Dell Latitude 7420 User Manual

Latitude 7420/Latitude 7420 2-in-1
Service Manual
Regulatory Model: P135G/P136G
Regulatory Type: P135G001/P136G001
July 2023
Rev. A04

Dell Latitude 7420 Specifications

General

Harmonized System (HS) code	84713000

Summary

Working on your computer

Safety instructions

Essential safety guidelines for working with the computer.

Service mode

Procedure to enter service mode for repairs without battery disconnection.

Before working inside your computer

Steps to take before starting internal computer procedures.

Safety precautions

Detailed safety measures to prevent damage and injury.

Electrostatic discharge—ESD protection

Methods and importance of protecting against ESD damage.

ESD field service kit

Components and usage of the ESD field service kit.

Transporting sensitive components

Guidelines for safely transporting sensitive computer parts.

After working inside your computer

Steps to follow after completing internal computer work.

Removing and installing components

Recommended tools

List of tools required for component removal and installation.

Screw List

Detailed list of screws used for various computer components.

Major components of your system

Visual identification of the main internal hardware components.

micro-SD card

Instructions for removing and installing the micro-SD card.

SIM card tray

Procedures for removing and installing the SIM card tray.

Base cover

Steps for removing and installing the computer's base cover.

Solid-state drive

Instructions for removing and installing the SSD.

WWAN card

Procedures for removing and installing the WWAN card.

Battery

Precautions and steps for removing/installing the rechargeable Li-ion battery.

Heat sink

Instructions for removing and installing the heatsink assembly.

Palmrest antenna module

Procedures for removing and installing the palmrest antenna module.

Display assembly

Steps for removing and installing the display assembly.

Audio board

Instructions for removing and installing the audio board.

Speakers

Procedures for removing and installing the speakers.

SmartCard reader

Steps for removing and installing the smart card reader.

System board

Detailed procedures for removing and installing the system board.

I/O board

Instructions for removing and installing the I/O board.

Power button with fingerprint reader

Steps for removing and installing the power button with fingerprint reader.

Keyboard

Procedures for removing and installing the keyboard.

Palmrest assembly

Instructions for removing and installing the palmrest assembly.

Software

Operating system

Supported operating systems for the Latitude 7420 laptop.

Drivers and downloads

Information on obtaining and installing system drivers.

BIOS setup

BIOS overview

Explanation of the BIOS and its function in managing computer data flow.

Entering BIOS setup program

Step-by-step guide to access the BIOS setup.

Navigation keys

Explanation of keys used for navigating BIOS setup menus.

One Time Boot menu

How to access and use the one-time boot menu.

System setup options

Overview of system setup configuration options.

Updating the BIOS

Procedures for updating the BIOS in Windows and via USB.

System and setup password

Information on setting, changing, and clearing system passwords.

Troubleshooting

Handling swollen rechargeable Li-ion batteries

Safety guidelines and procedures for swollen batteries.

Dell SupportAssist Pre-boot System Performance Check diagnostics

How to run hardware diagnostics using SupportAssist.

Built-in self-test (BIST)

Introduction to built-in self-test diagnostics for system components.

LCD Power rail test (L-BIST)

Procedure for testing the LCD power rail.

LCD Built-in Self Test (BIST)

How to perform a self-test on the laptop's LCD screen.

System-diagnostic lights

Interpretation of system diagnostic LED blink patterns for troubleshooting.

Recovering the operating system

Using Dell SupportAssist OS Recovery for system recovery.

Real-Time Clock (RTC Reset)

Procedure to reset the Real-Time Clock for system recovery.

Backup media and recovery options

Recommendations for creating backup and recovery media.

Wi-Fi power cycle

Steps to perform a Wi-Fi power cycle to resolve connectivity issues.

Drain residual flea power (perform hard reset)

How to drain residual power for hard reset and component safety.

Getting help and contacting Dell

Self-help resources

List of Dell resources for product information and support.