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Dell Latitude 9420 Service Manual
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Dell Latitude 9420 Service Manual

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Latitude 9420/Latitude 9420 2-in-1
Service Manual
Regulatory Model: P141G/P142G
Regulatory Type: P141G001/P142G001
December 2022
Rev. A03

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Summary of Contents for Dell Latitude 9420

  • Page 1 Latitude 9420/Latitude 9420 2-in-1 Service Manual Regulatory Model: P141G/P142G Regulatory Type: P141G001/P142G001 December 2022 Rev. A03...
  • Page 2 A WARNING indicates a potential for property damage, personal injury, or death. © 2021 Dell Inc. or its subsidiaries. All rights reserved. Dell Technologies, Dell, and other trademarks are trademarks of Dell Inc. or its subsidiaries. Other trademarks may be trademarks of their respective owners.

  • Page 3: Table Of Contents

    Contents Chapter 1: Working inside your computer..................6 Before working inside your computer..........................6 Safety precautions................................6 Electrostatic discharge—ESD protection........................7 ESD field service kit ................................8 After working inside your computer..........................8 Chapter 2: Removing and installing components................10 Recommended tools................................10 Screw list....................................11 Major components of your computer..........................13 Secure Digital (SD) Card..............................14 Removing the SD card..............................
  • Page 4 Deleting or changing an existing system setup password................. 75 Clearing BIOS (System Setup) and System passwords...................75 Chapter 5: Troubleshooting......................76 Handling swollen Lithium-ion batteries........................76 Dell SupportAssist Pre-boot System Performance Check diagnostics..............77 Running the SupportAssist Pre-Boot System Performance Check..............77 Built-in self-test (BIST)..............................77 M-BIST................................... 77 LCD Power rail test (L-BIST)...........................
  • Page 5 System diagnostic lights..............................79 Recovering the operating system..........................80 Backup media and recovery options..........................80 WiFi power cycle................................80 Drain residual flea power (perform hard reset)......................81 Chapter 6: Getting help and contacting Dell................82 Contents...

  • Page 6: Chapter 1: Working Inside Your Computer

    Ensure that your computer is shut down and the AC adapter is disconnected. a. Hold <B> key on the keyboard and press the power button for 3 seconds or until the Dell logo appears on the screen. b. Press any key to continue.

  • Page 7: Electrostatic Discharge-Esd Protection

    ESD protection is an increasing concern. Due to the increased density of semiconductors used in recent Dell products, the sensitivity to static damage is now higher than in previous Dell products. For this reason, some previously approved methods of handling parts are no longer applicable.

  • Page 8: Esd Field Service Kit

    It is recommended that all field service technicians use the traditional wired ESD grounding wrist strap and protective anti-static mat at all times when servicing Dell products. In addition, it is critical that technicians keep sensitive parts separate from all insulator parts while performing service and that they use anti-static bags for transporting sensitive components.
  • Page 9 Steps 1. Replace all screws and ensure that no stray screws remain inside your computer. 2. Connect any external devices, peripherals, or cables you removed before working on your computer. 3. Replace any media cards, discs, or any other parts that you removed before working on your computer. 4.

  • Page 10: Chapter 2: Removing And Installing Components

    Removing and installing components NOTE: The images in this document may differ from your computer depending on the configuration you ordered. Topics: • Recommended tools • Screw list • Major components of your computer • Secure Digital (SD) Card • SIM card tray •...

  • Page 11: Screw List

    Screw list NOTE: When removing screws from a component, it is recommended to note the screw type, the quantity of screws, and then place them in a screw storage box. This is to ensure that the correct number of screws and correct screw type is restored when the component is replaced.
  • Page 12 Table 1. Screw list (continued) Component Screw type Quantity Image Battery M1.6x3 M2x4 Left speaker M1.6x1.8 Right speaker M1.6x1.8 WLAN antenna module M1.6x1.8 M1.6x3 I/O daughter board M2x4 Power button with fingerprint M1.6x2.5 reader assembly System board M1.6x2.5 M2x4 Captive screw USH daughter board M1.2x2.5 WWAN main antenna module...

  • Page 13: Major Components Of Your Computer

    Major components of your computer 1. Base cover 2. Battery 3. Solid-state drive shielding cover 4. Wireless Wide Area Network (WWAN) shielding cover 5. Solid-state drive 6. Wireless Wide Area Network (WWAN) card 7. System board 8. Wireless Local Area Network (WLAN) Antenna module 9.

  • Page 14: Secure Digital (Sd) Card

    Secure Digital (SD) Card Removing the SD card Prerequisites Follow the procedure in Before working inside your computer. NOTE: Ensure that your computer is in Service Mode. For more information see, step 6 in Before working inside your computer. About this task The following image provides a visual representation of the SD card removal procedure.

  • Page 15: Sim Card Tray

    Steps Insert the SD card into its slot until it click into place. Next steps 1. Follow the procedure in After working inside your computer. NOTE: Ensure that your computer is in Service Mode. For more information see, step 6 in Before working inside your computer.

  • Page 16: Installing The Sim Card Tray

    Steps 1. Insert the SIM card removal pin into the release hole to release the SIM card tray. 2. Push the pin to disengage the lock, and eject the SIM card tray. 3. Slide the SIM card tray out of the slot on the system. 4.

  • Page 17: Base Cover

    Steps 1. Insert the SIM card removal pin into the release hole to remove the SIM card tray. 2. Push the pin to disengage the lock, and eject the SIM card tray. 3. Slide the SIM card tray out of the slot on the system. 4.
  • Page 18 2. Remove the card. 3. Remove the SIM card tray. About this task Removing and installing components...

  • Page 19: Installing The Base Cover

    Steps 1. Loosen the eight captive screws that secure the base cover to the system. 2. Using a plastic scribe, pry open the base cover starting from the recesses that are located in the U-shaped indents near the hinges at the top edge of the base cover. NOTE: Do not lift the base cover from the top side immediately after prying it from the recesses, as this will cause damage to the base cover.
  • Page 20 Removing and installing components...

  • Page 21: Solid-State Drive

    Steps 1. Align and place the base cover on the palm-rest assembly, and snap the base cover into place. 2. Tighten the eight captive screws to secure the base cover to the system. Next steps 1. Install the SIM card tray.

  • Page 22: Installing The Solid-State Drive

    NOTE: If the thermal pad located underneath the M.2 2230 SSD gets detached, adhere it back to the system board. Installing the solid-state drive Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure. About this task The following image indicates the location of the solid-state drive and provides a visual representation of the installation procedure.

  • Page 23: Wireless Wide Area Network (Wwan) Card

    4. Follow the procedure in After working inside your computer. NOTE: Ensure that your computer is in Service Mode. For more information see, step 6 in Before working inside your computer. Wireless Wide Area Network (WWAN) Card Removing the WWAN card Prerequisites 1.

  • Page 24: Installing The Wwan Card

    2. Lift the WWAN-card bracket out of the system. 3. Disconnect the antenna cables from the connectors on the WWAN card. 4. Using a plastic scribe pry open the WWAN card shielding cover from the bottom edge of the WWAN card shielding cover. 5.
  • Page 25 5. Align and place the WWAN-card bracket on the system board and WWAN card, and tighten the single captive screw. NOTE: For instructions on how to find your computer's IMEI (International Mobile Station Equipment Identity) number, see the knowledge base article 000143678 at www.dell.com/support. Removing and installing components...

  • Page 26: System Fan

    Next steps 1. Install the base cover. 2. Install the SIM card tray. 3. Install the card. 4. Follow the procedure in After working inside your computer. NOTE: Ensure that your computer is in Service Mode. For more information see, step 6 in Before working inside your computer.

  • Page 27: Installing The System Fan

    4. Lift the system fan off the palm-rest assembly. Installing the system fan Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure. About this task The following image indicates the location of the system fan and provides a visual representation of the installation procedure. Steps 1.

  • Page 28: Heat Sink

    Heat sink Removing the heat sink Prerequisites 1. Follow the procedure in Before working inside your computer. NOTE: Ensure that your computer is in Service Mode. For more information see, step 6 in Before working inside your computer. 2. Remove the card.

  • Page 29: Installing The Heat Sink

    CAUTION: Do not remove the shielding cover immediately after prying the cover, as this can damage the shielding cover. 4. Gently flip open the CPU shielding cover from the right side of the cover towards the left side. 5. Lift the CPU shielding cover off the system. 6.

  • Page 30: Display Assembly

    5. Adhere the piece of conductive tape and the piece of tape securing the system fan cable to the left side of the CPU shielding cover. Next steps 1. Install the base cover. 2. Install the SIM card tray. 3. Install the card.
  • Page 31 Removing and installing components...
  • Page 32 Steps 1. Disconnect the display cable from the connector on the system board. CAUTION: The connector for the display cable features a latch that locks it in place on the system board. Flip open the display cable latch from the two tabs on the top side of the latch. After flipping open the latch, hold the left and right sides of the cable's connector head and gently disconnect the display cable from the system board in a direct upward motion to prevent damage to the connector's pins.

  • Page 33: Installing The Display Assembly

    5. Lift the display assembly off the computer. Installing the display assembly Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure. NOTE: The display assembly installation procedure is the same for both laptop and 2-in-1 chassis. About this task The following image indicates the location of the display assembly and provides a visual representation of the installation procedure.

  • Page 34: Battery

    Steps 1. Align and place the palm-rest assembly under the hinges of the display assembly. 2. Replace the six (M2.5x3) screws that secure the display assembly to the system. 3. Connect the display and camera cable to the connector on the system board. Next steps 1.

  • Page 35: Removing The Battery

    ● If the battery gets stuck inside your computer as a result of swelling, do not try to release it as puncturing, bending, or crushing a lithium-ion battery can be dangerous. In such an instance, contact Dell technical support for assistance. See www.dell.com/contactdell.
  • Page 36 Steps 1. Peel off the two pieces of tape securing the gray WWAN antenna cable in place at the bottom side of CPU shielding cover and unroute the wireless antenna cables from the routing guides on the system board and the routing guides along the top side of the battery.

  • Page 37: Installing The Battery

    8. Peel off the piece of tape securing the speaker cable in place at the left side of the battery. 9. Unroute the speaker cables from the routing guides at the left and right side of the battery. 10. Remove the single (M1.6x3) screw and four (M2x4) screws that secures the battery to the plam-rest assembly. 11.

  • Page 38: Speakers

    Steps 1. Align and place the battery on the palm-rest assembly. 2. Replace the single (M1.6x3) screw and four (M2x4) screws to secure the battery to the palm-rest assembly. 3. Reconnect the battery cable to the connector on the system board. 4.

  • Page 39: Installing The Left Speaker

    Steps 1. Remove the single (M1.6x1.8) screw securing the Proximity sensor bracket to the plam-rest assembly. 2. Disconnect the Proximity sensor cable for the left speaker's WWAN antenna module from the RF board. 3. Disconnect the left speaker cable from connector on the system board, and unroute the speaker cable from the routing guides.

  • Page 40: Removing The Right Speaker

    Steps 1. Align and place the left speaker in the slot on the system. 2. Replace the single (M1.6x1.8) screw that secure the left speaker to the system. 3. Route the speaker cables through the routing guide and connect the speaker cable to the connector on the system board. 4.

  • Page 41: Installing The Right Speaker

    Steps 1. Remove the single (M1.6x1.8) screw that secure the right speaker. 2. Lift the right speaker off the system. Installing the right speaker Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure. About this task The following image indicates the location of the speaker and provides a visual representation of the installation procedure.

  • Page 42: Wireless Local Area Network (Wlan) Antenna Module

    Wireless Local Area Network (WLAN) Antenna module Removing the WLAN antenna module Prerequisites 1. Follow the procedure in Before working inside your computer. NOTE: Ensure that your computer is in Service Mode. For more information see, step 6 in Before working inside your computer.

  • Page 43: Installing The Wlan Antenna Module

    2. Peel off the piece of tape securing the WLAN antenna module's proximity sensor cable in place. 3. Disconnect the WLAN antenna module's Proximity sensor cable from the RF board and unroute the Proximity sensor cable from the routing guides. 4.

  • Page 44: I/O Daughter Board

    Next steps 1. Install the battery. 2. Install the WWAN card. 3. Install the base cover. 4. Install the SIM card tray. 5. Install the card. 6. Follow the procedure in After working inside your computer. NOTE: Ensure that your computer is in Service Mode. For more information see, step 6 in Before working inside your computer.

  • Page 45: Installing The I/O Daughter Board

    Steps 1. Disconnect the I/O daughter FPC cable from the connector on the system board. 2. Remove the single (M2x4) screw securing the I/O daughter board bracket to the palm-rest assembly. 3. Lift the I/O daughter board bracket off the system. 4.
  • Page 46 Steps 1. Connect the I/O daughter board FPC cable to the I/O daughter board. 2. Place the I/O daughter board with the FPC cable in the slot on the system. 3. Align and place the I/O board bracket on the I/O daughter board. 4.

  • Page 47: Power Button With Fingerprint Reader Assembly

    Power button with fingerprint reader assembly Removing the power button with fingerprint reader assembly Prerequisites NOTE: For system shipped with power button with fingerprint reader assembly only. 1. Follow the procedure in Before working inside your computer. NOTE: Ensure that your computer is in Service Mode. For more information see, step 6 in Before working inside your computer.

  • Page 48: System Board

    About this task The following image indicate the location of the power button and provide a visual representation of the installation procedure. Steps 1. Align and place power button with fingerprint reader assembly on the system. Adhere the power button with fingerprint reader assembly on the palm-rest assembly.
  • Page 49 5. Remove the solid-state drive 6. Remove the WWAN card. 7. Remove the heat sink. 8. Remove the battery. About this task 1. I/O daughter board cable connector 2. USH daughter board cable connector 3. WWAN Darwin cable connectors 4. WLAN antenna module connector 5.
  • Page 50 NOTE: Do not remove the system board together with the heat-sink, as this may damage the I/O daughter board, I/O daughter board FPC, and system board. The system features an I/O daughter board FPC which is connected to the system board underneath the heat-sink, as a result, the heat-sink must be removed first in order to disconnect the I/O daughter board FPC from the system board and then remove the system board.

  • Page 51: Installing The System Board

    NOTE: Flip open the display cable latch from the two tabs on the top side of the latch. Hold the left and right sides of the cable's connector head and gently disconnect the display cable in a direct upward motion to prevent damage to the connector.
  • Page 52 Steps 1. Align and place the system board on the palm-rest assembly. 2. Replace the four (M1.6x2.5) screws that secure the system board to the palm-rest assembly. 3. Replace the three (M2x4) screws that secures the USB Type-C bracket to the system board. 4.

  • Page 53: Ush Daughter Board

    13. Connect the display cable and camera cable to the connector on the system board. 14. Connect the display cable, and camera cable to the system board. 15. Connect the power button with fingerprint reader FPC cable to the connector on the system board (For the systems shipped with power button with fingerprint reader assembly).

  • Page 54: Installing The Ush Daughter Board

    Steps 1. Gently disconnect the power button with fingerprint reader FPC cable from the connector on the USH daughter board. 2. Peel off the USH daughter board FPC cable from the keyboard. 3. Remove the two (M1.2x2.5) screws securing the USH daughter board to the palm-rest assembly. 4.

  • Page 55: Wireless Wide Area Network (Wwan) Antenna Module

    Steps 1. Connect the USH daughter board FPC cable from USH daughter board. 2. Place the USH daughter board with the FPC cable in the slot on the system. 3. Replace the two (M1.2x2.5) screws securing the USH daughter board to the palm-rest assembly 4.

  • Page 56: Installing The Wwan Main Antenna Module

    2. Remove the card. 3. Remove the SIM card tray. 4. Remove the base cover. 5. Remove the WWAN card. 6. Remove the heat sink. 7. Remove the display assembly. 8. Remove the battery. 9. Remove the I/O daughter board. 10.

  • Page 57: Palm-Rest Assembly

    Steps 1. Align and place the WWAN main antenna module in the slot on the system. 2. Replace the four (M1.6x3) screws that secure the WWAN main antenna module to the palm-rest assembly. Next steps 1. Install the system board 2.

  • Page 58: Installing The Palm-Rest Assembly

    6. Remove the WWAN card. 7. Remove the heat sink. 8. Remove the display assembly. 9. Remove the battery. 10. Remove the left speaker. 11. Remove the right speaker. 12. Remove the WLAN antenna module. 13. Remove the I/O daughter board.
  • Page 59 Steps Place the palm-rest assembly on a flat surface. Next steps 1. Install the WWAN main antenna module. 2. Install the USH daughter board. 3. Install the system board 4. Install the power button with fingerprint reader (for systems shipped with a fingerprint reader). 5.

  • Page 60: Chapter 3: Software

    Downloading the drivers Steps 1. Turn on your computer. 2. Go to www.dell.com/support. 3. Enter the Service Tag of your computer, and then click Submit. NOTE: If you do not have the Service Tag, use the auto-detect feature or manually browse for your computer model.

  • Page 61: Chapter 4: Bios Setup

    BIOS setup CAUTION: Unless you are an expert computer user, do not change the settings in the BIOS Setup program. Certain changes can make your computer work incorrectly. NOTE: Depending on the computer and its installed devices, the items listed in this section may or may not be displayed. NOTE: Before you change BIOS Setup program, it is recommended that you write down the BIOS Setup program screen information for future reference.

  • Page 62: One Time Boot Menu

    Table 2. Navigation keys Keys Navigation Up arrow Moves to the previous field. Down arrow Moves to the next field. Enter Selects a value in the selected field (if applicable) or follow the link in the field. Spacebar Expands or collapses a drop-down list, if applicable. Moves to the next focus area.
  • Page 63 Table 3. System setup options—System information menu (continued) Overview Battery Level Displays the battery level of the computer. Battery State Displays the battery state of the computer. Health Displays the battery health of the computer. AC Adapter Displays whether the AC adapter is connected or not. Processor Information Processor Type Displays the processor type.
  • Page 64 Table 4. System setup options—Boot Configuration menu (continued) Boot Configuration Boot mode Displays the boot mode. Boot Sequence Displays the boot sequence. Secure Digital (SD) Card Boot Enable or disable the SD card read-only boot. By default, the Secure Digital (SD) Card Boot option is not enabled. Secure Boot Enable Secure Boot Enable or disable the secure boot feature.
  • Page 65 By default, the Video/Power only on Type-C Ports option is disabled. Type-C Dock Override Enables to use connected Type-C Dell Dock to provide data stream with external USB ports disabled. When Type-C Dock override is enabled, the Video/Audio/Lan submenu is activated.
  • Page 66 Table 6. System setup options—Storage menu (continued) Storage By default, the Secure Digital (SD) Card Read-Only Mode option is not enabled. Table 7. System setup options—Display menu Display Display Brightness Brightness on battery power Enable to set screen brightness when the computer is running on battery power.
  • Page 67 By default, the Optimized option is enabled. USB Wake Support Wake on Dell USB-C Dock When enabled, connecting a Dell USB-C Dock will wake the computer from standby. By default, the Wake on Dell USB-C Dock option is enabled. Block Sleep Enables to block entering sleep (S3) mode in the operating system.
  • Page 68 Table 10. System setup options—Security menu (continued) Security TPM 2.0 Security On Enable or disable TPM 2.0 security options. By default, the TPM 2.0 Security On option is enabled. Attestation Enable Enables to control whether the Trusted Platform Module (TPM) Endorsement Hierarchy is available to the operating system.
  • Page 69 Allow Non-Admin PSID Revert Enable Allow Non-Admin PSID Revert Controls access to the Physical Security ID (PSID) revert of NVMe hard-drives from the Dell Security Manager prompt. By default, the option is disabled. Table 12. System setup options—Update, Recovery menu...
  • Page 70 By default, the option is enabled. Dell Auto OS Recovery Threshold Controls the automatic boot flow for SupportAssist System Resolution Console and for Dell OS Recovery Tool. By default, the threshold value is set to 2. Table 13. System setup options—System Management menu...
  • Page 71 Table 15. System setup options—Pre-boot Behavior menu Pre-boot Behavior Adapter Warnings Enable Adapter Warnings Enable or disable the warning messages during boot when the adapters with less power capacity are detected. By default, the option is enabled. Warning and Errors Enable or disable the action to be done when a warning or error is encountered.

  • Page 72: Updating The Bios

    7. After the download is complete, browse the folder where you saved the BIOS update file. 8. Double-click the BIOS update file icon and follow the on-screen instructions. For more information, search in the Knowledge Base Resource at www.dell.com/support. Updating the BIOS in Linux and Ubuntu...

  • Page 73: Updating The Bios Using The Usb Drive In Windows

    One-Time boot menu on the computer. Most of the Dell computers built after 2012 have this capability, and you can confirm by booting your computer to the F12 One-Time Boot Menu to see if BIOS FLASH UPDATE is listed as a boot option for your computer. If the option is listed, then the BIOS supports this BIOS update option.

  • Page 74: System And Setup Password

    Steps 1. From a turn off state, insert the USB drive where you copied the flash into a USB port of the computer. 2. Turn on the computer and press F12 to access the One-Time Boot Menu, select BIOS Update using the mouse or arrow keys then press Enter.

  • Page 75: Deleting Or Changing An Existing System Setup Password

    Clearing BIOS (System Setup) and System passwords About this task To clear the system or BIOS passwords, contact Dell technical support as described at www.dell.com/contactdell. NOTE: For information on how to reset Windows or application passwords, refer to the documentation accompanying Windows or your application.

  • Page 76: Chapter 5: Troubleshooting

    ● Using a non-Dell or incompatible battery may increase the risk of fire or explosion. Replace the battery only with a compatible battery purchased from Dell that is designed to work with your Dell computer. Do not use a battery from other computers with your computer.

  • Page 77: Dell Supportassist Pre-Boot System Performance Check Diagnostics

    Check diagnostics About this task SupportAssist diagnostics (also known as system diagnostics) performs a complete check of your hardware. The Dell SupportAssist Pre-boot System Performance Check diagnostics is embedded with the BIOS and is launched by the BIOS internally. The embedded system diagnostics provides a set of options for particular devices or device groups allowing you to: ●...

  • Page 78: Lcd Power Rail Test (L-Bist)

    LCD Built-in Self Test (BIST) Dell laptops have a built-in diagnostic tool that helps you determine if the screen abnormality you are experiencing is an inherent problem with the LCD (screen) of the Dell laptop or with the video card (GPU) and PC settings.

  • Page 79: System Diagnostic Lights

    System diagnostic lights Battery-status light Indicates the power and battery-charge status. Solid white — Power adapter is connected and the battery has more than 5 percent charge. Amber — Computer is running on battery and the battery has less than 5 percent charge. ●...

  • Page 80: Recovering The Operating System

    It enables you to diagnose hardware issues, repair your computer, back up your files, or restore your computer to its factory state. You can also download it from the Dell Support website to troubleshoot and fix your computer when it fails to boot into their primary operating system due to software or hardware failures.

  • Page 81: Drain Residual Flea Power (Perform Hard Reset)

    6. Install the battery. 7. Install the base cover. 8. Connect the power adapter to your computer. 9. Turn on your computer. NOTE: For more information about performing a hard reset, search in the Knowledge Base Resource at www.dell.com/ support. Troubleshooting...

  • Page 82: Chapter 6: Getting Help And Contacting Dell

    Getting help and contacting Dell Self-help resources You can get information and help on Dell products and services using these self-help resources: Table 20. Self-help resources Self-help resources Resource location Information about Dell products and services www.dell.com Tips Contact Support In Windows search, type Contact Support, and press Enter.

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Latitude 9420 2-in-1P141gP142g

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