Troubleshooting

Dell™ Dimension™ C521 Service Manual

Dell Diagnostics

CAUTION: Before you begin any of the procedures in this section, follow the safety instructions in the Product Information Guide.

When to Use the Dell Diagnostics

If you experience a problem with your computer, perform the checks in this section and run the Dell Diagnostics before you contact Dell for technical assistance.

NOTICE: The Dell Diagnostics works only on Dell™ computers.

Turn on (or restart) your computer.
When the DELL™ logo appears, press <F12> immediately.

If you wait too long and the operating system logo appears, continue to wait until you see the Microsoft® Windows® desktop. Then shut down your computer and try again.

When the boot device list appears, highlight Boot to Utility Partition and press <Enter>.
When the Dell Diagnostics Main Menu appears, select the test you want to run (see Dell Diagnostics Main Menu).

Dell Diagnostics Main Menu

After the Dell Diagnostics loads and the Main Menu screen appears, click the button for the option you want.

Option

Function

Express Test

Performs a quick test of devices. This test typically takes 10 to 20 minutes and requires no interaction on your part. Run Express Test first to increase the possibility of tracing the problem quickly.

Extended Test

Performs a thorough check of devices. This test typically takes an hour or more and requires you to answer questions periodically.

Custom Test

Tests a specific device. You can customize the tests you want to run.

Symptom Tree

Lists the most common symptoms encountered and allows you to select a test based on the symptom of the problem you are having.

Option	Function
Express Test	Performs a quick test of devices. This test typically takes 10 to 20 minutes and requires no interaction on your part. Run Express Test first to increase the possibility of tracing the problem quickly.
Extended Test	Performs a thorough check of devices. This test typically takes an hour or more and requires you to answer questions periodically.
Custom Test	Tests a specific device. You can customize the tests you want to run.
Symptom Tree	Lists the most common symptoms encountered and allows you to select a test based on the symptom of the problem you are having.

If a problem is encountered during a test, a message appears with an error code and a description of the problem. Write down the error code and problem description and follow the instructions on the screen.

If you cannot resolve the error condition, contact Dell. For information about contacting Dell, see your Owner's Manual.

NOTE: The Service Tag for your computer is located at the top of each test screen. If you contact Dell, technical support will ask for your Service Tag.

If you run a test from the Custom Test or Symptom Tree option, click the applicable tab described in the following table for more information.

Tab

Function

Results

Displays the results of the test and any error conditions encountered.

Errors

Displays error conditions encountered, error codes, and the problem description.

Help

Describes the test and may indicate requirements for running the test.

Configuration

Displays your hardware configuration for the selected device.

The Dell Diagnostics obtains configuration information for all devices from system setup, memory, and various internal tests, and it displays the information in the device list in the left pane of the screen. The device list may not display the names of all the components installed on your computer or all devices attached to your computer.

Parameters

Allows you to customize the test by changing the test settings.

Tab	Function
Results	Displays the results of the test and any error conditions encountered.
Errors	Displays error conditions encountered, error codes, and the problem description.
Help	Describes the test and may indicate requirements for running the test.
Configuration	Displays your hardware configuration for the selected device. The Dell Diagnostics obtains configuration information for all devices from system setup, memory, and various internal tests, and it displays the information in the device list in the left pane of the screen. The device list may not display the names of all the components installed on your computer or all devices attached to your computer.
Parameters	Allows you to customize the test by changing the test settings.

Close the test screen to return to the Main Menu screen. To exit the Dell Diagnostics and restart the computer, close the Main Menu screen.

System Lights

Your power button light and hard-drive activity light may indicate a computer problem.

Power Light

Problem Description

Suggested Resolution

Off

The computer is in a normal "off" condition or in a power-conserving mode.

None. Press the power button to wake the computer or to turn the computer on.

Solid green

The computer has successfully booted and is operating normally.

None.

Blinking green

The computer is in a Windows standby power-saving state (S1 or S3).

None. Move the mouse, press the spacebar, or use another device that has been configured as a wake-up device to wake the computer.

Solid Amber

A pre-POST failure has occurred. The system has received a Power Good signal from the power supply.

See Diagnostic Lights for more information.

If this does not resolve your problem, contact Dell. For information about contacting Dell, see your Owner's Manual.

Blinking Amber

A possible power supply failure has occurred. The system has not received a Power Good signal from the power supply

Plug the computer into a working electrical outlet.

Power Light	Problem Description	Suggested Resolution
Off	The computer is in a normal "off" condition or in a power-conserving mode.	None. Press the power button to wake the computer or to turn the computer on.
Solid green	The computer has successfully booted and is operating normally.	None.
Blinking green	The computer is in a Windows standby power-saving state (S1 or S3).	None. Move the mouse, press the spacebar, or use another device that has been configured as a wake-up device to wake the computer.
Solid Amber	A pre-POST failure has occurred. The system has received a Power Good signal from the power supply.	See Diagnostic Lights for more information. If this does not resolve your problem, contact Dell. For information about contacting Dell, see your Owner's Manual.
Blinking Amber	A possible power supply failure has occurred. The system has not received a Power Good signal from the power supply	Plug the computer into a working electrical outlet.

Hard-Drive Activity Light

Problem Description

Suggested Resolution

Solid green

The hard-drive activity light is on when the computer reads data from or writes data to the hard drive. The light might also be on when a device such as a CD player is operating.

No corrective action is required.

Hard-Drive Activity Light	Problem Description	Suggested Resolution
Solid green	The hard-drive activity light is on when the computer reads data from or writes data to the hard drive. The light might also be on when a device such as a CD player is operating.	No corrective action is required.

Diagnostic Lights

CAUTION: Before you begin any of the procedures in this section, follow the safety instructions in the Product Information Guide.

To help you troubleshoot a problem, your computer has four lights labeled "1," "2," "3," and "4" on the front panel. When the computer starts normally, the lights flash. After the computer starts, all four lights display solid green. If the computer malfunctions, the color and sequence of the lights identify the problem.

Light Pattern

Problem Description

Suggested Resolution

The computer is in a normal condition or a possible pre-POST failure has occurred.

See System Lights.

The computer is in recovery mode.

None.

A possible processor failure was detected.

Contact Dell. For information about contacting Dell, see your Owner's Manual.

Memory modules are detected, but a memory failure has occurred.

If you have two or more memory modules installed, remove the modules, reinstall one module (see Memory), and then restart the computer. If the computer starts normally, reinstall an additional module. Continue until you have identified a faulty module or reinstalled all modules without error.
If available, install properly working memory of the same type into your computer (see Memory).
If the problem persists, contact Dell. For information about contacting Dell, see your Owner's Manual.

A possible graphics failure has occurred.

If the problem persists, contact Dell. For information about contacting Dell, see your Owner's Manual.

A possible floppy drive or hard drive failure has occurred.

Reseat all power and data cables and restart the computer.

A possible USB failure has occurred.

Reinstall all USB devices, check cable connections, and then restart the computer.

No memory modules are detected.

If you have two or more memory modules installed, remove the modules, reinstall one module (see Memory), and then restart the computer. If the computer starts normally, reinstall an additional module. Continue until you have identified a faulty module or reinstalled all modules without error.
If available, install properly working memory of the same type into your computer (see Memory).
If the problem persists, contact Dell. For information about contacting Dell, see your Owner's Manual.

Memory modules are detected, but a memory configuration or compatibility error exists.

Ensure that no special memory module/memory connector placement requirements exist (see Memory).
Verify that the memory modules that you are installing are compatible with your computer (see Memory).
If the problem persists, contact Dell. For information about contacting Dell, see your Owner's Manual.

A possible expansion card failure has occurred.

Determine whether a conflict exists by removing a card and restarting the computer (see Cards).
If the problem persists, reinstall the card that you removed, remove a different card, and then restart the computer.
Repeat this process for each card. If the computer starts normally, troubleshoot the last card removed from the computer for resource conflicts.
If the problem persists, contact Dell. For information about contacting Dell, see your Owner's Manual.

Routine system activity subsequent to video initialization.

Watch your monitor for on-screen messages.

System resource configuration in progress.

None.

System board failure has occurred.

Contact Dell. For information about contacting Dell, see your Owner's Manual.

During normal operation, all of the diagnostic lights turn on and then turn off before the system starts.

NOTE: If all of the diagnostic lights are on and the system does not start, there may be a problem with the power supply or with the processor.

If the system does not start, plug the computer into a working electrical outlet. Also see System Lights.

If there are no power problems and the system does not start, contact Dell. For information about contacting Dell, see your Owner's Manual.

Light Pattern	Problem Description	Suggested Resolution
	The computer is in a normal condition or a possible pre-POST failure has occurred.	See System Lights.
	The computer is in recovery mode.	None.
	A possible processor failure was detected.	Contact Dell. For information about contacting Dell, see your Owner's Manual.
	Memory modules are detected, but a memory failure has occurred.	If you have two or more memory modules installed, remove the modules, reinstall one module (see Memory), and then restart the computer. If the computer starts normally, reinstall an additional module. Continue until you have identified a faulty module or reinstalled all modules without error. If available, install properly working memory of the same type into your computer (see Memory). If the problem persists, contact Dell. For information about contacting Dell, see your Owner's Manual.
	A possible graphics failure has occurred.	If the problem persists, contact Dell. For information about contacting Dell, see your Owner's Manual.
	A possible floppy drive or hard drive failure has occurred.	Reseat all power and data cables and restart the computer.
	A possible USB failure has occurred.	Reinstall all USB devices, check cable connections, and then restart the computer.
	No memory modules are detected.	If you have two or more memory modules installed, remove the modules, reinstall one module (see Memory), and then restart the computer. If the computer starts normally, reinstall an additional module. Continue until you have identified a faulty module or reinstalled all modules without error. If available, install properly working memory of the same type into your computer (see Memory). If the problem persists, contact Dell. For information about contacting Dell, see your Owner's Manual.
	Memory modules are detected, but a memory configuration or compatibility error exists.	Ensure that no special memory module/memory connector placement requirements exist (see Memory). Verify that the memory modules that you are installing are compatible with your computer (see Memory). If the problem persists, contact Dell. For information about contacting Dell, see your Owner's Manual.
	A possible expansion card failure has occurred.	Determine whether a conflict exists by removing a card and restarting the computer (see Cards). If the problem persists, reinstall the card that you removed, remove a different card, and then restart the computer. Repeat this process for each card. If the computer starts normally, troubleshoot the last card removed from the computer for resource conflicts. If the problem persists, contact Dell. For information about contacting Dell, see your Owner's Manual.
	Routine system activity subsequent to video initialization.	Watch your monitor for on-screen messages.
	System resource configuration in progress.	None.
	System board failure has occurred.	Contact Dell. For information about contacting Dell, see your Owner's Manual.
	During normal operation, all of the diagnostic lights turn on and then turn off before the system starts. NOTE: If all of the diagnostic lights are on and the system does not start, there may be a problem with the power supply or with the processor.	If the system does not start, plug the computer into a working electrical outlet. Also see System Lights. If there are no power problems and the system does not start, contact Dell. For information about contacting Dell, see your Owner's Manual.

Beep Codes

Your computer might emit a series of beeps during start-up if the monitor cannot display errors or problems. This series of beeps, called a beep code, identifies a problem. One possible beep code consists of one long beep and then two short beeps. This beep code tells you that the computer encountered a memory test failure.

If your computer beeps during start-up:

Write down the beep code on the Diagnostics Checklist. The Diagnostics Checklist is located in your Owner's Manual.
Run the Dell Diagnostics to identify a more serious cause. See Dell Diagnostics.
Contact Dell for technical assistance. For information about contacting Dell, see your Owner's Manual.

Code

Cause

2 short, 1 long

BIOS checksum error

1 long, 2 short

Memory test failure (bad memory during memory sizing)

1 long, 3 short, 2 short

No memory

1 short

F12 key pressed

Code	Cause
2 short, 1 long	BIOS checksum error
1 long, 2 short	Memory test failure (bad memory during memory sizing)
1 long, 3 short, 2 short	No memory
1 short	F12 key pressed

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