Advanced Troubleshooting

Dell™ Dimension™ 2400 Series

Diagnostic Lights

To help you troubleshoot a problem, your computer has four lights labeled "A," "B," "C," and "D" on the back panel. The lights can be yellow or green. 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.

CAUTION: Before you begin any of the procedures in this section, follow the safety instructions in your Owner's Manual or Product Information Guide.

Light Pattern

Problem Description

Suggested Resolution

The computer is in a normal off condition or a possible pre-BIOS failure has occurred.
Verify that the computer is plugged into a working electrical outlet and that you have pressed the power button.

Memory modules are detected, but a memory failure has occurred.
If you have one memory module installed, reinstall it and restart the computer.

If you have two or more memory modules installed, remove the modules, reinstall one module, 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.

If the problem persists, see "Contacting Dell" in your Owner's Manual.

A possible expansion card failure has occurred.

Determine if a conflict exists by removing a card (not the video card) and then restarting the computer.
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 (see "Resolving Software and Hardware Incompatibilities" in your Owner's Manual).
If the problem persists, see "Contacting Dell" in your Owner's Manual.

A possible floppy 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.
Reinstall all memory modules and restart the computer.

To eliminate the possibility of a faulty memory connector, remove all memory modules, reinstall one memory module (if the computer supports a single module), and then restart the computer. If the computer starts normally, move the memory module to a different connector and restart the computer. Continue until you have identified a faulty connector or reinstalled all modules without error.

Memory modules are detected, but a memory configuration or compatibility error exists.
Ensure that no special memory module/memory connector placement requirements exist.

Verify that the memory modules that you are installing are compatible with your computer.

If the problem persists, see "Contacting Dell" in your Owner's Manual.

Another failure has occurred.
Ensure that the cables are properly connected to the system board from the hard drive, CD drive, and DVD drive.

If the problem persists, see "Contacting Dell" in your Owner's Manual.

The computer is in a normal operating condition after POST.
None.

Light Pattern	Problem Description	Suggested Resolution
	The computer is in a normal off condition or a possible pre-BIOS failure has occurred.	Verify that the computer is plugged into a working electrical outlet and that you have pressed the power button.
	Memory modules are detected, but a memory failure has occurred.	If you have one memory module installed, reinstall it and restart the computer. If you have two or more memory modules installed, remove the modules, reinstall one module, 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. If the problem persists, see "Contacting Dell" in your Owner's Manual.
	A possible expansion card failure has occurred.	Determine if a conflict exists by removing a card (not the video card) and then restarting the computer. 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 (see "Resolving Software and Hardware Incompatibilities" in your Owner's Manual). If the problem persists, see "Contacting Dell" in your Owner's Manual.
	A possible floppy 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.	Reinstall all memory modules and restart the computer. To eliminate the possibility of a faulty memory connector, remove all memory modules, reinstall one memory module (if the computer supports a single module), and then restart the computer. If the computer starts normally, move the memory module to a different connector and restart the computer. Continue until you have identified a faulty connector or reinstalled all modules without error.
	Memory modules are detected, but a memory configuration or compatibility error exists.	Ensure that no special memory module/memory connector placement requirements exist. Verify that the memory modules that you are installing are compatible with your computer. If the problem persists, see "Contacting Dell" in your Owner's Manual.
	Another failure has occurred.	Ensure that the cables are properly connected to the system board from the hard drive, CD drive, and DVD drive. If the problem persists, see "Contacting Dell" in your Owner's Manual.
	The computer is in a normal operating condition after POST.	None.

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 (code 1-3-1) consists of one beep, a burst of three beeps, and then one beep. This beep code tells you that the computer encountered a memory problem.

Reseating the memory modules may fix the beep code errors in the following table. If the problem persists, see "Contacting Dell" in your Owner's Manual for instructions on obtaining technical assistance.

Code

Cause

1-3-1 through 2-4-4
Memory not being properly identified or used

4-3-1
Memory failure above address 0FFFFh

Code	Cause
1-3-1 through 2-4-4	Memory not being properly identified or used
4-3-1	Memory failure above address 0FFFFh

If you hear one of the following beep codes, see "Contacting Dell" in your Owner's Manual for instructions on obtaining technical assistance.

Code

Cause

1-1-2
Microprocessor register failure

1-1-3
NVRAM

1-1-4
ROM BIOS checksum failure

1-2-1
Programmable interval timer

1-2-2
DMA initialization failure

1-2-3
DMA page register read/write failure

3-1-1
Slave DMA register failure

3-1-2
Master DMA register failure

3-1-3
Master interrupt mask register failure

3-1-4
Slave interrupt mask register failure

3-2-2
Interrupt vector loading failure

3-2-4
Keyboard Controller Test failure

3-3-1
NVRAM power loss

3-3-2
NVRAM configuration

3-3-4
Video Memory Test failure

3-4-1
Screen initialization failure

3-4-2
Screen retrace failure

3-4-3
Search for video ROM failure

4-2-1
No time tick

4-2-2
Shutdown failure

4-2-3
Gate A20 failure

4-2-4
Unexpected interrupt in protected mode

4-3-3
Timer-chip counter 2 failure

4-3-4
Time-of-day clock stopped

4-4-1
Serial or parallel port test failure

4-4-4
Cache test failure

Code	Cause
1-1-2	Microprocessor register failure
1-1-3	NVRAM
1-1-4	ROM BIOS checksum failure
1-2-1	Programmable interval timer
1-2-2	DMA initialization failure
1-2-3	DMA page register read/write failure
3-1-1	Slave DMA register failure
3-1-2	Master DMA register failure
3-1-3	Master interrupt mask register failure
3-1-4	Slave interrupt mask register failure
3-2-2	Interrupt vector loading failure
3-2-4	Keyboard Controller Test failure
3-3-1	NVRAM power loss
3-3-2	NVRAM configuration
3-3-4	Video Memory Test failure
3-4-1	Screen initialization failure
3-4-2	Screen retrace failure
3-4-3	Search for video ROM failure
4-2-1	No time tick
4-2-2	Shutdown failure
4-2-3	Gate A20 failure
4-2-4	Unexpected interrupt in protected mode
4-3-3	Timer-chip counter 2 failure
4-3-4	Time-of-day clock stopped
4-4-1	Serial or parallel port test failure
4-4-4	Cache test failure

System Messages

NOTE: If the message you received is not listed in the table, see the documentation for either the operating system or the program that was running when the message appeared.

Message

Possible Cause

Corrective Action

8042 Gate-A20 error
The keyboard controller failed its test.
If you receive this message after you make changes in the system setup program, enter the program and restore the original value(s).

Address Line Short!
An error in the address decoding circuitry in the memory has occurred.
Reseat the memory modules.

C: Drive Error
C: Drive Failure
The hard drive is not working or is not configured correctly.
Ensure that the drive is installed correctly in the computer and defined correctly in the system setup program.

Cache Memory Bad, Do Not Enable Cache
The cache memory is not operating.
See "Contacting Dell" in your Owner's Manual for instructions on obtaining technical assistance.

CH-2 Timer Error
An error is occurring on the timer on the system board.
See "Contacting Dell" in your Owner's Manual for instructions on obtaining technical assistance.

CMOS Battery State Low
CMOS Checksum Failure
CMOS System Options Not Set
CMOS Display Type Mismatch
CMOS Memory Size Mismatch
CMOS Time and Date Not Set
The system configuration information in the system setup program is incorrect or the battery charge may be low.
Enter the system setup program, verify the system configuration, and then restart the computer.

Diskette Boot Failure
Drive A or B is present but has failed the BIOS POST.
Ensure that the drive is installed correctly in the computer and defined correctly in the system setup program. Check the interface cable at both ends.

DMA Error
DMA 1 Error
DMA 2 Error
Error in the DMA controller on the system board.
The keyboard or system board may need to be replaced.

FDD Controller Failure
HDD Controller Failure
The BIOS cannot communicate with the floppy drive or hard drive controller.
Ensure that the floppy drive or the hard drive is installed correctly in the computer and defined correctly in the system setup program. Check the interface cable at both ends.

INTR1 Error
INTR2 Error
An interrupt channel on the system board failed to POST.
The keyboard or system board may need to be replaced.

Invalid Boot Diskette
The operating system cannot be located on drive A or drive C.
Enter the system setup program and confirm that drive A or drive C is properly identified.

Keyboard Error
The BIOS has detected a stuck key.
Ensure that nothing is resting on the keyboard; if a key appears to be stuck, carefully pry it up. If the problem persists, you may need to replace the keyboard.

KB/Interface Error
An error occurred with the keyboard connector.
Ensure that nothing is resting on the keyboard; if a key appears to be stuck, carefully pry it up. If the problem persists, you may need to replace the keyboard.

No ROM Basic
The operating system cannot be located on drive A or drive C.
Enter the system setup program and confirm that drive A or drive C is properly identified.

Message	Possible Cause	Corrective Action
8042 Gate-A20 error	The keyboard controller failed its test.	If you receive this message after you make changes in the system setup program, enter the program and restore the original value(s).
Address Line Short!	An error in the address decoding circuitry in the memory has occurred.	Reseat the memory modules.
C: Drive Error C: Drive Failure	The hard drive is not working or is not configured correctly.	Ensure that the drive is installed correctly in the computer and defined correctly in the system setup program.
Cache Memory Bad, Do Not Enable Cache	The cache memory is not operating.	See "Contacting Dell" in your Owner's Manual for instructions on obtaining technical assistance.
CH-2 Timer Error	An error is occurring on the timer on the system board.	See "Contacting Dell" in your Owner's Manual for instructions on obtaining technical assistance.
CMOS Battery State Low CMOS Checksum Failure CMOS System Options Not Set CMOS Display Type Mismatch CMOS Memory Size Mismatch CMOS Time and Date Not Set	The system configuration information in the system setup program is incorrect or the battery charge may be low.	Enter the system setup program, verify the system configuration, and then restart the computer.
Diskette Boot Failure	Drive A or B is present but has failed the BIOS POST.	Ensure that the drive is installed correctly in the computer and defined correctly in the system setup program. Check the interface cable at both ends.
DMA Error DMA 1 Error DMA 2 Error	Error in the DMA controller on the system board.	The keyboard or system board may need to be replaced.
FDD Controller Failure HDD Controller Failure	The BIOS cannot communicate with the floppy drive or hard drive controller.	Ensure that the floppy drive or the hard drive is installed correctly in the computer and defined correctly in the system setup program. Check the interface cable at both ends.
INTR1 Error INTR2 Error	An interrupt channel on the system board failed to POST.	The keyboard or system board may need to be replaced.
Invalid Boot Diskette	The operating system cannot be located on drive A or drive C.	Enter the system setup program and confirm that drive A or drive C is properly identified.
Keyboard Error	The BIOS has detected a stuck key.	Ensure that nothing is resting on the keyboard; if a key appears to be stuck, carefully pry it up. If the problem persists, you may need to replace the keyboard.
KB/Interface Error	An error occurred with the keyboard connector.	Ensure that nothing is resting on the keyboard; if a key appears to be stuck, carefully pry it up. If the problem persists, you may need to replace the keyboard.
No ROM Basic	The operating system cannot be located on drive A or drive C.	Enter the system setup program and confirm that drive A or drive C is properly identified.

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