42LH20. Direct View LCD

Transcription

1 42LH20 Direct View LCD Original: March 2009 Updated: February 11, 2010

2 OUTLINE Section 1 Contact Information, Preliminary Matters, Specifications, LCD Overview, General Troubleshooting Steps, Signal Distribution, Disassembly Instructions and Voltages Section 2 Circuit Board Operation, Troubleshooting of : Switch mode Power Supply Main Board T-CON Board Ft Control Board Side Keys 2

3 Overview of Topics to be Discussed 42LH20 LCD Direct View Display Section 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. 3

4 Preliminary Matters (The Fine Print) IMPORTANT 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. CAUTION 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. 4

5 ESD Notice (Electrostatic Static Discharge) 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 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. 5

6 Contact Information Customer Service (and Part Sales) (800) Technical Support (and Part Sales) (800) USA Website (GCSC) Customer Service Website LG Web Training LG CS Academy aic.lgservice.com us.lgservice.com lge.webex.com lgcsacademy.com Presentations with Audio/Video and Screen Marks LCD-DV: PLASMA: 32LG40, 32LH30, 37LH55, 42LG60, 42LG70, 42LH20, 42LH40, 42LH50, 42LH90, 42SL80, 47LG90, 47LH85 42PG20, 42PQ20, 42PQ30, 50PG20, 50PS80, 50PS60, 60PS11 Also available on the Plasma page Plasma Panel Alignment Handbook New Training Materials on the Learning Academy site Published March 2009 by LG Technical Support and Training LG Electronics Alabama, Inc. 201 James Record Road, Huntsville, AL, LCD or PLASMA 2009 Model

7 LCD Direct View Overview Safety and Handling Regulations 1. Approximately 20 minute pre-run time is required before any adjustments are performed. 2. SMPS adjustments are factory sealed. They are VR301 (Frequency) and VR302 (Current) 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. Always handle the circuit boards on the outside edges while using ESD protection. 5. Exercise care when making voltage and waveform checks to prevent costly short circuits from damaging the unit. 6. Be cautious of loose screws and other metal objects to prevent a possible short in the circuitry. Observe the following items 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 7

8 Basic 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 Diode Check 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. 8

9 42LH20 Product Information This section of the manual will discuss the specifications of the 42LH20 LCD Direct View Display Panel. 9

10 Basic Specifications Key Features 42" Screen 720p HD Resolution Two (2) HDMI(TM) (V.1.3 with Deep Color) ISFccc Ready Smart Energy Saving LG SimpLink (TM) (32-inch and above) LG Core Technologies (32-inch and above) Dynamic Contrast Ratio 12,000:1 Response Time (G to G) 8ms Brightness 500 cd/m2 Viewing Angle 178º / 178º Life Span (Typical) 60,000 hr Built-in Tuner ATSC/NTSC/Clear QAM HDMI /HDCP Input 2 v1.3 Cabinet Color Glossy Piano-Black Limited Warranty 1 Year Parts/Labor 10

11 Pixel Count Compared to Resolution HD RESOLUTION 720p HD Resolution Pixels: 1365 (H) 768 (V) High definition television is the highest performance segment of the DTV system used in the US. It s a wide screen, high-resolution video image, coupled with multi-channel, compact-disc quality sound. NTSC SD HD HD HD FORMATS 480I 480P 1080I 720P 1080P Interlaced Progressive Interlaced Progressive Progressive 240 Lines 480 Lines 540 Lines 720 Lines 1080 Lines BASIC PIXEL COUNTS 720P Panel 1365 (H) 768 (V) Possible Frame Rates: 24FPS 30FPS 60FPS Interlaced 2 Fields to make a Frame Progressive Each Field is a Frame 1080P Panel 1920 (H) x 1080 (V) Think of sync as the Panels Refresh Rate 11

12 Basic Specifications (LOGO Familiarization) Page 1 SIMPLINK Allows for convenient control of other LG SimpLink products using the existing HDMI connection. Clear Voice Technology Automatically enhances and amplifies the sound of the human voice frequency range to provide high-quality dialogue when background noise swells. 12

13 Remote Control Familiarization TOP PORTION BOTTOM PORTION 13 LCD or PLASMA 2009 Model

14 Accessing the Service Menu SIDE KEYS REMOTE TOP PORTION To access the Service Menu. 1) Turn the Set On 2) 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: If a Password is required to enter the Service Menu. Enter; LCD or PLASMA 2009 Model

15 Rear and Side Input Jacks Rear Input Jacks USB Port For Software Upgrades Only Main PWB Orientation 15

16 Software Upgrade Procedure 1) Create an LG_DTV folder on the USB Flash Drive Shows the Currently Installed Version 2) Copy new software (xxx.epk) to "LG_DTV" folder. Make sure to have correct software file. 3) With TV turned on, insert USB flash drive. 4) You can see the message TV Software Upgrade (See figure to right) 5) Cursor left and highlight "START" Button and push Enter button using the remote control. 6) You can see the download progress Bar. 7) Do not unplug until unit has automatically restarted. 8) When download is completed, you will see COMPLETE. 9) Your TV will be restarted automatically. Shows the Software Version found on the USB Flash Drive Shows the Software file found on the USB Flash Drive * CAUTION: Do not remove AC power or the USB Flash Drive. Do not turn off Power, during the upgrade process. 16

17 42LH20 Product Dimensions 42LH20 Dimensions There must be at least 4 inches of Clearance on all sides 40-3/8" 1028mm 3-3/8" 87.8mm 16-1/8" 410mm 7-7/8" 200mm 8-3/8" 223mm 25-11/16" 655mm 3-9/16" 90mm Center 7-7/8" 200mm Model No. Serial No. Label 28-1/8" 715.4mm 12-7/8" 327.5mm 9-1/16" 230mm Remove 4 screws to remove stand for wall mount 2-3/8" 60.4mm Weight: With Stand: 38.3 lbs / 17.4 kg Without Stand: 32.3 lbs / 15.6 kg 20-1/16" 510mm 11-5/8" 297mm 17

18 DISASSEMBLY AND TROUBLESHOOTING SECTION Disassembly: This section of the manual will discuss Disassembly, Layout and Circuit Board Identification, of the 42LH20 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. Troubleshooting: This section of the manual will also discuss troubleshooting. Upon completion of this section the Technician will have a better understanding of how to diagnosis and resolve problems. 18

19 Removing the Back Step (1) Lay the TV down on its face. Remove the 4 screws around stand indicated by the arrows. Remove the Stand by Pulling it out of its Retaining bracket. Reinsert the stand and stand the unit upright for service position to continue removing the back cover. Remove Remove the one screw hidden by the stand. 19

20 Removing the Back Cover Step 2 (Stand has to be removed) The Stand has to be removed first. Remove the 22 screws indicated. Pay attention to the size and type of screw as there are many different types. Putting in the improper screw when reassembling may Cause damage. Remove the one screw hidden under the stand. See previous page. 20

21 Circuit Board Layout T-CON Under Shield T-CON p/n: EAT POWER SUPPLY (Includes Ballast) LVDS Cable Side Key with Power Button Backlight Connection To Right Side Main PWB Backlight Connection To Left Side AC Input Rear Inputs RF Input Power Switch Ft IR/LED Control Speaker R Speaker L 21 LCD or PLASMA 2009 Model

22 Power Supply PWB Removal Disconnect P201, AC In and SK102, P401 and P402. P201 Remove the 6 screws indicated by the arrows. P402 P401 AC In SK102 22

23 Power Supply (Main Power Switch Type 1) Location There are three types of Main Power switch used in LG televisions. Type 1: Shuts off AC to the Power Supply. Type 2: Opens ground to the front IR board. (Stand-By 5V Remains, the Main board stays alive). This prevents any activity of the IR or the Key Board. When the Switch is opened, a line called Power Key pulls up high when ground opens. When the switch is closed, this same line called Power Key feeds back to the Microprocessor and the Micro. Turns on the Power. Type 3: Opens ground to the front IR board. (Stand-By 5V turns off, the Main board is dead). This prevents any activity of the IR or the Key Board. When the Switch is opened, a line called Power Key pulls up high when ground opens. This line feeds back to the Main board and from there it routes to the Power Supply. The high tells the Controller chip to turn off STBY-5V. When the switch is closed, this same line called Power Key now goes high and feeds back to the Power Supply and tells the controller chip to turn STBY-5V on. If the TV won t come on, be sure to check the Main Power Switch before assuming a failure has occurred. This switch breaks AC to the SMPS. MAIN POWER SWITCH LOCATION (Bottom Left Side viewed from rear) 23 On Off LCD or PLASMA 2009 Model

24 Power Supply (SMPS) PWB Layout Hot Ground Shock Hazard To Main P201 Pin 1 Pin 2 F A/25 Run 38 STBY 168V From Hot To Backlights Left Side P402 To Backlights Right Side P401 To Master Power Switch SK102 L N F A/25 AC IN AC IN SK101 24

25 42LH20 Power Supply Turn On Sequence AC In On Off 1 Master (Main) Power Sw At point 4 TV is in Stand-By state. Energy Star compliant. Less than 1 Watt L Primary side fuse: Stand-By 168V Run 38 Stand By 5V Bridge Stand By 5V Reg No AC Det in this model PWR On 12V/24V Regulators Inv On V 24V V Regulator Ballast Control IC 6 8 T-CON PWB 12V LVDS Along with Video On LVDS cable 12V 7 Ballast Section Of the Power Supply 135V B+ for the Ballast Inverter On Starts the Ballast Backlights Light Manipulates Backlights Analog Dimming Digital Dimming To Backlights Reset of Main Board 3 Reg For Micro 3 4 Other Regs 5V Switch Other Circuits 5V General 6 Power On 12V Video Processing 24V Audio Other Circuits 8 12V Power On Inv On/Off LVDS Panel Control Microprocessor IC100 Also Video Processor LVDS 12V Switch 7 5 LVDS Video A-DIM Fixed 9 Ft Control P-DIM Cust Menu for Backlight Picture Content Power Button Or Remote Key 25

26 42LH20 P700 Main Board to Power Supply P201 Turn On Circuit n/c PWR SBY5V 12V 24V n/c INV.On A.DIM ERR Out n/c PWM-DIM SMPS P201 1 n/c 2 PWR On 4.98V V 8 5V 9 5V 10 5V V 12V V V 19 n/c V V n/c V MAIN PWB P PWM-DIM (PWM Dimming) Manipulates the Backlight Brightness via Customer s OSD. Manipulates the Backlight Brightness via the BCM Chip. Darker Picture, Darker Backlights to facilitate improved Contrast Ratio. 0.6V ~ 3.3V Range LVDS 12V Panel Power PWR ON L704 INV ON/OFF +5V +5V General C pF L706 L707 C uF L701 C721 68uF L728 L715 L714 C uF Q701 12V C722 47uF 24V C727 68uF R714 R A-DIM (Analog Dimming) Fixed Value Q706 PWM-DIM (Digital Dimming) L L700 10K V 0.2V R703 STBY5V L708 10K R KΩ Q702 C706 1uF C725 1uF R739 47KΩ Q V R704 R743 0 Power On +5V General R719 1KΩ 12V R740 47KΩ Q705 STBY5V R Ω R759 0Ω 4.7K C182 1uF C181 1uF 0.6V R K R Q R237 R Ω STBY5V Relay On E5 GPIO 134 AB12 R253 10KΩ GPIO137 LVDS Panel Control IC100 BCM G5 GPIO 136 Inverter On/Off AB13 PWM0 A-DIM P-DIM PWM2 H5 R

27 Power 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 (38) measured at Fuse F501. This primary voltage develops all other voltages that are output from the power supply. During Stand-By, the 5 Volt Standby 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 5 Volt Standby. Loss of 5 Volt Standby would be a Power Supply Failure. Presence of 5 Volt Standby 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! The Main Board sends two commands to the Power Supply Board one being PWR the other is INV ON. These two voltages are used to control the power on turn on sequence. First via PWR (Pin 2) also known as POWER ON, activates the internal Ballast voltage and the 24 Volt and 12 Volt lines to the Main board. The 2 nd command is INV ON (P201 pin 20). It it the Lamp Lighting Command Signal. If either command (PWR-ON or INV-ON) is missing it will result in a no picture symptom. These voltages can easily be checked with the volt meter! Remove AC Power, unplug the two Connectors to the backlights P401/P402. 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 (2.8V) 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 3.3V. 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. 27

28 TEST 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 any of the pins 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. 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. Check that the 24V and 12V power supplies are turned on, P201 (24V pins 17 and 18) (12V pins 13 and 14) (2) Remove AC power. 28 Use P700 Side to insert resistors

29 TEST 2 Power Supply PWB Backlights Test P700 Connector disconnected from the Main PWB. Apply AC after adding jumpers. Continue if the 1 st 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) Apply AC Power. This simulates a Power On and Backlight On command. Observe the Backlights. a) If normal, the backlights should turn on. b) If the do not, recheck connectors P401 and P401. (Warning: Disconnect the AC Power first). These pins carry 1.2Kv when active. c) Confirm the INV On/Off line Pin 12 is going to at least 3V. d) If no backlight activity, SMPS is defective. 29 Use P700 Side to insert resistors

30 Power Supply Connector P201 Voltage and Diode Check P201 Odd "SMPS" to P700 "Main PWB" Pin Label nc 1 A.DIM nc 24V 12V 5V 5V nc STBY nc nc 5.14V 5.14V nc Run nc 1.66V nc 21.4V 12.3V 5.14V 5.14V nc Diode Check nc Open nc 0.71V 0.96V 1.67V 1.67V nc P201 Even "SMPS" to P700 "Main PWB" Pin Label 2 PDIM Err Out INV.ON 24V 12V 5V 5V PWR-ON STBY 5.14V 5.14V Run 3.2V 3.8V 21.4V 12.3V 5.14V 5.14V 4.98V Diode Check 1.68V Open 1.6V 0.71V 0.96V 1.67V 1.67V 0.886V 1 ADIM Pin 21 Fixed and not used 2 PDIM Pin 24 can vary according to type of signal being processed and the OSD Backlight setting. 0.6V 0% to 3.3V 100%. Output from the BCM chip. Diode Mode values taken with all Connectors Removed 30

31 Power Supply Connector SK101 and SK102 Voltage and Diode Check Diode Mode values taken with all Connectors Removed SK101 "SMPS" to AC IN Pin 1 2 Label L N STBY 12ac Run Diode Check OL OL AC Voltage Readings Across Pins 1 and 2 for STBY and RUN. Bottom Right of SMPS SK102 "SMPS" to MASTER POWER SWITCH Pin 1 2 Label n/a n/a STBY 12ac Run Diode Check OL OL AC Voltage Readings for either pin 1 or pin 2 in STBY and RUN with one lead on Neutral of SK101. With the Master Power Switch Closed (On) AC flows. When Open (Off) AC open and does not flow. Neutral SK102 Live SK101 31

32 General Backlight Information To Backlights Over 1.2KV Ballast Section of SMPS To Backlights Over 1.2KV Currently, number of lamps Unknown EEFL (External Electrode Fluorescent Lamp) LOW COST Large number of lamps driven by a single inverter 32

33 EEFL Compared to CCFL Simple structure, Low price Complicated structure Simple structure Lamp manufacturing process Lamp assembly structure Low Cost Large number of Lamp Drive by single inverter 33

34 EEFL Bulb Design 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 34

35 Ballast PWB Layout Viewed from rear SMPS PWB Backlights Test Point Bottom of R406 or R403 38V P/P To Backlights Left Side T Kv To Backlights Right Side T704 35

36 42LH20 P700 Main Board to Power Supply P201 Ballast Turn On Circuit BALLAST SECTION To Backlights 1.2Kv P402 P401 Two Transformers Drive Circuit FETs Q709/ Drive Control INV On/Off POWER SUPPLY Hot Ballast Power Stand By 5V Reg 38 Reg 16 Reg IC600 Ballast Control IC On Back of PWB On Back of PWB IC301 Controller 12V Reg 24V Reg P P V PWR 4.89V 12V 24V ERROR-OUT PWM-DIM STBY5V 0.3V~3.3V A-DIM 1.67V R Ω INV On/Off R KΩ STBY5V L733 L700 Q702 Active 5V Q701 R Ω R KΩ MAIN PWB R KΩ R719 1KΩ Q700 R706 +5V General R759 0Ω R703 R Ω R Ω R KΩ R Ω R Ω G5 E5 E8 AB13 AB12 IC100 BCM INV-On/Off GPIO 136 GPIO 134 RL-ON GPIO 197 ERROR-OUT PWM-2 PWB-0 VBR-A (Analog Dimming) This line is not used. VBR-B (PWM Dimming) Manipulates the Backlight Brightness via Customer s OSD. Manipulates the Backlight Brightness via the BCM Chip. Darker Picture, Darker Backlights to facilitate improved Contrast Ratio. 0.6V ~ 3.3V Range The Error Line will: Pulse high when the backlights 1 st attempt to fire, if they do it goes back low. If the do not, it goes low, then the backights attempt to fire again and it pulses high. This happens 4 times, on the 5 th attempt it goes high and shut off the television 36

37 Power Supply Backlight Drive Signal Effects Waveform taken using loose coupling. Clip the probe to one of the Backlight wires. Use caution, there is 1.2Kv in the wire. Slow scope setting to 2.4mSec to see the effects of PWM on the waveform. The PWM amount can cause the frequency to be measured differently. VBR-B PWM-DIM manipulates the ballast drive IC. VBR-A BR1 (A-DIM) is not used. 37 LCD or PLASMA 2009 Model

38 T-CON BOARD SECTION LCD Controller Board The T-Con IC UC1 receives from the Main Board at CN5 12 Bit LVDS Signals (Video) which it processes into TFT Drive Signals which through connectors CN3 and CN4 controls the LCD Panel. 12V is supplied to the T-Con Board on connector CN5 from the Main Board (easily measured at fuse F1). Diode LED1 is a boot up indicator and is helpful in troubleshooting as a quick indication of a loss of supply and or a Boot Up problem. There are two DC to DC converters that create (17V developed at the cathode of D14) and (3.3V developed at the cathode of D13). The 3.3V can also be measured at the ribbon connectors delivering signals to the TFT panel (CN3 pins 57, 58 or 59) and (CN4 pins 2, 3 or 4). 38

39 T-CON (TFT Drive) Board Removal Remove the 3 Screws in the T-CON shield and remove the shield The two screws shown in the picture below are for the Service Position. They would have been removed when removing the shield. Be sure to reinstall them if servicing the T-CON PWB. CN4 CN3 CN5 Disconnect CN3, CN4 and CN5. See next slide for details. 39

40 T-CON Board Removal (Continued) UNLOCKING CN3, CN4 and CN5 To remove the flex cables to the TFT Panel, CN3 or CN4: 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 3 (CN5) LVDS CN3 or CN4 Locked Press In Press In Fig 1 Pull Out Fig 2 Flip the lock up and back from the flex cable. Then the flex cable can be easily removed. Unlocked To remove the LVDS cable CN5; Press in on the two tabs and slowly rock the cable out of the connector. (Shown by the arrows in Fig 3) The locking tab is flipped upward 40

41 T-CON Board (With Shield) LVDS (Video and 12V) from Main PWB 41

42 T-CON (TFT Drive) PWB (Shield Removed) To TFT Panel CN4 T-CON p/n: EAT To TFT Panel CN3 FL114 D14 LED1 U7 UC1 D13 F1 CN5 U9 Remember to replace screws for ground purposes if testing the PWB. To Main PWB 42

43 T-CON (TFT Drive) PWB Checks D14 Cathode 3.3V Cathode 16.9V Anode Cathode LED1 Use LED1 to determine if The boot up sequence of The T-CON is OK. This LED will turn bright Blue Shortly after power is applied then go out shortly after backlights illuminate if all is OK. D13 Power Off Anode Cathode Power 1 st On Anode 3.3V Cathode Power On Anode 3.3V Cathode 1.3V T-CON PWB LED OFF LED ON LED OFF Check the Regulator U10 for Correct Voltage 3.3V 1.8V F1 Check Fuse F1 for 12V CN5 From Pins 2, 3, 4 and U10

44 T-CON (TFT Drive) Voltages for the Panel Checks 12V U7B+ 16V VDD 26V VGH_M Pin 8 3.3V VCC -5V VGL 44

45 T-CON (TFT Driver) Board CN3 and CN4 (3.3V Voltage Check) 3.3V Check 3.3V Check CN4 CN3 If the 3.3Volts is missing, check the 3.3V DC to DC converter. Check at D13 cathode. See previous page for location. T-CON PWB 45

46 T-CON PWB Connector CN5 to Main PWB Voltage and Diode Check CN5 CONNECTOR "T-CON PWB to P801 "Main" V 12.1V 12.1V 12.1V 1.2V 1.1V 1.2V 1.6V 1.6V 1.6V 1.6V Open 1.1V 1.1V 0.8V 1.1V Diode Mode values taken with all Connectors Removed LVDS 12V LVDS 12V LVDS 12V LVDS 12V LVDS-SEL OPC-EN TXA0- TXA0+ TXA1- TXA1+ TXA2- TXA2+ TXAC- TXAC+ TXA3- TXA3+ OPC-OUT *PWM-DIM 1.1V 1.2V 1.1V 1.1V 1.2V 1.2V 1.2V 3.3V 3.1V 1.1V 1.1V 1.1V 1.1V 1.1V 1.1V 1.1V Open 1.1V *Pin 29 PWM-DIM 3.15V (Max 100%) to 0.6V (Min 0%) Customer s Menu Backlight setting. But is Not Used by T-CON. NOTE: The outside pins on each side are actually not counted, they are both ground. But they are counted in the table. (See arrow on the T-CON PWB CN5) 46

47 MAIN BOARD SECTION Input Signal Processing IC100 is the main Microprocessor and the main Signal Processor and is responsible for : ATSC, NTSC, and QAM reception and processing RS 232 service only Port (software upgrades and home theater environment). Wired Remote Port (1) Component Input Y, Pr, Pb and Audio L R (2) HDMI Inputs (back) (1) HDMI (Side Input) RGB PC and (PC Audio) USB (software upgrades using flash drive). USB located on the Rear, no Side Inputs. AV Composite SIF and SAP Output Signals 10 Bit LVDS (10 Pin) to the T-CON Board 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 47

48 Removing the Main PWB Remove the one screws at the bottom of the Decorative plastic piece on the right side. Remove the plastic piece. Remove the two pieces of tape on the left side holding down the cables and the one at the top. Remove the remaining 11 screws indicated by the arrows. Flip the locking tabs upward, pull the LVDS ribbon out. P700 P801 Decorative Plastic NOTE: 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. P P1204

49 Main PWB Layout Look carefully on top and behind the Video Processor IC for Chocolate (Heat Transfer) material. Be sure to transfer to new PWB if replaced. P801 to T-CON PWB P801 VIDEO PROCESSOR IC100 RUNS HOT, THIS IS NORMAL. To SMPS P700 SW100 Reset IC100 Microprocessor and Video Processor X LD1000 LD1000 Tuner OK when Green X100 For Software Upgrade via Jig USB Tuner TU To Speakers P600 P1204 To Front PWB Assembly 49

50 Main PWB (Back View) Voltages given on the 11X17 foldout Interconnect Diagram IC1003 IC1002 IC102 IC601 IC702 Tuner IC501 IC501 IC500 50

51 42LH20 Main Board (Front View) Component Layout Q706 Switch (12V LVDS) (5V General) P700 (0.6V) To SMPS PWB 0.6V) Q702 Inv-On Control 3.85V () ( ) = Off Q706 1 (5V) 2 (0.48V) 3 (0.48V) 4 (6V) 5-6 (12.3V) 7-8 (5V) IC V-FE 1 (0.78V) 2 () 3 (5V) 4 (7.4V) 5 (2.12V) 6 (3.28V) 7 (3.28) 8 (5V) IC107 Power Det 1 (3.28V) 2 (Reset).3V 3 () Reset IC100 IC V_FE L710 IC107 IC V_DDR 1 (N/C) 2 (3.18V) 3 (3.18V) 4-5 (N/C) 6 (1.87V) 7 (0.8V) 8 () IC701 IC V_VDDC X Mhz IC V_VDDC 1 (0.78V) 2 () 3 (5V) 4 (5.9V) 5 (5V) 6 (1.3V) 7 (1.3V) 8 (3.16V) L726 IC105 IC105 HDCP EEPROM 1-2 () 3 (5V) 5-6 () 4-7 () 6 (1.2V) 7 (0.8V) 8 (5V) IC100 IC100 Micro and Video Processor Mstar Chip IC101 IC101 Flash Memory 1-2 () 3-4 () 5-6 () 7-8 (3.2V) P801 To T-CON (LVDS) X Mhz IC1003 IC1004 8vsb/ QAM TUNER 19 Video LD1000 C KEY B E IC1000 IC V_PVSB 1 (N/C) 2 (3.2) 3 (3.2V) 4-5 (N/C) 6 (1.2V) 7 (0.8V) 8 () IC600 Audio 56 Pin MAIN (Digital) Board Grayed Out ICs are located on Back 16 SIF 15 (5V) 13 DIF - 12 DIF + To Speakers P600 To Front Control P (5V) 51

52 Main PWB X100 and X1005 Check IC100 Microprocessor Crystal 2.28Vp/p 12Mhz 4.95Vp/p 25Mhz X100 X400 Set on or off Only when set is on X100 Location X1005 Location X1005 MAIN PWB Tuner Control IC1004 Crystal 52

53 Main PWB LD1000 Function LD1000 Use LD1000 as a visual aid. This lets you know if the tuner internal PLL (Phase Locked Loop) system is locked. Illuminated PLL is normal. Off is abnormal tuner lock. Main PWB LD1000 Location MAIN PWB 53

54 Main PWB Tuner with Shield Off (Pin ID)

55 Main PWB Tuner Video and SIF Output Check USING COLOR BAR SIGNAL INPUT Note: Video Out Signal only when receiving an analog Channel. MAIN PWB Tuner Location Pin 19 Video Signal Pin 1 Pin 16 SIF Signal 2.24Vp/p Pin 12 and Pin 13 Dig IF Signal 450mVp/p 700mVp/p Note: Dig IF Signal only when receiving a Digital Channel. 55

56 Main PWB Tuner Clock and Data Lines Note: SCL and SDA only active during an actual Channel Change. Pin 9 SCL 1V per/div 100uS 5V p/p Pin 8 SDA 1V per/div 100uS 5V p/p 56

57 Main PWB LVDS P801 Video Output Check To confirm that the Main PWB is outputting Picture Content signals, check P801 (LVDS) cable for output. Check pins 6-7, and Pins 9-10 carry the clock. 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 30 P801 Pin 1 2uS Pin 30, 29, 28, 27 (LVDS 12V) Pin 6 500nS P801 Location MAIN PWB 2uS Pin 18 This is just a sample of two pins on the LVDS. There are 8 pins on P801 carrying video. 500nS 57

58 Main PWB LVDS Connector P801 Pin Identification P V for T-CON PWB Screen Size Video Video Video Video Clock Video PWM Dim Not used on T-CON 58

59 Main PWB Connector P801 to T-CON T Voltage and Diode Check P801 CONNECTOR "Main" to CN5 "T-CON PWB" Diode Mode values taken with all Connectors Removed Pin LABEL TXA1- TXA0+ TXA0- OPC-EN LVDS-SEL LVDS 12V LVDS 12V LVDS 12V LVDS 12V LABEL *PWM-DIM OPC-OUT TXA3+ TXA3- TXAC+ TXAC- TXA2+ TXA2- TXA1+ SBY Run 3.1V 3.3V 1.2V 1.2V 1.2V 1.1V 1.1V 1.2V 1.1V Diode Check 1.1V Open 1.1V 1.1V 1.1V 1.1V 1.1V 1.1V 1.1V Pin SBY Run 1.2V 1.1V 1.2V 12.1V 12.1V 12.1V 12.1V Diode Check 1.1V 0.8V 1.1V 1.1V Open 1.6V 1.6V 1.6V 1.6V *Pin 3 PWM-DIM 3.15V (Max 100%) to 0.6V (Min 0%) Customer s Menu Backlight setting. But is Not Used on T-CON. 59 LCD or PLASMA 2009 Model

60 Main PWB Connector P700 to Power Supply Voltage and Diode Check Odd Pins P700 Main PWB" to P201 SMPS PWB" Even Pins Pin Label STBY Run Diode Check Pin Label STBY Run Diode Check 1 nc nc nc nc 2 PWR-ON 4.98V 1.87V V 5.14V 5.14V 1.1V 8 5V 5.14V 5.14V 1.1V 9 5V 5.14V 5.14V 1.1V 10 5V 5.14V 5.14V 1.1V V 12.3V 2.1V 14 12V 12.3V 2.1V V 21.4V Open 18 24V 21.4V Open 19 nc nc nc nc 20 Inv.Out 3.8V 1.9V 21 1 A.DIM 1.7V 2V 22 Err Out Open 23 nc nc nc nc 24 2 PDIM 3.2V Open 1 ADIM Pin 21 Fixed and not used 2 PDIM Pin 24 can vary according to type of signal being processed, OSD Backlight setting. 0.6V 0% to 3.3V 100% and the Intelligent Sensor. Output from the BCM chip. Diode Mode values taken with all Connectors Removed 60 LCD or PLASMA 2009 Model

61 Main PWB Connector P1204 to (Ft. IR/LED Control) Voltage and Diode D Check P1204 CONNECTOR "MAIN PWB" to P1 "Front IR / LED PWB Assy" Pin Label STBY Run Diode Check 1 SCL 3.3V 3.3V 1.14V 2 SDA 3.3V 3.3V 1.14V 3 4 Key1 3.3V 3.3V 1.08V 5 Key2 3.3V 3.3V 1.08V 6 5V ST 5.1V 5.1V 1.13V IR 4.8V 4.8V Open V_ST 3.29V 3.29V 0.6V 12 POWER On/Off 3.29V 2.17V Diode Mode values taken with all Connectors Removed 61 LCD or PLASMA 2009 Model

62 Main PWB Connector P600 to Speakers Voltage and Diode Check P600 CONNECTOR "Main" to "Speakers" Pin LABEL SBY Run Diode Check 1 SPK-R(-) 10.7V 1.5V 2 SPK-R(+) 10.7V 1.5V 3 SPK-L(-) 10.7V 1.5V 4 SPK-L(+) 10.7V 1.5V Use speaker out to test for defective Audio Amp IC600 Diode Mode values taken with all Connectors Removed 62 LCD or PLASMA 2009 Model

63 FRONT IR BOARD Front (IR and LED Control) Assembly Layout (Back View) The IR Sensor and Power LED control IC are located on the front of this Board P3 To Side Key PWB P1 To Main PWB P3 P1 Cover Cover Removed 63 LCD March LH20

64 Front PWB Assembly (IR and LED Control) Layout (Back View) Control IC U1 (Power LEDs) IR Sensor POWER LEDS (LED1 through LED10) 64

65 Front IR/LED Control Connector P1 and P3 to Main Voltage and Diode Check Pin P1 Connector IR/LED Control PWB to "MAIN PWB" P404 LABEL SCL SDA Key1 Key2 5V ST IR 3.3V_ST POWER On/Off STBY 3.3V 3.3V 3.3V 3.3V 5.1V 4.8V 3.29V Run 3.3V 3.3V 3.3V 3.3V 5.1V 4.8V 3.29V 3.29V Diode Check 2.4V 2.4V Open Open 1.5V 2V Open 2V Pin P3 Connector IR/LED Control PWB to Side Key" P3000 Label Key1 Key2 STBY 3.3V 3.3V Run 3.3V 3.3V Diode Check Open Open Diode Mode values taken with all Connectors Removed 65

66 KEY BOARD SECTION SW3001 SW3002 SW3003 SW3004 SW3005 SW3006 SW3007 P3000 SW3008 To Main PWB 66

67 Side Key Assembly P3000 Diode Check Measurements with Key pressed. KEY Power Pin 1 measured from Ohms KEY Volume (-) Pin 3 measured from Ohms Input 1.8K Ohms Volume (+) 1.8K Ohms Menu 4.8K Ohms CH (Dn) 4.8K Ohms Enter 10K Ohms CH (Up) 10K Ohms P3000 Voltage Measurements with Key pressed. KEY Power Pin 1 measured from 0.179V KEY Volume (-) Pin 3 measured from 0.179V Input 0.906V Volume (+) 0.906V Menu 1.65V CH (Dn) 1.65V Enter 2.24V CH (Up) 2.24V P3000 Connector Side Key" to IR/LED Control PWB P1 Pin Label STBY Run Diode Check 1 Key1 3.3V 3.3V Open 2 3 Key2 3.3V 3.3V Open 4 67

68 REASSEMBLY NOTES: Pay attention to the wire dress for the Side Key PWB. These wires can get pinched between the rear cover and lower left hand screw post. The wires can be dressed to the right of the post in the slot provided. 68

69 INTERCONNECT SECTION (11 X 17 Foldout) This section shows the 11X17 foldout that s s available in the Paper and Adobe version of the Training Manual. 69

70 42LH20 INTERCONNECT DIAGRAM P201 Odd "SMPS" to P700 "Main PWB" Pin Label STBY Run Diode Check 23 n/c n/c n/c n/c 21 A.DIM 1.7V Open 19 n/c n/c n/c n/c 17 24V 21.4V 0.71V V 12.3V 0.96V 11 9 STBY 5V 5.1V 5.14V 1.67 V 7 STBY 5V 5.1V 5.14V 1.67 V n/c n/c n/c n/c Right Side From Rear To Backlights Left Side From Rear P402 P401 Master Power Switch Bottom Left Back From rear Power Supply 3.15A / 25 Rating 335V Actual Reading F501 P201 *PWM DIM Pin 22 will vary according to OSD Backlight setting. 0.3V 0% to 3.4V 100% SMPS TEST 1: To Force Power Supply On. Disconnect P800 on Main PWB. Jump pin 9,10,11 or 12 (5V) to pin 19 using a 10K resistor. (Test Voltage Outputs 12V, 16V, and 24V). SMPS TEST 2: Jump pin 19 to pin 20 (INV-ON). (Ballast and all voltages should turn on). T704 T703 P3 Front IR/LED P3000 Side Key Pin 1 Label STBY Run Diode Check P3 6.3A / 25 A/C Fuse AC IN SK102 F100 SK101 L N P3000 Diode Check KEY 1 3.3V 3.3V 1.1V Open KEY 2 3.3V 3.3V 1.1V Open P201 Even "SMPS" to P700 "Main PWB" Pin Label STBY Run Diode Check 24 *PWM-DIM.6V ~ 3.3V Err Out 20 INV-On/Off 3.8V 18 24V 21.4V 0.71V V 12 STBY 5V STBY 5V 6 2 PWR_ON 12.3V 5.14V 5.14V 5.14V 5.14V V 1.68V Open 1.6V 0.96V 1.67 V 1.67 V 0.886V FL3 P Protect 1 st Test Warning: T-Con PWB under shield. Be sure to reinsert screws before operating set with shield removed. TO TFT MODULE TO TFT MODULE 3.3V 5V 10K PWR Side (Key) Controls CN4 D13 L1 2 nd Test P Use P700 Side to insert resistors INV ON 10K 10K 5V PWR Front PWB Assembly (Interface) P3000 L2 P3 16.9V D14 T-CON PWB (TFT Driver) F1 (12V) 63V/1.5A 12V to T-CON Pins 2, 3, 4 and 5. IR Receiver Power Button For Stand-By and Run voltages, see P201 Chart CN5 Pin P1 UC1 LVDS Label n/c STBY 5V STBY 5V 12V 24V n/c A.DIM n/c CN3 1) 2) 1.8V 3) 3.3V Far left pins 2, 3, 4 AND 5 for CN5 are 12V from Main PWB LVDS 12V Switch. Diode Check n/c 1.1 V 1.1 V 2.1V Open n/c 2V n/c LED1 U9 P700 Main to P201 SMPS Pin Protect FL3 Label PWR_ON STBY 5V STBY 5V 12V 24V INV-On/Off Err Out *PWM-DIM See LVDS Video Waveforms On Back of page. LED1 Set In Stby: LD1 Off Anode Cathode Power On: LD1 Lit Anode 3.3V Cathode Set On: LD1 Off Anode 3.3V Cathode 1.3V Diode Check 1.87V 1.1 V 1.1 V 2.1V Open 1.9V Open Open Q701 Q706 PWR On Q706 Switch (12V LVDS) (5V General) IC601 IC701 P700 IC601 (1.8V_Amp) IC702 (3.3V_ST) IC702 Q702 Inv-On Control To Speakers P600 P1204 Main to P1 Front IR/LED P1204 Main P1 IR/LED Pin Pin Label STBY Run Diode Check Diode Check 1 SCL 3.3V 3.3V 1.14V 2.4V 2 SDA 3.3V 3.3V n/c 1.14V 2.4V 3 n/c 4 KEY 1 3.3V 0.13V 3.3V 1.1V Open 5 KEY 2 3.3V 3.3V 1.1V Open 6 5V STBY 5.1V 5.1V 1.13V 1.5V IR 4.8V 4.8V Open 2V 10 n/c V STBY 3.29V 3.29V 1V 1. Open 12 Power On/Off 3.29V 1V 1. 2V P801 Main to CN5 T-CON Pin LABEL SBY Run Diode Check *PWM-DIM 3.1V 1.1V 4 OPC-OUT 3.3V Open 5 6 TXA3+ 1.2V 1.1V 7 TXA3-1.2V 1.1V 8 9 TXAC+ 1.2V 1.1V 10 TXAC- 1.1V 1.1V TXA2+ 1.1V 1.1V 13 TXA2-1.2V 1.1V TXA1+ 1.1V 1.1V IC704 IC107 L710 Reset BCM IC600 X100 Audio 12.00Mhz L726 IC100 Main (Digital) Board Grayed Out ICs are located on Back of the PWB P1204 IC705 IC105 IC100 Video Processor Mstar To Front Control Pin LABEL SBY Run Diode Check 16 TXA1-1.2V 1.1V TXA0+ 1.1V 0.8V 19 TXA0-1.2V 1.1V OPC-EN 1.1V 22 LVDS-SEL Open LVDS 12V 12.1V 1.6V 28 LVDS 12V 12.1V 1.6V 29 LVDS 12V 12.1V 1.6V 30 LVDS 12V 12.1V 1.6V *Pin 3 PWM-DIM 3.15V (Max 100%) to 0.6V (Min 0%) Customer s Menu Backlight setting. However, this is not used on the T-CON PWB C B E KEY IC101 (Flash Memory) 1-2 () 3-4 () 5-6 () 7-8 (3.2V) IC105 (HDCP EEPROM) 1-2 () 3 (5V) 5-6 () 4-7 () 6 (1.2V) 7 (0.8V) 8 (5V) IC107 (Power Det) 1 (3.28V) 2 (Reset).3V 3 () IC601 (1.8V Amp) 1 (3.2V) 2 (1.8V) 3 () Q701 (PWR ON) 1 () 2 (5V) 3 (5V) IC V_DDR 1 (N/C) 2 (3.18V) 3 (3.18V) 4-5 (N/C) 6 (1.87V) 7 (0.8V) 8 () P801 *LD1000 Illuminates indicating Tuner PLL is locked. IC101 IC702 (3.3V_ST) 1 (5V) 2 (3.3V) 3 () IC704 (3.3V-FE) 1 (0.78V) 2 () 3 (5V) 4 (7.4V) 5 (2.12V) 6 (3.28V) 7 (3.28) 8 (5V) Q702 (INV ON) 1 (0.6V) 2 (3.82V) 3 () X Mhz LD1000 IC1004 8vsb/QAM 19 Video 16 SIF 15 (5V) 13 DIF - 12 DIF + 4 (5V) 1 TUNER IC705 (1.26V_VDDC) 1 (0.78V) 2 () 3 (5V) 4 (5.9V) 5 (5V) 6 (1.3V) 7 (1.3V) 8 (3.16V) Q706 Switch (12V LVDS) (5V General) 1 (5V) 2 (0.48V) 3 (0.48V) 4 (6V) 5-6 (12.3V) 7-8 (5V) IC1002 IC1003 IC1000 IC503 IC1000 (1.2V_PVSB) 1 (N/C) 2 (3.2) 3 (3.2V) 4-5 (N/C) 6 (1.2V) 7 (0.8V) 8 () IC1003 (5V-Tuner source) 1 (12V) 2 () 3 (8.94V)

71 42LH20 LVDS P801 WAVEFORMS LVDS P801 PIN 4 (OPC-Out) LVDS P801 PIN 6 (TXA3+) LVDS P801 PIN 7 (TXA3-) LVDS P801 PIN 9 (TXAC+) LVDS P801 PIN 10 (TXAC-) LVDS P801 PIN 12 (TXA2+) LVDS P801 PIN 13 (TXA2-) LVDS P801 PIN 15 (TXA1+) LVDS P801 PIN 16 (TXA1-) LVDS P801 PIN 18 (TXA0+) LVDS P801 PIN 19 (TXA0-) 42LH20 P801 LVDS CABLE WAVEFORMS: Waveforms taken using NTSC Color Bar RF input.

72 42LH20 Main Board (Front View) Component Layout Q706 Switch (12V LVDS) (5V General) P700 (0.6V) To SMPS PWB 0.6V) Q702 Inv-On Control 3.85V () ( ) = Off Q706 1 (5V) 2 (0.48V) 3 (0.48V) 4 (6V) 5-6 (12.3V) 7-8 (5V) IC V-FE 1 (0.78V) 2 () 3 (5V) 4 (7.4V) 5 (2.12V) 6 (3.28V) 7 (3.28) 8 (5V) IC107 Power Det 1 (3.28V) 2 (Reset).3V 3 () Reset IC100 IC V_FE L710 IC107 IC V_DDR 1 (N/C) 2 (3.18V) 3 (3.18V) 4-5 (N/C) 6 (1.87V) 7 (0.8V) 8 () IC701 IC V_VDDC X Mhz IC V_VDDC 1 (0.78V) 2 () 3 (5V) 4 (5.9V) 5 (5V) 6 (1.3V) 7 (1.3V) 8 (3.16V) L726 IC105 IC105 HDCP EEPROM 1-2 () 3 (5V) 5-6 () 4-7 () 6 (1.2V) 7 (0.8V) 8 (5V) IC100 IC100 Micro and Video Processor Mstar Chip IC101 IC101 Flash Memory 1-2 () 3-4 () 5-6 () 7-8 (3.2V) P801 To T-CON (LVDS) X Mhz IC1003 IC1004 8vsb/ QAM TUNER 19 Video LD1000 C KEY B E IC1000 IC V_PVSB 1 (N/C) 2 (3.2) 3 (3.2V) 4-5 (N/C) 6 (1.2V) 7 (0.8V) 8 () IC600 Audio 56 Pin MAIN (Digital) Board Grayed Out ICs are located on Back 16 SIF 15 (5V) 13 DIF - 12 DIF + To Speakers P600 To Front Control P (5V)

73 42LH20 Main Board (Rear View) Component Layout C KEY B E IC1003 To Tuner 5V Regulator 1 (12V) 2 () 3 (8.94V) IC1003 IC1002 IC1002 Tuner 5V Regulator 1 (8.94V) 2 (2.37V) 3 (5V) 4 (N/C) 5 () TUNER 19 Video 16 SIF 15 (5V) 13 DIF - 12 DIF + IC102 NAN Flash Memory P801 IC1200 R,G,B PC/DDC Main (Digital) Board IC501 IC500 Q102 Power Det 12V B 0.78V C E IC104 EEPROM (Micro) V V V V Q102 Q103 Q600 Q104 Q103 Power Det 5V B 0.08V C 3.3V E 2 1 IC103 3 IC103 Reset Gen V V Reset SW100 Audio Mute Switch B 0.08V C C 3.26V E E B Q600 Q104 Power Det B 0.08V C 3.3V E Q600 Power On Delay B 0.08V C 1.95V E IC601 (1.8V_Amp) IC702 (3.3V_ST) IC702 1 (5V) 2 (3.3V) 3 () IC601 1 (3.2V) 2 (1.8V) 3 () P700 4 (5V) 1 IC V V V V IC500 / IC501 HDMI EDID IC501/IC V V V V To Front Control P1204 To Speakers P600

74 42LH20 Direct View LCD This concludes the 42LH20 training session.