Dell T5600 owner manual Troubleshooting Your Computer, Diagnostic LEDs

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Troubleshooting Your Computer

You can troubleshoot your computer using indicators like Diagnostic Lights, Beep Codes, and Error Messages during the operation of the computer.

Diagnostic LEDs

NOTE: The diagnostic LEDs only serve as an indicator of the progress through the Power-On Self Test (POST) process. These LEDs do not indicate the problem that caused the POST routine to stop.

The diagnostic LEDs are located on the front of the chassis next to the power button. These diagnostic LEDs are only active and visible during the POST process. Once the operating system starts to load, they turn off and are no longer visible.

Each LED has two possible states of OFF or ON. The most significant bit is labeled with the number 1, and the other three are labeled 2, 3, and 4, as you go down or across the LED stack. The normal operating condition after POST is for all four LEDs to be ON and then turn off as the BIOS hands control over to the operating system.

NOTE: The diagnostic lights will blink when the power button is amber or off, and will not blink when it is white.

Table 11. POST Diagnostic LED Patterns

Diagnostic LEDs

• The computer is either turned off or is not receiving power

• The computer is booted and operating normally.

PCI device configuration activity is in progress or PCI device failure was detected.

•If the computer is turned off , connect the AC power-supply and power-on the computer.

•Remove all peripheral cards from the PCI and PCI-E slots and reboot the computer. If the computer boots, add the peripheral cards back one by one until you find the bad one.

A possible processor failure has	• Re-seat the processor.
occurred.
Memory modules are detected, but a	• If two or more memory
memory power failure has occurred.
	modules are installed, remove
	the modules, then reinstall
	one module and re-start the
	computer. If the computer
	starts normally, continue to
	install additional memory
	modules (one at a time) until
	you have identified a faulty
	module or reinstalled all
	modules without error. If only
	one memory module is

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