CONFIDENTIAL
LED TV
SERVICE MANUAL
CHASSIS : LD70B
MODEL : 24LJ480U 24LJ480U-PZ
CAUTION
BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
P/NO : MFL70041005 (1704-REV00)
Copyright © 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.
CONTENTS
CONTENTS ............................................................................................... 2
SAFETY PRECAUTIONS.......................................................................... 3
SERVICING PRECAUTIONS..................................................................... 4
SPECIFICATION........................................................................................ 6
SOFTWARE UPDATE.............................................................................. 11
BLOCK DIAGRAM................................................................................... 12
EXPLODED VIEW ................................................................................... 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 1.5K/10watt resistor in parallel with a 0.15uF 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, 0.5mA.
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 1W), keep the resistor 10mm away from PCB.
Leakage Current Hot Check circuit
Keep wires away from high voltage or high temperature parts.
AC Volt-meter
Before returning the receiver to the customer,
always perform an AC leakage current check on the exposed Good Earth Ground
such as WATER PIPE,
metallic parts of the cabinet, such as antennas, terminals, etc., to CONDUIT etc.
To Instrument's
be sure the set is safe to operate without damage of electrical exposed
0.15µF
shock. METALLIC PARTS
Leakage Current Cold Check(Antenna Cold Check) 1.5 Kohm/10W
With the instrument AC plug removed from AC source, connect an
electrical jumper across the two AC plug prongs. Place the AC
When 25A is impressed between Earth and 2nd Ground
switch in the on position, connect one lead of ohm-meter to the AC for 1 second, Resistance must be less than 0.1
plug prongs tied together and touch other ohm-meter lead in turn to *Base on Adjustment standard
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 1MΩ and 5.2MΩ.
When the exposed metal has no return path to the chassis the
reading must be infinite.
An other abnormality exists that must be corrected before the
receiver is returned to the customer.
-3- Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
SERVICING PRECAUTIONS
CAUTION: Before servicing receivers covered by this service unit under test.
manual and its supplements and addenda, read and follow the 2. After removing an electrical assembly equipped with ES
SAFETY PRECAUTIONS on page 3 of this publication. devices, place the assembly on a conductive surface such as
NOTE: If unforeseen circumstances create conflict between the aluminum foil, to prevent electrostatic charge buildup or
following servicing precautions and any of the safety precautions on exposure of the assembly.
page 3 of this publication, always follow the safety precautions. 3. Use only a grounded-tip soldering iron to solder or unsolder ES
Remember: Safety First. devices.
4. Use only an anti-static type solder removal device. Some solder
General Servicing Precautions removal devices not classified as "anti-static" can generate
1. Always unplug the receiver AC power cord from the AC power electrical charges sufficient to damage ES devices.
source before; 5. Do not use freon-propelled chemicals. These can generate
a. Removing or reinstalling any component, circuit board electrical charges sufficient to damage ES devices.
module or any other receiver assembly. 6. Do not remove a replacement ES device from its protective
b. Disconnecting or reconnecting any receiver electrical plug or package until immediately before you are ready to install it.
other electrical connection. (Most replacement ES devices are packaged with leads
c. Connecting a test substitute in parallel with an electrolytic electrically shorted together by conductive foam, aluminum foil
capacitor in the receiver. or comparable conductive material).
CAUTION: A wrong part substitution or incorrect polarity 7. Immediately before removing the protective material from the
installation of electrolytic capacitors may result in an leads of a replacement ES device, touch the protective material
explosion hazard. to the chassis or circuit assembly into which the device will be
installed.
2. Test high voltage only by measuring it with an appropriate high CAUTION: Be sure no power is applied to the chassis or circuit,
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
Do not test high voltage by "drawing an arc". replacement ES devices. (Otherwise harmless motion such as
3. Do not spray chemicals on or near this receiver or any of its the brushing together of your clothes fabric or the lifting of your
assemblies. foot from a carpeted floor can generate static electricity
4. Unless specified otherwise in this service manual, clean sufficient 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% (by 1. Use a grounded-tip, low-wattage soldering iron and appropriate
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 1.25cm) 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 easily b. First, hold the soldering iron tip and solder the strand against
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 and component lead and the printed circuit foil, and hold it there
semiconductor "chip" components. The following techniques only until the solder flows onto and around both the
should be used to help reduce the incidence of component component lead and the foil.
damage 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. splashed solder with a small wire-bristle brush.
Alternatively, obtain and wear a commercially available
discharging wrist strap device, which should be removed to
prevent potential shock reasons prior to applying power to the
-4- Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
IC Remove/Replacement CAUTION: Maintain original spacing between the replaced
Some chassis circuit boards have slotted holes (oblong) through component and adjacent components and the circuit board to
which the IC leads are inserted and then bent flat against the prevent excessive component temperatures.
circuit foil. When holes are the slotted type, the following technique
should be used to remove and replace the IC. When working with Circuit Board Foil Repair
boards using the familiar round hole, use the standard technique Excessive heat applied to the copper foil of any printed circuit
as outlined in paragraphs 5 and 6 above. board will weaken the adhesive that bonds the foil to the circuit
board causing the foil to separate from or "lift-off" the board. The
Removal following guidelines and procedures should be followed whenever
1. Desolder and straighten each IC lead in one operation by gently this condition is encountered.
prying up on the lead with the soldering iron tip as the solder
melts. At IC Connections
2. Draw away the melted solder with an anti-static suction-type To repair a defective copper pattern at IC connections use the
solder removal device (or with solder braid) before removing the following procedure to install a jumper wire on the copper pattern
IC. side of the circuit board. (Use this technique only on IC
Replacement connections).
1. Carefully insert the replacement IC in the circuit board.
2. Carefully bend each IC lead against the circuit foil pad and 1. Carefully remove the damaged copper pattern with a sharp
solder it. knife. (Remove only as much copper as absolutely necessary).
3. Clean the soldered areas with a small wire-bristle brush. 2. carefully scratch away the solder resist and acrylic coating (if
(It is not necessary to reapply acrylic coating to the areas). used) from the end of the remaining copper pattern.
3. Bend a small "U" in one end of a small gauge jumper wire and
"Small-Signal" Discrete Transistor carefully crimp it around the IC pin. Solder the IC connection.
Removal/Replacement 4. Route the jumper wire along the path of the out-away copper
1. Remove the defective transistor by clipping its leads as close as pattern and let it overlap the previously scraped end of the good
possible to the component body. copper pattern. Solder the overlapped area and clip off any
2. Bend into a "U" shape the end of each of three leads remaining excess jumper wire.
on the circuit board.
3. Bend into a "U" shape the replacement transistor leads. At Other Connections
4. Connect the replacement transistor leads to the corresponding Use the following technique to repair the defective copper pattern
leads extending from the circuit board and crimp the "U" with at connections other than IC Pins. This technique involves the
long nose pliers to insure metal to metal contact then solder installation of a jumper wire on the component side of the circuit
each connection. board.
Power Output, Transistor Device 1. Remove the defective copper pattern with a sharp knife.
Removal/Replacement Remove at least 1/4 inch of copper, to ensure that a hazardous
1. Heat and remove all solder from around the transistor leads. condition will not exist if the jumper wire opens.
2. Remove the heat sink mounting screw (if so equipped). 2. Trace along the copper pattern from both sides of the pattern
3. Carefully remove the transistor from the heat sink of the circuit break and locate the nearest component that is directly
board. connected to the affected copper pattern.
4. Insert new transistor in the circuit board. 3. Connect insulated 20-gauge jumper wire from the lead of the
5. Solder each transistor lead, and clip off excess lead. nearest component on one side of the pattern break to the lead
6. Replace heat sink. of the nearest component on the other side.
Carefully crimp and solder the connections.
Diode Removal/Replacement CAUTION: Be sure the insulated jumper wire is dressed so the
1. Remove defective diode by clipping its leads as close as it does not touch components or sharp edges.
possible to diode body.
2. Bend the two remaining leads perpendicular y to the circuit
board.
3. Observing diode polarity, wrap each lead of the new diode
around the corresponding lead on the circuit board.
4. Securely crimp each connection and solder it.
5. Inspect (on the circuit board copper side) the solder joints of
the two "original" leads. If they are not shiny, reheat them and if
necessary, apply additional solder.
Fuse and Conventional Resistor
Removal/Replacement
1. Clip each fuse or resistor lead at top of the circuit board hollow
stake.
2. Securely crimp the leads of replacement component around
notch at stake top.
3. Solder the connections.
-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
This spec sheet is applied to the LD70B chassis.
2. Specification
Each part is tested as below without special appointment
1) Operating Temperature : 0˚C to 40˚C
2) Operating Humidity : Less than 80%
3) Storage Temperature : -20˚C to 60˚C
4) Storage Humidity : Less than 85%
5) Power Voltage : S tandard input voltage (100 - 240V~
50/60Hz)
S
tandard Voltage of each product is
marked by models
6) Specification and performance of each parts are followed
each drawing and specification by part number in accord-
ance with BOM .
7) The receiver must be operated for about5 minutes prior to
the adjustment
3.Test method
1) Performance : LGE TV test method followed
2) Demanded other specification
- Safety : CE,IEC specification
- EMC : CE,IEC specification
-6- Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
4. Model general specification
No Item Specification Remarks
1 Market EU/CIS DTV & Analog (Total 37 countries)
(PAL Market-37 Countries) DTV (MPEG2/4, DVB-T) : 26 countries
Germany, Netherland, Switzerland, Hungary, Austria, Slove-
nia, Bulgaria, France, Spain, , Belgium, Luxemburg, Greece,
Czech, Turkey, Moroco, Ireland, Latvia, Estonia, Lithuania,
Poland, Portugal, Romania, Albania, Bosnia, Slovakia,
Beralus
DTV (MPEG2/4, DVB-T2) :11 countries
UK(Ireland), Sweden, Denmark, Finland, Norway, Ukraine,
Kazakhstan
Russia, Italy, Croatia, Serbia
DTV (MPEG2/4, DVB-C) : 37 countries
Germany, Netherland, Switzerland, Hungary, Austria, Slove-
nia, Bulgaria, France, Spain, Italy, Belgium, Russia, Luxem-
burg, Greece, Czech, Croatia, Turkey, Moroco, Ireland, Lat-
via, Estonia, Lithuania, Poland, Portugal, Romania, Albania,
Bosnia, Serbia, Slovakia, Beralus, UK, Sweden, Denmark,
Finland, Norway, Ukraine, Kazakhstan
DTV (MPEG2/4,DVB-S) : 37 countries
Germany, Netherland, Switzerland, Hungary, Austria, Slove-
nia, Bulgaria, France, Spain,Belgium, Luxemburg, Greece,
Czech, Turkey, Moroco, Ireland, Latvia, Estonia, Lithuania,
Poland, Portugal, Romania, Albania, Bosnia, Slovakia,
Beralus, UK(Ireland), Sweden, Denmark, Finland, Norway,
Ukraine, Kazakhstan,Russia, Italy, Croatia, Serbia
Supported satellite : 35 satellites
ABS1 75.0E , AMOS 4.0W , ASIASAT3S 105.5E , ASTRA
19.2E , ASTRA 23.5E , ASTRA 28.2E , ASTRA 4.8E, ATLAN-
TIC BIRD2 8.0W , ATLANTIC BIRD3 5.0W , BADR 26.0E ,
DIRECTV-1R 56.0E , EUROBIRD 9A 9.0E , EUROBIRD3
33.0E , EUTELSAT 36 A/B 36.0E ,
EUTELSAT W2A 10.0E , EUTELSAT W3A 7.0E , EUTEL-
SAT7WA 7.3W
EUTELSAT 16.0E , EXPRESS AM1 40.0E , EXPRESS AM3
140.0E , EXPRESS AM33 96.5E , HELLASSAT 39.0E ,
HISPASAT 1CDE 30.0W
HOTBIRD 13.0E , INTELSAT10&7 68.5E , INTELSAT15
85.2E , INTELSAT1R 50.0W, INTELSAT903 33.5W , INTEL-
SAT904 60.0E
, NILESAT 7.0W , NSS12 57.0E , THOR 0.8W , TURKSAT
42.0E ,
YAMAL201 90.0E , OTHER
2 Television system 1) Digital TV
- DVB-T/T2
- DVB-C
- DVB-S/S2
2) Analogue TV
- PAL/SECAM B/G/I/D/K
- SECAM L/L’
-7- Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
No Item Specification Remarks
3 Program coverage 1) Digital TV
- VHF, UHF
- C-Band, Ku-Band
2) Analogue TV
- VHF : E2 to E12
- UHF : E21 to E69
- CATV : S1 to S20
- HYPER : S21 to S47
4 Receiving system Analog : Upper Heterodyne ► DVB-T
Digital : COFDM, QAM - 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 (Model : *L*V*-Z* (T2 only Model))
- 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
16-QAM : 1/2, 2/5, 2/3, 3/4, 5/6
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
- viterbi
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
5 SCART(N/A) DELETED
6 Video Input RCA(1EA) PAL, SECAM, NTSC4.43 4 System :
PAL, SECAM, NTSC4.43, PAL60
Hybrid Type
7 Head phone out (N/A) Antenna, AV, Component, HDMI1,
HDMI2, USB1
8 Component Input (1EA) Y/Cb/Cr Hybrid Type
Y/Pb/Pr
9 HDMI Input (2EA) HDMI1-DTV
HDMI2-DTV
10 Audio Input (3EA) DVI Audio L/R Input
Component
AV
11 SPDIF out SPDIF out
12 USB (1EA) EMF, DivX HD, For SVC (download) JPEG, MP3, DivX HD
13 Ethernet Connect(1EA) Ethernet Connect
14 PCMCIA Card slot PCMCIA slot
(1EA)
-8- Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
5. External Input Support Format
5.1. Component Video Input (Y, PB, PR)
No. Resolution H-freq(kHz) V-freq(Hz) Remark
1 720×480 15.75 60.00 SDTV, DVD 480i
2 720×480 15.73 59.94 SDTV, DVD 480i
3 720×480 31.47 59.94 480p
4 720×480 31.50 60.00 480p
5 720×576 15.62 50.00 SDTV, DVD 625
Line
6 720×576 31.25 50.00 HDTV 576p
7 1280×720 37.50 50.00 HDTV 720p
8 1280×720 44.96 59.94 HDTV 720p
9 1280×720 45.00 60.00 HDTV 720p
10 1920×1080 28.12 50.00 HDTV 1080i
11 1920×1080 33.75 60.00 HDTV 1080i
12 1920×1080 33.72 59.94 HDTV 1080i
13 1920×1080 56.25 50.00 HDTV 1080p
14 1920x1080 67.43 59.94 HDTV 1080p
15 1920×1080 67.50 60.00 HDTV 1080p
5.2. HDMI input
5.2.1. DTV mode
No. Resolution H-freq(kHz) V-freq(Hz) Proposed Remark
1 640*480 31.46 59.94 SDTV 480P
2 640*480 31.50 60.00 SDTV 480P
3 720*480 15.73 59.94 SDTV, DVD 480I(525I) Spec. out but display
4 720*480 15.75 60.00 SDTV, DVD 480I(525I)
5 720*576 15.62 50.00 SDTV, DVD 576I(625I) 50Hz
6 720*480 31.47 59.94 SDTV 480P
7 720*480 31.50 60.00 SDTV 480P
8 720*576 31.25 50.00 SDTV 576P
9 1280*720 44.96 59.94 HDTV 720P
10 1280*720 45.00 60.00 HDTV 720P
11 1280*720 37.50 50.00 HDTV 720P
12 1920*1080 28.12 50.00 HDTV 1080I
13 1920*1080 33.72 59.94 HDTV 1080I
14 1920*1080 33.75 60.00 HDTV 1080I
15 1920*1080 26.97 23.97 HDTV 1080P
16 1920*1080 27.00 24.00 HDTV 1080P
17 1920*1080 33.71 29.97 HDTV 1080P
18 1920*1080 33.75 30.00 HDTV 1080P
19 1920*1080 56.25 50.00 HDTV 1080P
20 1920*1080 67.43 59.94 HDTV 1080P
21 1920*1080 67.50 60.00 HDTV 1080P
-9- Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
5.2.2. PC mode
- FHD Model (FHD)
No. Resolution H-freq(kHz) V-freq(Hz) Proposed Remark
1 640 x 350 @70Hz 31.46 70.09 EGA
2 720 x 400 @70Hz 31.46 70.08 DOS
3 640 x 480 @60Hz 31.46 59.94 VESA(VGA)
4 800 x 600 @60Hz 37.87 60.31 VESA(SVGA)
5 1024 x 768 @60Hz 48.36 60.00 VESA(XGA)
6 1152 x 864 @60Hz 54.34 60.05 VESA
7 1280 x 1024 @60Hz 63.98 60.02 VESA(SXGA) FHD only
8 1360 x 768 @60Hz 47.71 60.01 VESA(WXGA)
9 1920 x 1080 @60Hz 67.5 60.00 WUXGA(CEA 861D) FHD only
24MT49S-PZS/28MT49S-PZS/24LJ480U-PZ (HD)
No. Resolution H-freq(kHz) V-freq(Hz) Proposed Remark
1 640 x 350 @70Hz 31.468 70.090 EGA
2 720 x 400 @70Hz 31.469 70.080 DOS
3 640 x 480 @60Hz 31.469 59.940 VESA(VGA)
4 800 x 600 @60Hz 37.879 60.317 VESA(SVGA)
5 1024 x 768 @60Hz 48.363 60.004 VESA(XGA)
6 1152 x 864 @60Hz 54.348 60.053 VESA
7 1360 x 768 @60Hz 47.712 60.015 VESA(WXGA)
- 10 - Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
SOFTWARE UPDATE
1. USB Download
1) Put the USB Stick to the USB socket
2) Automatically detecting update file in USB Stick
- If your downloaded program version in USB Stick is Lower,
it didn’t work. But your downloaded version is Higher, USB
data is automatically detecting (Download Version High &
Power only mode, Set is automatically Download)
3) Show the message “Copying files from memory”
4) Updating is starting.
5) Updating Completed, The Signage Set will restart automati-
cally
6) If your SIGNAGE SET is turned on, check your updated
version and Tool option. (explain the Tool option, next
stage)
* If downloading version is more high than your SIGNAGE
SET have, SIGNAGE SET can lost all channel data. In this
case, you have to channel recover. if all channel data is
cleared, you didn’t have a DTV/ATV test on production line.
* After downloading, have to adjust TOOL OPTION
again.
1) Push "IN-START" key in service remote control.
2) Select "Tool Option 1" and Push “OK” button.
3) Punch in the number. (Each model has their number.)
- 11 - Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
X_TAL
24MHz
TU_CVBS/SIF DDR3 1066MHz
AIR/Cable (512MB X 2EA)
TU_SCL/SDA
Digital Demod
LNB_TX
Tuner
LNB_OUT, DEMOD_RESET SYSTEM EEPROM
I2C 1 (256Kb)
DEMOD_SCL/SDA
Satellite
eMMC 5.0
IC101 (4GB)
SIDE OCP
USB1 1.5A USB
30P
LVDS
HDMI1
- 12 -
(ARC) HDMI
REAR
MUX
HDMI2 I2C_1 Audio AMP
※ Wireless Network/Wi-Fi Direct/Miracast
BLOCK DIAGRAM
Copyright ©
(2.4GHz/5GHz)
CVBS, Y/Pb/Pr, L/R USB_WIFI WIFI
AV/Component
(Built-in)
R
E Optical Digital SUB
A Audio Out SPDIF OUT ASSY
R IR IR / KEY
KEY
Only training and service purposes.
LAN ETHERNET
X_TAL
I2C 3 Sub Micom
32.768KHz
LG Electronics Inc. All rights reserved.
EXPLODED VIEW
IMPORTANT SAFETY NOTICE
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts
are identified by in the EXPLODED VIEW.
It is essential that these special safety parts should be replaced with the same components as recommended
in this manual to prevent Shock, Fire, or other Hazards.
Do not modify the original design without permission of manufacturer.
910
900
400
LV1
401
ARC1
541
120
AR1
540
700
831
570
832
200
720
OR
510
300
730
305
- - Copyright © LG Electronics Inc. All rights reserved.
Only training and service purposes.
TROUBLE SHOOTING GUIDE
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Contents of Standard Repair Process
* First of all, Check whether there is SVC Bulletin in GSCS System for these model.
No. Error symptom (High category) Error symptom (Mid category) Page Remarks
1 No video/Normal audio 1
2 No video/No audio 2
3 Tuning fail, Picture broken/ Freezing 3
A. Video error
4 Color error 4
Vertical/Horizontal bar, residual image, light spot,
5 5
external device color error
6 No power 6
B. Power error
7 Off when on, off while viewing, power auto on/off 7
8 No audio/Normal video 8
C. Audio error
9 Wrecked audio/discontinuation/noise 9
10 Remote control & Local switch checking 10
D. Function error
11 External device recognition error 11
12 E. Noise Circuit noise, mechanical noise 12
13 F. Exterior error Exterior defect 13
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process
Error Symptom A. Video Error Established date
1/13
Content No video / Normal audio Revised date
First of all, Check whether all of cables between board is inserted properly or not.
(Main B/D ↔ Adaptor, LVDS Cable, Speaker Cable, IR B/D Cable…)
☞A1 ☞A4
Y Y Y
No video Normal Check Back Light Check LVDS 12 V Normal
On Replace Module
Normal audio Audio On with naked eye of Main B/D Voltage
N N N
☞A2
Move to Check Main B/D to LED Back light Voltage Replace Main
No video/No audio B/D or Repair parts
Y
Normal Replace Module
Voltage
N
Replace Main
B/D or Repair parts
※Precaution ☞A3 & A6
Always check & record S/W Version and White
Replace Main Board Re-enter White Balance value
Balance value before replacing the Main Board
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process
Error Symptom A. Video Error Established date
2/13
Content No video / No audio Revised date
☞A13
No video / Check voltage 19V Normal Y Replace Main
No audio of Adaptor Voltage B/D or Repair parts
N
Replace Adaptor
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process
Error Symptom A. Video Error Established date
3/13
Content Tuning fail, Picture broken/freezing Revised date
. By using Digital signal level meter
☞ A5
. By using Diagnostics Setting on OSD
Check RF Signal level ( Setting → Customer Support(red button on remote control) → Signal Test )
- Signal strength (Normal : over 50%)
- Signal quality (Normal : over 50%)
Y Check whether other equipments have problem or not.
Normal
(By connecting RF Cable at other equipment)
Signal
→ DVD Player ,Set-Top-Box, Different maker TV etc`
N
☞ A6
Check RF Cable
Normal Y Check SVC N Check Normal Y
Connection End
1. Reconnection Picture S/W Version Bulletin Tuner soldering Picture
2. Install Booster
N Y N
N S/W Upgrade Replace
Normal Contact with signal distributor
Picture or broadcaster (Cable or Air) Main B/D
Y
Normal N
Picture
End
Y
End
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process
Error Symptom A. Video Error Established date
4/13
Content Color error Revised date
☞ A8 / A9
☞A7 Check and
replace Link Y Y
Check color by input Y
Color Cable Color Color
- External Input Replace Main B/D Replace module
error (LVDS) and error error
(COMPONENT/AV/HDMI)
contact
N N N
condition
Check error End
color input
mode
External
☞A10 Input External
Check external Y
Compon device/
Check Test pattern device and Replace Main B/D
ent, Cable
cable
HDMI Normal
error N
Request repair
for external
device/cable
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process
Error Symptom A. Video Error Established date
Vertical/Horizontal bar, Residual Image, 5/13
Content Revised date
Light spot, External device Color error
Vertical/Horizontal bar, residual image, light spot Replace
Module
☞A7 ☞ A8/ A9 N
Check external
Check color condition by input Y Y Check and
Screen device Screen Screen N Screen
- External Input replace Link Replace Main B/D
normal connection normal normal normal
(Component/AV/HDMI) Cable
condition
N N Y Y
☞A10 Replace Request repair End End
Module for external
Check Test pattern
device
External device screen error-Color error Connect other external
Check screen device and cable
Y condition by input External Y (Check normal operation of N
Check Screen Replace
Check S/W Version -External Input Input External Input, Component
Version normal Main B/D
(Component/AV/ error and HDMI by connecting
HDMI) N Jig, pattern Generator,
N Y
Set-top Box etc.
S/W Upgrade
End Request repair for
external device
Normal N
Screen
Y
End
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process
Error Symptom B. Power Error Established date
6/13
Content No power Revised date
☞A11
DC Power on Normal N
Check Power Y Replace
by pressing Power Key Operati
Power LED LED On Main B/D
On Remote control on
Stand-By : Red N Y
Check Adaptor/ End
Power cord
was inserted properly
Power Y
LED On
※
N Y
☞A16
Normal
Check ST-BY 3.4V
Voltage
N
Replace Adaptor or
Replace Main B/D
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process
Error Symptom B. Power Error Established date
7/13
Content Off when on/off while viewing, power auto on/off Revised date
☞A14
N Y CPU Y
Check outlet Adaptor Check Power Off
Error Abnorm Replace Main B/D Normal End
or A/C cord DC Out Mode
al
Y N
N
Abnorm
al1 Replace Adaptor
☞A13
Fix A/C cord & Outlet Replace
Adaptor (If Power Off mode
is not displayed) Normal Y
Replace Main B/D
Check Adaptor Voltage
voltage
N
Replace Adaptor
* Please refer to the all cases which Status Power off List Explanation
can be displayed on power off mode. "POWEROFF_REMOTEKEY" Power off by REMOTE CONTROL
"POWEROFF_OFFTIMER" Power off by OFF TIMER
"POWEROFF_SLEEPTIMER" Power off by SLEEP TIMER
"POWEROFF_INSTOP" Power off by INSTOP KEY
"POWEROFF_AUTOOFF" Power off by AUTO OFF
Normal "POWEROFF_ONTIMER" Power off by ON TIMER
"POWEROFF_RS232C" Power off by RS232C
"POWEROFF_RESREC" Power off by Reservated Record
"POWEROFF_RECEND" Power off by End of Recording
"POWEROFF_SWDOWN" Power off by S/W Download
"POWEROFF_UNKNOWN" Power off by unknown status except listed case
"POWEROFF_ABNORMAL1" Power off by abnormal status except CPU trouble
Abnormal
"POWEROFF_CPUABNORMAL" Power off by CPU Abnormal
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process
Error Symptom C. Audio Error Established date
8/13
Content No audio / Normal video Revised date
☞A15
Check user
Y
No audio Connection Connec Replace Speaker
Screen normal from Main tion or Main B/D
Speaker Cable
N
Insert wafer SPK Cable
Normal N
Audio
Y
End
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process
Error Symptom C. Audio Error Established date
9/13
Content Wrecked audio / Discontinuation / Noise Revised date
Check input ☞A13
Y Wrecked Audio/ Check and replace
signal Signal Check Voltage 19V
Discontinuation/ speaker and
-RF Normal of Adaptor
Noise for all audio connector
-External Input
N
Wrecked Audio/ Y
Normal
Discontinuation/ Replace Main B/D
Voltage
Noise only for D-TV
N
Wrecked Audio/
Discontinuation/ Replace Adaptor
Noise only for Analog
Wrecked Audio/
Connect and check
Discontinuation/
other external Replace Main B/D End
Noise only for
device
External Input
(When RF signal is not
received) N
Normal
Request repair to external Audio
cable/ANT provider
Y
(In case of
External Input
signal error) Check and fix external device
Check and fix
external device
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process
Error Symptom D. Function Error Established date
10/13
Content Remote control & Local switch checking Revised date
Replace
Main B/D
☞A16 Y
☞A16 ☞A16
Y Check & Repair N
Check R/C itself Normal Normal Check 3.4V Normal Y Check IR Normal
Cable connection
Operation Operating Operating On Main B/D Voltage Output signal Signal
Connector solder
N Y N N
☞A13
End Check Voltage 19V of Adaptor Replace
Check R/C Operating Check & Replace IR B/D
When turn off light Baterry of R/C
in room
If R/C operate,
Explain the customer Y
Normal
cause is interference End
Operating
from light in room.
N
Replace R/C
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process
Error Symptom D. Function Error Established date
11/13
Content External device recognition error Revised date
Check technical
Y N External Input and
Check input Signal information Technical
Component Replace Main B/D
signal Input - Fix information information
Recognition error
- S/W Version
N Y
Fix in
Check and fix accordance HDMI
external device/cable with technical Recognition error
information
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process
Error Symptom E. Noise Established date
12/13
Content Circuit noise, Mechanical noise Revised date
Identify Circuit Check location
Replace Main Board
nose type noise of noise
Mechanical Check location
noise of noise
※ When the noise is severe, replace the module
※ Mechanical noise is a natural (For models with fix information, upgrade the S/W or
phenomenon and apply the 1st level provide the description)
description. or
When the customer does not agree, apply ※ If there is a “Tak Tak” noise from the cabinet, refer
the process by stage. to the KMS fix information and then proceed as
shown in the solution manual
(For models without any fix information, provide the
description)
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process
Error Symptom F. Exterior Defect Established date
13/13
Content 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
damage
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Contents of Standard Repair Process Detail Technical Manual
* First of all, Check whether there is SVC Bulletin in GSCS System for these model.
No. Error symptom Content Page Remarks
1 Check LCD back light with naked eye A1
2 LED driver B+ measuring method A2
A. Video error_ No video/Normal audio
3 Check White Balance value A3
4 Power voltage measuring method A4
5 TUNER input signal strength checking method A5
A. Video error_ No video/Video lag/stop
6 Version checking method A6
7 Connection diagram A7
8 A8
A. Video error_Color error Check Link Cable (LVDS) reconnection condition
9 A9
10 Adjustment Test pattern - ADJ Key A10
11 Connection diagram A8
A. Video error_Vertical/Horizontal bar, A8
12 Check Link Cable reconnection condition
residual image, light spot A9
13 Adjustment Test pattern - ADJ Key A10
14 Exchange T-Con Board (1) A-1/5
15 Exchange T-Con Board (2) A-2/5
16 Defected Type caused by T-Con/ Inverter/ Exchange LED driver Board (PSU) A-3/5
Module
17 Exchange Module itself (1) A-4/5
18 Exchange Module itself (2) A-5/5
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Contents of Standard Repair Process Detail Technical Manual
* First of all, Check whether there is SVC Bulletin in GSCS System for these model.
No. Error symptom Content Page Remarks
19 Check front display LED A11
20 Check power input Voltage & ST-BY 3.4V A12
B. Power error_No power
21 Checking method when power is ON A13
22 Power voltage measuring method A4
B. Power error_Off when on, off while
23 POWER OFF MODE checking method A14
viewing
Checking method in Setting when there is no
24 C. Audio error_No audio/Normal video A15
audio
D. Function error_ No response in remote
25 Remote control operation checking method A16
control, key error
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process Detail Technical Manual
Error Symptom A. Video Error, No Video/Normal Audio Established date
A1
Content Check Back Light On with Naked eye Revised date
Power On -> disjoint back case -> check lighting
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process Detail Technical Manual
Error Symptom A. Video Error, No Video/Normal Audio Established date
A2
Content Main Board to LED back light Voltage Revised date
Measure DC Voltage applying to LED backlight from Main B/D
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process Detail Technical Manual
Error Symptom A. Video Error, No Video/Normal Audio Established date
A3
Content Check White Balance value Revised date
1. Press the ADJ button on the remote control for adjustment
2. Enter into White Balance of item 11
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
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process Detail Technical Manual
Error Symptom A. Video Error, No Video/Normal Audio Established date
A4
Content Power Voltage Measuring Method Revised date
HD Model : 27 ~ 30 pin
Check LVDS Voltage 12V
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process Detail Technical Manual
Error Symptom A. Video Error, Video lag/stop Established date
A5
Content Tuner Input Signal Strength Checking Method Revised date
All Settings Programmes
Programme Tuning & Settings
Manual Tuning
Select channel
When the signal is strong, use the
attenuator (-10dB, -15dB, -20dB etc.)
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process Detail Technical Manual
Error Symptom A. Video Error, No Video/Normal Audio Established date
A6
Content Version Checking Method Revised date
Checking SW version method for remote control for adjustment
Press the IN-START with the remote
control for adjustment
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process Detail Technical Manual
A. Video Error, Vertical/Horizontal bar, Residual Image,
Error Symptom Established date
Light spot A7
Content Connection diagram Revised date
As the part connecting to the external input, check the
screen condition by signal
* Jack spec. : depending on Model
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process Detail Technical Manual
Error Symptom A. Video Error, Color Error Established date A8/
Content Check and replace Link Cable(LVDS) and contact condition Revised date A9
1. Check and replace LVDS Cable
2. Check LVDS connection condition
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process Detail Technical Manual
Error Symptom A. Video Error, Color Error Established date
A10
Content Adjustment Test Pattern – ADJ Key Revised date
You can view 10 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)
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Appendix : Exchange T-Con Board (1)
Solder defect, CNT Broken Solder defect, CNT Broken Solder defect, CNT Broken
Solder defect, CNT Broken T-Con
T-Con Defect,
Defect,
Solder
T-Con CNT
defect,
Defect, CNT
CNT
CNT Broken
Broken
Broken
Broken Abnormal Power Section
Solder defect, Short/Crack Abnormal Power Section Solder defect, Short/Crack
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Appendix : Exchange T-Con Board (2)
Abnormal Power Section Abnormal Power Section Solder defect, Short/Crack
Solder defect, Short/Crack Fuse Open, Abnormal power section Abnormal Display
GRADATION Noise GRADATION
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Appendix : Exchange the Module (1)
Press damage Press damage Press damage
Un-repairable Cases
In this case please exchange the module.
Crosstalk Crosstalk
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Appendix : Exchange the Module (2)
Vertical Block Vertical Line Vertical Block
Source TAB IC Defect Source TAB IC Defect Source TAB IC Defect
Horizontal Block Horizontal Block Horizontal line
Gate TAB IC Defect Gate TAB IC Defect
Gate TAB IC Defect Gate TAB IC Defect Gate TAB IC Defect
Un-repairable Cases
In this case please exchange the module.
Horizontal Block
Gate TAB IC Defect
Gate TAB IC Defect
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process Detail Technical Manual
Error Symptom B. Power Error, No Power Established date
A11
Content Check front Display LED Revised date
ST-BY condition: Red
Front LED control :
All Settings General Standby Light On/Off
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process Detail Technical Manual
Error Symptom B. Power Error, No Power Established date A12/
Content Checking Method When Power is ON Revised date A13
Check Voltage 19V of Adaptor Power
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process Detail Technical Manual
Error Symptom B. Power Error, Off when on, off whiling viewing Established date
A14
Content Power off Mode checking method Revised date
1. Press the IN-START button of the remote control for adjustment
2. Check the entry into adjustment item 3
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process Detail Technical Manual
Error Symptom D. Function Error, No Response in remote control, Key error Established date
A16
Content Remote control operation checking method Revised date
P4101
③
1 +3.4V_ST
2 KEY1
3 KEY2
4 GND
5 LED_R
6 NC
① < Sub Ass’y> 7 GND
8 IR
② < Main Ass’y>
1, 2. Check IR cable condition between IR & Main board
3. Check the 3.4V_ST Voltage
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
Standard Repair Process Detail Technical Manual
Error Symptom C. Audio Error, No Audio/Normal Video Established date
A15
Content Checking method in Setting when there is no audio Revised date
① ② < Main Ass’y>
1. Check the contact condition of DC jack or 19V input voltage from adapter.
2. 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.
Copyright © 2017 LG Electronics Inc. All rights reserved.
Only training and service purposes.
