LG Flatron W1642C - User Manual

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Summary

SPECIFICATIONS

LCD CHARACTERISTICS

Details about the LCD panel's physical and visual properties.

OPTICAL CHARACTERISTICS

Information on viewing angles and contrast ratio.

SIGNAL

Technical specifications for video and sync input signals.

MAX. RESOLUTION

Defines the monitor's maximum supported display resolution.

POWER SUPPLY

Details on the monitor's power input and consumption.

ENVIRONMENT

Operating conditions and expected lifespan (MTBF, Lamp Life).

DIMENSIONS (with TILT;SWIVEL)

Physical measurements of the monitor unit.

WEIGHT (with TILT;SWIVEL)

Weight specifications for the monitor unit.

PRECAUTIONS

WARNING FOR THE SAFETY-RELATED COMPONENT

Critical safety components and replacement guidelines.

CAUTION

Warning about using plastic screwdrivers to avoid shock.

SERVICING PRECAUTIONS

General Servicing Precautions

General safety guidelines for servicing the unit.

Electrostatically Sensitive (ES) Devices

Precautions for handling sensitive electronic components.

DESCRIPTION OF BLOCK DIAGRAM

Video Controller Part

Explanation of the video signal processing and conversion circuit.

Power Part

Description of the power supply regulation and distribution system.

MICOM Part

Details on the microcontroller unit and its control functions.

LIPS Board Block Diagram

Operation description_Power

Functional description of the LIPS power supply board.

ADJUSTMENT

Port Setup

Procedure for configuring the communication port for adjustments.

EDID Read & Write

Instructions for reading and writing monitor EDID data.

SERVICE OSD

CLEAR ETI

Menu option to initialize the unit's usage time.

Module

Menu option for selecting the applied display module.

Auto Color

Menu option for automatic white balance and color adjustment.

NVRAM INIT

Menu option to initialize the EEPROM settings.

R;G;B-9300 K

Menu option for manual R/G/B adjustment at 9300K.

R;G;B-6500 K

Menu option for manual R/G/B adjustment at 6500K.

R;G;B-Offset

Menu option for manual R/G/B offset adjustment (Analog).

R;G;B-Gain

Menu option for manual R/G/B gain adjustment (Analog).

TROUBLESHOOTING GUIDE

NO POWER

Diagnostic steps for when the monitor does not power on.

NO RASTER (OSD IS NOT DISPLAYED) - LIPS

NO RASTER (OSD IS NOT DISPLAYED) - MAIN

This document outlines the service procedures and features for the LG FLATRON W1642C (W1642C-PFT.A**AP) color monitor, chassis LM73B. It is intended for internal use by service personnel and provides comprehensive information for maintenance and repair.

Function Description

The LG FLATRON W1642C is a color monitor designed to display video signals from a connected source. Its core function involves processing analog video input signals, converting them to a digital format, and then displaying them on a Thin-Film Transistor (TFT) Color Liquid Crystal Display (LCD) module. The monitor supports a maximum resolution of 1360 x 768 at 60Hz in analog mode.

The monitor's internal architecture includes a Video Controller Part responsible for amplifying and converting analog video signals to digital. This part utilizes a pixel clock, generated by a Phase-Locked Loop (PLL), which can range from 25MHz to 136MHz (or 28MHz to 146MHz in some cases). Key components within the video controller include a Scaler, an Analog-to-Digital Converter (ADC), a Transition Minimized Differential Signaling (TMDS) receiver, and a Low-Voltage Differential Signaling (LVDS) transmitter. The Scaler interpolates input signals to the native 1360 x 768 resolution and outputs 8-bit Red, Green, and Blue (RGB) signals to the transmitter.

The Power Part of the monitor is responsible for supplying the necessary voltages to various internal components. It includes 3.3V and 1.8V regulators that convert the 5V power supplied by the power board. Additionally, 18V is provided for the inverter, and 5V is supplied to the LCD panel and the Microcontroller (MICOM). The inverter converts DC 18V to AC 700Vrms to power the backlight lamps of the LCD module.

The MICOM Part integrates the video controller and includes an EEPROM (Electrically Erasable Programmable Read-Only Memory) IC, which stores control data, a Reset IC, and the MICOM itself. The MICOM identifies the polarity and frequency of the Horizontal (H) and Vertical (V) sync signals received from the signal cable, with controlled data for different display modes stored in the EEPROM.

The LIPS (LG Inverter Power Supply) Board, a critical component, handles power management. It comprises EMI (Electromagnetic Interference) components to comply with global marketing standards, an input rectifier and filter to convert AC voltage to DC, an energy transfer section utilizing a power transformer, and an output rectifier and filter for pulse width modulation control and output stabilization. A photo-coupler isolation mechanism feeds back DC output status to the primary controller, ensuring a stabilized DC output voltage. Signal collection functions gather changes from the DC output and feed them back to the primary via the photo-transistor.

Usage Features

The monitor is designed for ease of use and offers several operational modes and settings. Power consumption varies depending on the mode: less than 20W (max) or 18W (typ) in normal active mode (indicated by a blue LED), and less than 1W in stand-by, suspend, or DPMS (Display Power Management Signaling) off modes (indicated by an amber LED). When the power switch is off, consumption is also less than 1W, with no LED indication.

Users can access a Service OSD (On-Screen Display) menu for advanced adjustments and diagnostics. This menu is accessed by turning off the power, waiting 5 seconds, and then pressing the MENU and POWER switches for a 1-second interval. The Service OSD provides functions such as:

CLEAR ETI: Initializes settings based on time.
Auto Color: Automatically adjusts White Balance (W/B) balance, gain, and offset values (activated by pressing a key for over 3 seconds).
Module: Allows selection of the applied module.
NVRAM INIT: Initializes the EEPROM (24C08) by pressing a key for over 3 seconds.
R/G/B-9300K / R/G/B-6500K: Manually sets R/G/B values for 9300K or 6500K color temperatures.
R/G/B-Offset / R/G/B-Gain: Manually adjusts R/G/B offset and gain values for analog signals.

The monitor supports various display resolutions and timing charts, including 720x400, 640x480, 800x600, 832x624, 1024x768, and 1280x768, up to its maximum of 1360x768. These timings are crucial for ensuring compatibility with different video sources.

Maintenance Features

The service manual emphasizes safety precautions and detailed procedures for maintenance and repair. Safety Precautions:

Component Replacement: Special safety-related components, marked on schematic diagrams and parts lists, must be replaced with manufacturer-specified parts to prevent electric shock, fire, or other hazards.
Design Modification: Original designs should not be modified without manufacturer permission to avoid voiding warranties.
AC Power Disconnection: Always unplug the AC power cord before removing components, connecting test substitutes, or discharging the picture tube anode.
High Voltage Handling: Exercise extreme caution when dealing with high voltage, especially in the inverter circuit (up to 650Vrms). Use appropriate high voltage meters and discharge the picture tube anode safely.
ESD Protection: Protect the LCD module from Electrostatic Discharge (ESD) by grounding the technician's body with a wrist band and handling components carefully.
Chemical Use: Avoid spraying chemicals on or near the receiver. Clean electrical contacts with a specified acetone and isopropyl alcohol mixture.
Heat Sinks: Ensure all solid-state device heat sinks are correctly installed before applying AC power.

Handling the LCD Module with Backlight Unit:

Mounting: Mount the module using mounting holes in all four corners.
Panel Protection: Avoid pressing on the panel or edges, scratching it with sharp objects, or exposing it to high temperatures, humidity, direct sunlight, or water.
Cleaning: Clean the panel surface with a soft material.

Servicing Procedures:

Soldering Guidelines: Use a grounded-tip, low-wattage soldering iron with appropriate tip size and temperature (500-600°F). Use RMA resin-core solder (60% tin/40% lead) and keep the tip clean.
Unsoldering/Soldering Technique: Follow specific steps for heating, drawing melted solder, and applying new solder to avoid overheating the circuit board.
IC Removal/Replacement: Special techniques are provided for ICs with slotted holes, including desoldering, straightening leads, and carefully inserting and soldering replacements.
Discrete Transistor/Diode/Fuse/Resistor Replacement: Detailed steps are given for clipping leads, bending, crimping, and soldering replacements while maintaining original spacing.
Circuit Board Foil Repair: Procedures for repairing damaged copper patterns at IC connections and other points using jumper wires are outlined, emphasizing safety and proper insulation.

Troubleshooting Guide: The manual includes flowcharts for diagnosing common issues:

No Power: Checks voltage at J703, U602, U601, and U501, and crystal X501, guiding technicians to check the power board or specific ICs.
No Raster (OSD Not Displayed) – LIPS: Checks voltages at J703, J703 PIN9, and J703 PIN10, as well as the U501 inverter on/off port and MICOM DIM-ADJ port. It also involves checking the pulse at the lamp wire of the LCD module and suggests replacing the LCD module if necessary.
No Raster (OSD Not Displayed) – Main: Checks voltages at U501 PIN2 and PIN17, U501 PIN108 and PIN109, and H-SYNC/V-SYNC pulses at U501 PIN27 and PIN28. This guides troubleshooting to soldering conditions, crystal X501, U501, or the D-SUB cable/LCD module.
Trouble in DPM (Display Power Management): Checks R730 and R731 sync signals and U501 PIN27/28 sync pulses to diagnose issues related to the monitor entering DPM mode or problems with the H/V sync line.

The document also provides wiring diagrams and an exploded view with a parts list, including safety-marked components, to facilitate accurate identification and replacement of parts during service.