LG AS990 Service Manual

The LG AS990 is a high-performance mobile device featuring advanced connectivity, multimedia capabilities, and robust hardware specifications. This service manual provides comprehensive technical information for repair technicians, including disassembly procedures, component specifications, troubleshooting guides, and maintenance protocols. Below are key sections covering device overview, technical specifications, repair procedures, and diagnostic information.

1. Device Overview 2. Technical Specifications 3. Disassembly Procedures 4. Component Identification 5. Troubleshooting Guide 6. Board Schematics 7. Replacement Parts 8. Software Diagnostics 9. Safety Precautions 10. Calibration Procedures 11. Contact Information

Device Overview

Key components: Main board assembly, display module, battery unit, camera modules, connectivity boards, and external housing.

ComponentDescription
Main BoardCentral processing unit with integrated memory and storage
Display AssemblyLCD/LED screen with touch digitizer
Battery UnitLithium-ion power source with protection circuit
Camera ModulesFront and rear camera assemblies
Connectivity BoardWiFi, Bluetooth, and cellular radio modules
Audio BoardSpeaker, microphone, and audio processing components
Charging PortUSB-C/Micro-USB charging and data interface
Button AssembliesPower, volume, and function buttons
SIM/SD Card TrayDual SIM and external storage slot
HousingExternal case and structural framework

Technical Specifications

Disassembly Procedures

Follow these steps for safe device disassembly and component access.

  1. Power off device and remove SIM/SD card tray
  2. Apply heat to back cover edges to loosen adhesive
  3. Use suction cup and plastic opening tools to separate back cover
  4. Remove visible screws using appropriate screwdriver bits
  5. Disconnect battery connector before proceeding with component removal
  6. Carefully disconnect flex cables using plastic spudgers
  7. Remove components in recommended order: battery, main board, display

WARNING! Always disconnect battery first to prevent short circuits. Use proper ESD protection.

Component Identification

Main board contains primary ICs and connectors. Key components include:

ComponentPart NumberLocation
Main ProcessorSM8250-ACCenter, under shield
Memory PackageK3UH7H7Stacked on processor
Power ManagementS2MPB02Upper left quadrant
RF TransceiverSM4350Lower right section
Audio CodecCS35L41Near audio connectors
WiFi/BT ModuleBCM4375Lower left corner

Troubleshooting Guide

SymptomPossible CauseCorrective Action
No powerBattery, charging circuitCheck battery voltage; test charging port; inspect power IC
No displayScreen, flex cable, main boardTest with known good screen; check display connector; measure display voltages
No touch responseDigitizer, flex cableReplace digitizer; check touch connector; test touch controller
No cellular serviceAntenna, RF sectionCheck antenna connections; test RF components; verify SIM detection
Camera not workingCamera module, main boardSwap camera module; check camera connector; test camera power
OverheatingProcessor, batteryCheck thermal paste; test processor under load; inspect battery

Board Schematics

Reference schematics for circuit analysis and signal tracing.

Note: Schematics available in separate PDF document.

Replacement Parts

Genuine LG replacement parts with official part numbers.

ComponentPart NumberCompatibility
Display AssemblyEAS65412301Complete with frame
BatteryBL-51YF4000mAh original
Rear CameraCAM78451203Main 48MP module
Charging PortFPC88745612With flex cable
Main BoardMB987123456Complete assembly
Back CoverHC654789321Original housing

Software Diagnostics

Built-in diagnostic modes and software tools for comprehensive testing.

  1. Enter service mode: Dial *#546368#*990#
  2. Hardware test: Select individual component testing
  3. Sensor calibration: Accelerometer, gyroscope, proximity
  4. RF testing: Cellular, WiFi, Bluetooth signal analysis
  5. Display test: Color uniformity, touch accuracy
  6. Audio test: Speaker, microphone, headphone functionality
  7. Battery test: Health status and charging capability

Safety Precautions

Critical safety information for technicians and repair personnel.

CAUTION! Lithium-ion batteries can pose fire hazard if damaged. Handle with care.

Calibration Procedures

Step-by-step calibration processes for various device functions.

  1. Display calibration: Color accuracy and white balance adjustment
  2. Touch calibration: Digitizer accuracy and sensitivity settings
  3. Camera calibration: Focus, white balance, and image stabilization
  4. Sensor calibration: Accelerometer, gyroscope, and compass
  5. Audio calibration: Speaker output and microphone sensitivity
  6. Battery calibration: Capacity measurement and charging optimization

Contact Information

LG authorized service centers and technical support resources.

Note: Service available through authorized LG service centers only.

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