Service Manual

Troubleshooting
System diagnostic lights
The computer POST (Power On Self Test) ensures that it meets the basic computer requirements and the hardware is working
appropriately before the boot process begins. If the computer passes the POST, the computer continues to start in a normal mode.
However, if the computer fails the POST, the computer emits a series of LED codes in amber color during the start-up.
The following table shows different light patterns and what they indicate.
Table 9. Diagnostics
Number of Power LED flashes Problem description
1 System board: BIOS and ROM failure
2 No memory or RAM detected, system board, PSU
3 System board or chipset error
4 Memory or RAM failure
5 CMOS battery failure
6 Video card or chip failure
7 CPU failure
2,1 System board failure
2,2 No memory or RAM detected, system board, PSU
2,3 System board, memory or processor failure
3,6 BIOS recovery image not found
3,7 BIOS recovery image found but invalid
Recovering the operating system
When your computer is unable to boot to the operating system even after repeated attempts, it automatically starts Dell
SupportAssist OS Recovery.
Dell SupportAssist OS Recovery is a standalone tool that is preinstalled in all Dell computers installed with Windows 10 operating
system. It consists of tools to diagnose and troubleshoot issues that may occur before your computer boots to 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.
For more information about the Dell SupportAssist OS Recovery, see Dell SupportAssist OS Recovery User's Guide at
www.dell.com/
support.
Flashing BIOS (USB key)
Steps
1. Follow the procedure from step 1 to step 7 in "
Flashing the BIOS" to download the latest BIOS setup program file.
2. Create a bootable USB drive. For more information see the knowledge base article
SLN143196 at www.dell.com/support.
3. Copy the BIOS setup program file to the bootable USB drive.
4. Connect the bootable USB drive to the computer that needs the BIOS update.
5. Restart the computer and press F12 when the Dell logo is displayed on the screen.
6. Boot to the USB drive from the One Time Boot Menu.
7. Type the BIOS setup program filename and press Enter.
8. The BIOS Update Utility appears. Follow the instructions on the screen to complete the BIOS update.
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