Service Manual
Table Of Contents
- Latitude 3420 Service Manual
- Working inside your computer
- Removing and installing components
- Recommended tools
- Screw List
- Major components of your system
- MicroSD-card
- SIM card tray
- Base cover
- Battery cable
- Battery
- Memory module
- M.2 solid-state drive thermal plate
- M.2 solid-state drive conversion bracket
- M.2 solid-state drive
- Hard-disk drive
- WLAN card
- WWAN card
- I/O cable
- Display assembly
- System fan
- Heatsink assembly
- Power adapter port
- Coin-cell battery
- USB cable
- Ethernet port
- I/O board
- Power-button board
- System board
- Speakers
- Touchpad
- WWAN I/O board
- Palmrest assembly
- Display bezel
- Display panel
- Camera
- Display cable
- Display back-cover
- Drivers and downloads
- System setup
- Troubleshooting
- Built-in self-test (BIST)
- LCD Built-in Self Test (BIST)
- Dell SupportAssist Pre-boot System Performance Check diagnostics
- Diagnostic LED behavior
- Diagnostic error messages
- System error messages
- Recovering the operating system
- Real-Time Clock (RTC Reset)
- Flashing the BIOS
- Backup media and recovery options
- WiFi power cycle
- Flea power release
- Getting help and contacting Dell
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.
For more information about the Dell SupportAssist OS Recovery, see Dell SupportAssist OS Recovery User's Guide at
www.dell.com/support.
Real-Time Clock (RTC Reset)
The Real Time Clock (RTC) reset function allows you or the service technician to recover Dell Inspiron, systems from No
POST/No Power/No Boot situations. The legacy jumper enabled RTC reset has been retired on these models.
Start the RTC reset with the system powered off and connected to AC power. Press and hold the power button for thirty (30)
seconds. The system RTC Reset occurs after you release the power button.
Flashing the BIOS
About this task
You may need to flash (update) the BIOS when an update is available or when you replace the system board.
Follow these steps to flash the BIOS:
Steps
1. Turn on your computer.
2. Go to www.dell.com/support.
3. Click Product support, 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.
4. Click Drivers & downloads > Find it myself.
5. Select the operating system installed on your computer.
6. Scroll down the page and expand BIOS.
7. Click Download to download the latest version of the BIOS for your computer.
8. After the download is complete, navigate to the folder where you saved the BIOS update file.
9. Double-click the BIOS update file icon and follow the instructions on the screen.
Backup media and recovery options
It is recommended to create a recovery drive to troubleshoot and fix problems that may occur with Windows. Dell proposes
multiple options for recovering Windows operating system on your Dell PC. For more information. see Dell Windows Backup
Media and Recovery Options.
WiFi power cycle
About this task
If your computer is unable to access the internet due to WiFi connectivity issues a WiFi power cycle procedure may be
performed. The following procedure provides the instructions on how to conduct a WiFi power cycle:
NOTE: Some ISPs (Internet Service Providers) provide a modem/router combo device.
Steps
1. Turn off your computer.
2. Turn off the modem.
3. Turn off the wireless router.
Troubleshooting
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