LG 32LK610BPUA, 32LK610BBUA Schematic

LED TV
SERVICE MANUAL
CHASSIS : LA84J
MODEL : 32LK610BPUA
MODEL : 32LK610BBUA
CAUTION
BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
P/NO : MFL70504601 (1804-REV01)
CONTENTS
CONTENTS .............................................................................................. 2
SAFETY PRECAUTIONS ........................................................................ 3
SERVICING PRECAUTIONS ................................................................... 4
SPECIFICATION ....................................................................................... 6
SOFTWARE UPDATE .............................................................................. 8
BLOCK DIAGRAM ................................................................................... 9
EXPLODED VIEW .................................................................................. 10
ASSEMBLY GUIDE / DISASSEMBLY GUIDE ....................................... 12
TROUBLE SHOOTING GUIDE ................................................ APPENDIX
- 2 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
SAFETY PRECAUTIONS
IMPORTANT SAFETY NOTICE
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by in the Exploded View. It is essential that these special safety parts should be replaced with the same components as recommended in this manual to prevent Shock, Fire, or other Hazards. Do not modify the original design without permission of manufacturer.
General Guidance
An isolation Transformer should always be used during the servicing of a receiver whose chassis is not isolated from the AC power line. Use a transformer of adequate power rating as this protects the technician from accidents resulting in personal injury from electrical shocks.
It will also protect the receiver and it's components from being damaged by accidental shorts of the circuitry that may be inadvertently introduced during the service operation.
If any fuse (or Fusible Resistor) in this TV receiver is blown, replace it with the specified.
When replacing a high wattage resistor (Oxide Metal Film Resistor, over 1 W), keep the resistor 10 mm away from PCB.
Keep wires away from high voltage or high temperature parts.
Before returning the receiver to the customer,
always perform an AC leakage current check on the exposed metallic parts of the cabinet, such as antennas, terminals, etc., to be sure the set is safe to operate without damage of electrical shock.
Leakage Current Cold Check(Antenna Cold Check)
With the instrument AC plug removed from AC source, connect an electrical jumper across the two AC plug prongs. Place the AC switch in the on position, connect one lead of ohm-meter to the AC plug prongs tied together and touch other ohm-meter lead in turn to each exposed metallic parts such as antenna terminals, phone jacks, etc. If the exposed metallic part has a return path to the chassis, the measured resistance should be between 1 MΩ and 5.2 MΩ. When the exposed metal has no return path to the chassis the reading must be infinite. An other abnormality exists that must be corrected before the receiver is returned to the customer.
Leakage Current Hot Check (See below Figure)
Plug the AC cord directly into the AC outlet.
Do not use a line Isolation Transformer during this check. Connect 1.5 K / 10 watt resistor in parallel with a 0.15 uF capacitor between a known good earth ground (Water Pipe, Conduit, etc.) and the exposed metallic parts. Measure the AC voltage across the resistor using AC voltmeter with 1000 ohms/volt or more sensitivity. Reverse plug the AC cord into the AC outlet and repeat AC voltage measurements for each exposed metallic part. Any voltage measured must not exceed 0.75 volt RMS which is corresponds to
0.5 mA. In case any measurement is out of the limits specified, there is possibility of shock hazard and the set must be checked and repaired before it is returned to the customer.
Leakage Current Hot Check circuit
- 3 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
SERVICING PRECAUTIONS
CAUTION: Before servicing receivers covered by this service manual and its supplements and addenda, read and follow the
SAFETY PRECAUTIONS on page 3 of this publication. NOTE: If unforeseen circumstances create conict between the
following servicing precautions and any of the safety precautions on page 3 of this publication, always follow the safety precautions. Remember: Safety First.
General Servicing Precautions
1. Always unplug the receiver AC power cord from the AC power source before;
a. Removing or reinstalling any component, circuit board mod-
ule or any other receiver assembly.
b. Disconnecting or reconnecting any receiver electrical plug or
other electrical connection.
c. Connecting a test substitute in parallel with an electrolytic
capacitor in the receiver. CAUTION: A wrong part substitution or incorrect polarity installation of electrolytic capacitors may result in an explo­sion hazard.
2. Test high voltage only by measuring it with an appropriate high voltage meter or other voltage measuring device (DVM, FETVOM, etc) equipped with a suitable high voltage probe. Do not test high voltage by "drawing an arc".
3. Do not spray chemicals on or near this receiver or any of its assemblies.
4. Unless specied otherwise in this service manual, clean
electrical contacts only by applying the following mixture to the contacts with a pipe cleaner, cotton-tipped stick or comparable non-abrasive applicator; 10 % (by volume) Acetone and 90 % (by volume) isopropyl alcohol (90 % - 99 % strength)
CAUTION: This is a ammable mixture. Unless specied otherwise in this service manual, lubrication of
contacts in not required.
5. Do not defeat any plug/socket B+ voltage interlocks with which receivers covered by this service manual might be equipped.
6. Do not apply AC power to this instrument and/or any of its electrical assemblies unless all solid-state device heat sinks are correctly installed.
7. Always connect the test receiver ground lead to the receiver chassis ground before connecting the test receiver positive lead. Always remove the test receiver ground lead last.
8. Use with this receiver only the test xtures specied in this
service manual.
CAUTION: Do not connect the test xture ground strap to any
heat sink in this receiver.
Electrostatically Sensitive (ES) Devices
Some semiconductor (solid-state) devices can be damaged eas­ily by static electricity. Such components commonly are called Electrostatically Sensitive (ES) Devices. Examples of typical ES
devices are integrated circuits and some eld-effect transistors
and semiconductor “chip” components. The following techniques should be used to help reduce the incidence of component dam­age caused by static by static electricity.
1. Immediately before handling any semiconductor component or semiconductor-equipped assembly, drain off any electrostatic charge on your body by touching a known earth ground. 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 unit under test.
2. After removing an electrical assembly equipped with ES devices, place the assembly on a conductive surface such as aluminum foil, to prevent electrostatic charge buildup or expo­sure of the assembly.
3. Use only a grounded-tip soldering iron to solder or unsolder ES devices.
4. Use only an anti-static type solder removal device. Some solder
removal devices not classied as “anti-static” can generate electrical charges sufcient to damage ES devices.
5. Do not use freon-propelled chemicals. These can generate
electrical charges sufcient to damage ES devices.
6. Do not remove a replacement ES device from its protective package until immediately before you are ready to install it. (Most replacement ES devices are packaged with leads electri­cally shorted together by conductive foam, aluminum foil or comparable conductive material).
7. Immediately before removing the protective material from the leads of a replacement ES device, touch the protective material to the chassis or circuit assembly into which the device will be installed. CAUTION: Be sure no power is applied to the chassis or circuit, and observe all other safety precautions.
8. Minimize bodily motions when handling unpackaged replace­ment ES devices. (Otherwise harmless motion such as the brushing together of your clothes fabric or the lifting of your
foot from a carpeted oor can generate static electricity suf­cient to damage an ES device.)
General Soldering Guidelines
1. Use a grounded-tip, low-wattage soldering iron and appropriate tip size and shape that will maintain tip temperature within the range or 500 °F to 600 °F.
2. Use an appropriate gauge of RMA resin-core solder composed of 60 parts tin/40 parts lead.
3. Keep the soldering iron tip clean and well tinned.
4. Thoroughly clean the surfaces to be soldered. Use a mall wire­bristle (0.5 inch, or 1.25 cm) brush with a metal handle. Do not use freon-propelled spray-on cleaners.
5. Use the following unsoldering technique
a. Allow the soldering iron tip to reach normal temperature.
(500 °F to 600 °F) b. Heat the component lead until the solder melts. c. Quickly draw the melted solder with an anti-static, suction-
type solder removal device or with solder braid.
CAUTION: Work quickly to avoid overheating the circuit board printed foil.
6. Use the following soldering technique. a. Allow the soldering iron tip to reach a normal temperature
(500 °F to 600 °F)
b. First, hold the soldering iron tip and solder the strand against
the component lead until the solder melts.
c. Quickly move the soldering iron tip to the junction of the
component lead and the printed circuit foil, and hold it there only until the solder ows onto and around both the compo­nent lead and the foil. CAUTION: Work quickly to avoid overheating the circuit board printed foil.
d. Closely inspect the solder area and remove any excess or
splashed solder with a small wire-bristle brush.
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Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
IC Remove/Replacement
Some chassis circuit boards have slotted holes (oblong) through which the IC leads are inserted and then bent at against the cir­cuit foil. When holes are the slotted type, the following technique should be used to remove and replace the IC. When working with boards using the familiar round hole, use the standard technique as outlined in paragraphs 5 and 6 above.
Removal
1. Desolder and straighten each IC lead in one operation by gently prying up on the lead with the soldering iron tip as the solder melts.
2. Draw away the melted solder with an anti-static suction-type solder removal device (or with solder braid) before removing the IC.
Replacement
1. Carefully insert the replacement IC in the circuit board.
2. Carefully bend each IC lead against the circuit foil pad and solder it.
3. Clean the soldered areas with a small wire-bristle brush. (It is not necessary to reapply acrylic coating to the areas).
"Small-Signal" Discrete Transistor Removal/Replacement
1. Remove the defective transistor by clipping its leads as close as possible to the component body.
2. Bend into a "U" shape the end of each of three leads remaining on the circuit board.
3. Bend into a "U" shape the replacement transistor leads.
4. Connect the replacement transistor leads to the corresponding leads extending from the circuit board and crimp the "U" with long nose pliers to insure metal to metal contact then solder each connection.
Power Output, Transistor Device Removal/Replacement
1. Heat and remove all solder from around the transistor leads.
2. Remove the heat sink mounting screw (if so equipped).
3. Carefully remove the transistor from the heat sink of the circuit board.
4. Insert new transistor in the circuit board.
5. Solder each transistor lead, and clip off excess lead.
6. Replace heat sink.
Diode Removal/Replacement
1. Remove defective diode by clipping its leads as close as 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.
3. Solder the connections. CAUTION: Maintain original spacing between the replaced component and adjacent components and the circuit board to prevent excessive component temperatures.
Circuit Board Foil Repair
Excessive heat applied to the copper foil of any printed circuit board will weaken the adhesive that bonds the foil to the circuit board causing the foil to separate from or "lift-off" the board. The following guidelines and procedures should be followed whenever this condition is encountered.
At IC Connections
To repair a defective copper pattern at IC connections use the following procedure to install a jumper wire on the copper pattern side of the circuit board. (Use this technique only on IC connec­tions).
1. Carefully remove the damaged copper pattern with a sharp knife. (Remove only as much copper as absolutely necessary).
2. carefully scratch away the solder resist and acrylic coating (if used) from the end of the remaining copper pattern.
3. Bend a small "U" in one end of a small gauge jumper wire and carefully crimp it around the IC pin. Solder the IC connection.
4. Route the jumper wire along the path of the out-away copper pattern and let it overlap the previously scraped end of the good copper pattern. Solder the overlapped area and clip off any excess jumper wire.
At Other Connections
Use the following technique to repair the defective copper pattern at connections other than IC Pins. This technique involves the installation of a jumper wire on the component side of the circuit board.
1. Remove the defective copper pattern with a sharp knife. Remove at least 1/4 inch of copper, to ensure that a hazardous condition will not exist if the jumper wire opens.
2. Trace along the copper pattern from both sides of the pattern break and locate the nearest component that is directly con­nected to the affected copper pattern.
3. Connect insulated 20-gauge jumper wire from the lead of the nearest component on one side of the pattern break to the lead of the nearest component on the other side. Carefully crimp and solder the connections. CAUTION: Be sure the insulated jumper wire is dressed so the it does not touch components or sharp edges.
Fuse and Conventional Resistor Removal/Replacement
1. Clip each fuse or resistor lead at top of the circuit board hollow stake.
2. Securely crimp the leads of replacement component around notch at stake top.
- 5 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
SPECIFICATION
NOTE : Specifications and others are subject to change without notice for improvement
.
1. Application range
This spec sheet is applied all of the LED TV with LA84J chassis
2. Test condition
Each part is tested as below without special notice.
(1) Temperature : 25 ºC ± 5 ºC, CST : 40 ºC±5 ºC (2) Relative Humidity: 65 % ± 10 % (3) Power Voltage
Standard input voltage (100~240V@ 50/60Hz) * 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.
3. Test method
(1) Performance: LGE TV test method followed (2) Demanded other specification
- Safety : CE, IEC specification
- EMC: CE, IEC
4. Electrical Specification
No Item Specication Remark
1 Receiving system ATSC / NTSC-M / 64 QAM / 256 QAM
2 Available Channel VHF : 2~13
UHF : 14~69
DTV : 2-69
CATV : 1 ~ 135
CADTV : 1 ~ 135
3 Video Input AC 100 ~ 240V@ 50/60Hz
4 Market North America
5 Screen Size 32”, 40”, 43”, 49”, 55”
6 Aspect Ratio 16:9
7 Tuning System FS
8 Operating Environment Temp : 0 ~ 40 deg
Humidity : ~ 80 %
9 Storage Environment Temp. : -20 ~ 60 deg
Humidity : ~ 85%
- 6 -
Copyright © LG Electronics Inc. All rights reserved. Only for 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.(kHz) Pixel clock(MHz) Proposed
1 720*480 15.73 59.94 13.50 SDTV ,DVD 480I
2 720*480 15.75 60.00 13.5135 SDTV ,DVD 480I
3 720*480 31.47 59.94 27.00 SDTV 480P
4 720*480 31.50 60.00 27.027 SDTV 480P
5 1280*720 44.96 59.94 74.176 HDTV 720P
6 1280*720 45.00 60.00 74.25 HDTV 720P
7 1920*1080 33.72 59.94 74.176 HDTV 1080I
8 1920*1080 33.75 60.00 74.25 HDTV 1080I
9 1920*1080 67.432 59.94 148.352 HDTV 1080P
10 1920*1080 67.50 60.00 148.50 HDTV 1080P
5.2. HDMI Input (PC/DTV)
No. Resolution H-freq(kHz) V-freq.(kHz) Pixel clock(MHz) Proposed
DTV
1 640*480 31.46 59.94 25.125 SDTV 480P
2 640*480 31.50 60.00 25.125 SDTV 480P
3 720*480 31.47 59.94 27.00 SDTV, DVD 480I(525I)
4 720*480 31.50 60.00 27.027 SDTV, DVD 480I(525I)
5 1280*720 44.96 59.94 74.176 SDTV, DVD 576I(625I) 50Hz
6 1280*720 45.00 60.00 74.25 SDTV 480P
7 1920*1080 33.72 59.94 74.176 SDTV 480P
8 1920*1080 33.75 60.00 74.25 SDTV 576P
9 1920*1080 26.97 23.97 74.176 HDTV 720P
10 1920*1080 27.00 24.00 74.25 HDTV 720P
11 1920*1080 33.71 29.97 74.176 HDTV 720P
12 1920*1080 33.75 30.00 74.25 HDTV 1080I
13 1920*1080 67.43 59.94 148.352 HDTV 1080I
14 1920*1080 67.50 60.00 148.50 HDTV 1080I
15 1920*1080p 26.97 23.97 63.29 HDTV 1080P
16 1920*1080p 27.00 24.00 63.36 HDTV 1080P
PC DDC
1 640*350 @70Hz 31.46 70.09 25.17 EGA X
2 720*400 @70Hz 31.46 70.08 28.32 DOS O
3 640*480 @60Hz 31.46 59.94 25.17 VESA(VGA) O
4 800*600 @60Hz 37.87 60.31 40.00 VESA(SVGA) O
5 1024*768 @60Hz 48.36 60.00 65.00 VESA(XGA) O
6 1152*864 @60Hz 54.34 60.05 80.002 VESA O
7 1280*1024 @60Hz 63.98 60.02 108.0 VESA (SXGA) O FHD only
8 1360*768 @60Hz 47.71 60.01 85.50 VESA (WXGA) O
9 1920*1080 @60Hz 67.5 60.00 148.5 WUXGA(CEA 861D) O FHD only
- 7 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
SOFTWARE UPDATE
1. USB
(1) Insert the USB memory Stick to the USB port (2) Automatically detect the SW Version and show the below
message
(3) Click [YES]: initiate the download and install of the update.
2. NSU
(This Function is needed to connect to the internet)
(1) Menu -> All Settings -> General -> About This TV
(2) Click [CHEK FOR UPDATES] : system check newest
version
(4) Click [Check Now]: move to “About This TV” page for
update
(5) TV is updating
(6) After finished the update, below Pop-up appear
(7) Click [Yes] : TV will be DC OFF -> ON (8) After TV turned on, Check the updated SW Version and
Tool Option
(3) Click [DOWNLOAD AND INSTALL] (4) TV is updating
(5) After finished the update, below Pop-up appear
(6) Turn OFF the TV and On. Check the updated SW Version
and Tool Option
- 8 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
BLOCK DIAGRAM
Main IC
Audio AMP
Digital Demod
DIF (+/-)
IR / Key / Sensor
HDMI
MUX
LVDS
USB
SPDIF OUT
ETHERNET
USB1
USB2
OCP
1.5A
OCP
1.5A
HDMI1
HDMI2
(ARC)
REAR
OPTIC
LAN
51P(FHD)
DDR3 2133 4Gb x16
X_TAL
24MHz
WIFI 11ac only
SUB
ASSY
USB_WIFI
DDR3 2133 4Gb x16
HDMI3
SIDE
CVBS/YPbPr
AV/COMP
REAR
EEPROM (256Kb)
eMMC 5.0 (4GB)
I2S
I2C
I2C
Analog Demod
2100
CVBS/SIF
30P(HD)
IR / I2C / KEY
- 9 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
EXPLODED VIEW
IMPORTANT SAFETY NOTICE
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by in the EXPLODED VIEW. It is essential that these special safety parts should be replaced with the same components as recommended in this manual to prevent Shock, Fire, or other Hazards. Do not modify the original design without permission of manufacturer.
400
200P
810
800
521
571
570
500
501
900
120
HW1
HS1
LV1
540
HP1
530
700
820
A10
ARC1
200C
200A
AR1
- 10 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
POL(Front) Panel
Ass’y
POL(Rear) Optical Sheet
Rear Side
200PPF
200PPR
200P
200PC 200SL1 200SR1
EXPLODED VIEW(MODULE)
IMPORTANT NOTICE
MRC use only
* MRC : Module Repair Center
- 11 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
[Disassembly Guide]
2
2
1 1
1
3
32LK61 Screw 6 Points
32LK61 Latch 15 Points
(1) Lay the TV Set on a flat.
(2) Remove Screw (1, 2, 3).
ASSEMBLY / DISASSEMBLY GUIDE
* Prohibition : Pull the upward on bottom side.
Please remove Screw and Latch rst. * SCREW TORQUE : 5 ~ 7Kgf.cm
(3) Remove the latch.
1) Hold the left bottom handle and lift the B/C. At the same time, gently pushing the push points.
And Lift the right direction repeatedly (Separate the B/C from bottom to top direction)
* If push with strong force from left side, Side Latch will break.
- 12 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
1) Without S tand
2) With Stand
43 Back Cover
32” Back Cover
Push
Pull
Latch
Pull
Hold
Step1) Left Side
Pull
Hold
Push
Pull
Latch
Step2) Right Side
- 13 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
(4) After holding the left/right bottom handle and lift the bottom of the B/C, push the B/C in the upward direction .
- Caution : Hook can be separated on the top position, don’t pull it hard for upward
- 14 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
[Assembly Guide]
49L K61 La tc h 20 P oints
Press directio n
- Oblique direction from the outer surface
32LK61 La tc h 15 Point s
2
2
1 1
1
3
32LK61 S crew 6 Points
(1) Place the B/C on the module plate and Press Latch Points to assemble the B/C. (Assemble from bottom to top about B/C)
(2) Check whether gap occurs in the Top/left side/right side of the B/C
(3) Assemble the screws. (8ea)
- 15 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
ASSEMBLY / DISASSEMBLY GUIDE (MODULE)
[Disassemble Guide]
(1) Disassemble back cover
* Loosen the screws (6ea) and uncover the back cover
(2) Disassemble the IR and Wi-fi bracket
(3) Detach the EMI tapes from the S-PCB
* The EMI tape (6ea) should be reused, therefore, attach them to the C/bottom as a right figure
(4) Disassemble the FFC cables from the S-PCB and
* Open the black connector shield first * Separate FFC cable from the connector
- 16 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
(5) Disassemble the S-PCBs from the holder
(6) Disassemble the case top
* Loosen the side screws – 14ea (upper - 5ea, L, R and bottom – 3ea for each) * Flip the whole module and disassemble the case top to the upper side
(7) Disassemble the panel
* Firstly, detach the EMI tape at left and right side of the guide panel
* Starting from the bottom side, raise up the panel carefully until it
stands vertically
* When you handle the panel, standing it vertically first and carrying
the panel is recommended
- 17 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
(8) Disassemble the guide panel
* Uncover latches on the guide panel with the thin and narrow tool (ex, a flat head screwdriver) * Be careful about fragile latches
(9) Disassemble the sheets and diffuser plate
* Uncover latches on the guide panel with thin and narrow tool (ex, a flat head screwdriver) * Be careful about fragile latches
(11) Disassemble the reflector sheet
* Be careful about damaging the reflector sheet
- 18 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
(12) Disassemble the LED array
* Press the connectors from the both side, at the same time, pull the connector up to the direction of the upper side * Detach the whole LED array bars
- 19 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
[Assemble Guide]
(1) Assemble the LED array
* Assemble the LED array and press LED Array to cover bottom
(2) Assemble the reflector sheet
* Assemble the reflector sheet according to the guide embossing * Assemble the reflector sheet bellow the lens with your fingers * Check the upper and lower side of sheet at corner and arrange it
according to the remarks
* Make sure that all the holes of sheet is fastened on the racks of
cover bottom
(3) Assemble the DP and sheet
- 20 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
(4) Assemble the guide panel
(5) Assemble the panel
* Arrange the upper left/right side first, and then, assemble the bottom left/right side of the panel
(6) Attach the EMI pad on the panel and guide panel
(7) Assemble the case top and flip the module
- 21 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
(8) Arrange the S-PCBs to the holders
(9) Connect FFC cable to the S-PCB
(10) Attach the EMI tape (6ea)
(11) Tighten the case top screw (14ea)
- 22 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
(12) Assemble the Wi-fi and RF bracket
(13) Assemble the back cover
* Tighten the screws (6ea) and cover the back cover
- 23 -
Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
TROUBLE SHOOTING GUIDE
Copyright © 2018 LG Electronics Inc. All rights reserved. Only for training and service purposes.
Contents of Standard Repair Process
Copyright © 2018 LG Electronics Inc. All rights reserved. Only for training and service purposes.
No. Error symptom (High category) Error symptom (Mid category) Page Remarks
1
2 No video/No audio 2
3 Picture broken/ Freezing 3
4 Color error 4
5
6
7
8
9 Wrecked audio/discontinuation/noise 10
10 11 Wifi operating checking 12
A. Video error
B. Power error
C. Audio error
D. Function error
No video/Normal audio 1
Vertical/Horizontal bar, residual image, light spot, external device color error
No power 6 Off when on, off while viewing, power auto
on/off No audio/Normal video 9
Remote control & Local switch checking 11
5
7,8
12 External device recognition error 13
13 E. Noise Circuit noise, mechanical noise 14
14 F. Exterior error Exterior defect 15
First of all, Check whether there is SVC Bulletin in GSCS System for these model.
Standard Repair Process
Copyright © 2018 LG Electronics Inc. All rights reserved. Only for training and service purposes.
Error
symptom
A. Video error
No video/ Normal audio
Established
date
Revised date
First of all, Check whether all of cables between board is inserted properly or not.
(Main B/D Power B/D, LVDS or EPI Cable, Speaker Cable, IR B/D Cable,,,)
A18 ☞A1
No video Normal audio
Normal
audio
N
Move to No video/No audio
Y
Check Back Light On with naked eye
A18
Check Power Board 13.2V output
On
Normal voltage
N
Repair Power Board or parts
Y N Check Power
Board
13.2V etc.
Y
Replace Inverter
or module
Normal
voltage
N
Repair Power Board or parts
End
Replace T-con/Main
Y
Board or module
1/16
Precaution
Always check & record S/W Version and White Balance value before replacing the Main Board
A4 & A2
Replace Main Board
1
Re-enter White Balance value
Standard Repair Process
Copyright © 2018 LG Electronics Inc. All rights reserved. Only for training and service purposes.
Error
symptom
No Video/ No audio
A18
Check various voltages of Power Board (13.2V…)
A. Video error
No video/ No audio
Normal
voltage?
Replace Power Board and repair parts
Y
N
Check and replace MAIN B/D
Established
date
Revised date
End
2/16
2
Standard Repair Process
Copyright © 2018 LG Electronics Inc. All rights reserved. Only for training and service purposes.
A3
Check RF Signal level
Normal Signal?
N
Check RF Cable
Connection
1. Reconnection
2. Install Booster
Normal
Picture?
Y
Close
Y
N
Error
symptom
A. Video error
Picture broken/ Freezing
Established
date
Revised date
. By using Digital signal level meter . By using Diagnostics menu on OSD
( Advanced→ Channels→ Channel Tuning→ Manual Tuning → Check the Signal )
- Signal strength (Normal : over 50%)
- Signal Quality (Normal: over 50%)
Check whether other equipments have problem or not.
(By connecting RF Cable at other equipment)
→ DVD Player ,Set-Top-Box, Different maker TV etc`
A4
Normal
Picture?
Contact with signal distributor
or broadcaster (Cable or Air)
Y
S/W Version
N
Check
SVC
Bulletin?
S/W Upgrade
Normal
Picture?
Y
N
Y
N
Check
Tuner soldering
N
Replace
Main B/D
Y
3/16
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Close
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