LG Flatron L1720P Service Manual

The LG Flatron L1720P is a 17-inch LCD monitor featuring 1280x1024 resolution, 250 cd/m² brightness, 500:1 contrast ratio, analog and digital inputs, pivot function, wall mount capability, and comprehensive service and troubleshooting information. Below are key sections for technical specifications, disassembly instructions, circuit diagrams, troubleshooting, and replacement procedures.

1. Product Overview 2. Technical Specifications 3. Safety Precautions 4. Disassembly Instructions 5. Main Board Circuit Diagram 6. Power Supply Circuit 7. LCD Panel Specifications 8. Troubleshooting Flowchart 9. Replacement Parts List 10. Adjustment Procedures 11. Block Diagram

Product Overview

The LG Flatron L1720P LCD monitor features a slim design with comprehensive connectivity options and service-friendly construction.

ComponentDescription
LCD Panel17-inch TFT active matrix
Resolution1280 x 1024 (SXGA)
Input ConnectorsD-Sub 15-pin, DVI-D
Power SupplyInternal switching power supply
Main BoardSignal processing and control
Inverter BoardCCFL backlight power
Control ButtonsPower, Menu, Auto, Select, +/-

Technical Specifications

Safety Precautions

Before servicing, read all safety instructions carefully.

  1. Disconnect power before disassembly.
  2. Use anti-static wrist strap when handling boards.
  3. Discharge capacitors before testing power supply.
  4. Handle LCD panel with care to avoid damage.
  5. Use proper tools for disassembly.

WARNING! High voltage present in power supply and inverter circuits. Exercise extreme caution when servicing.

Disassembly Instructions

Step-by-step procedure for monitor disassembly.

  1. Remove stand: Press release button and separate stand from monitor.
  2. Remove rear cover screws: 4 screws located on back cover.
  3. Separate front bezel: Carefully pry plastic clips around perimeter.
  4. Remove metal shield: Unscrew shield from main assembly.
  5. Disconnect cables: Note positions before disconnecting LVDS, inverter, and control cables.
  6. Remove boards: Unscrew main board, power supply, and inverter boards.

CAUTION! Handle LCD panel edges only. Avoid pressure on screen surface.

Main Board Circuit Diagram

Main board contains video processing, microcontroller, and input circuitry.

Refer to schematic diagram page 12 for complete circuit details.

Power Supply Circuit

Switching power supply provides multiple DC voltages.

OutputVoltageCurrentPurpose
VCC112V3AInverter board
VCC25V2AMain board logic
VCC33.3V1.5ASignal processing

Main Components:

LCD Panel Specifications

Panel model: LG-Philips LM170E01

Troubleshooting Flowchart

SymptomCheck PointsSolution
No powerPower cord, fuse, standby voltageReplace fuse, check power board components
No displayBacklight, main board voltagesTest inverter output, check LVDS cable
Dim displayBacklight intensity, CCFL lampsReplace CCFL tubes or inverter board
No imageInput signal, main board operationCheck input source, test scaler IC
Color problemsLVDS connection, panel driveReseat LVDS cable, check T-con board
Power cyclesOvercurrent protection, capacitorsReplace bulging capacitors on power board

Replacement Parts List

Part NumberDescriptionQty
6871C-0146AMain Board Assembly1
6871C-0147APower Supply Board1
6871C-0148AInverter Board1
6871C-0149ALCD Panel LM170E011
6871C-0150AFront Control Board1
6871C-0151ARear Cover Assembly1
6871C-0152AStand Assembly1
F001Fuse 3.15A/250V1

Adjustment Procedures

Factory adjustment and calibration procedures.

  1. White Balance: Enter service mode, adjust R/G/B gain and offset
  2. Geometry: Adjust horizontal/vertical position and size
  3. Clock/Phase: Auto-adjust or manual fine tuning
  4. Backlight Level: Set brightness to factory specification
  5. Color Temperature: Calibrate to 6500K standard

Service Mode Access: Power off, hold MENU button, power on

Block Diagram

System block diagram showing signal flow and power distribution.

Refer to page 15 for detailed block diagram illustration.

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