- Notes, cautions, and warnings
- Working on your computer
- Removing and installing components
- Recommended tools
- Screw list
- Major components of your system
- SIM card tray
- Micro Secure Digital (SD) Card
- Base cover
- Wireless card
- Wireless Wide Area Network (WWAN) Card
- Solid-state drives
- Memory
- Battery
- Battery cable
- Assembly-inner frame
- LED board
- Heat sink and fan assembly
- Speakers
- USB type-C bracket
- System board
- Power-button board
- Smart card reader
- Coin-cell battery
- Keyboard assembly
- Keyboard bracket
- Display assembly
- Display bezel
- Display panel
- Camera/microphone module
- eDP/display cable
- Sensor board
- Display hinges
- Display back cover
- Dummy SIM-card slot filler
- Palm-rest assembly
- Drivers and downloads
- System setup
- Troubleshooting
- Handling swollen rechargeable Li-ion batteries
- Dell SupportAssist Pre-boot System Performance Check diagnostics
- Built-in self-test (BIST)
- System diagnostic lights
- Recovering the operating system
- Real-Time Clock (RTC Reset)
- Backup media and recovery options
- Network power cycle
- Drain flea power (perform hard reset)
- Getting help
Latitude 5421 Service Manual
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 a sleep state, hibernation, or turned off.
The power and battery-status light blinks amber along with beep codes indicating failures.
For example, the power and battery-status light blinks amber two times followed by a pause, and then blinks white three times followed by a pause. This 2,3 pattern continues until the computer is turned off indicating no memory or RAM is detected.
The following table shows different power and battery-status light patterns and associated problems.
| Blinking Pattern | Problem description | |
|---|---|---|
| 1 | 1 | TPM detection failure |
| 1 | 2 | Unrecoverable SPI flash failure |
| 1 | 5 | EC unable to program i-Fuse |
| 1 | 6 | Generic catch-all for ungraceful EC code flow errors |
| 2 | 1 | CPU failure |
| 2 | 2 | System board failure (included BIOS corruption or ROM error) |
| 2 | 3 | No memory/RAM detected |
| 2 | 4 | Memory/RAM failure |
| 2 | 5 | Invalid memory installed |
| 2 | 6 | System board/chipset error |
| 2 | 7 | Potential LCD panel damage and/or LCD cable failure (SBIOS message) |
| 2 | 8 | Power rail failure at the system board side |
| 3 | 1 | CMOS battery failure |
| 3 | 2 | PCI or video card/chip failure |
| 3 | 3 | BIOS recovery image not found |
| 3 | 4 | BIOS recovery image found but invalid |
| 3 | 5 | Power rail failure |
| 3 | 6 | Flash corruption detected by SBIOS |
| 3 | 7 | Timeout waiting on ME to reply to HECI message |
| 4 | 3 | LCD panel failure (potential cracked panel) |
| 4 | 4 | Power rail failure at system board side |
| 4 | 5 | LCD panel failure and power rail failure at system board side. |
| 4 | 6 | Display cable (EDP) failure |
Camera status light: Indicates whether the camera is in use.
- Solid white — Camera is in use.
- Off — Camera is not in use.
Caps Lock status light: Indicates whether Caps Lock is enabled or disabled.
- Solid white — Caps Lock enabled.
- Off — Caps Lock disabled.
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