LG 32LD350 Troubleshooting Manual
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LG 32LD350 Troubleshooting Manual

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See also: Service Manual , Owner's Manual
720P
720P
Direct View LCD
Training
32LD350
32LD350
32LD350
32LD350
Direct View LCD
Direct View LCD
LCD-DV Troubleshooting
32" Class HD 720P
LCD TV (31.5" diagonally)
Published November 16
Updated February23rd, 201 1
th
, 2010

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  • Page 1 720P 720P 32LD350 32LD350 32LD350 32LD350 Direct View LCD Direct View LCD Direct View LCD Training LCD-DV Troubleshooting 32" Class HD 720P LCD TV (31.5" diagonally) Published November 16 , 2010 Updated February23rd, 201 1...
  • Page 2 Signal Distribution, Disassembly Instructions and Voltages Disassembly Section: Removal of Circuit Boards Troubleshooting Section: Board Operation Troubleshooting of : • Switch Mode Power Supply • Ballast (Backlight Driver) • Main Board • Ft Control Board • Key Board • Speakers November LCD TV 32LD350...

  • Page 3: Overview Of Topics To Be Discussed

    Overview of Topics to be Discussed Overview of Topics to be Discussed 32LD350 LCD Direct View Display 32LD350 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.

  • Page 4: Preliminary Matters (The Fine Print)

    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 user injury.

  • Page 5: Esd Notice

    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. November LCD TV 32LD350...

  • Page 6: Lg Contact Information

    Training Manuals, Schematics with Navigational Bookmarks, Start-Up Sequence, Owner’s Guides, Interconnect Diagrams, Dimensions, Connector IDs, Product Pictures and Features. 32LD350 32LG40 32LH30 37LH55 42LG60 42LG70 42LH20 42LH40 42LH50 42LH90 32LD350, 32LG40, 32LH30, 37LH55, 42LG60, 42LG70, 42LH20, 42LH40, 42LH50, 42LH90, LCD-DV:...

  • Page 7: Lcd Direct View Overview

    2. Check the model label. Verify model names and board model matches. 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… November LCD TV 32LD350...

  • Page 8: Basic Troubleshooting Steps

    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 perform a Safety AC Leakage Test before returning the product back to the Customer. November LCD TV 32LD350...
  • Page 9 32LD350 PRODUCT INFORMATION SECTION 32LD350 PRODUCT INFORMATION SECTION This section of the manual will discuss the specifications of the 32LD350 LCD Direct View Display November LCD TV 32LD350...
  • Page 10 • AV Mode (Cinema, Sports, Game) • Clear Voice II • ISFccc® Ready ISFccc® Ready • 24P Real Cinema • 2 HDMI™ 1.3 Inputs • SIMPLINK™ Connectivity SIMPLINK™ C ti it • Dolby® Digital 5.1 Decoder • Infinite Sound November LCD TV 32LD350...
  • Page 11 Clear Voice Clearer dialogue sound Automatically enhances and amplifies the sound of the human voice frequency range to provide high-quality dialogue when background noise swells noise swells. November LCD TV 32LD350...
  • Page 12 Dolby Digital (AC3), the reigning standard in surround-sound technology, produces 5.1-channel surround sound at the movies and in your home theater. To see it real is to hear it real. LG's Infinite Sound, which is tuned by the well- known sound specialist Mr. Mark Levinson, enhancements your High definition TV experience with maximum surround sound.
  • Page 13 32LD350 Remote Control 32LD350 Remote Control BOTTOM PORTION TOP PORTION p/n AKB72915206 November LCD TV 32LD350...

  • Page 14: Accessing The Service Menu

    2) Press “In-Start” 3) A Password screen appears. 4) Enter the Password. Note: A Password is required to enter the Service Menu. Enter; 0000 te ; 0000 Note: If 0000 does not work use 0413. MKJ39170828 105-201M November LCD TV 32LD350...

  • Page 15: Tv Rear Input / Output Jacks

    TV Rear Input / Output Jacks USB for Software Upgrades, Side In/Out Music and Photos Rear In/Out Jacks Rear In/Out Jacks USB 1 USB 1 HDMI 2 Head Phones MAIN BOARD Rear and Side Input/Output locations Component Inputs Inputs November LCD TV 32LD350...
  • Page 16 Do not turn off Power, during the upgrade 8) When download is completed, you will see process. “COMPLETE” COMPLETE . Software Files are available from 9) Your TV will be restarted automatically. the GSFS or GCSC web sites. November LCD TV 32LD350...
  • Page 17 4) Cursor Left to only highlight the briefcase on the left on the left. 2) Bring up the Customer’s Menu and highlight Options 3) The Option Menu appears 5) Press the (1) Key 5 to 8 times. See next page for more details. November LCD TV 32LD350...
  • Page 18 Channel Selected Host Information Channel Info : Digital 19-2 Blocked or not Blocked Parental Control : Channel is not blocked Model Name : 32LD350-UB (Liquid Crystal Display) Memory DVI/HDMI Status FLASH : 16384 KB Can’t display this information now DRAM : 131072 KB...
  • Page 19 Service Menu: Downloading EDID Data Pg 1 of 2 1) Press “ADJ” key on the 2) Scroll down to Item 8 “EDID D/L” 3) Opening EDID D/L screen Service Remote. and press the Select Key. appears. Continue on next page. November LCD TV 32LD350...
  • Page 20 5) After Erasing, EDID now “Select” key. Erasing begins. indicates “NG”. 6) Highlight “Start” then press 7) After Writing completes, “Select” key Writing begins Select key. Writing begins. EDID now indicates “OK” EDID now indicates OK . November LCD TV 32LD350...
  • Page 21 32LD350 Product Dimensions 32LD350 Product Dimensions 31-1/2" 2-7/8" Wattage 800mm 73.66mm AVG: 110W STBY: <1W 11-3/4" 6-5/16" 7-7/8" 298mm 160mm 200mm Model No. Serial No. 3-15/16" Side Label 100mm 22-3/16" 563.88mm Center 20" 508mm 11 1/8" 10" 281.78mm 254mm Remove 4 screws to remove stand for wall mount 2-3/16"...

  • Page 22: Disassembly Section

    DISASSEMBLY SECTION DISASSEMBLY SECTION Disassembly: This section of the manual will discuss Disassembly, Layout (Circuit Board Identification) of the 32LD350 LCD Direct View Television. it B d Id tifi ) f th 32LD350 LCD Di t Vi Upon completion of this section the Technician will have a better...

  • Page 23: Removing The Back Cover

    Cause as there are many damage. different types. Stand Base is Glass Handle with Care The Stand does not have to be removed before removing the back. November LCD TV 32LD350...

  • Page 24: Board Layout

    Clips hold front frame in place, use caution. Suggest adding screw while servicing. Warning: The Frame may have sharp edges Panel Interface Board Ballast LVDS Cable Power Supply (SMPS) M i B Main Board Keyboard AC Input IR/LED IR/LED Invisible Invisible Invisible Invisible Speaker Right Speaker Left Board November LCD TV 32LD350...
  • Page 25 P802 P402 MAIN BOARD SMPS Used in the 32LD350: EAY60868901 32LD350 AUSWLJR or Main Boards Used in the 32LD350: AUSDLFR or AUSDLUR or AUSDLJR EBU60850009 32LD350 AUSWLJR and AUSDLFR EAY60869101 32LD350 CUSWLH or EBR66049702 32LD350 AUSDLJR CUSDLH or CUSWLHO EBU60850010 32LD350 AUSDLUR...

  • Page 26: Power Supply Board Removal

    Disconnect P201, P203 and AC In SK100. Press in gently on the two tabs to release lock SMPS Used in the 32LD350: EAY60868901 32LD350 AUSWLJR or AUSDLFR or Remove the 4 AUSDLUR or AUSDLJR screws indicated EAY60869101 32LD350 EAY60869101 32LD350 SK100 by the arrows.

  • Page 27: Removing The Main Board

    NOTE: Always check on top and behind the Large ICs. And look for a piece of Chocolate Main Boards Used in the 32LD350: (Heat Transfer Material). EBU60850009 32LD350 AUSWLJR and AUSDLFR Be sure to transfer to EBR66049702 32LD350 AUSDLJR new Board if present new Board if present.
  • Page 28 NOTE: If Servicing the Board, return the screws to provide stability and grounding. Lift the Board up slightly on the right side and slide the board to the right to release the board from the Backlight connectors. Backlight connector November LCD TV 32LD350...
  • Page 29 Inverter. Make sure to return them to there correct positions if they should fall or pull off with the board. Connectors to the Backlights. The Inverter board slides into these connectors. Cushion pieces behind the Inverter November LCD TV 32LD350...
  • Page 30 Removing Front IR Board Removing Front IR Board p/n EBR64965302 Disconnect J1 and J2 connectors. Remove the 1 screw and pull the board forward. IR board / Intelligent Sensor IR board / Intelligent Sensor November LCD TV 32LD350...

  • Page 31: Troubleshooting Section

    This section of the manual will discuss troubleshooting. Upon completion of this section the Technician will have Upon completion of this section the Technician will have a better understanding of how to diagnosis and resolve problems. November LCD TV 32LD350...

  • Page 32: Power Supply Section

    P203 Connector: (To the Ballast) 24V is routed out P204 pins 1 through 5. Other SMPS Used in the 32LD350: EAY60868901 32LD350 AUSWLJR or AUSDLFR or AUSDLUR or AUSDLJR EAY60869101 EAY60869101 32LD350 CUSWLH or CUSDLH or CUSWLHO November LCD TV 32LD350...

  • Page 33: Power Supply (Smps) Board Layout

    Power Supply (SMPS) Board Layout Power Supply (SMPS) Board Layout p/n EAY60868901 Cold Gnd Hot Gnd F501 F501 3.15A/250V STBY 0V Run 388V From Hot Gnd Hot Ground Shock F100 Hazard 5A/250V 5A/250V AC Protect November LCD TV 32LD350...
  • Page 34 32LD350 Television Start Up Sequence 32LD350 Television Start Up Sequence Primary side fuse: Stand-By 0V Run 390V BALLAST AC In Bridge Relay 24V B+ for the Ballast Regulator Rectifier POWER SUPPLY (SMPS) Inverter On Starts the Ballast. Backlights Light. Stand...
  • Page 35 32LD350 P403 on Main to SMPS P201 Television Turn On Circuit 32LD350 P403 on Main to SMPS P201 Television Turn On Circuit THREE STEP TURN ON PROCESS: 11.97V 11.97V R439 10KΩ Stand-By: STBY_3.5V arrives on main. Powers up MStar (Micro /...
  • Page 36 The Backlights should turn on at this point. If the 24V and the Inverter On command is arriving at the Ballast, but no backlights, then see Ballast Section for further testing. (B) Remove AC power and Remove Jumper. SMPS and Ballast are OK. November LCD TV 32LD350...

  • Page 37: Power Supply Connector P201 Voltage And Diode Check

    (5) PWM-DIM Pin 24 (To P203 pin 14 Silk Screened PWM-DIM 0.65V~3.25V Open Error_Out) can vary according to incoming video IRE level and OSD Backlight setting Output from the Video Processor IC100. Range 0.65V to 3.25V. Diode Mode values taken with all Connectors Removed November LCD TV 32LD350...

  • Page 38: Power Supply Connector P203 Voltage And Diode Check

    (4) PWM-DIM Pin 14 (From P201 pin 24 Silk Screened Error_Out) can vary according to incoming video IRE level and OSD Backlight setting Output from the Video Processor IC100. Range 0.65V to 3.25V. Diode Mode values taken with all Connectors Removed November LCD TV 32LD350...

  • Page 39: Power Supply

    F100 (Diode Check) Red or Black Lead on Fuse (Open) Other Lead on Hot Ground Diode Mode values taken with all Connectors Removed November LCD TV 32LD350...
  • Page 40 P-DIM is delivered from the Main board through the SMPS to the Inverter on CN1 pin 14. The Ballast responsible for delivering approx. 1.2kV to each of the 8 Cold Cathode Florescent bulbs. This is accomplished by 8 step-up transformers, 1 for each lamp. Cover On Cover Off November LCD TV 32LD350...
  • Page 41 Ballast Component and Connector Identification Ballast Component and Connector Identification Top Half Bottom Half Fuse November LCD TV 32LD350...
  • Page 42 32LD350 Main Board to Ballast Turn On Commands 32LD350 Main Board to Ballast Turn On Commands P203 P201 P402 MAIN PWB IC100 3.3V_Normal MStar BALLAST POWER SUPPLY Q405 INV On/Off INV-On/Off INV On/Off 3.32V 3.5V_ST 9 10 11 12 9 10...
  • Page 43 30V / 80% PWM DIM 30V p/p 80% PWM-DIM 15 15V / 80% PWM DIM 15.15V p/p 80% PWM-DIM Checking T103 ~ T110 Pi 1 Pin 1 Pin 2 Pin 3 24.07V Warning: Pin 4 has 1.2Kv p/p November LCD TV 32LD350...
  • Page 44 DIM (Global Dimming) Explained: P- - DIM (PWM (PWM- - DIM may also be called P DIM may also be called P- - DIM, VBR DIM, VBR- - B, PDS, BCM B, PDS, BCM- - VBR VBR- - B) B) November LCD TV 32LD350...
  • Page 45 Inverter (Main) Fuse F101 Check Center Right of the Board Inverter (Main) Just under CN1 Connector F1 (Di d M d Ch F1 (Diode Mode Check) Open (Red Lead on Fuse) 0.9V (Black Lead on Fuse) F101 F101 November LCD TV 32LD350...
  • Page 46 Backlight Drive Signal PWM Backlight Drive Signal PWM- - DIM Effects DIM Effects November LCD TV 32LD350...
  • Page 47 ERROR Pin 11. Normal low. Goes high when the Backlights are told to turn on by INV_ON. After backlights fire, go back low. Will repeat 5 times then shut off the set. Diode Mode values taken with all Connectors Removed November LCD TV 32LD350...

  • Page 48: Main Board Section

    • +1.2V_PVSB (Made from 3.3V_TU) 1.26V_VDDP, 3.3V_VDDP, • +3.3V_PVSB (Made from 3.3V_TU) +3.3V_AVDD_MPLL WIRELESS VOLTAGES • 24V (Switched from 24V from SMPS) 24V (Switched from 24V from SMPS) •T-CON IC9001 •T-CON IC9001 • 3.3V_VCC, -5V_VGL, 27V_VGH, 16V_VDD and HVDD (7.8V) November LCD TV 32LD350...

  • Page 49: Mainboard Layout

    Side Audio Audio Composite TUNER Inputs P600 P2401 To EBU60850003 32LD350 CUSDLH (The one shown) To Speakers Front IR EBU60850009 32LD350 AUSWLJR and AUSDLFR EBR66049702 32LD350 AUSDLJR EBR66049702 32LD350 AUSDLJR EBU60850010 32LD350 AUSDLUR EBU61005102 32LD350 CUSWLH and CUSWLHO November LCD TV 32LD350...
  • Page 50 32LD350 Main Component Layout (Front View) 32LD350 Main Component Layout (Front View) L415 P802 IC403 IC401 IC407 P402 L406 IC105 IC1000 L423 MAIN BOARD SW100 Microprocessor p/n: EBU60850003 Reset L422 IC1450 IC100 Mstar IC101 Q100 Micro and Video IC406 USB1...
  • Page 51 32LD350 Main (Front Side) Component Voltages IC101 Serial Flash IC403 (+1.26V_VDDC) IC407 (D1.8V) IC5001 (+1.26V) for Tuner Memory Regulator Regulator Regulator [1] 0.05V [1] 0.79V [1] 0.8V [1] 3.3V (In) [2] 3.28V [2] 0V (Gnd) [2] 0V (Gnd) [2] 1.26V (Out) [3] 2.26V...
  • Page 52 32LD350 Main Component (Back Side) Layout 32LD350 Main Component (Back Side) Layout Q407 Q406 Q409 Q402 Q405 Q401 IC408 IC103 IC104 IC7702 IC400 IC102 D7706 IC601 A1 A2 D7703 D102 IC1100 Q1101 Q600 Q1102 Q7701 Q7703 IC7701 Q5004 IC1201 IC1104...
  • Page 53 32LD350 Main (Back Side) Component Voltages IC103 Reset IC1100 Earphone IC1201 RS232 IC7702 EDID Data Q1101-2 EARPHONE Generator Data Buffer HDMI4 MUTE [1] Gnd [1] 2.14V [1] 3.34V [1] 0V (Gnd) B 0V [2] 0V [2] 0V (Gnd) [2] 3.48V...
  • Page 54 IC1004 VSB QAM Demodulator Processor Crystal X1005 X100 Runs all Runs only 25Mhz 12Mhz 12Mhz the time the time when set when set is on 3.64V p/p 4.59V p/p 3.61V p/p 2.91V p/p X100 X1005 MAIN Board November LCD TV 32LD350...
  • Page 55 (5) P-DIM Pin 24 (Silk Screened Error_Out) can vary according to incoming video IRE level and OSD Backlight setting Output from the Video Processor IC100. Range 0.65V to 3.25V. Diode Mode values taken with all Connectors Removed November LCD TV 32LD350...
  • Page 56 12V_LVDS Pins 27~30 Note: The Panel has an additional board that sets on top and takes the Th P dditi d th t d t k 12V to generate the 5 usable voltages for the Panel. November LCD TV 32LD350...
  • Page 57 Differential Pair LVDS Signal. All waveforms shown are the (+) part of the differential pair. The (-) part is exactly the same only inverted inverted. All waveforms are at the same 5uSec per/div rate and 100Mv per/div. November LCD TV 32LD350...
  • Page 58 0.79V TXAC- 1.2V 0.79V Panel_VCC 11.97V 2.59V TXA2+ 1.16V 0.79V TXA2- 1.35V 0.79V Panel_VCC 11.97V 2.59V Panel_VCC 11.97V 2.59V TXA1+ TXA1+ 1 15V 1.15V 0 79V 0.79V Panel VCC Panel_VCC 11 97V 11.97V 2 59V 2.59V November LCD TV 32LD350...
  • Page 59 LED_B 2.3V 1 98V 1.98V Open +3.3V_Normal 0.02V 3.3V 0.58V LED R/BUZZ LED_R/BUZZ 2 49V 2.49V 2 14V 2.14V No Clock or Data pulses IR pulses (1.6V p/p) Diode Mode values taken with all Connectors Removed November LCD TV 32LD350...

  • Page 60: Main Board Connector P600 To Speakers Voltage And Diode Check

    SPK R( ) 12 95V 12.95V Open Open SPK-R(+) 12.95V Open SPK-L(-) 12.95V Open SPK-L(+) 12.95V Open Diode Mode values taken with all Connectors Removed P600 Circuit Location on the Main Board R- R+ L- L+ November LCD TV 32LD350...
  • Page 61 IR b d i J3 J1 K 2 li (Key 1 pin 4 and Key 2 pin 5). Arriving at P2401 pins 4 and 5 on the Main Board. Then to the Microprocessor Pins A4 and B4. November LCD TV 32LD350...
  • Page 62 Front IR Board (Connections Identified) Front IR Board (Connections Identified) p/n EBR64965302 Key Board P3000 To Main Board IR board IR board November LCD TV 32LD350...

  • Page 63: Power Leds

    Front IR Board Remote Receiver Check p/n EBR64965302 IR board IR Receiver Diode Check R indicates Red Lead R indicates Red Lead B indicates Black Lead IR Center Leg Ground (2.8V) (2.34V) (0.68V) B B (0.65V) Power LEDs November LCD TV 32LD350...
  • Page 64 3.5V_ST 3.41V 3.39V Open LED_B Open 1.98V Open +3.3V_Normal 0.02V 3.3V Open LED R/BUZZ LED_R/BUZZ 2 49V 2.49V Open No Clock or Data pluses IR pulses (1.6V p/p) Diode Mode values taken with all Connectors Removed November LCD TV 32LD350...

  • Page 65: Key Board Section

    Diode Check on Key 1 and Key Enter 0.98M 0.10V 2 is Open. Voltage with no key pressed 3.4V STBY and 3.39V RUN Label Function Resistance Voltage Key 2 CH + 1.70V CH - 1.09V Power 5.27M 0.52V Input 0.98M 0.10V November LCD TV 32LD350...
  • Page 66 Speaker p/n EAB60961401 / EAB60961401 The 32LD350 contains the Invisible Speaker system. The Full Range Speakers point downward, so there is no front viewable speaker grill or air ports. It uses the dual split magnet style of thin profile speaker.

  • Page 67: Interconnect Diagram (11 X 17 Foldout Section)

    This Power Point shows a graphical representation of the 1 1 X 17 foldout page so clarity is limited foldout page so clarity is limited foldout page so clarity is limited. foldout page so clarity is limited. November LCD TV 32LD350...
  • Page 68 STBY Diode ST_3.3V 3.41V 3.39V 0.9V 2.97V 50% P-DIM Key 2 24.19V Open Main Boards Used in the 32LD350: 1,2,3,4,5 Resistance To all Speakers Function Voltage EBU60850009 32LD350 AUSWLJR and AUSDLFR Pin 3 of T103 ~ T110 LED_B 2.3V Open...
  • Page 69 32LD350 MAIN (FRONT SIDE) SIMICONDUCTORS IC101 Serial Flash IC403 (+1.26V_VDDC) IC407 (D1.8V) IC5001 (+1.26V) for Tuner Q7702 HDMI 4 Memory Regulator Regulator Regulator [1] 0.05V [1] 0.79V [1] 0.8V [1] 3.3V (In) B 0.63V [2] 3.28V [2] 0V (Gnd) [2] 0V (Gnd) [2] 1.26V (Out)
  • Page 70 5uSec per/div 534.1mV p/p 5uSec per/div 583.9mV p/p 5uSec per/div 395mV p/p 32LD350 P802 LVDS CABLE WAVEFORMS: Waveforms taken using SMTP Color Bar input. All readings give the Scale 100mV and 5uSec per division Time Base related to scope settings.
  • Page 71 32LD350 Conclusion Direct View LCD Direct View LCD Page This concludes the 32LD350 training session.

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