LG 49LH5700, 43LH5700 Schematic

Internal Use Only

LED TV

SERVICE MANUAL

CHASSIS : LA66L

MODEL : 43LH5700 43LH5700-UD

MODEL : 49LH5700 49LH5700-UD

CAUTION

BEFORE SERVICING THE CHASSIS,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

Printed in KoreaP/NO : MFL69442202 (1602-REV00)

CONTENTS

CONTENTS .............................................................................................. 2

SAFETY PRECAUTIONS ........................................................................ 3

SERVICING PRECAUTIONS ................................................................... 4

SPECIFICATION ....................................................................................... 6

ADJUSTMENT INSTRUCTION ................................................................ 9

BLOCK DIAGRAM ...................................................................................17

EXPLODED VIEW .................................................................................. 18

SCHEMATIC CIRCUIT DIAGRAM ........................................... APPENDIX

TROUBLESHOOTING .............................................................. APPENDIX

Only for training and service purposes

- 2 -

LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.

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
Schematic Diagram and 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

Only for training and service purposes

- 3 -

LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.

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.

Only for training and service purposes

- 4 -

LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.

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.

Only for training and service purposes

- 5 -

LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.

SPECIFICATION

NOTE : Specifications and others are subject to change without notice for improvement

.

1. Application range

This spec sheet is applied to the LED TV used LA66L chassis

2. Test condition

Each part is tested as below without special notice.

(1) Temperature : 25 ºC±5 ºC (77 ºC±9ºC), CST : 40 ºC±5 ºC
(2) Relative Humidity: 65 % ± 10 %
(3) Power Voltage

Standard input voltage (100~240V@ 50/60Hz)

(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 : UL, CSA, IEC specification

- EMC: FCC, ICES, IEC specification

4. General Specification

No Item Specication Result Remark

1 Receiving System ATSC / NTSC-M / 64 & 256 QAM

2 Available Channel 1) VHF : 02~13

2) UHF : 14~69

3) DTV : 02-69

4) CATV : 01~135

5) CADTV : 01~135

3 Input Voltage AC 100 ~ 240V 50/60Hz Mark : 110V, 60Hz

4 Market NORTH AMERICA

5 Screen Size 32", 43”, 49", 55”

6 Aspect Ratio 16:9

7 Tuning System FS

8 Module HC320DXN-SLNS5 LGD

HC430DUN-SLNX1 LGD

NC490DUE-SADP1 LGD

LC550DUE-MGA3

9 Operating Environment 1) Temp : 0 ~ 40 deg

2) Humidity : ~ 80 %

10 Storage Environment 1) Temp : -20 ~ 60 deg

2) Humidity : ~ 85 %

Only for training and service purposes

- 6 -

LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.

5. Supported video resolutions

5.1. Component 2D input(Y, CB/PB, CR/PR)

No Resolution H-freq(kHz) V-freq.(Hz) Pixel clock(MHz) Proposed

1 720*480 15.730 60.000 13.513 SDTV ,DVD 480I

2 720*480 15.730 59.940 13.500 SDTV ,DVD 480I

3 720*480 31.500 60.000 27.027 SDTV 480P

4 720*480 31.470 59.940 27.000 SDTV 480P

5 1280*720 45.000 60.000 74.250 HDTV 720P

6 1280*720 44.960 59.940 74.176 HDTV 720P

7 1920*1080 33.750 60.000 74.250 HDTV 1080I

8 1920*1080 33.720 59.940 74.176 HDTV 1080I

9 1920*1080 67.500 60.000 148.500 HDTV 1080P

10 1920*1080 67.432 59.940 148.352 HDTV 1080P

11 1920*1080 27.000 24.000 74.250 HDTV 1080P

12 1920*1080 26.970 23.976 74.176 HDTV 1080P

13 1920*1080 33.750 30.000 74.250 HDTV 1080P

14 1920*1080 33.710 29.970 74.176 HDTV 1080P

Only for training and service purposes

- 7 -

LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.

5.2. HDMI Input (PC/DTV)

No Resolution H-freq(kHz) V-freq.(Hz) Pixel clock(MHz) Proposed

PC

1 640*350 31.46 70.09 25.17 EGA

2. 720*400 31.46 70.08 28.32 DOS

3. 640*480 31.46 59.94 25.17 VESA(VGA)

4 800*600 37.87 60.31 40.00 VESA(SVGA)

5 1024*768 48.36 60.00 65.00 VESA(XGA)

6 1152*864 54.34 60.05 80.00 VESA

7 1280*1024 63.98 60.02 108.00 VESA (SXGA) FHD only

8 1360*768 47.71 60.01 85.50 VESA (WXGA)

9 1920*1080 67.5 60.00 148.5 WUXGA

(Reduced Blanking)

DTV

1 640 * 480 31.46 59.94 25.125 SDTV 480P

2 640 * 480 31.5 60.00 25.125 SDTV 480P

3 720 * 480 15.73 59.94 13.500 SDTV 480I Spec. out but display

4 720 * 480 15.75 60.00 13.514 SDTV 480I Spec. out but display

5 720 * 480 31.47 59.94 27.00 SDTV 480P

6 720 * 480 31.5 60 27.027 SDTV 480P

7 1280*720 44.96 59.94 74.176 HDTV 720P

8 1280*720 45 60.00 74.25 HDTV 720P

9 1920*1080 33.72 59.94 74.176 HDTV 1080I

10 1920*1080 33.75 60.00 74.25 HDTV 1080I

11 1920*1080 26.97 23.97 63.296 HDTV 1080P

12 1920*1080 27.00 24.00 63.36 HDTV 1080P

13 1920*1080 33.71 29.97 79.120 HDTV 1080P

14 1920*1080 33.75 30.00 79.20 HDTV 1080P

15 1920*1080 67.43 59.94 148.350 HDTV 1080P

16 1920*1080 67.5 60.00 148.50 HDTV 1080P

FHD only

Only for training and service purposes

- 8 -

LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.

ADJUSTMENT INSTRUCTION

1. Application

This spec. sheet applies to LA66L Chassis applied LED TV all
models manufactured in TV factory

2. Specification

(1) Because this is not a hot chassis, it is not necessary to use

an isolation transformer. However, the use of isolation

transformer will help protect test instrument.
(2) Adjustment must be done in the correct order.
(3) The adjustment must be performed in the circumstance of

25 ±5 ºC of temperature and 65±10% of relative humidity if

there is no specific designation
(4) The input voltage of the receiver must keep 100~240V,

50/60Hz
(5) The receiver must be operated for about 5 minutes prior to

the adjustment when module is in the circumstance of over

15

ºC

In case of keeping module is in the circumstance of 0°C, it

should be placed in the circumstance of above 15°C for 2

hours
In case of keeping module is in the circumstance of below

-20°C, it should be placed in the circumstance of above

15°C for 3 hours.

※ Caution
When still image is displayed for a period of 20 minutes or
longer (especially where W/B scale is strong.
Digital pattern 13ch and/or Cross hatch pattern 09ch), there
can some afterimage in the black level area

3. Adjustment items

3.1. Main PCBA Adjustments

(1) ADC adjustment(OTP) : Component
(2) EDID downloads for HDMI

3.2. Final assembly adjustment

(1) White Balance adjustment
(2) RS-232C functionality check
(3) Factory Option setting per destination
(4) Shipment mode setting (In-Stop)
(5) GND and HI-POT test

4. MAIN PCBA Adjustments

4.1. ADC Calibration

- An ADC calibration is not necessary because MAIN SoC
(LGExxxx) is already calibrated from IC Maker

- If it needs to adjust manually, refer to appendix.

4.2. MAC Address, ESN Key and Widevine
Key download

4.2.1. Equipment & Condition

(1) Play file: keydownload.exe

4.2.2. Communication Port connection

(1) Key Write: Com 1,2,3,4 and 115200 (Baudrate)
(2) Barcode: Com 1,2,3,4 and 9600 (Baudrate)

4.2.3. Download process

(1) Select the download items.
(2) Mode check: Online Only
(3) Check the test process

- US, Canada models: DETECT -> MAC_WRITE ->

WIDEVINE_WRITE

- Korea, Mexico models: DETECT -> MAC_WRITE ->

WIDEVINE_WRITE
(4) Play : START
(5) Check of result: Ready, Test, OK or NG

4.2.4. Communication Port connection

(1) Connect: PCBA Jig -> RS-232C Port == PC -> RS-232C

Port

4.2.5. Download

(1) All models (16Y LCD TV + MAC + Widevine + ESN Key

and HDCP2.2)

3.3. Appendix

(1) Tool option menu, USB Download (S/W Update, Option and

Service only)
(2) Manual adjustment for ADC calibration and White balance.
(3) Shipment conditions, Channel pre-set

Only for training and service purposes

4.2.6. Inspection

- In INSTART menu, check these keys.

- 9 -

LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.

4.3. LAN port Inspection (Ping Test)

4.3.1. Equipment setting

(1) Play the LAN Port Test PROGRAM.
(2) Input IP set up for an inspection to Test Program.

* IP Number : 12.12.2.2.

4.3.2. LAN PORT inspection (PING TEST)

(1) Play the LAN Port Test Program.
(2) connect each other LAN Port Jack.
(3) Play Test (F9) button and confirm OK Message.
(4) remove LAN CABLE

4.4.3. EDID DATA

4.4.3.1. HD PCM (2D 8bit xvYCC : off) : 32LH570B-UC
(1) HDMI1 (6D , 08)

(2) HDMI2 (6D , F8)

Step 1) Step 3) Check ‘OK’ Signal

4.4. EDID Download

4.4.1 Overview

▪ It is a VESA regulation. A PC or a MNT will display an

optimal resolution through information sharing without any
necessity of user input. It is a realization of “Plug and Play”.

4.4.2 Equipment

▪ Since embedded EDID data is used, EDID download JIG,

HDMI cable and D-sub cable are not need.

▪ Adjust remocon

4.4.3.2. HD AC3 (2D 8bit xvYCC : off) : 32LH570B-UC
(1) HDMI1 (6D , 96)

Only for training and service purposes

- 10 -

LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.

(2) HDMI2 (6D , 86)

4.4.3.3. HD DTS (2D 8bit xvYCC : off) : 32LH570B-UC
(1) HDMI1 (6D , 8D)

4.4.3.4. FHD PCM (2D 8bit xvYCC : off) : 43/49/55LH5700-UD
(1) HDMI1 (E5 , CC)

(2) HDMI2 (E5 , BC)

(2) HDMI2 (6D , 7D)

Only for training and service purposes

4.4.3.5. FHD AC3 (2D 8bit xvYCC : off) : 43/49/55LH5700-UD
(1) HDMI1 (E5 , 5A)

- 11 -

LGE Internal Use OnlyCopyright © LG Electronics. Inc. All rights reserved.