Brand: Dell
Category: Laptop
Document Type: Manual
Language: EN
Available Languages: EN , ES
Manual for 3420
Uploaded: Sept. 12, 2025, 4:24 a.m.
Manual Publish Date: 2021-07-01
Warranty Information
Contact Dell support or refer to warranty documentation for specific warranty details.
Working inside your computer
Before performing any service, ensure you are aware of the safety instructions, including prerequisites and precautions for handling components and electrostatic discharge (ESD). The manual details procedures for entering and exiting Service Mode, which allows for repairs without disconnecting the battery cable.
Removing and installing components
This section provides a list of recommended tools and a detailed screw list. It outlines the steps for removing and installing various components such as the microSD-card, SIM card tray, base cover, battery cable, memory module, M.2 solid-state drive, hard disk drive, WLAN card, WWAN card, system fan, battery, I/O cable, display assembly, display panel, display bezel, heatsink assembly, power adapter port, coin-cell battery, USB cable, Ethernet port, I/O board, and power button.
BIOS setup
Covers BIOS overview, entering the setup program, navigation keys, boot menu options, system setup options, and updating the BIOS through various methods (Windows, Linux/Ubuntu, USB drive, F12 One-Time boot menu). It also details system and setup password management and clearing CMOS settings.
Troubleshooting
Provides guidance on handling swollen Lithium-ion batteries, running Dell SupportAssist Pre-boot System Performance Check diagnostics, and built-in self-tests (BIST) like M-BIST, LCD Power rail test (L-BIST), and LCD Built-in Self Test (BIST). It includes a table of system-diagnostic lights and their corresponding resolutions. Further sections cover recovering the operating system, Real-Time Clock (RTC) reset, backup media options, WiFi power cycle, and draining residual flea power.
Getting help and contacting Dell
Offers self-help resources such as the Dell website and My Dell app, along with contact information for support and knowledge base articles.
Troubleshooting and error codes
| Blinking pattern | Possible Problem | Suggested resolution | |
|---|---|---|---|
| Amber | White | ||
| 2 | 1 | CPU Failure | Replace the system board. |
| 2 | 8 | LCD Power Rail Failure | Replace the system board. |
| 1 | 1 | TPM Detection Failure | Replace the system board. |
| 1 | 2 | Unrecoverable SPI Failure | Replace the system board. |
| 1 | 5 | EC unable to program i-Fuse | Replace the system board. |
| 1 | 6 | Generic catch-all for ungraceful EC code flow errors | Disconnect all power source (AC, battery, coin cell) and drain flea power by pressing and holding down power button for 3~5 seconds. Run the Dell Support Assist/Dell Diagnostics tool. If problem persists, replace the system board. |
| 2 | 1 | CPU failure | Run the Dell Support Assist/Dell Diagnostics tool. If problem persists, replace the system board. |
| 2 | 2 | System board failure (included BIOS corruption or ROM error) | Flash latest BIOS version If problem persists, replace the system board. |
| 2 | 3 | No memory/RAM detected | Confirm that the memory module is installed properly. If problem persists, replace the memory module. |
| 2 | 4 | Memory/RAM failure | Reset and swap memory modules among the slots. If problem persists, replace the memory module. |
| 2 | 5 | Invalid memory installed | Reset and swap memory modules among the slots. If problem persists, replace the memory module. |
| 2 | 6 | System board/Chipset Error | Replace the system board. |
| 2 | 7 | LCD failure (SBIOS message) | Replace the LCD module. |
| 2 | 8 | LCD failure (EC detection of power rail failure) | Replace the system board. |
| 3 | 1 | CMOS battery failure | Reset the main battery connection. If problem persists, replace the main battery. |
| 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. | Press power button for over 25 seconds to do RTC reset. If problem persists, replace the system board. Disconnect all power source (AC, battery, coin cell) and drain flea power by pressing and holding down power button 3~5 seconds to ensure all power are drained. Run "BIOS recovery from USB", and the instructions are in the website Dell support. If problem persists, replace the system board. |
| 3 | 7 | Timeout waiting on ME to reply to HECI message. | Replace the system board. |