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LED TV
SERVICE MANUAL
CHASSIS : UBX3D
MODEL : 50UN7240PVG / 7300PTC
50UN7340PVC / 7350PTD
50UN731C0GC/TC/VC
CAUTION
BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
P/NO : MFL71710503 (2010-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 ............................................................................. 10
BLOCK DIAGRAM .................................................................................. 11
EXPLODED VIEW ................................................................................... 12
ASSEMBLY / DISASSEMBLY GUIDE .................................................... 13
TROUBLE SHOOTING GUIDE ................................................. APPENDIX
-2- Copyright © LG Electronics Inc. All rights reserved.
Only 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 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
on page 3 of this publication, always follow the safety precau- ES devices.
tions. Remember: Safety First. 4. Use only an anti-static type solder removal device. Some sol-
der 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 6. Do not remove a replacement ES device from its protective
module or any other receiver assembly. package until immediately before you are ready to install it.
b. Disconnecting or reconnecting any receiver electrical plug (Most replacement ES devices are packaged with leads elec-
or other electrical connection. trically 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 mate-
installation of electrolytic capacitors may result in an explo- rial to the chassis or circuit assembly into which the device will
sion hazard. be installed.
2. Test high voltage only by measuring it with an appropriate CAUTION: Be sure no power is applied to the chassis or cir-
high voltage meter or other voltage measuring device (DVM, cuit, 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 appropri-
(by volume) isopropyl alcohol (90 % - 99 % strength) ate tip size and shape that will maintain tip temperature within
CAUTION: This is a flammable mixture. the range or 500 °F to 600 °F.
Unless specified otherwise in this service manual, lubrication 2. Use an appropriate gauge of RMA resin-core solder composed
of 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 Do not use freon-propelled spray-on cleaners.
are 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
ily by static electricity. Such components commonly are called against 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 discharg-
ing wrist strap device, which should be removed to prevent
potential shock reasons prior to applying power to the unit
under test.
-4- Copyright © LG Electronics Inc. All rights reserved.
Only 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 when-
gently prying up on the lead with the soldering iron tip as the ever 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 remain- good copper pattern. Solder the overlapped area and clip off
ing 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 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 UBX3D (1) Performance: LGE TV test method followed
chassis. (2) Demanded other specification
- Safety : CE, IEC specification
- EMC : CE, IEC specification
2. Requirement for Test
Each part is tested as below without special notice
(1) Temperature: 25 °C ± 5 °C(77 °F ± 9 °F), CST: 40 °C ± 2 °C
(2) Relative Humidity: 60 % ± 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 20 minutes prior
to the adjustment.
4. Model General Specification
No. Item Specification Remarks
1 Market Oceania, Asia, Middle East, Africa
(1) Digital TV : DVB-T/T2, DVB-C, DVB-S/S2
2 Broadcasting system (2) Analogue TV : P AL B/B, PAL B/G, PAL D/K, PAL-I, SECAM Only *V* models supprot DVB-S/S2
B/G, SECAM D/K, NTSC-M
3 Program coverage ATV & DVB-T/T2 : 3,000EA, DVB-S/S2 : 6,000EA Only *V* models supprot DVB-S/S2
► DVB-T
- Guard Interval(Bitrate_Mbit/s): 1/4, 1/8, 1/16, 1/32
- Modulation : Code Rate
QPSK : 1/2, 2/3, 3/4, 5/6, 7/8
16-QAM : 1/2, 2/3, 3/4, 5/6, 7/8
64-QAM : 1/2, 2/3, 3/4, 5/6, 7/8
► DVB-T2
- Guard Interval(Bitrate_Mbit/s)
1/4, 1/8, 1/16, 1/32, 1/128, 19/128, 19/256,
- Modulation : Code Rate
QPSK : 1/2, 2/5, 2/3, 3/4, 5/6
Analogue : Upper Heterodyne 16-QAM : 1/2, 2/5, 2/3, 3/4, 5/6
4 Receiving system
Digital : COFDM, QAM 64-QAM : 1/2, 2/5, 2/3, 3/4, 5/6
256-QAM : 1/2, 2/5, 2/3, 3/4, 5/6
► DVB-C
- Symbolrate : 4.0Msymbols/s to 7.2Msymbols/s
- Modulation : 16QAM, 64-QAM, 128-QAM and 256-QAM
► DVB-S/S2
- Symbolrate
DVB-S2 (8PSK / QPSK) : 2 ~ 45Msymbol/s
DVB-S (QPSK) : 2 ~ 45Msymbol/s
- Code rate
DVB-S mode : 1/2, 2/3, 3/4, 5/6, 7/8
DVB-S2 mode: 1/2, 2/3, 3/4, 3/5, 4/5, 5/6, 8/9, 9/10
HDMI 1 Support 6Gbps
HDMI 2 Support 6Gbps, Support ARC
5 HDMI Input PC / DTV Format
HDMI 3 Support 6Gbps
HDMI 4 Support 6Gbps(* Some models do not support HDMI4)
6 USB Input My Media(Movie/Photo/Music List) or SVC 2EA
7 Component Input Y/Pb/Pr Except UB92x for Middle East and Africa
8 Video Input PAL, SECAM, NTSC 4 System : PAL, SECAM, NTSC, PAL60
9 Audio Input DVI Audio, Component, AV
10 SPDIF out Optical Audio out
11 Ethernet Connect
-6- Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
5. External Input Support Format
5.1. Component input(Y, CB/PB, CR/PR)
No. Resolution H-freq(kHz) V-freq(Hz) Pixel clock(MHz) Proposed
1 720*480i 15.73 59.94 13.50 SDTV, DVD 480I(525I)
2 720*480i 15.75 60.00 13.51 SDTV, DVD 480I(525I)
3 720*576i 15.62 50.00 13.50 SDTV, DVD 576I(625I) 50Hz
4 720*480p 31.47 59.94 27.00 SDTV 480P
5 720*480p 31.50 60.00 27.03 SDTV 480P
6 720*576p 31.25 50.00 27.00 SDTV 576P 50Hz
7 1280*720 44.96 59.94 74.18 HDTV 720P
8 1280*720 45.00 60.00 74.25 HDTV 720P
9 1280*720 37.50 50.00 74.25 HDTV 720P 50Hz
10 1920*1080 28.12 50.00 74.25 HDTV 1080I 50Hz
11 1920*1080 33.72 59.94 74.18 HDTV 1080I
12 1920*1080 33.75 60.00 74.25 HDTV 1080I
13 1920*1080 56.25 50.00 148.50 HDTV 1080P
14 1920*1080 67.43 59.94 148.50 HDTV 1080P
15 1920*1080 67.50 60.00 148.50 HDTV 1080P
5.2. HDMI input(DTV)
No. Resolution H-freq(kHz) V-freq.(kHz) Pixel clock(MHz) Proposed Remarks
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 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.
-7- Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
No. Resolution H-freq(kHz) V-freq.(kHz) Pixel clock(MHz) Proposed Remarks
20 1920*1080 134.86 119.88 296.7 UDTV 2160P
21 1920*1080 135 120 297 UDTV 2160P
22 3840*2160 53.95 23.98 296.7 UDTV 2160P
23 3840*2160 54 24 297 UDTV 2160P
24 3840*2160 56.25 25 297 UDTV 2160P
Not Support for FHD.
25 3840*2160 61.43 29.97 296.7 UDTV 2160P
26 3840*2160 67.5 30 297 UDTV 2160P
27 3840*2160 112.5 50 594 UDTV 2160P
28 3840*2160 134.86 59.94 593.4 UDTV 2160P
29 3840*2160 135 60 594 UDTV 2160P
30 3840*2160 225 100 1188 UDTV 2160P
4K120 model (K6Hp HDMI
31 3840*2160 269.73 119.88 1186.8 UDTV 2160P
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
34 4096*2160 54 24 297 UDTV 2160P
35 4096*2160 56.25 25 297 UDTV 2160P
36 4096*2160 61.43 29.97 296.7 UDTV 2160P
Not Support for FHD.
37 4096*2160 67.5 30 297 UDTV 2160P
38 4096*2160 112.5 50 594 UDTV 2160P
39 4096*2160 134.86 59.94 593.4 UDTV 2160P
40 4096*2160 135 60 594 UDTV 2160P
41 4096*2160 225 100 1188 UDTV 2160P
4K120 model (K6Hp HDMI
42 4096*2160 269.73 119.88 1186.8 UDTV 2160P
3,4 port, O20) or 8K model
43 4096*2160 270 120 1188 UDTV 2160P
44 7680*4320 107.89 23.98 1188 8K
45 7680*4320 108 24 1188 8K
46 7680*4320 110 25 1188 8K
47 7680*4320 131.87 29.97 1188 8K
8K Model Only.
48 7680*4320 132 30 1188 8K
49 7680*4320 220 50 2376 8K
50 7680*4320 263.74 59.94 2376 8K
51 7680*4320 264 60 2376 8K
-8- Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
5.3. HDMI Input (PC)
No. Resolution H-freq(kHz) V-freq.(kHz) Pixel clock(MHz) Proposed Remarks
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
11 1920*1080 135 120 297 UDTV 2160P
12 3840*2160 53.95 23.98 296.7 UDTV 2160P
13 3840*2160 54 24 297 UDTV 2160P
14 3840*2160 56.25 25 297 UDTV 2160P
15 3840*2160 61.43 29.97 296.7 UDTV 2160P
16 3840*2160 67.5 30 297 UDTV 2160P
17 3840*2160 112.5 50 594 UDTV 2160P
18 3840*2160 134.86 59.94 593.4 UDTV 2160P
Not Support for FHD.
19 3840*2160 135 60 594 UDTV 2160P
20 4096*2160 53.95 23.98 296.7 UDTV 2160P
21 4096*2160 54 24 297 UDTV 2160P
22 4096*2160 56.25 25 297 UDTV 2160P
23 4096*2160 61.43 29.97 296.7 UDTV 2160P
24 4096*2160 67.5 30 297 UDTV 2160P
25 4096*2160 112.5 50 594 UDTV 2160P
26 4096*2160 134.86 59.94 593.4 UDTV 2160P
27 4096*2160 135 60 594 UDTV 2160P
(UHD 60Hz models only),
28 2560*1440 88.78 59.95 241.5 3K Support only when UHD
DeepColor is On
(UHD, 8K 120Hz models
29 2560*1440 182.99 119.99 497.7 3K only), Support only when
UHD DeepColor is On
-9- Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
SOFTWARE UPDATE
1. USB DOWNLOAD 2. NSU DOWNLOAD
(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 → Support → Software Update
(3) Click [YES]: initiate the download and install of the update. (2) Click [CHEK FOR UPDATES]: system check newest version.
(4) Click [Check Now]: move to “About This TV” page for update. (3) Click [DOWNLOAD AND INSTALL].
(5) TV is updating. (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. (6) Turn OFF the TV and On. Check the updated SW Version
(8) After TV turned on, Check the updated SW Version and and Tool Option.
Tool Option.
- 10 - Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
0.96V 1.5V 3.3V 5V
13V 0.96V 3.5V_ST 1.5V 13V 3.3V 13V 5V
Core&CPU DDR Normal Normal X_TAL
27MHz
0.95V 1.5V 3.3V 1V 1.8V 3.5V_ST
1V 1.8V 3.5V_ST
3.5V_ST 3.3V 3.5V
1.0V 1.8V 13V
ST_B DDR3 2133 x16
Eth 48bit
Y (512MB X 3EA)
13V
EPI block 13V(PANEL_VCC) 13V(PANEL_VCC) 3.5V_ST
Sub Main I2C_5 NVRAM (256Kb)
GST/MCLK/GCLK/EO/I2C 6
PMIC PMIC
MICOM eMMC 3.3V
eMMC (8GB)
CLK/DATA/STRB
5V 1.8V
Vx1 / EPI/ CEDS
EPI 60P (65”:8 lane, 55”↓:6lane), CEDS 68P
FCIC SPI/ I2C 3 USB1 (2.0)
OCP
Vx1 51P (8 lane) USB2 (2.0) From
- 11 -
HDMI1(2.0) Power
To 13V 3.3V Main SoC
I2S Out HDMI2(ARC) Board
Panel Audio AMP
I2C 0 HDMI3(2.0)
USB_WIFI HDMI4(2.0) (depend on model)
IF
IF (+/-)
BLOCK DIAGRAM
Copyright ©
3.3V
Signal flow
SPDIF OUT
USB_WIFI
ETHERNET
CVBS/YPbPr I2C 1/2 TUNER
Supplied Voltage
3.5V_ST
In/output Voltage
3.5V_ST
Air/Cable
Only training and service purposes.
IR / KEY LAN
SPDIF
To Wi-Fi/BT
Sub
AV/COMP
PCBA Combo PCBA
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
400
120
902
540
570
HS1
HW1
800
200A
LV1
HP1
121
500
530
700
820
Stand Screw
200T
A10
AR2
Depending On Model
200P
ARC1
AR1
- 12 - Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
ASSEMBLY / DISASSEMBLY GUIDE
1. Unscrew (“1” : 9 EA, “2” : 5 EA, “3” : 1 EA) to uncover back cover assembling from
module.
1 1 1 1 1
1 1
2
3
2 2
2 2 1
1
2. Remove a cable after uncovering the back cover.
(1) MODULE “A” → POWER P801
(2) MAIN P1000 → POWER P201
(3) MAIN P4000 → WIFI Ass’y
(4) MAIN P5800 → SPEAKER “B”, “C”
“A”
P801
P201
P1000
P5800
P4000
“B” “C”
- 13 - Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
3. Unscrew (“4” : 1 EA) and then remove wifi bracket.
4
4. Unscrew (“5” : 9 EA) and then remove harness cable MAIN P7600 → MODULE “D”.
5 5
5 5
P7600
5 5 5
5 5
“D”
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Only training and service purposes.
5. Remove all boards, cables and speakers.
6. Unscrew (“6” : 4 EA) to remove VESA brackets and then pick them out.
6 6
6 6
- 15 - Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
7. Remove insulation sheet “E” from module.
“E”
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Only training and service purposes.
ASSEMBLY / DISASSEMBLY GUIDE (MODULE)
1. LED Array Disassemble
(1) Disassemble connector.
(2) From cover bottom, LED Array remove.
(3) From cover bottom, LED Array double tape remove.
2. LED Array Assemble
(1) Double tape attach
1) Attach double tape along cover bottom’s guide line(4 EA).
2) Remove double tape protective film.
*C/Bottom guide line
* Completion of double tape attach (4 EA)
(2) LED Array attach
1) Cover Bottom’s guide embo & LED Array arrange and attach.
2) LED array squeeze, along cover bottom's surface.
3) Connect LED Array to connector.
NG OK
* Completion of LED Array assemble
(4 EA)
- 17 - Copyright © LG Electronics Inc. All rights reserved.
Only 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 MR20 operating checking 12
D. Function error
12 Wi-Fi 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 boards is assembled properly or not.
(Main B/D↔ Power B/D, Vx1 or EPI Cable, Speaker Cable, IR B/D Cable and so on)
☞A1 ☞A18
No video Normal Y Check backlight on Y Check 13.2V from Normal Y Replace T-con/Main B/D
On
Normal audio audio with the naked eye Power B/D voltage or module
N ☞A18 N N
Move to Check voltage from Power B/D to backlight Repair Power B/D
No video/No audio or parts
Normal Y
Replace module
voltage
N End
Replace Power B/D
or repair parts
※Precaution
☞A2& A4
Always check & record S/W Version, White
Replace Main Board Re-write Tool option, Area option and 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 13.2V from Normal Y Check and
No audio Power B/D voltage? replace Main B/D
N End
Replace Power B/D
or 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
☞ A3 . By using Digital signal level meter
. By using Diagnostics menu on OSD
Check RF Signal level ( All Settings → Programmes → Programme Tuning & Settings → 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
Normal Y Check SVC N Check Tuner Y
Connection End
1. Reconnection Picture? S/W Version Bulletin? soldering
2. Install Booster
Y N
N
S/W Upgrade
Normal N Contact with signal distributor Replace
Picture? or broadcaster (Cable or Air) Main B/D
Normal N
Y Picture?
Y
End
End
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/CEDS Replace Main B/D Replace module
- Component/AV error? error? error?
or Vx1 Cable)
- HDMI
and connect
N N N
condition
Check error End
color input
mode
☞A28
External Input/ Check external External Y
Check Test pattern Component/AV device and device/cable Replace Main/T-con B/D
error cable normal
N
Request repair
for external
device/cable
N
External Y
HDMI Check external
device/cable Replace Main/T-con B/D
error device and 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 Y Check and
- External Input Screen Y Screen N Screen
device Normal? replace Link Replace Main/T-con B/D
- Component/AV normal? normal? normal?
connection Cable
- HDMI For LGD/BOE panel
condition
N N Y Y
Replace Main B/D
Replace Request repair
End End
☞A28 module for external For other panel
device
Check Test pattern
External device screen error-Color error
Check screen
N condition by input External Connect other external device
Check
Check S/W Version - External Input Input and cable
version N
- Component/AV error (Check normal operation of Replace
Screen
- HDMI External Input, Component, Main/T-con
Y AV and HDMI by connecting normal?
B/D
Component/AV Jig, pattern Generator ,Set-top
S/W Upgrade Box etc. Y
error
Request repair for
external device
Normal Connect other external
screen? Y
N device and cable
N Replace
(Check normal operation of Screen
HDMI External Input, Component, Main /T-con
Y normal?
AV and HDMI by connecting B/D
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
Check Power Y Normal N Check Power Y Replace
by pressing Power Key OK?
Power LED LED On? operation? On ‘”High” Power B/D
on Remote control
. Stand-By: Red or Turn On
N Y N
. 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 Normal Y
☞A18 voltage?
Replace Main B/D
Normal
End Check St-by 7.8V
Y
voltage? N
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
Y N
Check for all 2- phase
Replace Power B/D
power out No Poling
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
☞A20 ☞A21+A18
Check user N Check audio Y
No audio Normal
menu > off 13.2V of Power
Normal video voltage
Speaker off Board
Y N
Cancel off Replace Power B/D or repair parts
Check N Y
Speaker Disconnection Replace Speaker or cable Normal End
connection
Y N
Reassemble Speaker and cable Replace Main B/D
Y
Normal End
N
Replace Speaker or cable
Y
Normal End
N
Replace Main B/D
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
☞A21+A18
Wrecked audio/
Check and replace
Discontinuation/ Check audio
speaker and
Noise for B+ Voltage (13.2V)
connector
all audio
Check input signal
Signal Y
- RF
normal? Wrecked audio/
- External Input Normal Y
Discontinuation/
Replace Main B/D voltage?
N 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
Connect and check Normal N
External Input
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
Replace
Main B/D
☞A22
☞A22 ☞A22
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 input signal
Connector solder
N
Y N N
☞A18
Check R/C Operating Check & Replace Repair/Replace
End Check 13.2V from Power B/D IR B/D
When turn off light Baterry of R/C
Replace Power B/D
in room
If R/C operate, Normal Y
End
Explain the customer operating?
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
☞A4
Check the RF Receiver N Check MR20 Normal Y Press the Is show ok N Turn off/on the set
ver is
INSTART menu itself Operation operating? message? and press the
“00.00”? wheel
wheel
N
Y
Y
☞A23
Check & Replace
Check & Repair End
Battery of MR20
RF assy
connection
Normal Y
☞A4 operating?
End
Press the
Is show ok N
RF Receiver message? Home+Back key
N
Ver is End N about 5sec
“00.00”? Y
Replace
MR20
Y End
Replace 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
Wi-Fi operating checking Revised date
☞A4 ☞A23
Wi-Fi Mac Check the voltage
Check the N Normal N Replace
value is at 1pin of Wi-Fi wafer Voltage?
INSTART menu Main B/D
“NG”?
Y
☞A23 Y
End
Check & Repair
Wi-Fi cable
connection
☞A4
Wi-Fi Mac N
value is End
“NG”?
Y
Replace the Wi-Fi 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
Y External Input
Check Signal information Technical N
and Component Replace Main B/D
input signal input? - Fix information information?
Recognition error
- S/W Version
N Y
HDMI, Optical
Check and fix Recognition
Fix in Replace Main B/D
external device/cable accordance error
with technical
information
14
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
Replace PSU
nose type noise of noise
Mechanical Check location
noise of 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)
15
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
16
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 back light with naked eye A1
A. Video error_No video / Normal audio
2 Check White Balance value A2
3 Tuner input signal strength checking method A3
4 A. Video error_video error / Version checking method A4
Video lag / stop
5 Tuner Checking Part A5
A. Video error_Vertical/Horizontal bar,
6 Connection diagram A6
residual image, light spot
Check Link Cable (Vx1 or EPI/CEDS)
7 A. Video error_Color error A7
reconnection condition
A-1/11
8 Check Cable (1) ~ (2)
A-2/11
A-3/11 ~
9 Exchange Main Board (1) ~ (3)
A-5/11
A-6/11 ~
10 Defected Type caused by Parts Exchange Module (1) ~ (3)
A-8/11
A-9/11 ~ Only for using
11 Exchange T-Con (1) ~ (2)
A-10/11 T-con board
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 Power Indicator in front A17
B. Power error_No power
14 Check input/output of Power board 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 Factory SVC 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 back light with naked eye date A1
After disassembling a back cover and turning on TV, 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 date A2
1. Press ‘ADJ’ button of the Factory SVC remote control.
2. Enter into ‘11. White Balance’.
3. After recording the R, G, B value(Gain, Cut) of each Color Temp (Cool/Medium/Warm),
write the value after replacing a 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
Revised
Content Tuner input signal strength checking method date A3
When the signal is strong, use the
attenuator (-10dB, -15dB, -20dB etc.)
All Settings Programmes Programme Tuning & Settings Manual Tuning
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
Revised
Content Version checking method date A4
Version
Press ‘IN START’ button
of the on Factory SVC remote
control.
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 date A5
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 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
Check Link Cable(Vx1 or EPI/CEDS) Revised
Content date A7
reconnection condition
Check connect condition of the Link Cable, especially dust or misassembling.
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
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 Indicator in front date A17
ST-BY condition : On or Off (Depending on
‘Standby Light’ setting
in Additional Settings)
Power On condition : Turn Off
A17
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 input/output of power board date A18
Applied Model Power P/N
50UN72/73/74 EAY65769221 (LGP50T-20U1)
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+
SK100 (AC input)
Power Board is no problem if all the conditions are satisfied. A18
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
1. Press ‘IN START’ button of the Factory SVC Remote control.
2. Check the entry into ‘3. Power On/Off Status’.
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
1. Press the Setting button on the remote control
2. Select the Sound function of the Menu
3. Select the Sound Out
4. Select Internal 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-
2 SPK_R+
3 SPK_L-
4 SPK_L+
1. Check the connect condition of Main board and Power 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 +3.5V_WIFI
2 WIFI_DM
3 WIFI_DP
4 GND
5 WOL/WIFI_POWER_ON
6 +3.5V_WIFI
7 WIFI_SUSPEND/RESUME
8 GND
9 COMBO_RESET
10 BT_WAKEUP_HOST
11 GND
12 +3.5V_WIFI
13 NC
14 NC
15 NC
16 EYE_SDA
17 EYE_SCL
18 GND
19 IR
20 LED_R
21 GND
22 +3.5V_ST
23 KEY2
24 GND
1. Check IR cable connect condition between IR & Main board. 25 GND
2. Check the +3.5V_ST on the terminal 22 pin.
3. As checking the Pre-Amp on IR/LED board, 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 Motion Remote operation checking method date A23
Pin Pin name
1 +3.5V_WIFI
2 WIFI_DM
3 WIFI_DP
4 GND
5 WOL/WIFI_POWER_ON
6 +3.5V_WIFI
7 WIFI_SUSPEND/RESUME
8 GND
9 COMBO_RESET
10 BT_WAKEUP_HOST
[ Wi-Fi/BT board : Front ] 11 GND
12 +3.5V_WIFI
13 NC
14 NC
15 NC
16 EYE_SDA
17 EYE_SCL
18 GND
[ Wi-Fi/BT board : Rear ] 19 IR
20 LED_R
21 GND
22 +3.5V_ST
23 KEY2
24 GND
25 GND
1. Check connect condition between Wi-Fi/BT board and Main board.
2. Check +3.5V_WIFI on the terminal 1, 6, 12.
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 Factory SVC remote control date A24
1. How to access Factory SVC Remote control.
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 Factory SVC 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 Original 4:3 Vertical Zoom 4-Way Zoom 16:9
Change in the order of Vivid Standard APS(ECO) Cinema Cricket(Football)
PSM
HDR Effect FILMMAKER MODE Expert(Bright Room) Expert(Dark Room)
Change in the order of AI Sound Standard Cinema Clear Voice III Cricket(Football)
SSM (Added Function)
Music Game AI Sound
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 Function) Access to the Simplink-connected device
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 Factory SVC Remote control date A26
B-TOOTH (Added function) Connected to Blue-Tooth
Enter into Instart menu (Model Name, Serial Number, S/W Version, Used Total Time, Power
IN START
On/Off Status and so on
ADJ Enter into Adjust menu(Test Pattern, Tool/Area option, White Balance and so on)
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 function) Moves forward/backward of recorded contents
MUTE Mute function (0 Volume)
IN STOP Set to outgoing condition
VOL + - Volume Up/Down
CH + - Channel Up/Down
AV1,2,3 (Added function) Change to AV 1,2,3
COMP1,2 (Added function) Change to Component 1,2
HDMI1,2,3,4 (Add function) Change to HDMI 1,2,3,4
DVI (Add function) Change 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
1. Press ‘IN START’ button of the Factory SVC remote control.
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 ‘ADJ’ button of the Factory SVC remote control.
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 E. Etc date
Revised
Content Adjustment Test pattern - ADJ Key date A28
You can view 9 types of patterns using ‘ADJ’ button
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.
