Latitude 5420 Service Manual Regulatory Model: P137G Regulatory Type: P137G001,P137G002 August 2021 Rev.
Notes, cautions, and warnings NOTE: A NOTE indicates important information that helps you make better use of your product. CAUTION: A CAUTION indicates either potential damage to hardware or loss of data and tells you how to avoid the problem. WARNING: A WARNING indicates a potential for property damage, personal injury, or death. © 2021 Dell Inc. or its subsidiaries. All rights reserved. Dell, EMC, and other trademarks are trademarks of Dell Inc. or its subsidiaries.
Contents Chapter 1: Working inside your computer...................................................................................... 5 Before working inside your computer.............................................................................................................................5 Safety precautions.............................................................................................................................................................. 5 Enter service mode................
Operating system.............................................................................................................................................................. 86 Downloading the drivers.................................................................................................................................................. 86 Chapter 5: BIOS setup.................................................................................................................87 BIOS overview...........
1 Working inside your computer Topics: • • • • • • Before working inside your computer Safety precautions Enter service mode Electrostatic discharge—ESD protection ESD field service kit After working inside your computer Before working inside your computer About this task NOTE: The images in this document may differ from your computer depending on the configuration you ordered. Steps 1. Save and close all open files and exit all open applications. 2. Shut down your computer.
Unplugging, pressing and holding the power button for 20 seconds should discharge residual power in the system board. Remove the battery from notebooks. Bonding Bonding is a method for connecting two or more grounding conductors to the same electrical potential. This is done through the use of a field service electrostatic discharge (ESD) kit. When connecting a bonding wire, ensure that it is connected to bare metal and never to a painted or non-metal surface.
3. Press any key to continue. NOTE: The Service Mode procedure automatically skips this step if the Owner Tag of the system is not set up in advance by the manufacturer. 4. When the ready-to-proceed message appears on the screen, press any key to proceed. The system emits three short beeps and shuts down immediately. NOTE: If the AC adapter has not been disconnected, a message prompting you to remove the AC adapter appears on the screen.
Once the system shuts down, you can perform the replacement procedures without disconnecting the battery cable from the system board. 5. To exit Service Mode after finishing replacement procedures, connect AC adapter and press the power button to power on the system. The system automatically returns to normal functioning mode.
ESD field service kit The unmonitored Field Service kit is the most commonly used service kit. Each Field Service kit includes three main components: anti-static mat, wrist strap, and bonding wire. Components of an ESD field service kit The components of an ESD field service kit are: ● Anti-Static Mat – The anti-static mat is dissipative and parts can be placed on it during service procedures.
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. Connect your computer and all attached devices to their electrical outlets. 5. Turn on your computer.
2 Major components of your computer 11
Major components of your computer 12 Major components of your computer
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.
3 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 Disassembly and reassembly Recommended tools The procedures in this document may require the following tools: ● Phillips screwdriver #0 ● Plastic scribe 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.
Table 1. Latitude 5420 screw list (continued) Component Screw type Quantity M2x5 3 Captive screws 4 System Fan M2x5 2 eDP cable/bracket M2x3 2 USB Tyoe-C support bracket M2x5 3 System board M2x3 4 Power button M2x2.5 2 Smart card reader M2x2.5 3 Battery LED board M2x3 1 Keyboard assembly M2x2 6 Keyboard bracket M2x2 17 Display assembly M2.5x5 (display hinge to palm-rest assembly) 4 Display hinge M2.5x3 (display hinge to display back cover) 4 Display panel M2.
CAUTION: Removing the SIM card with the computer turned on, may cause data loss or damage to the card. Ensure that your computer is turned off or the network connections are disabled. About this task The following images indicate the location of the SIM card and provide a visual representation of the removal procedure. Steps 1. Insert a pin into the hole of the SIM card tray and push inward until the tray is released 2. Slide the SIM card tray out of the slot on the computer. 3.
Steps 1. Insert a pin into the hole of the SIM card tray and push inward until the tray is released 2. Slide the SIM card tray out of the slot on the computer. 3. Place the SIM card into the SIM card tray with the metallic contact facing up. 4. Align the SIM card tray with the slot on the computer and carefully slide it in. 5. Slide the SIM card tray into the slot, until it clicks into place. Next steps 1. Follow the procedure in After working inside your computer.
Steps 1. Push the microSD card to release it from the computer. 2. Slide the microSD card out of the computer. Installing the microSD card About this task The following image indicates the location of the microSD card and provides a visual representation of the installation procedure. Steps 1. Align the microSD card to its slot on the computer. 2. Slide the microSD card into the slot until it clicks into place.
Next steps Follow the procedures in After working inside your computer. Base cover Removing the base cover Prerequisites 1. 2. 3. 4. Follow the procedure in Before working inside your computer. Enter service mode. Remove the SIM card. Remove the microSD card. About this task The following images indicate the location of the base cover and provide a visual representation of the removal procedure.
Steps 1. Loosen the eight captive screws that secure the base cover to the palm-rest assembly and keyboard assembly. 2. Using a plastic scribe, pry the base cover from the U-shaped indents at the top edge of the base cover to remove the base cover from the palm-rest assembly and keyboard assembly. 3. Grasp the left side and the right side of the base cover and remove the base cover from the palm-rest assembly and keyboard assembly.
Removing and installing components 21
Steps 1. Align the screw holes on the base cover with the screw holes on the palm-rest assembly and keyboard assembly, and then snap the base cover into place. 2. Tighten the eight captive screws that secure the base cover to the palm-rest assembly and keyboard assembly. Next steps 1. Install the microSD card. 2. Install the SIM card. 3. Follow the procedure in After working inside your computer. WLAN card Removing the WLAN card Prerequisites 1. 2. 3. 4. 5.
Steps NOTE: When removing the WLAN card from the system, if the adhesive pad which helps secure the WLAN card in place is removed from the system along with the WLAN card, adhere it back to the system. 1. Remove the screw (M2x2.5) that secures the WLAN card bracket to the WLAN card. 2. Slide and remove the WLAN card bracket off the WLAN card. 3. Disconnect the antenna cables from the WLAN card. 4. Slide and remove the WLAN card from the WLAN card slot.
Steps 1. Connect the antenna cables to the wireless card. The following table provides the antenna-cable color scheme: Table 2. Antenna-cable color scheme Connectors on the wireless card Antenna-cable color Main (white triangle) White Auxiliary (black triangle) Black 2. Place the WLAN-card bracket on the WLAN card. 3. Align the notch on the wireless card with the tab on the WLAN card slot.
WWAN card Removing the WWAN card Prerequisites 1. 2. 3. 4. 5. Follow the procedure in Before working inside your computer. Enter service mode. Remove the SIM card. Remove the microSD card. Remove the base cover. About this task The following image indicates the location of the WWAN card and provide a visual representation of the removal procedure. Steps 1. Remove the screw (M2x2.5) that secures the WWAN card bracket to the WWAN card. 2. Slide and remove the WWAN card bracket off the WWAN card. 3.
Installing the WWAN card 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 WWAN card and provides a visual representation of the installation procedure. Steps 1. Connect the antenna cables to the WWAN card. The following table provides the antenna-cable color scheme: Table 3.
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. Next steps 1. 2. 3. 4. Install the base cover. Install the microSD card. Install the SIM card. Follow the procedure in After working inside your computer. Solid-state drive Removing the M.2 2280 solid-state drive Prerequisites 1. 2. 3. 4. 5. Follow the procedure in Before working inside your computer. Enter service mode.
Installing the M.2 2280 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 M.2 2280 solid-state drive and provides a visual representation of the installation procedure. Steps 1. Align the notch on the M.2 2280 solid-state drive with the tab on the solid-state drive slot. 2. Slide the M.
About this task The following images indicate the location of the M.2 2230 solid-state drive and provide a visual representation of the removal procedure. Steps 1. Remove the two screws (M2x3) that secures the M.2 2230 solid-state drive thermal plate to the M.2 2230 solid-state drive holder. 2. Remove the single screw (M2x3) that secure the M.2 2230 solid-state drive holder to the system board. 3. Lift the M.2 2230 solid-state drive holder off the system board. 4. Flip the M.
Steps 1. Flip the M.2 2230 solid-state drive holder and align the notch on the M.2 2230 solid-state drive with the tab on the M.2 2230 solid-state drive holder. 2. Replace the single screw (M2x3) that secure the M.2 2230 solid-state drive to the M.2 2230 solid-state drive holder. 3. Align and insert the M.2 2230 solid-state drive holder on the system board to accommodate the M.2 2230 solid-state drive. 4. Replace the single screw (M2x3) that secure the M.2 2230 solid-state drive holder to the system board.
Memory modules Removing the memory modules Prerequisites 1. 2. 3. 4. 5. Follow the procedure in Before working inside your computer. Enter service mode. Remove the SIM card. Remove the microSD card. Remove the base cover. About this task The following images indicate the location of the memory modules and provide a visual representation of the removal procedure. Steps 1. Using your fingertips, spread apart the securing clips on the memory-module slot until the memory module pops up. 2.
Steps 1. Align the notch on the memory module with the tab on the memory-module slot. 2. Slide the memory module firmly into the slot at an angle and press the memory module down until it clicks into place. NOTE: If you do not hear the click, remove the memory module and reinstall it. Next steps 1. 2. 3. 4. Install the base cover. Install the microSD card. Install the SIM card. Follow the procedure in After working inside your computer.
● 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. ● Always purchase genuine batteries from www.dell.com or authorized Dell partners and resellers. ● Swollen batteries should not be used and should be replaced and disposed properly.
Installing the 3-cell battery 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 3-cell battery and provides a visual representation of the installation procedure. NOTE: If battery is disconnected from system board for service, then there is a delay during system boot-up as the system undergoes RTC battery reset. Steps 1.
NOTE: If battery is disconnected from system board for service, then there is a delay during system boot-up as the system undergoes RTC battery reset. About this task The following images indicate the location of the battery and provide a visual representation of the removal procedure. Steps 1. Disconnect the battery cable from the system board, if it was not disconnected earlier. 2. Remove the three screws (M2x5) that secure the battery to the palm-rest assembly and keyboard assembly. 3.
Steps 1. Align and place the battery from the left side on the computer. 2. Replace the three screws (M2x5) that secure the battery to the palm-rest assembly and keyboard assembly. 3. Connect the battery cable to the system board. Next steps 1. 2. 3. 4. Install the base cover. Install the microSD card. Install the SIM card. Follow the procedure in After working inside your computer. Battery cable Removing the battery cable Prerequisites 1. 2. 3. 4. 5. 6.
Steps 1. Flip the battery and unroute the battery cable from the routing guides on the battery. 2. Disconnect the battery cable from the connector on the battery. 3. Lift the battery cable away from the battery. Installing the battery cable Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure.
Steps 1. Align and place the battery cable on the battery. 2. Route the battery cable through the routing guides on the battery. 3. Connect the battery cable to the connector on the battery. Next steps 1. 2. 3. 4. 5. Install the battery. Install the base cover. Install the microSD card. Install the SIM card. Follow the procedure in After working inside your computer. Assembly inner frame Removing the assembly inner frame Prerequisites 1. 2. 3. 4. 5. 6. 7. 8. 9.
Steps 1. Unroute the antenna cables from the routing guides on the assembly inner frame. 2. Disconnect the LED-board cable from the connector on the system board. 3. Disconnect the speaker cable from the connector on the system board and unroute the cable from the routing guides on the assembly inner frame. 4. Remove the three screws (M2x5) that secures the assembly inner frame to the system board and the palm-rest assembly. 5.
Installing the assembly inner frame 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 assembly inner frame and provides a visual representation of the installation procedure.
Steps 1. Align the screw holes on the assembly inner frame with the screw holes on the system board and the palm-rest assembly. NOTE: Ensure that the tab on the top-left corner of the assembly inner frame is installed underneath the tab on the palm-rest assembly. 2. Replace the seven screws (M2x3) that secure the assembly inner frame to the system board and the palm-rest assembly. 3. Replace the three screws (M2x5) that secure the assembly inner frame to the system board and the palm-rest assembly. 4.
Steps 1. Disconnect the LED-board cable from the connector on the system board. 2. Remove the single screw (M2x3) that secures the LED board to the palm-rest assembly. 3. Lift the LED board and cable away from the palm-rest assembly. Installing the LED board Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure.
Steps 1. Align the screw hole on the LED board with the screw hole on the palm-rest assembly. 2. Replace the single screw (M2x3) to secure the LED board to the palm-rest assembly. 3. Route the LED-board cable and connect the cable to the connector on the system board. Next steps 1. 2. 3. 4. 5. Install the battery. Install the base cover. Install the microSD card. Install the SIM card. Follow the procedure in After working inside your computer. Heat sink Removing the heat sink Prerequisites 1.
Steps 1. Disconnect the system fan cable from the connector on the system board. 2. Remove the two screws (M2x5) that secures the heat sink to the system board. 3. Loosen the four captive screws that secure the heat sink to the system board. 4. Lift the heat sink off the system board. Installing the heat sink Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure.
Steps 1. Align the screw holes on the heat sink with the screw holes on the system board. 2. Connect the system fan cable to the connector on the system board. 3. Tighten the four captive screws that secure the heat sink to the system board. 4. Replace the two screws (M2x5) that secures the heat sink to the system board. Next steps 1. 2. 3. 4. 5. Install the battery. Install the base cover. Install the microSD card. Install the SIM card. Follow the procedure in After working inside your computer.
Steps 1. Disconnect the speaker cable from the connector on the system board. 2. Unroute the speaker cable from the routing guides on the assembly inner frame and palm-rest assembly. 3. Lift the speakers along with the cable off the palm-rest assembly. Installing the speaker Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure.
Steps 1. Using the alignment posts and rubber grommets, place the speakers in the slots on the palm-rest assembly. 2. Route the speaker cable through the routing guide on the assembly inner frame and palm-rest assembly. 3. Connect the speaker cable to the connector on the system board. Next steps 1. 2. 3. 4. 5. Install the battery. Install the base cover. Install the microSD card. Install the SIM card. Follow the procedure in After working inside your computer.
Steps NOTE: The system board can be removed and installed with the heat sink attached in order to simplify the procedure and preserve the heat sink between the system board and heat-sink. In order to do so, technicians must also remove the two (M2x5) screws the secure the system fan to the system board.
4. Using the pull tab, disconnect the display cable from the connector on the system board. 5. Disconnect the coin-cell battery cable from the connecter on the system board. NOTE: When you disconnect the coin-cell battery cable from the connecter on the system board, the CMOS setting is cleared. 6. Open the latch and disconnect the USH board cable from the connector on the system board. 7. Open the latch and disconnect the touch-pad cable from the connector on the system board. 8.
Steps NOTE: The system board can be removed and installed with the thermal module attached in order to simplify the procedure and preserve the thermal bond between the system board and heat-sink. In order to do so, technicians must also remove the two (M2x5) screws the secure the system fan to the system board. 1.
Power-button board Removing the power-button board Prerequisites 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. Follow the procedure in Before working inside your computer. Remove the SIM card. Remove the microSD card. Remove the base cover. Remove the WLAN card. Remove the WWAN card. Remove the memory module. Remove the solid-state drive. Remove the battery. Remove the assembly inner frame. Remove the system board.
Installing the power-button board About this task The following images indicate the location of the power-button board and provide a visual representation of the installation procedure. Steps 1. Align and place the power-button board on the palm-rest assembly. 2. Replace the two screws (M2x2.5) that secure the power-button board to the palm-rest assembly. Next steps 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 52 Install the system board. Install the assembly inner frame. Install the battery.
Smart card reader Removing the smart card reader Prerequisites 1. 2. 3. 4. 5. 6. 7. 8. 9. Follow the procedure in Before working inside your computer. Remove the SIM card. Remove the microSD card. Remove the base cover. Remove the WLAN card. Remove the WWAN card. Remove the solid-state drive. Remove the battery. Remove the assembly inner frame. About this task The following images indicate the location of the smart card reader and provide a visual representation of the removal procedure.
Steps 1. Open the latch and disconnect the smart card reader cable from the connector on the USH board. 2. Remove the four screws (M2x2.5) that secure the smart card reader to the palm-rest assembly. 3. Lift the smart card reader off the palm-rest assembly. Installing the smart card reader Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure.
Next steps 1. 2. 3. 4. 5. 6. 7. 8. 9. Install the assembly inner frame. Install the battery. Install the solid-state drive. Install the WWAN card. Install the WLAN card. Install the base cover. Install the microSD card. Install the SIM card. Follow the procedure in After working inside your computer. Keyboard assembly Removing the keyboard assembly Prerequisites 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. Follow the procedure in Before working inside your computer. Remove the SIM card. Remove the microSD card.
Steps 1. Open the latch and disconnect the keyboard cable from the connector on the touch pad. 2. Remove the 17 screws (M2x2) that secure the keyboard assembly to the palm-rest assembly. 3. Remove the keyboard assembly off the palm-rest assembly. Installing the keyboard assembly Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure.
Steps 1. Align and place the keyboard assembly on the palm-rest assembly. 2. Replace the 17 screws (M2x2) that secure the keyboard assembly to the palm-rest assembly. 3. Connect the keyboard cable to the connector on the touch-pad. Next steps 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. Install the system board. Install the assembly inner frame. Install the battery. Install the solid-state drive. Install the memory module. Install the WWAN card. Install the WLAN card. Install the base cover.
2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. Remove Remove Remove Remove Remove Remove Remove Remove Remove Remove Remove the the the the the the the the the the the SIM card. microSD card. base cover. WLAN card. WWAN card. memory module. solid-state drive. battery. assembly inner frame. system board. keyboard assembly. About this task The following images indicate the location of the keyboard bracket and provide a visual representation of the removal procedure. Steps 1.
Steps 1. Align and place the keyboard on the keyboard bracket. 2. Replace the six screws (M2x2) to secure the keyboard to the keyboard bracket. Next steps 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. Install the keyboard assembly. Install the system board. Install the assembly inner frame. Install the battery. Install the solid-state drive. Install the memory module. Install the WWAN card. Install the WLAN card. Install the base cover. Install the microSD card. Install the SIM card.
About this task The following images indicate the location of the display assembly and provide a visual representation of the removal procedure.
Steps 1. Remove the two screws (M2x3) that secure the eDP cable bracket to the system board. 2. Lift the eDP cable bracket away from the system. 3. Peel the tape that secures the display cable to the system board. 4. Using the pull tab, disconnect the display cable from the connector on the system board. 5. Disconnect the eDP cable from the connector on the system board and unroute it from the routing guide. 6.
Removing and installing components
Steps 1. Place the display assembly on the system. Align the screw holes on the display hinges with screw holes on the palm-rest assembly. 2. Replace the four screws (M2.5x3) that secure the display hinges to the palm-rest assembly. 3. Close the display. 4. Route the antenna cables through the routing guide and adhere the tape to secure the cables to the system board. 5. Route the display and eDP cable through the routing guide on the system board. 6.
About this task The following images indicate the location of the display bezel and provide a visual representation of the removal procedure. Steps NOTE: The display bezel is adhered to the display panel with adhesive. Insert a plastic scribe into the recesses near both hinge caps to start the prying process to release the display bezel. Pry along the outside edge of the display bezel and work your way around the entire display bezel until the display bezel is separated from the display cover.
Steps 1. Align and place the display bezel on the display assembly. 2. Gently snap the display bezel into place. Next steps 1. 2. 3. 4. 5. 6. 7. Install the display assembly. Install the WWAN card. Install the WLAN card. Install the base cover. Install the microSD card. Install the SIM card. Follow the procedure in After working inside your computer. Display panel Removing the display panel Prerequisites 1. 2. 3. 4. 5. 6. 7. 8. 9. Follow the procedure in Before working inside your computer.
About this task The following images indicate the location of the display panel and provide a visual representation of the removal procedure.
Removing and installing components 67
Steps NOTE: The display panel is preassembled with the display brackets as a single service part. Do not pull the Stretch Release (SR) tapes and separate the brackets from the display panel. 1. Remove the two screws (M2.5x3) that secure the display panel to the display back cover. NOTE: While removing the display panel, disengage the display panel tabs from the display cover before flipping it over 2. Lift and open the display panel to access the display cable. 3.
Removing and installing components 69
Removing and installing components
Steps 1. Connect the display cable to the connector on the display panel and close the latch. 2. Adhere the conductive tape to secure the display cable to the display panel. 3. Close the display panel and the display back cover to assemble. NOTE: Ensure that the display panel tabs are inserted into the slots on the display cover. 4. Replace the two screws (M2.5x3) to secure the display panel to the display back cover. Next steps 1. 2. 3. 4. 5. 6. 7. 8. Install the display bezel.
Camera/microphone module Removing the camera/microphone module Prerequisites 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Follow the procedure in Before working inside your computer. Enter service mode. Remove the SIM card. Remove the microSD card. Remove the WLAN card. Remove the WWAN card. Remove the base cover. Remove the display assembly. Remove the display bezel. Remove the display panel.
About this task The following image indicates the location of the camera/microphone module and provides a visual representation of the installation procedure. Steps 1. Align and place the camera/microphone module into the slot on the display back cover. 2. Connect the camera/microphone cable to the connector on the camera/microphone module. Next steps 1. 2. 3. 4. 5. 6. 7. 8. 9. Install the display panel. Install the display bezel. Install the display assembly. Install the WWAN card. Install the WLAN card.
About this task The following images indicate the location of the eDP cable and provide a visual representation of the removal procedure. Steps 1. Disconnect the eDP/display cable from the connector on the camera/microphone module. 2. Peel the conductive tape and unroute the eDP/display cable to release it from adhesive and lift the eDP/display cable from the display back cover.
Steps 1. Connect the eDP/display cable to the connector on the camera. 2. Adhere the eDP/display cable to the display back cover. 3. Adhere the conductive tape and route the eDP/display cable to the display back cover. Next steps 1. 2. 3. 4. 5. 6. 7. 8. 9. Install the display panel. Install the display bezel. Install the display assembly. Install the WWAN card. Install the WLAN card. Install the base cover. Install the microSD card. Install the SIM card.
Sensor board Removing the sensor board Prerequisites 1. 2. 3. 4. 5. 6. 7. 8. 9. Follow the procedure in Before working inside your computer. Enter service mode. Remove the SIM card. Remove the microSD card. Remove the base cover. Remove the WLAN card. Remove the WWAN card. Remove the display assembly. Remove the display bezel. About this task The following images indicate the location of the sensor board and provide a visual representation of the removal procedure. Steps 1.
Steps 1. Align and place the sensor board on the display back cover. 2. Connect the display cable to the connector on the sensor board and close the latch. Next steps 1. 2. 3. 4. 5. 6. 7. 8. Install the display bezel. Install the display assembly. Install the WWAN card. Install the WLAN card. Install the base cover. Install the microSD card. Install the SIM card. Follow the procedure in After working inside your computer. Display hinges Removing the display hinges Prerequisites 1. 2. 3. 4. 5. 6. 7. 8. 9.
Steps 1. Remove the two screws (M2.5x3) that secures the right hinge to the display back cover. 2. Lift and remove the right hinge from the display back cover. 3. Remove the two screws (M2.5x3) that secures the left hinge to the display back cover. 4. Lift and remove the left hinge from the display back cover. Installing the display hinges Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure.
Steps 1. Align the screw hole on the left hinge with the screw hole on the display back cover. 2. Replace the two screws (M2.5x3) to secure the left hinge to the display back cover. 3. Align the screw hole on the right hinge with the screw hole on the display back cover. 4. Replace the two screws (M2.5x3) to secure the right hinge to the display back cover. Next steps 1. 2. 3. 4. 5. 6. 7. 8. 9. Install the display panel. Install the display bezel. Install the display assembly. Install the WWAN card.
Display back cover Removing the display back cover Prerequisites 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. Follow the procedure in Before working inside your computer. Enter service mode. Remove the SIM card. Remove the microSD card. Remove the base cover. Remove the WLAN card. Remove the WWAN card. Remove the display assembly. Remove the display bezel. Remove the display panel. Remove the camera/microphone module. Remove the eDP/display cable. Remove the sensor board. Remove the display hinges.
About this task The following images indicate the location of the display back cover and provides a visual representation of the installation procedure. Steps Place the display back cover on a flat surface. Next steps 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. Install the display hinges. Install the sensor board. Install the eDP/display cable. Install the camera/microphone module. Install the display panel. Install the display bezel. Install the display assembly. Install the WWAN card.
6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. Remove Remove Remove Remove Remove Remove Remove Remove Remove Remove Remove Remove the the the the the the the the the the the the WWAN card. memory module. solid-state drive. battery. assembly inner frame. system board. smart card reader. LED board. power-button board. keyboard assembly. display assembly. palm-rest assembly.
About this task The following image indicates the location of the dummy SIM-card slot filler and provides a visual representation of the dummy SIM-card slot filler installation procedure. Steps 1. Place the dummy SIM-card slot filler into its compartment on the palm rest. NOTE: Ensure that the dummy SIM-card slot filler is aligned with the ribs on the palm-rest assembly. 2. Press the dummy SIM-card slot filler until it clicks into place and ensure it fits securely into the SIM card slot. Next steps 1. 2.
Palm-rest assembly Removing the palm-rest assembly Prerequisites 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. Follow the procedure in Before working inside your computer. Remove the SIM card. Remove the microSD card. Remove the base cover. Remove the WLAN card. Remove the WWAN card. Remove the memory module. Remove the solid-state drive. Remove the battery. Remove the assembly inner frame. Remove the system board. Remove the smart card reader. Remove the LED board. Remove the power-button board.
Installing the palm-rest assembly Prerequisites If you are replacing a component, remove the existing component before performing the installation procedure. About this task The following image indicates the palm-rest assembly and provides a visual representation of the installation procedure. Steps NOTE: For non-WWAN LTE configuration, you must remove and transfer the dummy SIM card filler when replacing the palm-rest assembly. 1. Place the palm-rest assembly on a flat surface. 2.
4 Software This chapter details the supported operating systems along with instructions on how to install the drivers. Topics: • • Operating system Downloading the drivers Operating system Your Latitude 5420 supports the following operating systems: ● ● ● ● ● Windows 10 Pro, 64-bit Windows 10 Home, 64-bit Windows 10 Pro Education, 64-bit Windows 10 Enterprise N, 64-bit Ubuntu Linux 20.04 LTS, 64-bit Downloading the drivers Steps 1. Turn on your computer. 2. Go to www.dell.com/support. 3.
5 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.
Table 4. 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. Tab Moves to the next focus area. NOTE: For the standard graphics browser only. Esc Moves to the previous page until you view the main screen.
Table 5. System setup options—System information menu (continued) Overview Primary Displays that battery is primary. 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. Maximum Clock Speed Displays the maximum processor clock speed.
Table 6. System setup options—Boot Configuration menu Boot Configuration Boot Sequence 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. By default, the option is not enabled. Secure Boot Mode Enable or disable to change the secure boot mode options.
Table 7. System setup options—Integrated Devices menu (continued) Integrated Devices By default, the option is disabled. Video/Power only on Type-C Ports Enable or disable the Type-C port functionality to video or only power. 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.
Table 8. System setup options—Storage menu (continued) Storage By default, the Secure Digital (SD) Card option is enabled. Secure Digital (SD) Card Read-Only Mode Enable or disable the SD card read-only mode. By default, the Secure Digital (SD) Card Read-Only Mode option is not enabled. Table 9. 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.
Table 10. System setup options—Connection menu (continued) Connection Control WWAN radio Sense the connection of the computer to a wired network and subsequently disable the selected wireless radios (WWAN). By default, the option is disabled. HTTPs Boot Feature HTTPs Boot Enable or disable the HTTPs Boot feature. By default, the HTTPs Boot option is enabled. HTTPs Boot Mode With Auto Mode, the HTTPs Boot extracts Boot URL from the DHCP.
Table 12. System setup options—Security menu Security TPM 2.0 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. By default, the Attestation Enable option is enabled.
Table 13. System setup options—Passwords menu (continued) Passwords Upper Case Letter Reinforces password must have at least one upper case letter. By default, the option is disabled. Lower Case Letter Reinforces password must have at least one lower case letter. By default, the option is disabled. Digit Reinforces password must have at least one digit. By default, the option is disabled. Special Character Reinforces password must have at least one special character.
Table 14. System setup options—Update, Recovery menu (continued) Update, Recovery By default, the option is enabled. BISOConnect Enable or disable cloud Service OS recovery if the main operating system fails to boot with the number of failures equal to or greater than the value specified by the Auto OS Recovery Threshold setup option and local Service OS does not boot or is not installed. By default, the option is enabled.
Table 17. 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. By default, the Prompt on Warnings and Errors option is enabled. Fastboot Enable to set the speed of the boot process.
Table 19. System setup options—System Logs menu (continued) System Logs By default, the Keep option is enabled. Thermal Event Log Clear Thermal Event Log Display Thermal events. By default, the Keep option is enabled. Power Event Log Clear Power Event Log Display power events. By default, the Keep option is enabled. License Information Displays the license information of the computer.
system will ask for this on each reboot. If the recovery key is not known this can result in data loss or an unnecessary operating system re-install. For more information on this subject, see Knowledge Article: https:// www.dell.com/support/article/sln153694 Steps 1. Follow the procedure from step 1 to step 6 in Updating the BIOS in Windows to download the latest BIOS setup program file. 2. Create a bootable USB drive. For more information, see the knowledge base article 000145519 at www.dell.com/support.
5. Select the file and double-click the flash target file, and then click Submit. 6. Click Update BIOS. The computer restarts to flash the BIOS. 7. The computer will restart after the BIOS update is completed. System and setup password Table 20. System and setup password Password type Description System password Password that you must enter to log in to your system. Setup password Password that you must enter to access and make changes to the BIOS settings of your computer.
About this task To enter the System Setup, press F12 immediately after a power-on or reboot. Steps 1. In the System BIOS or System Setup screen, select System Security and press Enter. The System Security screen is displayed. 2. In the System Security screen, verify that Password Status is Unlocked. 3. Select System Password, update, or delete the existing system password, and press Enter or Tab. 4. Select Setup Password, update, or delete the existing setup password, and press Enter or Tab.
6 Troubleshooting Topics: • • • • • • • • Handling swollen Lithium-ion batteries Dell SupportAssist Pre-boot System Performance Check diagnostics Built-in self-test (BIST) System diagnostic lights Recovering the operating system Backup media and recovery options WiFi power cycle Drain residual flea power (perform hard reset) Handling swollen Lithium-ion batteries Like most laptops, Dell laptops use lithium-ion batteries. One type of lithium-ion battery is the lithium-ion polymer battery.
Dell SupportAssist Pre-boot System Performance 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.
Table 21. LED error codes Blinking Pattern Possible Problem Amber White 2 1 CPU Failure 2 8 LCD Power Rail Failure 1 1 TPM Detection Failure 2 4 Unrecoverable SPI Failure 4. If there is no failure with the system board, the LCD will cycle through the solid color screens described in the LCD-BIST section for 30 seconds and then power off. LCD Power rail test (L-BIST) L-BIST is an enhancement to the single LED error code diagnostics and is automatically initiated during POST.
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. Off ● Power adapter is connected and the battery is fully charged. ● Computer is running on battery and the battery has more than 5 percent charge. ● Computer is in sleep state, hibernation, or turned off.
Blinking Pattern Problem description Suggested resolution 3 2 PCI or Video card/chip failure Replace the system board. 3 3 BIOS recovery image not found Flash latest BIOS version. If problem persists, replace the system board. 3 4 BIOS recovery image found but invalid Flash latest BIOS version. If problem persists, replace the system board. 3 5 Power rail failure Replace the system board. 3 6 Flash corruption detected by SBIOS. Replace the system board.
2. Turn off the modem. 3. Turn off the wireless router. 4. Wait for 30 seconds. 5. Turn on the wireless router. 6. Turn on the modem. 7. Turn on your computer. Drain residual flea power (perform hard reset) About this task Flea power is the residual static electricity that remains in the computer even after it has been powered off and the battery is removed.
7 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 22. 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. Online help for operating system www.dell.com/support/windows www.dell.
