LG Flatron F700B Service Manual PDF

The LG Flatron F700B is a 17-inch CRT monitor featuring a 0.27mm dot pitch, maximum resolution of 1280x1024 at 60Hz, and support for multiple video inputs. This service manual provides comprehensive technical information for service technicians, including disassembly instructions, circuit diagrams, troubleshooting procedures, and replacement part specifications.

1. Product Overview 2. Technical Specifications 3. Disassembly Instructions 4. Circuit Diagrams 5. PCB Layouts 6. Troubleshooting Guide 7. Parts List 8. Adjustment Procedures 9. Safety Precautions 10. Block Diagrams 11. Service Notes

Product Overview

The LG Flatron F700B features a flat square CRT tube with anti-glare coating, digital controls, and multiple display modes. Key components include main PCB, deflection yoke, high voltage section, and power supply unit.

Component	Description
CRT Tube	17-inch flat square, 0.27mm dot pitch
Deflection Circuit	Horizontal: 30-69kHz, Vertical: 50-160Hz
Video Bandwidth	110MHz
Power Supply	Switch mode, 90-264V AC input
Input Connectors	15-pin D-sub analog RGB
Controls	Digital OSD with front panel buttons
Safety Standards	TCO '99, UL, CSA, TUV
Dimensions	402mm(W) x 415mm(H) x 445mm(D)
Weight	17.5kg
Power Consumption	85W maximum

Technical Specifications

Display Type: 17-inch CRT, Flat Square
Viewable Area: 16.0-inch diagonal
Dot Pitch: 0.27mm
Maximum Resolution: 1280 x 1024 @ 60Hz
Recommended Resolution: 1024 x 768 @ 85Hz
Horizontal Frequency: 30-69kHz
Vertical Frequency: 50-160Hz
Video Bandwidth: 110MHz
Input Signal: Analog RGB, 0.7Vp-p
Power Requirements: 90-264V AC, 50/60Hz
Power Consumption: 85W (max), 15W (standby)

Disassembly Instructions

Follow these steps carefully for safe disassembly and reassembly.

Power off and unplug monitor from AC outlet
Remove base stand by pressing release button
Remove rear cover screws (4 pcs)
Carefully separate front and rear casings
Discharge CRT anode using proper grounding tool
Remove deflection yoke connectors
Remove main PCB mounting screws
Lift PCB assembly from chassis

WARNING! High voltage present even when unplugged. Always discharge CRT before servicing.

Circuit Diagrams

Complete schematic diagrams included for all major sections:

Power Supply Circuit (IC801, T801)
Deflection Circuit (IC701, T701)
Video Amplifier Circuit (IC301-IC303)
Microprocessor Circuit (IC101)
OSD Circuit (IC201)
High Voltage Circuit (Flyback Transformer)

All diagrams include component values, test points, and voltage specifications.

PCB Layouts

Detailed printed circuit board layouts for:

PCB	Description	Components
Main Board	Primary control and processing	IC101, IC201, IC301-303
Power Supply	AC/DC conversion	IC801, T801, D801-809
CRT Board	CRT socket and components	CRT socket, focus divider
Front Panel	Control buttons and LEDs	SW101-SW105, LED101

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
No power	Fuse, power supply	Check F801, measure +B voltage, check IC801
No display	High voltage, video circuit	Check flyback, CRT voltages, video ICs
Horizontal collapse	Deflection circuit	Check IC701, horizontal output transistor
Vertical collapse	Vertical IC	Check IC601, vertical deflection coil
Poor focus	Focus voltage	Adjust focus pot, check focus divider
Color problems	Video amplifier	Check IC301-303, CRT drive voltages
Geometry issues	Deflection yoke	Adjust geometry controls, check yoke

Parts List

Critical replacement parts and components:

IC101: Microprocessor (M6759)
IC201: OSD Controller (LSC4350)
IC301-303: Video Amplifier (LM2439)
IC601: Vertical Deflection (TDA4866)
IC701: Horizontal Deflection (TDA4856)
IC801: Power Supply IC (UC3842)
T801: Power Transformer
T701: Flyback Transformer
CRT: A48JAR90X (or equivalent)

Adjustment Procedures

Factory adjustment procedures using service remote or service mode:

Enter service mode: Power off, hold MENU button, power on
White balance adjustment (R/G/B drive)
Geometry adjustment (pincushion, trapezoid)
Convergence adjustment (static/dynamic)
Focus adjustment
High voltage adjustment (25kV typical)
Save settings and exit service mode

CAUTION! Use proper test equipment and follow safety procedures.

Safety Precautions

Essential safety information for service technicians:

Always discharge CRT anode before working on monitor
Use isolation transformer when servicing power supply
Wear safety glasses when handling CRT
Work in well-ventilated area
Use proper grounding techniques
Follow electrostatic discharge (ESD) precautions
Replace safety critical components with exact equivalents

WARNING! Lethal voltages present. Only qualified technicians should perform service.

Block Diagrams

System block diagrams showing signal flow and interconnections:

Overall System Block Diagram
Power Supply Block Diagram
Video Signal Processing Block Diagram
Deflection System Block Diagram
Microprocessor Control Block Diagram

Each block diagram includes signal paths, control lines, and power distribution.

Service Notes

Important service tips and common issues:

Common failure: Horizontal output transistor (Q702)
Power supply issues: Check electrolytic capacitors C807-C809
Geometry problems: Often related to deflection yoke
Color purity: May require degaussing
Focus issues: Check focus voltage and divider network
Intermittent operation: Check solder joints on power components

Service Support: LG Service Center, Technical Hotline