65 VESA(XGA)
6 1360*768 47.71 60.01 84.75 VESA(WXGA)
7 1152*864 54.34 60.05 80 VESA
8 1280*1024 63.98 60.02 109 SXGA Support to HDMI-PC
9 1920*1080 67.5 60 158.4 WUXGA(Reduced
Blanking)
10 1920*1080 134.86 119.88 296.7 UDTV 2160P Not Support for FHD.
11 1920*1080 135 120 297 UDTV 2160P Not Support for FHD.
12 3840*2160 53.95 23.98 296.7 UDTV 2160P Not Support for FHD.
13 3840*2160 54 24 297 UDTV 2160P Not Support for FHD.
14 3840*2160 56.25 25 297 UDTV 2160P Not Support for FHD.
15 3840*2160 61.43 29.97 296.7 UDTV 2160P Not Support for FHD.
16 3840*2160 67.5 30 297 UDTV 2160P Not Support for FHD.
17 3840*2160 112.5 50 594 UDTV 2160P Not Support for FHD.
18 3840*2160 134.86 59.94 593.4 UDTV 2160P Not Support for FHD.
19 3840*2160 135 60 594 UDTV 2160P Not Support for FHD.
20 4096*2160 53.95 23.98 296.7 UDTV 2160P Not Support for FHD.
21 4096*2160 54 24 297 UDTV 2160P Not Support for FHD.
22 4096*2160 56.25 25 297 UDTV 2160P Not Support for FHD.
23 4096*2160 61.43 29.97 296.7 UDTV 2160P Not Support for FHD.
24 4096*2160 67.5 30 297 UDTV 2160P Not Support for FHD.
25 4096*2160 112.5 50 594 UDTV 2160P Not Support for FHD.
26 4096*2160 134.86 59.94 593.4 UDTV 2160P Not Support for FHD.
27 4096*2160 135 60 594 UDTV 2160P Not Support for FHD.
28 2560*1440 88.78 59.95 241.5 3K (UHD 60Hz models only),
Support only when UHD
DeepColor is On
29 2560*1440 182.99 119.99 497.7 3K (UHD, 8K 120Hz models
only), Support only when
UHD DeepColor is On
No. Resolution H-freq(kHz) V-freq.(kHz) Pixel clock(MHz) Proposed Remarks
HDMI-DTV
1 640*480 31.46 59.94 25.12 SDTV 480P
2 640*480 31.5 60 25.12 SDTV 480P
3 720*480 31.47 59.94 27 SDTV 480P
4 720*480 31.5 60 27.02 SDTV 480P
5 720*576 31.25 50 27 SDTV 576P
6 1280*720 44.96 59.94 74.17 HDTV 720P
-7- Copyright © LG Electronics Inc. All rights reserved.
Only for training and service purposes.
No. Resolution H-freq(kHz) V-freq.(kHz) Pixel clock(MHz) Proposed Remarks
7 1280*720 45 60 74.25 HDTV 720P
8 1280*720 37.5 50 74.25 HDTV 720P
9 1920*1080 28.12 50 74.25 HDTV 1080I
10 1920*1080 33.72 59.94 74.17 HDTV 1080I
11 1920*1080 33.75 60 74.25 HDTV 1080I
12 1920*1080 26.97 23.97 63.29 HDTV 1080P
13 1920*1080 27 24 63.36 HDTV 1080P
14 1920*1080 33.71 29.97 79.12 HDTV 1080P
15 1920*1080 33.75 30 79.2 HDTV 1080P
16 1920*1080 56.25 50 148.5 HDTV 1080P
17 1920*1080 67.43 59.94 148.35 HDTV 1080P
18 1920*1080 67.5 60 148.5 HDTV 1080P
19 1920*1080 112.5 100 297 UDTV 2160P Not Support for FHD.
20 1920*1080 134.86 119.88 296.7 UDTV 2160P Not Support for FHD.
21 1920*1080 135 120 297 UDTV 2160P Not Support for FHD.
22 3840*2160 53.95 23.98 296.7 UDTV 2160P Not Support for FHD.
23 3840*2160 54 24 297 UDTV 2160P Not Support for FHD.
24 3840*2160 56.25 25 297 UDTV 2160P Not Support for FHD.
25 3840*2160 61.43 29.97 296.7 UDTV 2160P Not Support for FHD.
26 3840*2160 67.5 30 297 UDTV 2160P Not Support for FHD.
27 3840*2160 112.5 50 594 UDTV 2160P Not Support for FHD.
28 3840*2160 134.86 59.94 593.4 UDTV 2160P Not Support for FHD.
29 3840*2160 135 60 594 UDTV 2160P Not Support for FHD.
30 3840*2160 225 100 1188 UDTV 2160P 4K120 model
31 3840*2160 269.73 119.88 1186.8 UDTV 2160P (K6Hp HDMI 3,4 port,
O20) or 8K model
32 3840*2160 270 120 1188 UDTV 2160P
33 4096*2160 53.95 23.98 296.7 UDTV 2160P Not Support for FHD.
34 4096*2160 54 24 297 UDTV 2160P Not Support for FHD.
35 4096*2160 56.25 25 297 UDTV 2160P Not Support for FHD.
36 4096*2160 61.43 29.97 296.7 UDTV 2160P Not Support for FHD.
37 4096*2160 67.5 30 297 UDTV 2160P Not Support for FHD.
38 4096*2160 112.5 50 594 UDTV 2160P Not Support for FHD.
39 4096*2160 134.86 59.94 593.4 UDTV 2160P Not Support for FHD.
40 4096*2160 135 60 594 UDTV 2160P Not Support for FHD.
41 4096*2160 225 100 1188 UDTV 2160P 4K120 model
42 4096*2160 269.73 119.88 1186.8 UDTV 2160P (K6Hp HDMI 3,4 port,
O20) or 8K model
43 4096*2160 270 120 1188 UDTV 2160P
44 7680*4320 107.89 23.98 1188 8K 8K Model Only.
45 7680*4320 108 24 1188 8K 8K Model Only.
46 7680*4320 110 25 1188 8K 8K Model Only.
47 7680*4320 131.87 29.97 1188 8K 8K Model Only.
48 7680*4320 132 30 1188 8K 8K Model Only.
49 7680*4320 220 50 2376 8K 8K Model Only.
50 7680*4320 263.74 59.94 2376 8K 8K Model Only.
51 7680*4320 264 60 2376 8K 8K Model Only.
-8- Copyright © LG Electronics Inc. All rights reserved.
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 (1) Menu -> All Settings -> Support -> Software Update
message
(3) Click [YES]: initiate the download and install of the update.
(4) C lick [Check Now]: move to “About This TV” page for
update (2) C lick [CHEK FOR UPDATES] : system check newest
(5) TV is updating version
(6) After finished the update, below Pop-up appear (3) Click [DOWNLOAD AND INSTALL]
(4) TV is updating
(7) Click [Yes] : TV will be DC OFF -> ON
(8) After TV turned on, Check the updated SW Version and
Tool Option
(5) After finished the update, below Pop-up appear
(6) Turn OFF the TV and On. Check the updated SW Version
and Tool Option
-9- Copyright © LG Electronics Inc. All rights reserved.
Only for training and service purposes.
0.96V 1.5V 3.3V 5V
0.96V 13V 13V 5V
13V 3.5V_ST 1.5V 3.3V
Core&CP Normal
DDR Normal X_TAL
U
27MHz
0.95V 1.5V 3.3V 1V 1.8V 3.5V_ST
1V 1.8V 3.5V_ST 5V
3.5V_ST 1.0V 3.3V 13V 3.5V P_TS_IN
1.8V DDR3 2133 x16
Eth ST_BY 48bit P_TS_OUT CI Slot
(512MB X 3EA)
13V
EPI block 13V(PANEL_VCC) 13V(PANEL_VCC) 3.5V_ST
Sub Main GST/MCLK/GCLK/EO/I2C I2C_5 NVRAM (256Kb)
PMIC PMIC 6
MICOM eMMC 3.3V
eMMC (8GB)
CLK/DATA/STRB
Vx1 / EPI/ 5V 1.8V
EPI 60P (65”:8 lane, 55” ↓ :6lane), CEDS 68P CEDS Main IC
FCIC SPI/ I2C USB1 (2.0)
OCP
Vx1 51P (8 lane) 3 USB2 (2.0) From
- 10 -
HDMI1(2.0) Power
To 13V 3.3V
I2S Out HDMI2(ARC)
Panel MAIN Audio AMP I2C 0
B/ D
HDMI3(2.0)
USB_WIF HDMI4(2.0) (depend on model)
I IF
IQ (+/ - ), IP(+/ - ) IF (+/ - )
Copyright ©
BLOCK DIAGRAM
IF_S 3.3V
TS
Signal flow
TUNER TUNER
SPDIF OUT
ETHERNET
USB_WIFI
CVBS/YPbPr
I2C 1/2
Supplied Voltage (T2/C/A )
(S,S2)
3.5V_ST I2C 2
In/ output Voltage
LNB 13V
AMP
Air/
T2/C/S/S2 H - NIM tuner
MAX323
DVB- S
3.5V_ST Cable
Only for training and service purposes.
IR / KEY LAN
H/P
SPDIF
RS- 232
To WIFI/ BT
Sub
AV/COMP
Assy Combo
Area OPT
LG Electronics Inc. All rights reserved.
EXPLODED VIEW (SET)
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.
901
901
400
902
902
120
LV2
540
LV1
570
200A
HS1
800
HW1
500
HP1
121
700
530
A10
820
AR2
200P
ARC1
AR1
- 11 - Copyright © LG Electronics Inc. All rights reserved.
Only for training and service purposes.
EXPLODED VIEW(MODULE)
IMPORTANT NOTICE
MRC use only
* MRC : Module Repair Center
Optical Sheet
200PPR
POL(Rear)
200SR1
Rear Side
200P
Ass’y
Panel
200SL1
200PC
200PPF
POL(Front)
- 12 - Copyright © LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ASSEMBLY / DISASSEMBLY GUIDE (SET)
1
2 2 2 2 2
3
2 2
2
2 2
2
chassis
2 2 2 2 2
2 2
# When assembling the back cover, First align the upper part and Second align the lower part of the chassis.
- Back Cover Work Order
1. Back Cover (1) + Module Bottom Assembly
2. Screw (2) Assembly
3. Rear AV Screw (3) Assembly
* Do not wear items that may damage the appearance of the product
* SCREW TORQUE : 5 ~ 7Kgf.cm
# Insert your finger in the left/right triangle hole (indicated by the red circle) to disassemble the back cover
- Back Cover Work Order
1. Back Cover Screw disassemble
2. Insert the finger of the back cover bottom section triangle hole and disassemble it
* Do not wear items that may damage the appearance of the product
* SCREW TORQUE : 5 ~ 7Kgf.cm
- 13 - Copyright © LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ASSEMBLY / DISASSEMBLY GUIDE (MODULE)
[Case Top]
(Step 1) Disassemble the Main, PSU, SPK, Wifi & IR.
(Step 2) Disassemble the S-PCB Cover Shield .
* Rear Sliver screw 5EA
(Step 3) Disassemble the Case Top Screw.(back screw)
* Screw top 7 EA / side L 5EA / side R 5EA
(Step 4) LCM reverse and disassemble Source PCB from Holder
(Step 5) Disassemble the Case Top Screw (side screw) and Case Top.
* Screw down 7 EA * Hook top 6EA / side L 5 EA / side R 5 EA
- 14 - Copyright © LG Electronics Inc. All rights reserved.
Only for training and service purposes.
(Step 6) 6 Disassemble the Panel.
(Step 7) 6 Disassemble the guide panel.
* Hook top 8 EA / side L 4 EA / side R 4 EA / down 7 EA
(Step 8) Disassemble the Optical Sheet (Prism up, Prism down, DP)
(Step 9) Disassemble the DPS, LED Fixer & Reflector Sheet
* Rotate the DPS to remove (9 EA) * Push LED fixer in back (4 EA)
- 15 - Copyright © LG Electronics Inc. All rights reserved.
Only for training and service purposes.
[LED Array Disassemble]
(1) Disassemle the CNT form LED Array.
(2) Separate the LED Array from Cover Bottom.
(3) Remove the double tape form Cover Bottom.
[LED Array Assemble]
(Step 1) Attach the Double Tape
1) Attach the Double Tape in Guide Line of Cover Bottom (4ea)
2) Remove the protect film of Double Tape
* C/Bottom Guide Line * Completion of double tape attach (4ea)
(Step 2) Attach the LED Array
1) Attach the LED Array to the round hole on Cover Bottom embo.
2) Press the LED Array on the surface of Cover Bottom.
3) Connect the CNT to the LED Array.
NG OK
* Finish the Attached LED Array (4 EA)
- 16 - Copyright © LG Electronics Inc. All rights reserved.
Only for training and service purposes.
TROUBLE SHOOTING GUIDE
Copyright © 2020 LG Electronics Inc. All rights reserved.
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, light
5 5
spot, external device color error
6 No power 6
B. Power error Off when on, off while viewing, power auto
7 7-8
on/off
8 No audio/Normal video 9
C. Audio error
9 Wrecked audio/discontinuation/noise 10
10 Remote control & Local switch checking 11
11 MR19 operating checking 12
D. Function error
12 Wifi operating checking 13
13 External device recognition error 14
14 E. Noise Circuit noise, mechanical noise 15
15 F. Exterior error Exterior defect 16
First of all, Check whether there is SVC Bulletin in GSCS System for these model.
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Standard Repair Process
Established
Error A. Video error date
symptom
No video/ Normal audio Revised date
First of all, Check whether all of cables between board is inserted properly or not.
(Main B/D↔ Power B/D, LVDS or EPI Cable, Speaker Cable, IR B/D Cable,,,)
☞A1 ☞A18
No video Normal Y Check Back Light Y Check Power Y Replace T-con/Main
On Normal
Normal audio audio On with naked eye Board Board or module
voltage
13.2V etc.
N N N
Move to No Check Power Board 13.2V output Repair Power
☞A18
video/No audio Board or parts
Normal Y Replace Inverter
voltage or module
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 © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Standard Repair Process
Established
Error A. Video error date
symptom
No video/ No audio Revised date
☞A18
No Video/ Check various Check and
Y
No audio voltages of Power Normal
replace
Board (13.2V…) voltage?
MAIN B/D
N End
Replace Power
Board and repair
parts
2
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Standard Repair Process
Established
Error A. Video error date
symptom
Picture broken/ Freezing Revised date
. By using Digital signal level meter
☞ A3
. By using Diagnostics menu on OSD
Check RF Signal level ( Advanced→ Channels→ Channel Tuning→ Manual Tuning → Check the Signal )
- Signal strength (Normal : over 50%)
- Signal Quality (Normal: over 50%)
Check whether other equipments have problem or not.
Normal Y
(By connecting RF Cable at other equipment)
Signal?
→ DVD Player ,Set-Top-Box, Different maker TV etc`
N
☞ A4
Check RF Cable N
Normal Y Check SVC Check Tuner Y
Connection Close
1. Reconnection Picture? S/W Version Bulletin? soldering
2. Install Booster N
Y
N
S/W Upgrade
Normal N Contact with signal distributor
Picture? or broadcaster (Cable or Air)
Normal N
Y Picture? Replace
Main B/D
Y
Close
Close
3
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Standard Repair Process
Established
Error A. Video error date
symptom
Color error Revised date
☞ A7
☞A6 ※ Check and
replace Link
Check color by input
Y Cable Y Y
-External Input Color Color Color
(EPI or Vx1 Replace Main B/D Replace module
-AV error? error? error?
Cable) and
-HDMI
N contact N N
condition
Check error End
color input
mode
☞A28
External Input/ Check external External Y
Check Test pattern Component device and device/ Cable Replace Main/T-con B/D
error cable normal
N
Request repair
for external
device/cable
N
Check external External Y
HDMI
device and device/ Cable Replace Main/T-con B/D
error
cable normal
4
Copyright © 2020 LG Electronics Inc. All rights reserved.
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
Vertical/Horizontal bar, residual image, light spot Replace
Module
☞A6 ☞ A7 N
Check
Check color condition by input external Check and
Screen Y Y Screen N Screen
-External Input device Normal? replace Link Replace Main/T-con B/D
normal? normal? normal?
-HDMI connection Cable
condition
N N For LGD panel Y
Y
Replace Main B/D
Replace Request repair End End
module for external
☞A28 device
Check Test pattern
For other panel
External device screen error-Color error
Check screen
N condition by input External Connect other external
Check
Check S/W Version -External Input Input device and cable
version
-Component error (Check normal operation of Screen N Replace
-HDMI/DVI External Input, Component, normal? Main/T-con
Y RGB and HDMI/DVI by B/D
Component connecting Jig, pattern
error Y
S/W Upgrade Generator ,Set-top Box etc.
Request repair for
external device
Y
Connect other external
Normal N
device and cable N Replace
screen? HDMI/ (Check normal operation of Screen
Main /T-con
DVI External Input, Component, normal?
B/D
Y RGB and HDMI/DVI by
connecting Jig, pattern
Generator ,Set-top Box etc.
End
5
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Standard Repair Process
Established
Error B. Power error date
symptom
No power Revised date
☞A17 ☞A18
DC Power on Replace
Check Power Y Normal N Check Power Y
by pressing Power Key OK? Power
LED 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
Measure voltage of each output of Power B/D
N
Normal?
Y Y Y
Normal
Replace Main B/D
voltage?
Normal
Close Check ST-BY 7.8V
Y
voltage? N
☞A18 Replace Power B/D
N
Replace Power
B/D
6
Copyright © 2020 LG Electronics Inc. All rights reserved.
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
Check outlet
N CPU Y
Check A/C cord Error? Replace Main B/D Normal? End
Abnormal
N
Check for all 2- phase
Y Abnormal Replace Power B/D
power out
1
Fix A/C cord & Outlet
and check each 2
phase out
7
Copyright © 2020 LG Electronics Inc. All rights reserved.
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
* Please refer to the all cases which can be displayed on power off mode.
Power Off list Explanation Action contents
Power off when TV is not turned off during a certain time
KEYTIMEOUT RESULT : micom force to trigger TV power off. Check & Change Main B/D
CONDITION : When pressing power key while power on/off status, CPU does not response within 8 seconds
Almost the same as Power Off by KEYTIMEOUT. If there is no vaild communication
Bet ween CPU and MICOM for more than 5 seconds, the MICOM switcheds off PSU and
1SEC Power OFF Check & Change Main B/D
Records. Power off by 1SEC Power off. In this case, we don’t have information where the
malfunction exactly occurred. But in in indicates that CPU had stopped and rebooted.
In case of AC Off (It is normal when the power cord is unplugged.) Normal
ACDET
If there are many ACDETs connected, Power Board is defective Check & Change Power B/D
Power off by unstable AC power detect.
RESULT : micom check the stable power.
5V MNT Check & Change Power B/D
CONDITION : When AC on or DC on, stabilization check routine (Power Detect High
Check) fail after multi power on.
CPUABNORMAL If the CPU attempts to reset in case of abnormal operation and Shut Down in case of failure. Check & Change Main B/D
Power off when receiving no ack.
NO POLING RESULT : TV power off/on (Reboot) Check & Change Main B/D
CONDITION : There is no I2C response from CPU for 15 seconds.
CPUCMD Power off by main SoC command. Check & Change Main B/D
Power off by module error (OLED)
INV_ERROR Check & Change OLED Module
CONDITION : OLED Module send signal to micom
ONRF_FAIL RESULT : Reboot, CONDITION : OLED module compensation is running but fails. Check & Change OLED Module
PNWASHFAIL Power off by panel noise wash function fail case. Check & Change OLED Module
RESET When Micom is reset by AC Off
KEY Power off by Local key
OFFTIMER Power off by Off timer
SLEEPTIMER Power off by sleep timer
NOSIG Power off by No Signal
FANSTOP Power off by FAN operation stopped
INSTOP Power off by Instop Key
Normal Case
AUTO OFF Power off by auto off function
RESREC Power off by reserved recording
RECEND Power off when recording stops
SWDOWN Reboot by SW down load function
UNKNOWN No meaning (same as initial value)
COMP_END OLED threshold voltage degradation(Compensation) completes.
PNWASHDONE Power off by panel noise wash function complited. (OLED)
8
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Standard Repair Process
Established
Error C. Audio error date
symptom
No audio/ Normal video Revised date
☞A21 ☞A22+A18
No audio
Check user N Check audio
Normal Y
menu > Off 13.2V 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
9
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Standard Repair Process
Established
Error C. Audio error date
symptom
Wrecked audio/ discontinuation/noise Revised date
→ abnormal audio/discontinuation/noise is same after “Check input signal” compared to No audio
Wrecked audio/
☞A22+A18
Check and replace
Discontinuation/ Check audio
speaker and
Noise for B+ Voltage (13.2V)
connector
Check input all audio
signal Y
Signal
-RF
normal? Wrecked audio/ Y
-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
10
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Standard Repair Process
D. Function error Established
Error date
symptom
Remote control & Local switch checking Revised date
1. Remote control(R/C) operating error Replace
Main B/D
☞A22 ☞A22 ☞A23
Check & Repair N Y Y
Check R/C itself Normal Y Normal Check B+3.5V 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 3.5v 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
11
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Standard Repair Process
D. Function error Established
Error date
symptom
MR20 operating checking Revised date
2. MR20(Magic Remote control) operating error
☞A4
Check the RF Receiver ver N Check MR20 Normal Y Press the Is show ok N Turn off/on the
INSTART menu is “00.00”? itself Operation operating? wheel message? set and press
the wheel
N
Y
Y
☞A24
Check & Replace Close
Check & Repair Battery of MR20
RF assy
connection
Normal Y
☞A4 operating? Close
Press the
Is show ok N
message? Home+Back key
RF Receiver ver N
Close N about 5sec
is “00.00”?
Y
Replace
MR20
Y Close
Change the RF Receiver assy
* If you conduct the loop at 3times, change the MR20.
12
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Standard Repair Process
D. Function error Established
Error date
symptom
Wifi operating checking Revised date
3.Wifi operating error
☞A4 ☞A24
Wi-Fi Mac Check the Wifi wafer
Check the N Normal N Replace
value is 1pin Voltage?
INSTART menu Main B/D
“NG”?
Y
☞A24 Y
Close
Check & Repair
Wifi cable
connection
☞A4
Wi-Fi Mac value N
is “NG”? Close
Y
Change the Wifi
assy
13
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Standard Repair Process
Established
Error D. Function error date
symptom
External device recognition error Revised date
Check technical
Check Y External Input
Signal information Technical N
input and 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 Recognition Replace Main B/D
external device/cable accordance error
with technical
information
15
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Standard Repair Process
Established
Error E. Noise date
symptom
Circuit noise, mechanical noise Revised date
Identify
Circuit Check location
nose Replace PSU
noise of noise
type
Mechanical Check location of
noise noise
※ When the nose is severe, replace the module
※ Mechanical noise is a natural (For models with fix information, upgrade the
phenomenon, and apply the 1st level S/W or provide the description)
description. When the customer does not OR
agree, apply the process by stage.
※ If there is a “Tak Tak” noise from the
※ Describe the basis of the description in
cabinet, refer to the KMS fix information and
“Part related to nose” in the Owner’s
then proceed as shown in the solution manual
Manual.
(For models without any fix information,
provide the description)
16
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Standard Repair Process
Established
Error F. Exterior defect date
symptom
Exterior defect Revised date
Zoom part with Module
Replace module
exterior damage damage
Cabinet
Replace cabinet
damage
Remote
control Replace remote control
damage
Stand
Replace stand
dent
17
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Contents of Standard Repair Process Detail Technical Manual
No. Error symptom Content Page Remarks
1 Check LCD back light with naked eye A1
A. Video error_ No video/Normal audio
2 Check White Balance value A2
TUNER input signal strength checking
3 A3
method
A. Video error_ video error /Video
4 lag/stop Version checking method A4
5 Tuner Checking Part A5
A. Video error _Vertical/Horizontal bar,
6 Connection diagram A6
residual image, light spot
Check Link Cable (Vx1/EPI) reconnection
7 A. Video error_ Color error A7
condition
A-1/11
8 Check Cable (1) ~ (2)
A-2/11
A-3/11 ~
9 Exchange Main Board (1) ~ (3)
A-5/11
Defected Type caused by T-Con/ A-6/11 ~
10 Exchange Module (1) ~ (3)
Inverter/ Module A-8/11
A-9/11 ~ Only using
11 Exchange T-Con (1) ~ (2)
A-10/11 T-con model
12 Exchange Power Board(PSU) A-11/11
Continue to the next page
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Contents of Standard Repair Process Detail Technical Manual
Continued from previous page
No. Error symptom Content Page Remarks
13 Check front display LED A17
B. Power error_ No power
14 Check power input Voltage & ST-BY 7.8V A18
B. Power error_Off when on, off
15 POWER OFF MODE checking method A19
while viewing
Checking method in menu when there is no
16 A20
C. Audio error_ No audio/Normal audio
video Voltage and speaker checking method when
17 A21
there is no audio
18 Remote control operation checking method A22
D. Function error
19 Motion Remote operation checking method A23
20 How to use the Service remote control A24-A26
21 E. Etc Check items after Main B/D replacement A27
22 Adjustment Test pattern - ADJ Key A28
Copyright © 2020 LG Electronics Inc. All rights reserved.
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
After turning on the power and disassembling the case, check with the naked eye,
whether you can see light from locations.
A1
Copyright © 2020 LG Electronics Inc. All rights reserved.
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 method
1. Press the ADJ button on the remote control for adjustment.
2. Enter into White Balance.
3. After recording the R, G, B (GAIN, Cut) value of Color Temp
(Cool/Medium/Warm), re-enter the value after replacing the MAIN BOARD.
A2
Copyright © 2020 LG Electronics Inc. All rights reserved.
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 Programmes
Programme Tuning & Settings Manual Tuning
All Settings
When the signal is strong,
use the attenuator (-10dB, -
15dB, -20dB etc.)
A3
Copyright © 2020 LG Electronics Inc. All rights reserved.
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
65UN81006LB
Version
Press the IN-START with the remote
control for adjustment
A4
Copyright © 2020 LG Electronics Inc. All rights reserved.
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 © 2020 LG Electronics Inc. All rights reserved.
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
Copyright © 2020 LG Electronics Inc. All rights reserved.
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/EPI) reconnection condition date A7
43/49/55/65UN73
Check the contact condition of the Link Cable, especially dust or mis insertion.
A7
Copyright © 2020 LG Electronics Inc. All rights reserved.
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/EPI) reconnection condition date A7
50/60UN73
Check the contact condition of the Link Cable, especially dust or mis insertion.
A7
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Appendix. Examples of Symptoms(Image error) Check for poor cable contact
Symptom
Item Cause Symptom Image
Name
CABLE Color smear Poor broken pin of FFC cable
Color is Excessive due to FFC Cable
CABLE R Color Excessive
Contact.
screen is dark due to poor contact due
CABLE Screen darkness to disconnection of the FFC cable pin.
G color transient due to poor FFC cable
CABLE G Color Excessive connection
A - 1/11
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Appendix. Examples of Symptoms(Image error) Check for poor cable contact
Symptom
Item Cause Symptom Image
Name
CABLE Color spread FFC connection problem
CABLE Color spread FFC connection problem
CABLE Color spread FFC connection problem
Due to foreign substance within
CABLE Screen stop FFC PIN
A - 2/11
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Appendix. Examples of Symptoms(Main) Check parts by symptom
Symptom
Item Cause Symptom Image
Name
Main Screen noise Bit noise from horizontal screen
Broken screen due to
Main Screen noise
Main IC problem
Main Dark picture Dark left-side screen
Top/bottom screen part
Main Broken picture Picture problem due to tuner
Inner side quality problem
A - 3/11
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Appendix. Examples of Symptoms(Main) Check parts by symptom
Symptom
Item Cause Symptom Image
Name
Main Broken screen Broken screen in a horizontal manner
Main Screen spread Screen corner appears blurry
Main Color Spread Color spread on the screen
Main Blurry Screen Blurry picture on the screen
A - 4/11
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Appendix. Examples of Symptoms(Main) Check parts by symptom
Symptom
Item Cause Symptom Image
Name
No problem at the initial stage,
Main Broken picture G-color spread after 10 minutes
Right-side
Main
Screen Right-side screen problem
problem
LG logo
Main Screen picture spread problem
Screen problem
No problem at the initial stage.
Right-side
Main During Heat run, right-side picture
picture problem
problem
A - 5/11
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Appendix. Examples of Symptoms(Module) Check parts by symptom
Symptom
Item Cause Symptom Image
Name
Isometric Isometric horizontal bars occur
MODULE
Horizontal Bar throughout the screen
MODULE Internal matter BLU internal foreign matter inflow
MODULE Image broken 6 block image broken
MODULE Image broken Screen sync signal broken
A - 6/11
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Appendix. Examples of Symptoms(Module) Check parts by symptom
Symptom
Item Cause Symptom Image
Name
Internal damage and image breakage
MODULE Image broken
due to external impact
Bend on the Bending due to lateral external impact
MODULE
screen and internal bending of BLU
Vertical spreading on cube screen in no
MODULE Vertical smear
signal
MODULE Over color Screen contour part brightly Over color
A - 7/11
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Appendix. Examples of Symptoms(Module) Check parts by symptom
Symptom
Item Cause Symptom Image
Name
MODULE Vertical bar Center Vertical Bar
MODULE Screen darkness Center of the screen 1 block dark
MODULE Vertical bar Center Vertical Bar
Darkness at the
MODULE bottom of the MODULE internal BLU breakage
screen
A - 8/11
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Appendix. Examples of Symptoms(Only if using T-con Board) Check parts by symptom
Symptom
Item Cause Symptom Image
Name
screen lower T-Con is defective and the picture below
T-CON
image broken the screen is broken
screen lower T-Con is defective and the picture below
T-CON
image broken the screen is broken
screen lower T-Con is defective and the picture below
T-CON
image broken the screen is broken
screen lower T-Con is defective and the picture below
T-CON
image broken the screen is broken
A - 9/11
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Appendix. Examples of Symptoms((Only if using T-con Board) )Check parts by symptom
Symptom
Item Cause Symptom Image
Name
T-CON Wafer Locking The strength is
T-CON Image Broken
weak and cable contact failure occurs
Darkness at the Initial normal operation,
T-CON
top of the screen upper darkness during heat run
The entire screen is dark and bit noise
T-CON Image Broken
occurs
The entire screen is dark and bit noise
T-CON Image Broken
occurs
A - 10/11
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Appendix : Exchange Power Board (PSU)
No Light No picture/Sound Ok
A - 11/11
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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 7.8V A18
date
SET Model
43UN72/73/74/75/78/80/81 Series
Power Check Sequence
1. AC input Check : SK100 (100~240Vac)
2. PWR-ON Check : P201, 1 pin
- SET On : above 3V
- SET St-by : 0V
3. 13.2V DC Check : P201, 4~8 pin
- SET On : 13.2V
- SET St-by : 7.8V
4. MS Level Check : P201, 11 Pin
MS Level Range [V] LED On/Off
MS (0V) 0 ~ 0.25 Off
MS (2V) 1.75 ~ 2.25 On (Home mode)
MS (3V) 2.75 ~ 3.25 On (Store Mode)
※ Home mode : General Customer
Store mode : use Store
5. LED voltage Check : P801, LED B+
Picture Condition : VIVID
(Back light 100)
전압 Min Max
SK100 (AC input)
LED B+ 114 V 140 V
※ Depending on Model Power Board is different.
all condition meets, Power Board OK. But Interface(P801, P201) and Spec is same
Copyright © 2020 LG Electronics Inc. All rights reserved.
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 7.8V A18
date
SET Model
49LG73 & 49UN69/71/72/73/74/7800 Series
Power Check Sequence
1. AC input Check : SK100 (100~240Vac)
2. PWR-ON Check : P201, 1 pin
- SET On : above 3V
- SET St-by : 0V
3. 13.2V DC Check : P201, 4~8 pin
- SET On : 13.2V
- SET St-by : 7.8V
4. MS Level Check : P201, 11 Pin
MS Level Range [V] LED On/Off
MS (0V) 0 ~ 0.25 Off
MS (2V) 1.75 ~ 2.25 On (Home mode)
MS (3V) 2.75 ~ 3.25 On (Store Mode)
※ Home mode : General Customer
Store mode : use Store
5. LED voltage Check : P801, LED B+
Picture Condition : VIVID
(Back light 100)
전압 Min Max SK100 (AC input)
LED B+ 100 V 124 V
※ Depending on Model Power Board is different.
all condition meets, Power Board OK. But Interface(P801, P201) and Spec is same
Copyright © 2020 LG Electronics Inc. All rights reserved.
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 7.8V A18
date
SET Model
50UN69/72/73/7400 Series
Power Check Sequence
1. AC input Check : SK100 (100~240Vac)
2. PWR-ON Check : P201, 1 pin
- SET On : above 3V
- SET St-by : 0V
3. 13.2V DC Check : P201, 4~8 pin
- SET On : 13.2V
- SET St-by : 7.8V
4. MS Level Check : P201, 11 Pin
MS Level Range [V] LED On/Off
MS (0V) 0 ~ 0.25 Off
MS (2V) 1.75 ~ 2.25 On (Home mode)
MS (3V) 2.75 ~ 3.25 On (Store Mode)
※ Home mode : General Customer
Store mode : use Store
5. LED voltage Check : P801, LED B+
Picture Condition : VIVID
(Back light 100)
SK100 (AC input)
전압 Min Max
LED B+ 152 V 186 V
※ Depending on Model Power Board is different.
all condition meets, Power Board OK. But Interface(P801, P201) and Spec is same
Copyright © 2020 LG Electronics Inc. All rights reserved.
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 7.8V A18
date
SET Model
55LG73 & 55UN72/73/74/75/78/79/80/8100 Series
Power Check Sequence
1. AC input Check : SK100 (100~240Vac)
2. PWR-ON Check : P201, 1 pin
- SET On : above 3V
- SET St-by : 0V
3. 13.2V DC Check : P201, 4~8 pin
- SET On : 13.2V
- SET St-by : 7.8V
4. MS Level Check : P201, 11 Pin
MS Level Range [V] LED On/Off
MS (0V) 0 ~ 0.25 Off
MS (2V) 1.75 ~ 2.25 On (Home mode)
MS (3V) 2.75 ~ 3.25 On (Store Mode)
※ Home mode : General Customer
Store mode : use Store
5. LED voltage Check : P801, LED B+
Picture Condition : VIVID
(Back light 100)
전압 Min Max
LED B+ 175 V 215V SK100 (AC input)
※ Depending on Model Power Board is different.
all condition meets, Power Board OK. But Interface(P801, P201) and Spec is same
Copyright © 2020 LG Electronics Inc. All rights reserved.
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 7.8V A18
date
SET Model
65LG73 & 65UN72/73/74/75/79/80/81/8500 Series
Power Check Sequence
1. AC input Check : SK100 (100~240Vac)
2. PWR-ON Check : P201, 1 pin
- SET On : above 3V
- SET St-by : 0V
3. 13.2V DC Check : P201, 4~8 pin
- SET On : 13.2V
- SET St-by : 7.8V
4. MS Level Check : P201, 11 Pin
MS Level Range [V] LED On/Off
MS (0V) 0 ~ 0.25 Off
MS (2V) 1.75 ~ 2.25 On (Home mode)
MS (3V) 2.75 ~ 3.25 On (Store Mode)
※ Home mode : General Customer
Store mode : use Store
5. LED voltage Check : P801, LED B+
Picture Condition : VIVID
(Back light 100)
전압 Min Max
LED B+ 244 V 299 V SK100 (AC input)
※ Depending on Model Power Board is different.
all condition meets, Power Board OK. But Interface(P801, P201) and Spec is same
Copyright © 2020 LG Electronics Inc. All rights reserved.
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
65UN81006LB
K6LP
Entry method
1. Press the IN-START button of the remote control for adjustment.
2. Check the entry into adjustment item 3.
A19
Copyright © 2020 LG Electronics Inc. All rights reserved.
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
Copyright © 2020 LG Electronics Inc. All rights reserved.
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
②
①
③ 1 SPK_R-FT
2 SPK_R+FT
3 SPK_L-FT
4 SPK_L+FT
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
Copyright © 2020 LG Electronics Inc. All rights reserved.
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
Pin Pin name
1 VCC
① 2 USB_DM
IR & EYE Sensor 3 USB_DP
4 GND
5 WOL/WIFI_ON
6 VCC
7 WIFI_Suspend/Resume
③ 8 GND
9 Combo_Reset
10 BT_WAKEUP_HOST
11 GND
12 VCC
13
14
15
16 EYE_SDA
17 EYE_SCL
18 GND
19 IR
20 LED_R
21 GND
Checking order to check remote control ② 22 VCC
23 KEY2
24 KEY1
Checking order 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 6 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
Copyright © 2020 LG Electronics Inc. All rights reserved.
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 A23
Pin Pin name
1 VCC
① Wifi & BT Front 2 USB_DM
③ 3 USB_DP
4 GND
5 WOL/WIFI_ON
6 VCC
7 WIFI_Suspend/Resume
8 GND
9 Combo_Reset
10 BT_WAKEUP_HOST
11 GND
Wifi & BT Rear 12 VCC
13
14
15
16 EYE_SDA
17 EYE_SCL
18 GND
19 IR
20 LED_R
21 GND
② 22 VCC
Checking order to check motion remote/wifi 23 KEY2
24 KEY1
Checking order 25 GND
1. Check BT/Wifi cable condition between BT/Wifi assy & Main board.
2. Check the 3.5V on the terminal 22.
A23
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Standard Repair Process Detail Technical Manual
Error Established
symptom E. Etc date
Revised
Content How to use the Service remote control date A24
1. How to access the remote control
65UN81006LB
K6LP
0 4 1 3
0 4 1 3
A24
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Standard Repair Process Detail Technical Manual
Error Established
symptom E. Etc date
Revised
Content How to use the Service remote control date A25
2. Remote control part definition
POWER Power On/Off
[ETC] Each time pressing the KEY button, Mode gets changed to ETC and P-ONLY each time
ETC (Added Function) All KEY function [PIP PR-][PIP PR+][SWAP]
[PIP INPUT][DVI] KEY Function
Changed to factory mode
P-ONLY (Added
Function)
All KEY function &[INFO][STILL][HDMI HOT][USB HOT][HDMI4] KEY Action
INPUT Change to the external device mode
ARC Change in the order of 16:9=>Zoom1=>Zoom2=>Cinema Zoom=>Aucto Screen=>4:3=>16:9
Changes in the order of Bright Picture=>Easy Picture=>Cinema=>Spots=>Game=>
PSM
Custom PIcture1=>Custom Picture2=>Bright Picture
SSM (Added Function) Standard(user)=>music=>cinema=>sports=>game=>standard(user)
PIP Picture In Picture is activated
TEXT Access to the Power Only mode
CAP Broadcasting caption(on/off)
MPX Stereo mode (mono, stereo, foreign language) access
Used when in factory mode
Simplink (Added
Access to the Simplink-connected device
Function)
Digital EYE function ON/OFF
EYE
For some Model, access to the Test Pattern
TILT Used for screen tilting change (Access to the old PDP control mode)
A25
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Standard Repair Process Detail Technical Manual
Error Established
symptom E. Etc date
Revised
Content How to use the Service remote control date A26
B-TOOTH
Connected to Blue-Tooth
(Added function)
Model Nam ex) 42PG60D-NA Current Model Name S/W Version ex)
IN-START V03.11.0 Current S/W version
MICOM Version ex) V3.05.0 current Mi-Com version UTT ex) User TV total usage time
POWER OFF STATUS ex) Shows power-off status
ADJ
Test Pattern (Off=>White=>Red=>Green=>Blue=>Black=>Pattern=>Off) Change
X-STUDIO (Added function) HDD,USB, external device’s HDD screen is activated
MENU User function gets activated
EXIT Exit from the current mode
TIME SHIFT (Added
Moves forward/backward of recorded contents
function)
MUTE Mute function (0 Volume)
IN-STOP SET to factory mode
VOL + - Volume Up/Down
CH + - Channel Up/Down
AV1,2,3 (Added function) Connects to external input 1,2,3
COMP1,2 (Added function) Connects to Component 1,2
HDMI1,2,3,4
Connects to HDMI 1,2,3,4
(Add function)
DVI (Add function) Connects to DVI
A26
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Standard Repair Process Detail Technical Manual
Error Established
symptom E. Etc date
Revised
Content Check items after Main B/D replacement date A27
Check items afer Main B/D(Model Number D/L, White Balance)
1. Press the Service remote control instart Key.
65UN81006LB
No.7 Select Model Number D/L
- Key in the model name and serial number
after checking the ID label on the back cover.
2. Press the Service remote control ADJ Key.
No.11 Select White Balance
- Record the R, G, B (GAIN, Cut) value of the
color temperature before main board
replacement.
After replacing the main board, key in the
recorded value.
A27
Copyright © 2020 LG Electronics Inc. All rights reserved.
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 A28
You can view 9 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!)
A28
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
