LG 37LH55 LCD TV Presentation Training Manual

37LH5537LH55

Direct View LCD

October, 2009 Updated 11/03/2009

LCD DV 37LH552 October 2009

OUTLINEOUTLINE

• Ballast Board• Main Board• T-CON Board

Circuit Board Operation, Troubleshooting of :• Switch mode Power Supply

Section 1

Section 2

Contact Information, Preliminary Matters, Specifications,LCD Overview, General Troubleshooting Steps, Signal Distribution, Disassembly Instructions and Voltages

• Ft Control Board

New P-DIM (Digital Dimming) Routed from the Main board to the T-CON to the Ballast.

37LH55


37LH55 LCD Direct View DisplaySection 1

This Section will cover Contact Information and remind the Technician of Important Safety Precautions for the Customers Safety as well as the Technician and the Equipment.

Basic Troubleshooting Techniques which can save time and money sometimes can be overlooked. These techniques will also be presented.

This Section will get the Technician familiar with the Disassembly, Identification and Layout of the LCD Display Panel.

At the end of this Section the Technician should be able to Identify the Circuit Boards and have the ability and knowledge necessary to safely remove and replace any Circuit Board or Assembly.

Overview of Topics to be DiscussedOverview of Topics to be Discussed


IMPORTANT SAFETY NOTICEIMPORTANT SAFETY NOTICE

The information in this training manual is intended for use by persons possessing an adequate background in electrical equipment, electronic devices, and mechanical systems. In any attempt to repair a major Product, personal injury and property damage can result. The manufacturer or seller maintains no liability for the interpretation of this information, nor can it assume any liability in conjunction with its use. When servicing this product, under no circumstances should the original design be modified or altered without permission from LG Electronics. Unauthorized modifications will not only void the warranty, but may lead to property damage or user injury. If wires, screws, clips, straps, nuts, or washers used to complete a ground path are removed for service, they must be returned to their original positions and properly fastened.

CAUTIONCAUTION

To avoid personal injury, disconnect the power before servicing this product. If electrical power is required for diagnosis or test purposes, disconnect the power immediately after performing the necessary checks. Also be aware that many household products present a weight hazard. At least two people should be involved in the installation or servicing of such devices. Failure to consider the weight of an product could result in physical injury.

Preliminary Matters (The Fine Print)Preliminary Matters (The Fine Print)


Today’s sophisticated electronics are electrostatic discharge (ESD) sensitive. ESD can weaken or damage the electronics in a manner that renders them inoperative or reduces the time until their next failure. Connect an ESD wrist strap to a ground connection point or unpainted metal in the product. Alternatively, you can touch your finger repeatedly to a ground connection point or unpainted metal in the product. Before removing a replacement part from its package, touch the anti-static bag to a ground connection point or unpainted metal in the product. Handle the electronic control assembly by its edges only. When repackaging a failed electronic control assembly in an anti-static bag, observe these same precautions.

REGULATORY INFORMATIONREGULATORY INFORMATION

This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a residential installation. This equipment generates, uses, and can radiate radio frequency energy, and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures: Reorient or relocate the receiving antenna; Increase the separation between the equipment and the receiver; Connect the equipment to an outlet on a different circuit than that to which the receiver is connected; or consult the dealer or an experienced radio/TV technician for help.

ESDESD NoticeNotice (Electrostatic Static Discharge)(Electrostatic Static Discharge)


Safety and Handling Regulations

1. Approximately 20 minute pre-run time is required before any adjustments are performed.

2. Refer to the Voltage Sticker on the Switch Mode Power Supply silk screening. (+/- ½ volt).

3. Be cautious of electric shock from the Backlight section, it uses high voltage AC. Check that the Power Supply and Drive Circuits are completely discharged because of residual current stored before Circuit Board removal.

4. C-MOS circuits are sensitive to static electricity. Use caution when dealing with these IC and circuits.

5. Exercise care when making voltage and waveform checks to prevent costly short circuits from damaging the unit.

6. Be cautious of lost screws and other metal objects to prevent a possible short in the circuitry. Especially when removing the T-CON and/or the Ballast.

1. Check the appearance of the Replacement Panel and Circuit Boards for both physical damage and part number accuracy.

2. Check the model label. Verify model names and board model matches.3. Check details of defective condition and history. Example: Oscillator failure dead set,

etc…

Checking Points to be Considered

LCD Direct View Overview SectionLCD Direct View Overview Section


Basic Troubleshooting StepsBasic Troubleshooting Steps

Define, Localize, Isolate and Correct

•Define Look at the symptom carefully and determine what circuits could be causing the failure. Use your senses Sight, Smell, Touch and Hearing. Look for burned parts and check for possible overheated components. Capacitors will sometimes leak dielectric material and give off a distinct odor. Frequency of power supplies will change with the load, or listen for relay closing etc. Observation of the front Power LED may give some clues.

•Localize After carefully checking the symptom and determining the circuits to be checked and after giving a thorough examination using your senses the first check should always be the DC Supply Voltages to those circuits under test. Always confirm the supplies are not only the proper level but be sure they are noise free. If the supplies are missing check the resistance for possible short circuits.

•Isolate To further isolate the failure, check for the proper waveforms with the Oscilloscope to make a final determination of the failure. Look for correct Amplitude Phasing and Timing of the signals also check for the proper Duty Cycle of the signals. Sometimes “glitches” or “road bumps” will be an indication of an imminent failure.

•Correct The final step is to correct the problem. Be careful of ESD and make sure to check the DC Supplies for proper levels. Make all necessary adjustments and lastly always perform a Safety AC Leakage Test before returning the product back to the Customer.


This section of the manual will discuss the specifications of the 37LH55LCD Direct View Display Panel.

37LH55 PRODUCT INFORMATION SECTION37LH55 PRODUCT INFORMATION SECTION

37” Full HD 1080p 240Hz LCD TV (37.0” diagonal)

Introducing LG’s first HDTV with TruMotion™ 240Hz technology. Now you can watch blazing-fast action with virtually no motion blur in crystal clear detail. All of your

favorite sports, action movies and video games in crystal clear, Full HD 1080p. It’s still an HDTV, but you might

decide it’s something better.


37LH55 Basic Specifications37LH55 Basic Specifications

• TruMotion 240Hz• Intelligent Sensor Mode• Full HD 1080p HD Resolution• 80,000:1 Dynamic Contrast Ratio• 2.4ms Response Time (GTG)• 500 cd/m2 Brightness• Wide Color Gamut• Super IPS Panel• Wide Viewing Angle• XD Engine®• 24p Real Cinema• ISFccc® Ready• Picture Wizard• AV Mode II (Cinema, Sports, Game)• 60,000 Hour Panel Life (typical)• NTSC/ATSC Tuners with Clear QAM


Basic Specifications (LOGO Familiarization) Page 1Basic Specifications (LOGO Familiarization) Page 1

Full HD 1080p Resolution Displays HDTV programs in full 1920 x 1080presolution for a more detailed picture.


TOP PORTIONBOTTOM PORTIONRemote Control FamiliarizationRemote Control Familiarization

p/n MKJ42519621


Accessing the Service MenuAccessing the Service Menu

REMOTETOP PORTION

SIDE KEYS

To access the Service Menu.1) Turn the Set On2) Simultaneously, Press and “Hold”

the Menu Key on the Side Key pad and Press and “Hold” the Menu Key on the Remote approximately 5 seconds.

3) If Customer’s Menu appears, continue to hold until it disappears.

4) The Service Menu appears

Note: It is possible, dependant upon the Software Version, a Password may be required to enter the Service Menu.

If a password is required, enter0000


Side Input Jacks

Rear and Side Input JacksRear and Side Input Jacks

Main PWBOrientation

Rear Input Jacks

37LH55 PRODUCT DIMENSIONS37LH55 PRODUCT DIMENSIONS

15

7-7/8"200mm

2-9/16"65mm

37"939.8mm

Remove 4 screws to remove stand for wall mount

Model No.Serial No.Side Label

14"364mm

20-1/16"510mm

3-5/8"91.4mm

11-11/16"297mm

7-7/8"200mm

Weight without Stand: 32 lbWeight with Stand: 35.9 lb

8-1/8"206mm

3-13/16"97mm

11-3/4"298.5mm

23-1/2"597mm

26-1/16"662mm

WattageSTBY: >1W

Center

13 1/16"331mm


This section of the manual will discuss Disassembly, Layout and Circuit Board Identification, of the 37LH55 LCD Direct View Television.

Upon completion of this section the Technician will have a better understanding of the disassembly procedures, the layout of the printed circuit boards and be able to identify each board.

DISASSEMBLY and TROUBLESHOOTING SECTIONDISASSEMBLY and TROUBLESHOOTING SECTION


Removing the Back CoverRemoving the Back Cover

The Stand does not need to be removedRemove the 16 screws indicated.

Pay attention to the size and type of screwas there are many different types.

Putting in the improper screw when reassembling may Cause damage.


Circuit Board LayoutCircuit Board Layout

T-CON

MAIN

SMPS

BALLAST

FRONT CONTROL (IR)KEY BOARD

LVDS

LVDS

T-CON p/n EAT60664401Ballast p/n EAT60664401


POWER SUPPLY SECTIONPOWER SUPPLY SECTION

This set utilizes a Switch Mode Power Supply.

Input Voltages: AC

Stand-By Output Voltages:

• +5V (Stand By 5V) to the Main.

Run Output Voltages:

• +5V (Stand By 5V) to the Main• 12V to the Main

(Video Processing and T-CON B+)• 24V to the Main

(Audio B+)• 24V to the Ballast

Stand-By Output Signals:

• AC Det. (Releases reset on Main)

Run Input Signals from Main:

• PWR-ON (Relay On Command)Brings the SMPS out of Stand-By

• INV-ON (In and Out to the Ballast)Turns on the Backlights


Power Supply PWB RemovalPower Supply PWB Removal

Disconnect P201, P203, SK101 and AC In SK100.

Remove the 6 screws indicated by the arrows.

P201

SK100

P203

SK101To Main Power Switch

To Main board

To Ballast board

SK100 AC In

Caution: Be careful when touching the back side of the Power Supply as some capacitors can still hold a charge.


Power Supply (Master Power Switch) LocationPower Supply (Master Power Switch) Location

MASTER AC SWITCH LOCATION(Bottom Left Side viewed from rear)

OnOff

If the TV won’t come on, be sure

to check the Master Power Switch before assuming a failure has occurred.


Power Supply (SMPS) PWB LayoutPower Supply (SMPS) PWB Layout

Hot Ground Shock Hazard

To MainP201

AC INSK100

F1005A/250V

AC IN

F5013.15A/250VRun 380V

STBY 168VFrom Hot Gnd

L

N

Pin 1 Pin 2

To BallastP203

ToMaster Power Switch

SK101

Pin 1

POWER SUPPLY (SMPS)

To Backlights

Ballast

T-CON PWB12V LVDS

Along with VideoOn LVDS cable

Inverter OnStarts the Ballast.LED1 Lights first.

Backlights Light 2nd.

24V B+ for the Ballast

Stand By 5V

Power ButtonOr Remote Key

Reset ofMain Board

MAIN PWB

5V Q706 Switch

PWROn

12V VideoProcessing

InvOn

24VRegulator

12V/24V Regulators

Other Regs

StandBy 5V Reg

1

2 6 66 8

8

6

3

5

37LH55 POWER SUPPLY START UP SEQUENCE37LH55 POWER SUPPLY START UP SEQUENCE

6

6

6Primary side fuse:

Stand-By 156VRun 390V (Hot Gnd)

4

24V Audio

12V 24V

8

RegFor

Micro

LVDS12V

Switch12V

7

7

At point TV is in Stand-By state. Energy Star compliant.Less than 1 Watt

4

Other Circuits 5V General

PWM-DIMDigital

Dimming

Manipulates Backlights

Other C

ircuits

10

Cust Menu for Backlightand

Picture ContentManipulate P-DIM

Power O

n

3

8

No AC Det in this

model

LVDSVideo

12V

AC In

23

Ft Control

24V

INV On

LVDS Panel ControlInv On/Off

Microprocessor IC100Also Video Processor

Power On(RL_ON)

To Panel3.3V, 26.2V, -7.47V, 16.3V

Video

P801

P800

910

Tru-MotionLVDS Video

IC7043.3V

IC103

Q706

PWM-DIM

CN4

CN1

P201

CN3

MainPowerSwitch

Bridge

P203

To Panel

BALLAST

37LH55 P700 ON MAIN PWB TO SMPS P201 TURN ON CIRCUIT37LH55 P700 ON MAIN PWB TO SMPS P201 TURN ON CIRCUIT

INV ON/OFF

PWR ON

100ΩR714

C71115pF

P700

12V12V

Gnd

Gnd

Gnd

Gnd

0V

n/c

4.98V

1.8V

PWR On

P201

ERR Out

PWR

A.DIMINV.On

n/c

SMPS

IC100Mstar

100

n/c

GndGndGndGnd

H5R245100GPIO137

SBY5V

MAINPWB

5V

5V5V5V

GndGnd

12V

2

1

4

3

6

5

8

7

10

9

11

12

14

13

16

15

18

17

20

19

22

21

23

24

2

1

4

3

6

5

8

7

10

9

11

12

14

13

16

15

18

17

20

19

22

21

23

24

21.3V24V

GndGnd

GndGndGndGnd

n/c n/c

n/c3.38V

E5GPIO 134L706

L70424V

C72168uF

C72768uF

L70712V

C7200.1uF C722

47uF

L701

Q701R703R706

R257

G5

R719 1KΩ

Q702 R759 0Ω

R717 3.3KΩ

GPIO 136

R244 100Ω

+5V General

Power On

Inverter On/Off

3

1

2

6

5

8

7

Q706

+5VL715

+5V GeneralL709

LVDS 12V TCONL728

Q703

R251 100Ω0.2V

6V

0.6V

4Q704Q705

LVDS Panel Control

L708

0V0.6V

12V

R739 47KΩ

R740 47KΩ

C726220uF

Relay On

21.3V

3.8V

0K20K

R771

0KR776 0Ω

5V_ST

GPIO 138

F6

Power On/Off

A.DIM

R71810KΩ

3.3V-ST

R757 0Ω

R72910KΩ

R7430Ω

5V_ST

5V_ST

R72610KΩ

3.3V-ST

R25310KΩ

R72710KΩ

R732 22KΩ

R707 4.7KΩ

R201 100Ω

E8GPIO 97

Error

R185 1.2KΩ AB13 PWM 0

AB12 PWM 2VBR-B

R189 100Ω

T-CON

R8430Ω

448

CN1 P800

3

CN3

3

CN1

12

14

11

P203

CN4

3.8V

1.8V

12 11 14n/c

PWM-DIM

PWM-DIM (PWM Dimming) Manipulates the Backlight Brightness via Customer’s OSD. Manipulates the Backlight Brightness via the video processor IC100. Darker Picture, Darker Backlights to facilitate improved Contrast Ratio. 0.6V ~ 3.3V Range

A-DIM (Analog Dimming) Fixed Voltage

Error: If backlights fail to fire on the 4th attempt, this line goes high and power is turned off.

To pins 1, 2, 3 and 4 of P800 to T-CON

24


Power Supply (SMPS) PWB Operational TroubleshootingPower Supply (SMPS) PWB Operational Troubleshooting

Power Supply Troubleshooting

Ac voltage is supplied to the Power Supply at Connector SC100. This set does not use AC Detect. The AC input generates a Hot Ground primary power supply that runs in two states, Stand-By (168) and Run (380V) measured at Fuse F501 from Hot Ground. This primary voltage develops all other voltages that are output from the SMPS. During Stand-By, the 5 Volt Standby (5V_ST) should be present at connector P201, Pins 7,8,9 or 10. If Missing remove AC Power and unplug Connector P201, apply AC Power and recheck for presence of 5V_ST. Loss of 5V_ST would be a SMPS Failure. Presence of 5V_ST would be an indication of a failure on the Main Board or possibly the Front PWB (IR) assembly. Suspect a possible short circuit loading the supply. Remember to observe the Front Power Indicating LED this may save some time. A lit LED indicates the Stand-By 5V voltage is present and the Microprocessor is communicating with the front LED driver IC!

The Main Board sends two commands to the Power Supply Board one being PWR the other is INV ON. These two signals are used to control the SMPS turn on sequence. First the command PWR (Pin 2) also known as POWER ON, activates the Ballast voltage 24V and the 24Vt and 12V lines to the Main board. The 2nd command is INV ON (P201 pin 20). It is the Lamp Lighting Command Signal. If either command (PWR-ON or INV-ON) is missing it will result in a no picture symptom and the backlights will not turn on.

These voltages can easily be checked with the volt meter! Remove AC Power, unplug the Connector to the Ballast P203. Reapply AC Power and press the ON-OFF Button on either the Remote Control or Power Button on the Unit. Watch for the Power ON LED to change color from red to blue. This is an indication the PWR Signal was created on the the Main board. Check P700 or P201 pin 2 for the PWR-ON command (4.9V) to the Power Supply. Check P201 for 24V (Pins 17 or 18) and 12V (Pins 13 or 14). Confirm Pin 20 of P201 went to 4.8V. This is the INV ON signal needed to light the Lamps.Problems with either voltage can be easily solved by following the simple steps on the next page.


Test 1 Power Supply PWB Low Voltage TestTest 1 Power Supply PWB Low Voltage Test

AC Should not be applied at any time while adding resistors or while unplugging connectors as damage to the circuit PWB may occur.

a) The SMPS PWB “MUST” be producing STBY 5V on either pin 7, 8, 9 or 10 (5V).

If 5V Standby is not being generated, the SMPS PWB is defective and must be replaced. There is no need to continue with the next test.

(b) Unplug P700 on the Main PWB and P203 to the Ballast.

TEST 1:

(1) Add a 10K resistor between (5V STBY) pin 7, 8, 9 or 10 and Pin 2 (PWR). Apply AC. This will turn on the power supply.a) Check that the 24V and 12V power supplies are

turned on, P201 (24V pins 17 and 18) (12V pins 13 and 14) and 24V to the Ballast P203 Pins 1~5.

(2) Remove AC power. Reinsert the plug P203 to the Ballast.

Use P700 Side toInsert resistors


Continue if the 1st test was successful. Leave original 10K resistor in place.

(3) Add another 10K resistor between (5V) pin 7, 8, 9 or 10 and Pin 20 (INV On).

(4) Unplug the small ribbon connector CN1 (This floats P-DIM)

(5) Apply AC Power. This simulates a Power On and Backlight On command.

Backlights Normal:a) If all is normal, the backlights should turn on.

Backlights Abnormal:b) Recheck connector P203 and confirm 24V on pins 1~5.

1) If low or missing, use diode mode to check the 24V line on Ballastconnector CN1. If low, this indicates a shorted output FET).

2) If open, check the Ballast Fuse, possible Open.c) Confirm the INV On/Off line P203 Pin 10 is going to 3V. d) Confirm Pin 3 of CN1 has >2V.

1) If not, you will need to add 3V by adding a 10K resistor from 5V_ST to pin 3 of CN1. Backlights should light.

REMOVE AC POWER:d) Check the connections to the Backlights. DO NOT check these when AC

is applied as they carry 1.2Kv each.

Test 2 Power Supply PWB Backlights TestTest 2 Power Supply PWB Backlights Test

P700 Connector disconnected from the Main PWB. Apply AC after adding jumper.

Use P700Side to insert

resistors


Power Supply Connector P201 Voltage and Diode CheckPower Supply Connector P201 Voltage and Diode Check

Diode Check taken with meter in Diode Mode with all Connectors Removed

1.69V4.99V0VPWR-ON2

Open4.8V0VINV.ON20

Open0V0VErr Out22

Open3.24V0V2PDIM24

ncncncnc1

GndGndGndGnd3-6

Open5.09V5.14V*5V7-10

GndGndGndGnd11-12

Open12.15V0V12V13-14

GndGndGndGnd15-16

0.73V24.8V0V24V17-18

ncncncnc19

Open1.67V0V1BR121

ncncncnc23

Diode CheckRun STBYLabelPin

P201 Odd "SMPS" to P700 "Main PWB"2 PDIM Pin 24 is not used by the Ballast.

PDIM is routed through the T-CON in this set.This line will fluctuate.

1 BR1 (A-DIM)Pin 21

Fixed and not used

* Stand By 5V


Power Supply P203 to Ballast CN4 Voltage and Diode CheckPower Supply P203 to Ballast CN4 Voltage and Diode Check


Open0VError14

Open3.40VPWM-DIM13

Open3.45VINV On/Off12

Open1.67VBR111

GndGndGnd6-10

0.73V24.83V24V1-5

Diode CheckRun LabelPin

P203 "SMPS" to CN1 "Ballast"

There are no Stand-By voltages.


Power Supply Connector SK100 and SK101 Voltage and Diode CheckPower Supply Connector SK100 and SK101 Voltage and Diode Check


AC Voltage Readings Across Pins 1 and 2 for STBY and RUN.

OLN2

OL120Vac

L1


AC Voltage Readings for either pin 1 or pin 2 in STBY and RUN with one lead on Neutral of SK101.

OLn/a2

OL120Vac

n/a1


SK100 "SMPS" to AC IN SK101 "SMPS" to MASTER POWER SWITCH

SK101

SK100

Bottom Left of SMPS

Live

Neutral

With the Master Power Switch Closed (On) AC flows.When Open (Off) AC open and does not flow.

Power Switch

AC In


Ballast Board

The Ballast receives it B+ from the Switch Mode Power Supply. 24V (CN1 pins 1~5) is delivered when the “Power On” command arrives at the SMPS.

The Backlights are turned on with the “Inverter On”command arrives. INV-ON is sent from the Main board through the SMPS to the Ballast.

The Backlights are manipulated by the control signal “P-DIM (Digital Dimming)” coming from the T-CON board via CN4 pin 3.

BALLAST SECTIONBALLAST SECTION


General Backlight InformationGeneral Backlight InformationTo Backlights Over 1.2KV

Currently, number of lamps “Unknown” Approx 12

To Backlights Over 1.2KV

EEFL (External Electrode Fluorescent Lamp)LOW COST Large number of lamps driven by a single inverter

Ballast

Connection board

Connection board

Connection board

Connection board





Simple structure, Low price

Complicated structureSimple structure

Lamp manufacturing processLamp assembly structure

Low CostLarge number of Lamp Drive by single inverter

Introducing EEFL Compared to CCFLIntroducing EEFL Compared to CCFL


Key: Long Life Time

• For CCFL, Hg gas is consumed mainly near the internal electrode• For EEFL, longer life time is expected because there is no internal electrode consuming Hg gas

EEFL Compared to CCFL ElectrodesEEFL Compared to CCFL Electrodes


Ballast PWB Assembly (With Shield) LayoutBallast PWB Assembly (With Shield) Layout

Transformers

p/n EAY60713901

Transformers

To Backlights Top Left

To Backlights Top Right

To Backlights Bottom Left

To Backlights Bottom Right

CN1

CN4

Ballast Start DetLED (LED1)

The bright blue LED (LED1) assist the backlights in firing in low room light conditions.

F110A/125V

To CN3 of T-CON

To P203 of SMPS


Ballast PWB Assembly LayoutBallast PWB Assembly Layout Warning: Do not Run the Ballast with Shield Removed.

To Backlights Top Left

To Backlights Top Right

To Backlights Bottom Left

To Backlights Bottom Right

CN1

CN4

Ballast Start DetLED (LED1)

The bright blue LED (LED1) assist the backlights in firing in low room light conditions.

F110A/125V

Transformers

Transformers

FET Drivers

FET Drivers

Driver ICs


Ballast Transformer WaveformsBallast Transformer Waveforms

T1, T2, T3 or T4 Pin 1

34V p/p 48kHz22.2V p/p 48kHz

Bottom TransformersTop Transformers are upside down

Warning, secondaryis over 1.2Kv

WarningDo not Run the Ballast with Shield Removed.

T1, T2, T3 or T4 Pin 6

Primary

6 1 6 1

FET Drivers

IC100Mstar

37LH55 P700 on Main PWB To Power Supply P201 Out P203 To Ballast MCN137LH55 P700 on Main PWB To Power Supply P201 Out P203 To Ballast MCN1

INV On/Off

4.82V20

P700

POWER SUPPLY

PWR2.86V

2

13

14

17

18

CN1

24V

BALLAST

12INV On/Off

ERR 0V2214

ERR

P201P203

MAIN PWB

20

22

2

5

4

12

3

14

G5

Relay On

R237 100Ω

R7130Ω

R71910KΩ

Q702

Inverter On

R771 0Ω

R257 100Ω

R70620KΩ

5V_ST

Q701

E5

5V GeneralStby 5V7 8 9 10

12V

24V24VReg

14

17

18

13

21

24VReg

24V

12VReg

SMPSControler

2

5

4

1

3

R8430Ω

38

PWM-DIM

VBR-BPWM-2R189

100Ω

AB12

PWM-DIM (PWM Dimming) Manipulates the Backlight Brightness via Customer’s OSD.Manipulates the Backlight Brightness via the video processor IC100. Darker Picture, Darker Backlights to facilitate improved Contrast Ratio. 0.6V ~ 3.3V Range

T-CON PWB

44

8

P800

CN13 CN3

CN4

3

AB13 VBR-APWM-0

2111 2111

A-DIM (Analog Dimming) Fixed Voltage 1.67V

R7074.7KΩ

R201100Ω GPIO97E8

R1851.2KΩ

ERROR 4th time this line goes high, power shuts off.

R720 10KΩ

R717 3.3KΩ

R714100Ω

3.3V_ST

L701

R7760Ω

R703 0Ω

GPIO131

GPIO136

Hi if Lamps do not light

A-DIM

4.82V

24.83V

0V

1.67V 1.67V

LVDS Cable

1.2kVOut

1.2kVOut

24Ballast Driver 1

Ballast Driver 2

Drive signalsTo the FETs

Fixed

13 24P-DIM not used13n/c

80% on Backlight Bar In Customer’s OSD (3.0V PDIM Pin 13 MCN1)

700uS

3.3mS



5.3mS

7.7mS

5.2mS

3.2mS

Waveform taken from either of the two pins 1 or 6 of the Ballast Transformer on the Primary Side.Slow scope setting to 2.5mS to see PWM results.The PWM amount can cause the frequency to be measured differently.

120Hz

37LH55 BACKLIGHT DRIVE SIGNAL (Digital Dimming Effects)37LH55 BACKLIGHT DRIVE SIGNAL (Digital Dimming Effects)

39

PWM-DIM manipulates the Burst Triangle Oscillator in the ballast drive IC.

ADIM also manipulates the Burst Triangle Oscillator But it is not used.

48Khz


Ballast Removal (Heat Sink and Insulators)Ballast Removal (Heat Sink and Insulators)

Protects the Output FETs

Be sure to replace “All”heat sink materials.Shield

Flipped over

Do not Run the Ballast with Shield Removed.

Heat Transfer material

Heat Transfer material

Remove 5 screws.

Be careful not to drop these screws.


Ballast Connector CN1 and CN4 Voltage and Diode CheckBallast Connector CN1 and CN4 Voltage and Diode Check


Open0VError14

Open3.40VPWM-DIM13

Open3.45VINV On/Off12

Open1.67VBR111

GndGndGnd6-10

0.73V24.83V24V1-5


CN1 "Ballast" to P203 "SMPS"

There are no Stand-By voltages.

GndGndn/c4

Open*3.3VC_23

GndGndC_12

0.73VGndGnd1


CN4 "Ballast" to CN3 “T-CON"

Pin 3 PDIM (Digital Dimming)Can vary according to the

brightness level of the video signal and the OSD Backlight setting. 0.6V 0% to 3.3V 100%. Output from the Video Processing chip

IC100 (Mstar).

Pin 13 PDIM (Digital Dimming)This pin is not used. See CN4


LCD Controller BoardThe T-Con IC UC1 receives from the Main Board LVDS at CN1 and CN2.

This is a duel 24 Bit LVDS Video Signal which it processes into TFT Drive Signals which are delivered through connectors CN4 and CN5 to the LCD TFT Panel.

12V is supplied to the T-Con Board on connector CN1 from the Main Boardeasily measured at fuse F1, (3A and 125V).

There is a DC to DC converter that creates; (16.3V Measured at VDD). (26.2V Measured at D5 cathode). (3.3V Measured at VCC). (-7.47V Measured at D6 bottom left leg).

These Voltages can also be measured at the ribbon connectors delivering signals to the TFT panel (CN4 26.2V pin 8, -7.4V pin 11, 3.3V pins 53, 54 and 16.3V pins 56, 57).(CN5 26.2V pin 7, -7.4V pin 6, 3.3V pins 53, 54 and 16.3V pins 56, 57).

See the 11X17 Foldout (Interconnect Diagram) for more details.

TT--CON (TFT DRIVE) SECTIONCON (TFT DRIVE) SECTION


TT--CON (TFT Drive) PWB (With Shield)CON (TFT Drive) PWB (With Shield)

Remove the 2 Screws in the T-CON shield.

Note: There are Chocolate (Heat Transfer) material pieces on the back side of the T-CON Heat sink.

They dissipate heat from the UC1 and US3 ICs.Be sure to return these pieces whenReinstalling the Heat Sink (Shield).

Heat Transfer

Heat Transfer

Remember, these two screws have to be replaced in the board if the TV is to be run without the T-CON shield in place.


TT--CON (TFT Drive) PWB RemovalCON (TFT Drive) PWB Removal

Remember to reinstall the 2 screws for the Service Position if the T-CON board needs to be turned on for test purposes. These would have been removed when taking off the shield.

CN5CN4

CN1

Disconnect CN1, CN2, CN4 and CN5. See next slide for details.

UC1

U3

U4

CN2CN3

U2

U5

T-CON p/n: EAT60664401


To remove the flex cables to the TFT Panel, CN4 or CN5: Place a soft thin object like a fingernail underneath the black locking tab and gently pull forward.

(Shown by the arrows in Fig 1)

Fig 1

Fig 2

Unlocked

Flip the lock up and back from the flex cable. Then the flex cable can be easily removed.

To remove the LVDS cable CN1; Press in on the two tabs and slowly rock the cable out of the connector.

(Shown by the arrows in Fig 3)

Fig 3 (CN1) LVDS

UNLOCKING CN1, CN4 and CN5UNLOCKING CN1, CN4 and CN5

The locking tab is flipped upward

Press In Press In

CN4 or CN5 Locked

TT--CON (TFT Drive) PWB Removal ContinuedCON (TFT Drive) PWB Removal Continued

Pull Out

Pull Out

Fig 4 (CN3)P-DIM

T-CON (TFT Drive) PWB (Shield Removed) Components IdentifiedT-CON (TFT Drive) PWB (Shield Removed) Components Identified

Warning:T-Con PWB under shield. Be sure to reinsert screws before operating set with shield removed.

CN5

UC1

CN4

FL7 Gnd

FL6Gnd

12V LVDSPins 48-51

D1

D2

B CE

Q2

Q1

A

C

A

A

C

A

A

C

AD3

Q3

Q4

AC

A

D5

D4

D6

X1

FL1

FL3

FL4 FL5

CN1 CN2

C43C42C41C40

C102C103

11

856/57 53/54

C38

C39 C

36

12V

16.34V

16.3V

16V12V

16.3V

20.5V-2.79V

Gnd

C30

C69

8.18V

1) 6.9V2) 7.47V3) 7.47V

12V-7.47V

U4F1 (12V)125V/3A

U5

2.72V3.28V 3.26V

26.2V

1.6V3.8V P/P9.97Mhz

26.6V12.2V26.4V

16.3VB

CE

Gnd

C94

16.3V 3.3V26.2V

-7.47V

56/57

16.3V

53/54

3.3V

Gnd

1.2V3.24V

1.2V

726.2V

6-7.47V

16.3V

3.3V3.3V

3.3V

1) 6.9V2) Gnd3) 7.46V

CN3

U18) 0V7) 3V6) 0V5) 3.25V

1) 0V2) 0V3) 0V4) 0V

1) 7.06V2) 16.27V3) 2.36V4) 13.4V5) 0V6) 11.14V7) 10.4V8) Gnd9) 0V10) 16.26V11) 8.39V12) 8.1V13) 3.23V14) 3.24V

15) 6.89V16) 16.27V17) 2.36V18) 3.11V19) 0V20) 16.29V21) 16.27V22) 5.25V23) 6V24) 0V25) 0V26) 0V27) 0V28) 3.25V

U2

L1

L2

1) 1.15V2) 0.5V3) 16.35V4) 11.79V5) 11.75V6) Gnd7) Gnd

15) 1.82V16) 0V17) 3.5V18) 3.5V19) 1.21V20) Gnd21) 11.84V

U422) 11.84V23) 11.82V24) 0V25) 3.33V26) 11.02V27) 11.85V28) 1.22V

8) 16.35V9) 11.84V10) 3.51V11) 7.17V12) 3.78V13) 0V14) 1.22V

U2

U3

p/n EAT60664401

To UC1 Pin 192P-Dim in Pin 8

GndPin 1, 2, 4

P-DimPin 3

U1

VDD

VCC

46


TT--CON (TFT Drive) PWB ChecksCON (TFT Drive) PWB ChecksT-CON PWB (Locations)

1.2V

3.24V

Gnd US2

Check the Regulator US2 for Correct Voltage

Check Fuse F1 for 12Vfrom CN1

Pins 48, 49, 50, and 51.

F1

CN1Cathode

3.3V

D2

D1

Cathode 16.34V

Check Fuse

F1 (12V)

Black band indicates Cathode


TT--CON (TFT Drive) CON (TFT Drive) Panel Voltage Panel Voltage Development ChecksDevelopment Checks

The development for the voltages on the CN4 and CN5 connectors are shown here

from the Interconnect diagram. They are outlined in the rounded cornered boxes.


TT--CON PWB Connector CN1 to Main PWB Voltage and Diode CheckCON PWB Connector CN1 to Main PWB Voltage and Diode Check


CN1 CONNECTOR "T-CON PWB“ to P800 "Main"

*Pin 8 PWM-DIM 3.15V (Max 100%) to 0.6V (Min 0%) Customer’s Menu Backlight setting.

1.1V1.3VURSA_A+224

1.1V1.3VURSA_A-225

1.1V1.1VBIT_SEL27

1.1V1.3VURSA_B+028

1.1V1.3VURSA_B-029

1.1V1.3VURSA_B+130

1.1V1.3VURSA_B-131

1.1V1.3VURSA_B+232

1.1V1.3VURSA_B-233

1.1V1.2VURSA_BCK+35

1.1V1.1VURSA_BCK-36

1.1V1.3VURSA_B+338

1.1V1.3VURSA_B-339

1.1V1.3VURSA_B+440

1.1V1.3VURSA_B-441

3.18V12.06V12V T-CON48-51

Diode CheckRunLabelPin

1.95V0VLVDS_SEL7

1.3V*3.2VPWM-DIM8

1.75V3.2VOPC_OUT19

1.75V0.6VOPC_EN10

GndGndOPC_OUT211

1.1V1.3VURSA_A+012

1.1V1.3VURSA_A-013

1.1V1.3VURSA_A+114

1.1V1.3VURSA_A-115

1.1V1.2VURSA_A+216

1.1V1.1VURSA_A-217

1.1V1.1VURSA_ACK+19

1.1V1.2VURSA_ACK-20

1.1V1.3VURSA_A+322

1.1V1.3VURSA_A-323


See arrow on the T-CON board CN1 indicating pin 1

Pins 2, 3, 4, 5, 6 and 47 are all no connection.

Pins 1, 18, 21, 26, 34, 37, 42, 43, 44, 45 and 46 are all ground.


TT--CON PWB Connector CN2 to the Main PWB (Voltage and Diode Check)CON PWB Connector CN2 to the Main PWB (Voltage and Diode Check)

Diode Mode values taken with all Connectors Removed

CN2 “T-CON“ to P801 CONNECTOR "Main"

Open1.3VURSA-C+320

Open1.2VURSA-C-321

Open1.13VURSA-C+422

Open1.18VURSA-C-423

GndGndGnd24

GndGndGnd25

Diode TestRunLabelPin

GndGndGnd19

Open1.23VURSA-CCK-18

Open1.23VURSA-CCK+17

GndGndGnd16

Open1.2VURSA-C-215

Open1.3VURSA-C+214

Open1.2VURSA-C-113

Open1.3VURSA-C+112

Open1.2VURSA-C-O11

Open1.28VURSA-C+010

n/cn/cn/c1-9


GndGndGnd40-41

Open1.15VURSA-D-439

Open1.4VURSA-D+438

Open1.25VURSA-D-337

Open1.3VURSA-D+336

GndGndGnd35

Open1.29VURSA-DCK-34

Open1.23VURSA-DCK+33

GndGndGnd32

Open1.2VURSA-D-231

Open1.3VURSA-D+230

Open1.3VURSA-D-129

Open1.29VURSA-D+128

Open1.25VURSA-D-027

Open1.29VURSA-D+026


MAIN BOARD SECTIONMAIN BOARD SECTION

Input Signal Processing IC100 is the main Microprocessor and the main Signal Processor. The Main board is responsible for :

• ATSC, NTSC, and QAM reception and processing• RS 232 service only Port (software upgrades and home theater environment).• Wired Remote Port• (2) Component Input Y, Pr, Pb and Audio L R• (3) HDMI Inputs (back) (1) HDMI (Side Input) • RGB PC and (PC Audio)• USB (software upgrades using flash drive). USB located on the Side.• AV Composite (1 Rear and 1 Side Input)• SIF and SAP

Output Signals• Dual 20 Bit LVDS to the T-CON Board via P800 and P801. Including 12V T-CON.• Audio output signals to the Speakers• Digital Audio Output Coaxial and Optical• ON OFF Controls to the SMPS turning on low voltage generation and Backlights• Backlight intensity control signal (Digital Dimming) P-DIM sent to the T-CON board.


Removing the Main PWBRemoving the Main PWB

Remove any tape holding down any

cables.

P1200NOTE: Be sure to check on top and behind the Video Processor IC. Look for a piece of

Chocolate(Heat Transfer Material).

Be sure to transfer to new PWB if present.

P700

Remove the 6 screws indicated by the

arrows.P800 P801

P600

Disconnect P700, P800, P801, P1200 and P600

Flip the locking tabs upward, pull the LVDS ribbon up and out

P800

P801


Main PWB Main PWB LayoutLayout

VIDEO PROCESSOR IC100 RUNS HOT, THIS IS NORMAL.

P700 To SMPS

P1200

To Front PWB Assembly

P800 to T-CON PWB

To Speakers

Look carefully on top and behind the Video

Processor IC for Chocolate

(Heat Transfer) material.

Be sure to transfer to new PWB if replaced.

SW100Reset

P600

P801 to T-CON PWB

IC100Microprocessor and

Video Processor

37LH55 Main PWB (Front View) Component Identification37LH55 Main PWB (Front View) Component Identification

54

MAIN (Digital) Board

To S

peakers

SW100

L726

P600

IC100Video

ProcessorMstar

1

16 SIF

19 Video

4 (5V)

12 DIF +13 DIF -15 (5V)

IC600Audio

L606

L607

IC1002

Q1202

IC1

IC706

IC701

IC704

IC705Q706

Q702P700

P1200

Q106

IC502HDMI Sel

IC1004Tuner Ctrl

TUNERTU1001

TDVW-H103F

IC900

IC901

12345

IC708

IC1000

Q100

IC101 IC707

L712

IC1001

P801P800

P104N/C

US

BH

DM

I4

Video

Aud L

Aud RQ1200

HDMI1

HDMI2

HDMI3

Y Pr/Pb 1

Y Pr/Pb 2

AV In

Remote Optical

RGB

RS232

Audio

Audio

L710

B

C E

IC801Tru-Motion

LVDS LVDS

IC105

BC E

LD1000

Resets IC100

B

C

E

B

C

E

BCE

1 2 3 4 5

IC2

L718

X100525Mhz

X80012Mhz

X10012Mhz

12V T-CONPins 1~4

37LH55 Main PWB (Back Side) Component Identification37LH55 Main PWB (Back Side) Component Identification

55

TU1001TDVW-H103F

US

BH

DM

I4

IC901

1

TUNER

16 SIF

19 Video

4 (5V)

12 DIF +13 DIF -15 (5V)

IC1202

IC1200

IC1201

D1223

AA

C

Q1000

Q1001

IC601

IC1003

Q600

D102

Q105

IC103

BC E

3 12

BC

E

IC702

AA C

D1239

AA C

IC104

D1204

D1240D1238

IC1073

12

Q705

B CE

B CE

B CE

Q704Q703IC800

BCE

BC E

IC501

AA

C

D500

Q701

B

C

E

IC1203


Main PWB X100 and X1005 CheckMain PWB X100 and X1005 Check

X800Location

X100 Location

2.28Vp/p12Mhz

Set on or off

IC100 Microprocessor Crystal

MAIN PWB

2.8Vp/p 12Mhz

X800

Crystal for TruMotion IC801

Only when set is on

X100

1.62V

1.58V

1.6V

1.58V


Main PWB X1005 and LD1000 FunctionMain PWB X1005 and LD1000 Function

Main PWBLD1000 Location

Use LD1000 as a visual aid.This lets you know if the tuner

is receiving a signal. If illuminated, then there’s no signal. Normally this LED

should be Off.

LD1000

X1005 Location

X1005

Crystal for Tuner Controller IC1004

Only when set is on

1.56V

1.64V


Main PWB Tuner with Shield Off (Pin ID)Main PWB Tuner with Shield Off (Pin ID)

1

19

18

4

13

12

9

8


MAIN PWB

Main PWB Tuner Video and SIF Output CheckMain PWB Tuner Video and SIF Output Check

Tuner Location

450mVp/p

Pin 19 “Video” Signal

Pin 16 “SIF” Signal

2.24Vp/p

USING COLOR BAR SIGNAL INPUT

Pin 12 and Pin 13“Dig IF” Signal

Note:“Dig IF” Signal only when receiving a Digital Channel.

700mVp/p

Pin 1

Note: “Video Out” Signal only when receiving an analog Channel.


Main PWB Tuner Clock and Data LinesMain PWB Tuner Clock and Data Lines

Pin 8 SDA

100uS1V per/div 5V p/p

Pin 9 SCL

100uS1V per/div 5V p/p

Note:SCL and SDA only active

during an actualChannel Change.


MAIN PWB

Main PWB LVDS P800 Video Output CheckMain PWB LVDS P800 Video Output Check

P800Location

To confirm that the Main PWB is outputting Picture Content signals, check P800 (LVDS) cable for output. Check pins 11-14,16-17, 19-24, 27-30, 32-33 and 35-40. Pins 35-36 carry the clock for TA and 19-20 carry the clock for TB. These signals vary from each other, but looking for signals like the ones shown below on any of these pins will confirm the output of video content. This signal is using standard SMTE Color Bar output from a generator as the input source.

Pin 1

Pin 39

This is just a sample of two pins on the LVDS.There are 8 pins on P801 carrying video.

2uS

500nS

2uS

500nS

Pin 51

Pin 1, 2, 3, 4 (LVDS 12V)

P800

Pin 11


Main PWB Connector P700 to Power Supply Voltage and Diode CheckMain PWB Connector P700 to Power Supply Voltage and Diode Check


1BR1 (A-DIM) Pin 21 Fixed and not used2 PDIM Pin 24 is not used by the Ballast.The voltage fluctuates, but is not used.

P700

1

Open4.99V0VPWR-ON2

Open4.8V0VINV.ON20

Open0V0VErr Out22

1.25V3.24V0V2PDIM24

ncncncnc1

GndGndGndGnd3-61.1V5.09V5.14V*5V7-10GndGndGndGnd11-122.3V12.15V0V12V13-14GndGndGndGnd15-16

Open24.8V0V24V17-18ncncncnc19

Open1.67V0V1BR121

ncncncnc23


P700 “Main” to P201 “SMPS”

Stand By 5V


Main PWB LVDS Connector P800 Pin IdentificationMain PWB LVDS Connector P800 Pin Identification

12V forT-CON PWB

Pin 44 PDIM (Digital Dimming) Can vary according to the brightness level of the video signal and the OSD Backlight setting. 0.6V 0% to 3.3V 100%. Output from the Video Processing chip IC100 (Mstar).

Video

Video

Video

10bit TA or 10bit TB

Resolution

Video

51 1

P800

Video

Video

TA Clock

TB Clock


Main PWB Connector P800 to TMain PWB Connector P800 to T--CON Voltage and Diode CheckCON Voltage and Diode CheckDiode Check taken with meter in Diode Mode with all Connectors Removed

P800 "Main" CONNECTOR to CN1 "T-CON PWB“

*Pin 44 PWM-DIM 3.2V (Max 100%) to 0.6V (Min 0%) Customer’s Menu Backlight setting. The T-CON then routes P-DIM to the Ballast. (Pin 1) is on the right

Pins 6,7,8,9,10, 15, 18, 26, 31, 34, and 51 are all ground.

1.1V1.3VURSA_A-227

1.1V1.1VBIT_SEL25

1.1V1.3VURSA_B+024

1.1V1.3VURSA_B-023

1.1V1.3VURSA_B+122

1.1V1.3VURSA_B-121

1.1V1.3VURSA_B+220

1.1V1.3VURSA_B-219

1.1V1.2VURSA_BCK+17

1.1V1.1VURSA_BCK-16

1.1V1.3VURSA_B+314

1.1V1.3VURSA_B-313

1.1V1.3VURSA_B+412

1.1V1.3VURSA_B-411

3.18V12.06V12V T-CON1~4


1.95V0VLVDS_SEL45

1.3V*3.2VPWM-DIM44

1.75V3.2VOPC_OUT143

1.75V0.6VOPC_EN42

GndGndOPC_OUT241

1.1V1.3VURSA_A+040

1.1V1.3VURSA_A-039

1.1V1.3VURSA_A+138

1.1V1.3VURSA_A-137

1.1V1.2VURSA_A+236

1.1V1.1VURSA_A-235

1.1V1.1VURSA_ACK+33

1.1V1.2VURSA_ACK-32

1.1V1.3VURSA_A+330

1.1V1.3VURSA_A-329

1.1V1.3VURSA_A+228


Pins 5, 46, 47, 48, 49 and 50 are all no connection.


Main PWB Connector P801 to the TMain PWB Connector P801 to the T--CON PWB Voltage and Diode CheckCON PWB Voltage and Diode Check

Diode Mode values taken with all Connectors Removed

P801 CONNECTOR "Main" to CN2 “T-CON"

GndGndGnd18

GndGndGnd17

Open1.29VURSA-D+016

Open1.25VURSA-D-015

Open1.29VURSA-D+114

Open1.3VURSA-D-113

Open1.3VURSA-D+212

Open1.2VURSA-D-211

GndGndGnd10

Open1.23VURSA-DCK+9

Open1.29VURSA-DCK-8

GndGndGnd7

Open1.3VURSA-D+36

Open1.25VURSA-D-35

Open1.4VURSA-D+44

Open1.15VURSA-D-43

GndGndGnd1-2


n/cn/cn/c34-41

n/cn/cn/c33

Open1.28VURSA-C+032

Open1.2VURSA-C-O31

Open1.3VURSA-C+130

Open1.2VURSA-C-129

Open1.3VURSA-C+228

Open1.2VURSA-C-227

GndGndGnd26

Open1.23VURSA-CCK+25

Open1.23VURSA-CCK-24

GndGndGnd23

Open1.3VURSA-C+322

Open1.2VURSA-C-321

Open1.13VURSA-C+420

Open1.18VURSA-C-419


(Pin 1) is on the right


Main PWB Connector P1200 to (Ft. IR/LED Control) Voltage and DMain PWB Connector P1200 to (Ft. IR/LED Control) Voltage and Diode Checkiode Check


P1200 CONNECTOR "MAIN PWB" to P1 "Front IR / LED PWB Assy"

Open3.29V0VPOWER On/Off120.6V3.29V3.29V3.3V_ST11GndGndGndGnd10

Open3.9V3.9VIR9GndGndGndWarm8GndGndGndGnd71.5V5.0V5.1V5V ST61.1V3.3V3.3VKey251.4V3.3V3.3VKey14GndGndGndGnd3

1.67V3.2V1.5VSDA2Open3.2V1.5VSCL1


1


Main PWB Connector P600 to Speakers Voltage and Diode CheckMain PWB Connector P600 to Speakers Voltage and Diode Check


SPK-L(+)

SPK-L(-)

SPK-R(+)

SPK-R(-)

LABEL

1.05V12.4V0V4

1.05V12.4V0V3

1.05V12.4V0V2

1.05V12.4V0V1

Diode CheckRunSBYPin

P600 CONNECTOR "Main" to "Speakers"

Use speaker out to test for defective Audio Amp IC600

1

IC600


FRONT IR AND KEY BOARD SECTIONFRONT IR AND KEY BOARD SECTION

The Front IR board contains the Infrared receiver and the Power LEDs.

This board receives its B+ (STBY5V) from the Main PWB. It also has connections to the side Key board. The 3.3V pull up for the keys is routed from the Main board through the Front IR board to the Side Key board.

The Front Power LEDs pulsate or appear to move. This is accomplished using multiple LEDs and a driver IC U2 which communicates with the Main board via Clock and Data lines.

There are several Zener diodes on the board as well and since it receives STAND-BY 5V (STBY 5V) it could make the Power Supply or the Main boardappear to be defective if a short was introduced to the stand by line.


Front PWB Assembly (IR and Power LED) Layout (Front and Back VieFront PWB Assembly (IR and Power LED) Layout (Front and Back View)w)

To Main PWB

To Main PWBTo SideKey PWB

Note: STBY5V is routed to this board. Be aware of a

possibility for a short.

P1P2

Main Power SW

IR Sensor Intelligent Sensor

Power LEDs

U2 LED Driver

P1P2

1

1


Front PWB Assembly (IR and Power LED) Zener CheckFront PWB Assembly (IR and Power LED) Zener Check

ZD3 = 2.1VZD1 = 2.2VZD2 = 0.67V

ZD3 = 0.556VZD1 = 0.712VZD2 = Open


Front IR/LED Control Connector P1 and P2 to Main Voltage and DiFront IR/LED Control Connector P1 and P2 to Main Voltage and Diode Checkode Check


Open

Open

Gnd

Open

Open

Gnd

2.3V

Open

Open

Gnd

Open

Open

Diode Check

3.2V1.5VSCL13.2V1.5VSDA2GndGndGnd33.3V3.3VKey143.3V3.3VKey255.0V5.1V5V ST6GndGndGnd7GndGndGnd83.9V3.9VIR9GndGndGnd10

3.29V3.29V3.3V_ST113.29V0VPOWER On/Off12

RunSTBYLABELPin

P1 Connector “IR/LED Control PWB“to "MAIN PWB" P404

P2 Connector “IR/LED Control PWB“to “Side Key" P3000

Gnd

Key2

Gnd

Key1

Label

Gnd

Open

Gnd

Open

Diode Check

GndGnd4

3.3V3.3V3

GndGnd2

3.3V3.3V1

Run STBYPin


SIDE KEY BOARD SECTIONSIDE KEY BOARD SECTION

To Ft. Control

SW3008

SW3007

SW3006

SW3005

SW3004

SW3003

SW3002

SW3001

P3000 P3000

1


Side Key Assembly P3000 InformationSide Key Assembly P3000 InformationP3000 Resistance Measurements with Key pressed.

CH (Up)CH (Dn)

Volume (+)Volume (-)

KEY

10K Ohms4.8K Ohms1.8K Ohms270.5 Ohms

Pin 3 measured from Gnd

10K Ohms4.8K Ohms1.8K Ohms270.5 Ohms


EnterMenuInput

Power

KEY

P3000 Voltage Measurements with Key pressed.

CH (Up)CH (Dn)

Volume (+)Volume (-)

KEY

2.24V1.65V

0.906V0.179V


2.24V1.65V

0.906V0.179V


EnterMenuInput

Power

KEY

P3000 Connector “Side Key" to “IR/LED Control PWB“ P1

GndKey2GndKey1

Label

GndOpenGndOpen

Diode Check

GndGnd43.3V3.3V3GndGnd23.3V3.3V1

Run STBYPin

1

P3000


Side Key Assembly RemovalSide Key Assembly Removal

Tab

Bottom board slot

To remove the Key Board, there are two tabs that hold the board in place. Using a thin flat

object, push the tabs to the right, first the bottom then the top to release the board.

Tab

Tab

Push


INVISIBLE SPEAKER SYSTEM SECTIONINVISIBLE SPEAKER SYSTEM SECTION

The 37LH55 contains the full progression of the Invisible Speaker system.First: The full range speaker layout is the basic system. The Full Range Speakers point downward, so there is no front viewable speaker grill or air ports.

Tweeterp/n EAB58536001

15W 6OHM 0DB 0HZ 45X22X20

Full Rangep/n EAB5830430310W 8OHM 81DB

130HZ 130X50

Tweeter(High Frequencies)

Main Speaker(Full Range Frequencies)

Magnet (Weight)Prevents vibrations

Invisible Speaker System Overview (Full Range Speakers)Invisible Speaker System Overview (Full Range Speakers)

Reading across speaker wires, 8.2 ohm.


Invisible Speaker System Overview (Tweeters)Invisible Speaker System Overview (Tweeters)

Invisible Speaker has a sticky surface which

adheres to front bezel.

Invisible Speaker Tweetershown separately. The Front (down) has sticky surface which adheres to

front bezel. Note, there is no diaphragm, only voice coil.

OutlinedCircle

SpeakerAttachment

post

Cabinet works as a diaphragm.

2nd: ProgressionElimination of the

conventional speaker.

The front bezel is shown below. Note: the outlined circle is the location for the front sticky pad on the

Invisible Speaker. This prevent the coil from bouncing off the plastic causing vibrations.

WARNING: Removing the Tweeter will destroy the speaker as shown above. The diaphragm/spider is glued to the

front bezel. When removing, it will tear.

Tweeterp/n EAB58536001


Main Power Switch NoteMain Power Switch Note

ON

OFF

Pay attention to the Main Power Switch. Don’t forget to leave it in

the On Position.


11 X 17 Foldout Section11 X 17 Foldout Section

This section shows the 11X17 foldout thatThis section shows the 11X17 foldout that’’s available in the Paper s available in the Paper and Adobe version of the Training Manual.and Adobe version of the Training Manual.

37LH55 INTERCONNECT DIAGRAM

P3000

SMPS TEST 1: Low Voltage test.To Force Power Supply On.Disconnect P800 on Main PWB.Jump pin 7,8,9 or 10 (5V) to pin 2 using a 10K resistor. (Test Voltage Outputs 12V, and 24V).

SMPS TEST 2: Backlight test. (Connectors from Test 1 remain.)Jump pin 2 to pin 20 (INV-ON). Remove CN3 from the T-CON PWB to the Ballast. (All voltages and the Backlights should turn on).If not, confirm that pin 3 of CN1 on the Ballast is >3V. If not, with CN3 disconnected from T-CON, Jump pin 7,8,9 or 10 (5V) through a 100 ohm to pin 3 of CN1 on the Ballast.

20 bit LVDS

Warning:T-Con PWB under shield. Put screws back in before operating set with shield

removed.

P800 CONNECTOR "MAIN” AND CN1 T-CON PWB

Ballast

1.2KV1.2KV

Side (Key) C

ontrols

GndKey2GndKey1

Label

GndOpenGndOpen

Diode Check

GndGnd43.3V3.3V3GndGnd23.3V3.3V1

Run STBYPinP2

P1

Front PWB Assembly(Interface)

IR ReceiverPower Button

MainPowerSwitch

P3000 o P2 Front PWB

Note: CN1 Pin 1 is P800 Pin 51

To BacklightBottom Left Side

To BacklightBottom Right Side

Do not run Ballast without heat sink

attached

Pins 6-10, 15, 18, 26, 31, 34 and 51 are all Ground.Pins 5 and 46-50 are not used.

Pin 3 PDIM (Digital Dimming)Can vary according to the brightness level of the video signal and the OSD Backlight setting. 0.6V 0% to 3.3V 100%. Output from the Video Processing chip IC100 (Mstar).

P1200 CONNECTOR "MAIN PWB" to P1 "Front IR / LED PWB

1.2KV

To BacklightTop Left Side

To BacklightTop Right Side

12V to T-CON Pin 48 ~ 51

1) 7.06V2) 16.27V3) 2.36V4) 13.4V5) 0V6) 11.14V7) 10.4V8) Gnd9) 0V10) 16.26V11) 8.39V12) 8.1V13) 3.23V14) 3.24V

15) 6.89V16) 16.27V17) 2.36V18) 3.11V19) 0V20) 16.29V21) 16.27V22) 5.25V23) 6V24) 0V25) 0V26) 0V27) 0V28) 3.25V

U2

TO TFT MODULE

CN5

UC1

CN4

FL7 Gnd

FL6Gnd

12V LVDSPins 48-51

B CE

Q2

Q1

A

C

A

A

C

A

A

C

A

Q3

Q4

ACA

D5

D4

D6

X1

FL4

CN1 CN2

C43C42C41C40

C102C103

C38

C39 C

36

12V

16.34V

16.3V

16V12V

16.3V

20.5V-2.79V

Gnd

C30

C69

8.18V

1) 6.9V2) 7.47V3) 7.47V

12V

U4F1 (12V)125V/3A

U1

2.72V3.28V 3.26V

1.6V

3.8V P/P9.97Mhz

26.6V 12.2V

26.4V

B

CE

Gnd

C94

56/57

Gnd1.2V

3.24V1.2V

3.3V

1) 6.9V2) Gnd3) 7.46V

U18) 0V7) 3V6) 0V5) 3.25V

1) 0V2) 0V3) 0V4) 0V

U2

L1

L2

1) 1.15V2) 0.5V3) 16.35V4) 11.79V5) 11.75V6) Gnd7) Gnd

15) 1.82V16) 0V17) 3.5V18) 3.5V19) 1.21V20) Gnd21) 11.84V

U422) 11.84V23) 11.82V24) 0V25) 3.33V26) 11.02V27) 11.85V28) 1.22V

8) 16.35V9) 11.84V10) 3.51V11) 7.17V12) 3.78V13) 0V14) 1.22V

P-DimPin 3

U5

7 6

11 853/54

53/543.3V56/57

16.3V

3.3V

16.3V

D316.34V

D2

D1

-7.47V26.2V

P-DimPin 8

U3

16.3V3.3V -7.47V 26.2V16.3V 3.3V

26.2V -7.47V

TO TFT MODULE

p/n EAT60664401

p/n EAY60701701

MAIN (Digital) Board

To Speakers

Resets IC100

L726

P600

IC100Video

ProcessorMstar

1

16 SIF

19 Video

4 (5V)

12 DIF +13 DIF -15 (5V)

IC600Audio

L606

L607

IC1002

Q1202

IC1

Q701 IC706

IC701

IC704

IC705Q706

IC2

Q702

P700

P1200

Q106

IC502HDMI Sel

IC1004Tuner Ctrl

TUNERTU1001

TDVW-H103F

X100525Mhz

IC900

IC901

12345

X80012Mhz

IC708

IC1000

Q100

IC101 IC707

L712

IC1001

P801P800

L718P104N/C

US

BH

DM

I4

Video

Aud L

Aud RQ1200

HDMI1

HDMI2

HDMI3

Y Pr/Pb 1

Y Pr/Pb 2

AV InRemote Optical

RGB

RS232

Audio

Audio

X10012Mhz

IC901

IC1202

IC1200

IC1201

D1223

Q1000

Q1001

IC601

IC1003

Q600

D102

Q105

IC103B

CE

312

BC

E

IC702

AA

C

D1239

AA

C

IC104

D1204

D1240D1238

IC1073

1 2

Q705

BCE

BCE

BCE

Q704

Q703 IC800

B CE

B CE

IC501

D500

L710

B

C E

A

AC

A A

C

IC801Tru-Motion

LVDS LVDS

IC105

B

C

E

B

C

E

B

C

E

B CE

1 2 3 4 5

SW100

LD1000

B

C E

Grayed out components are on the back side

GndPin 1, 2, 4

FL1FL3

FL5

CN3

LED1On then Off after ballast

fires

T3

16

OutLow

T2

1 6

Out Low

T4

1 6

OutLow

F112A/65V

LED1

U1 U2

Q1

Q2 Q18

Q16

Q5

Q6 Q19

Q17

CN4

CN1

35uF/680V

- +

35uF/680V35uF/680V

- +

- +

CN3 CN6

CN2 CN5

1.2KV

To pin 192 UC1

R+ to R

-8.2 Ohm

L+ to L-8.2 Ohm

LD1000Lights when

tuner OK

Power Supply

P201

SK100

N

3.15A / 250V335V (Hot Gnd)

D254

D201

D251

D252

Q102

Q602

D602

A/C

Rec

tifie

r 4A

SK101

F501

IC500

IC501 IC502

IC101

n/c

P203

L601

C104

C101

F100 5A/250V

T100

5V = 2.0A12V = 2.0A24V = 6.1A

Primary

Secondary

Q101

+

-

~~L102

L

AC IN

Note: Pin 3 is P-DIM from the T-CON.The T-CON receives P-DIM on CN1 pin 8 which is from the Main board via LVDS cable Main P800 pin 44.The T-CON outputs P-DIM on pin 3 of CN3 to CN4 on the Ballast board.

CN4 "Ballast" to CN3 "T-CON"

22V p/p / 126kHZ 39V p/p / 64Khz

Pin 1 Pin 6Pin 1 or 6 of any transformer

All others Open

Diode Check

P1

For voltagesSee P1200

2.3V pin 6

Gnd pin 3,7,10

Open3.29V0V120.6V3.29V3.3V_ST11GndGndGndGnd10Open3.9V3.9VIR9GndGndWarm8GndGndGndGnd7

1.5V5.0V5.1V5V ST61.4V3.3V3.3VKey251.4V3.3V3.3VKey14GndGndGndGnd31.8V3.2V1.5VSDA21.8V3.2V1.5VSCL1


POWER On/Off3.29V


P201 “SMPS” to P700 “Main”

1.69V4.99V0VPWR-ON2

Open0V0VErr Out22

1.2V3.24V0VP-DIM24CheckRun STBYLabelPin

ncncncnc1

GndGndGndGnd3,4,5,6

ncncncnc23

Open5.09V5.1V5V7,8,9,10GndGndGndGndOpen12.15V0V12VGndGndGndGnd

0.73V24.8V0V24V

11,1212V13,14

15,160V17,18

ncncncnc19Open4.8V0VINV.ON20Open1.67V0.6VBR121

Diode

P600 "MAIN" to “Speakers”

PIN LABEL RUN Diode Check

1 R- 13V 1.05V2 R+

3 L- 13V 1.05V4 L+

13V 1.05V

13V 1.05V11

Gnd6

D201, D254Gen PT #LOC

FCH10A10

D251, D252 MBRF10100CT

Q101, Q102 K6A60D

Q602 F15NM60N

D602 FSU10B60

EL817IC101, 501, 502

ICE3B0365JIC500

B2M2883IC100L6562AIC600

Back of the board

P203 "SMPS" to CN4 "Ballast"PIN LABEL RUN Diode Check1-5 VBL / 24V 24.83V 0.73V

6-10 Gnd Gnd Gnd11 VBR-A BR1 1.67V Open12 INV On/Off Open13 *PWM-DIM 3.24V Open14 Status/Error Open0V

4.8V

IC101

IC600

Grayed out components are on the back side

Tuner Data

20

16151413121110

987654321TDVW-H103F

TU1001NC_1

RF-AGC+B (5V)GND (1)

SDASCLAS

NC-2

AUDIO_OUT

SIF

Shield

Not Used

Not Used

191817 NC-4

VIDEO_OUT

IF_AGC

DIF (+)DIF (-)

NC-(VT)GND (2)

Not Used

Not Used NC-3

+B (2)

Not Used

Outputs OnDigital Channels

Outputs OnAnalog Channels

Gnd

IC1203

VDD

VCC

*PWM-DIM (Note this line is not used.) It is open (n/c) on the Ballast board.

PIN LABEL RUN Diode Check1 Gnd Gnd Gnd2 C_13* C_2 *3.3V Open4 n/c

Gnd Gnd

Gnd Gnd

1.1V1.3V291.1V1.3V1.1V1.2V

30

1.1V1.1V3233

1.1V1.3V351.1V1.3V361.1V1.3V37

GndGnd1.75V0.6V

1.1V1.3V381.1V1.3V391.1V1.3V40

4142

1.75V3.2V431.3V*3.3V44

1.95V0V45

P800 Diode TestRun VPin IDURSA_A-3URSA_A+3

URSA_ACK-URSA_ACK+URSA_A-2URSA_A+2

URSA_A-1URSA_A+1URSA_A-0URSA_A+0OPC_OUT2

OPC_EN

OPC_OUT1PWM_DIMLVDS_SEL

232220191716151413121110987

CN11-4111213

3.18V12.06V12V_TCON1.1V1.3VURSA_B-41.1V1.3VURSA_B+41.1V1.3VURSA_B-31.1V1.3VURSA_B+31.1V1.1V

14

1.1V1.2V1.1V1.3V

URSA_BCK-

1.1V1.3V1.1V1.3V

URSA_B-2

161719

1.1V1.3V

URSA_B+2

1.1V1.3V

URSA_B-1

2021

1.1V1.3V

URSA_B+1

1.1V1.1V

URSA_B-0

1.1V1.3V

URSA_B+0

1.1V1.3V

BIT_SEL

22232425

Diode TestRun VPin ID

URSA_BCK+

URSA_A-227URSA_A+228

48-51414039383635333231302928272524

P800CN1

T1

16

Out Low

LED1 assist the backlights in the firing process when ambient room light is minimal. Exciting the Selenium gas.

37LH55 MAIN (FRONT SIDE) ICs

IC101 Flash Memory from Boot IC701 1.8V DDR Reg IC705 +3.3V / +1.26_VDDC IC707 1.8V_MEMC Reg IC1000 +1.2V_PVSB RegulatorPin for Saturn IC100 Pin Pin Pin Pin[1] 0V [1] n/c (0V) [1] 0.8V [1] 0.9V [1] n/c[2] 3.2V [2] 3.24V [2] Gnd [2] Gnd [2] 3.4V[3] 2.54V [3] 3.24V [3] 5V [3] 5V [3] 3.4V[4] Gnd [4] n/c (0V) [4] 6.08V [4] 6.47V [4] n/c[5] 0V [5] n/c (0V) [5] 4.96V [5] 4.85V [5] n/c[6] 0V [6] 1.88V [6] 1.3V [6] 1.86V [6] 1.2V[7] 3.24V [7] 0.8V [7] 1.3V [7] 1.86V [7] 10.8V[8] 3.24V [8] Gnd [8] 3.2V [8] 4.89V [8] Gnd

IC105 EEPROM Memory IC704 +3.3V / +3.3V_MEMC IC706 5V EXT Regulator IC708 1.26V_MEMC Reg IC1001 3.3V-PVSB and FE RegPin for Saturn IC100 Pin Pin Pin Pin[1] Gnd [1] 0.8V [1] 0.8V [1] Gnd [1] 4.9V[2] Gnd [2] Gnd [2] Gnd [2] 0.8V [2] 4.9V[3] 5V [3] 4.96V [3] 12V [3] 1.3V [3] Gnd[4] Gnd [4] 7.68V [4] 6.63V [4] 1.28V [4] 3.4V[5] 3.24V [5] 4.9V [5] 4.98V [5] 1.8V [5] 1.2V[6] 3.24V [6] 3.3V [6] 4.98V [6] 5V[7] 5V [7] 3.3V [7] 0V [7] 1.28V IC1002 Tuner 5V Reg[8] 5V [8] 2V [8] 5V [8] 5V Pin

[1] 8.9V[2] 1.93V[3] 5V[4] n/c[5] Gnd

37LH55 MAIN (FRONT SIDE) TRANSISTORS AND DIODES

Q100 WP Flash Memory Q706 5V General Switch Q1202 5V Wireless Switch Pin for Boot IC101 Pin 12V LVDS Switch Pin Controls Q504[B] 0V [1] 5V [B] 0V[C] 2.54V [2] 0.3V [C] 3.29V[E] Gnd [3] 12V [E] Gnd

[4] 4VQ106 Reset Switch S100 [5] 12V

Pin (Saturn) video processor [6] 12V[B] 0V [7] 5.0V[C] 3.29V [8] 5.0V[E] 0V

Q702 INV On driver Q1200 IR Buffer RS232Pin to P601 pin 20 Pin[B] 0.07V [B] 0.64V[C] 4.8V [C] 0V[E] Gnd [E] Gnd

37LH55 MAIN (BACK SIDE) TRANSISTORS AND DIODES

Q105 Power On Delay Q703 5V General Switch Q1000 SIF (Tuner) Sound D500 IC501 PIV protectPin Pin +5V Switch Pin Pin[B] 0V [B] 0.64V [B] 2.37V [A1] 0V[C] 1.97V [C] 0V [C] Gnd [A2] 3.28V[E] Gnd [E] Gnd [E] 3.02V [C] 0V

Q600 Audio Mute Q704 Panel Switch Control Q1001 SIF (Tuner) Sound D1204 Moving LEDPin for IC600 Pin Pin Pin[B] 0V [B] 0V [B] 1.69V [A1] 0V[C] 3.27V [C] 0.64V [C] Gnd [A2] 0V[E] Gnd [E] Gnd [E] 3.2V [C] 0V

Q701 RL On driver Q705 Panel Switch Control D102 Audio Mute (Route) D1223 5V to IC1200Pin to P700 pin 2 Pin Pin Pin[B] 2.93V [B] 0.64V [A1] 0V [A1] 5V[C] 4.98V [C] 0V [A2] 0V [A2] 0V[E] 5.08V [E] Gnd [C] 0.1V [C] 4.79V

D1238 Key2 (Zener) Protect D1239 IR (Zener) Protect D1240 Key1 (Zener) Protect

(A) Gnd (C) 3.3V (A) Gnd (C) 3.3V (A) Gnd (C) 3.3V

37LH55 MAIN (BACK SIDE) SIMICONDUCTORS

IC103 Reset IC501 HDMI CEC IC800 SPI Flash IC1201 RS232 Tx/Rx IC1202 USB 5V OverPin Pin Pin Pin Pin Current Protection[1] Gnd [1] 3.21V [1] 0V [1] 3.3V [1] 4.9V[2] 0V [2] 3.29V [2] 1.3V [2] 5.3V [2] Gnd[3] 3.3V [3] n/c [3] 3.25V [3] 0V [3] 0V

[4] n/c [4] Gnd [4] 0V [4] 0VIC104 BCM EEPROM [5] n/c [5] 0V [5] (-5.28V) [5] 0V

Pin [6] 3.2V [6] 0V [6] (-5.3V) [6] 4.93V[1] Gnd [7] 3.25V [7] (-5.3V)[2] Gnd IC601 1.8V_AMP Regulator [8] 3.25V [8] 0V IC1203[3] Gnd Pin [9] 3.25V Pin[4] Gnd [1] Gnd IC1003 Tuner 9V Reg [10] 0.14V [1] 1.59V[5] 3.24V [2] 1.8V Pin [11] n/c [2] 3.23V[6] 3.24V [3] 3.24V [1] 12V [12] n/c [3] 0V[7] 0V [2] Gnd [13] 0V [4] 1.62V[8] 3.24V IC702 3.3V_ST Regulator [3] 8.9V [14] 5.37V [5] 3.23V

Pin [15] GndIC107 Power Det [1] Gnd IC1200 RGB Serial [16] 3.3V

Pin for Micro [2] 3.3V Pin[1] Gnd [3] 5.08V [1] Gnd[2] 3.3V [2] Gnd[3] 4V [3] Gnd

[4] Gnd[5] 4.79V[6] 4.79V[7] 4.79V[8] 4.79V

37LH5537LH55Direct View LCD

This concludes the 37LH55training session.

LG 37LH55 LCD TV Presentation Training Manual

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Transcript of LG 37LH55 LCD TV Presentation Training Manual