Advanced Troubleshooting

Dell™ Dimension™ 9150 Service Manual

Power Lights

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

The power button light located on the front of the computer illuminates and blinks or remains solid to indicate different states:

If the power light is green and the computer is not responding.

Ensure the display is connected and powered on.
If the display is connected and powered on, see "Diagnostic Lights".

If the power light is blinking green, the computer is in standby mode. Press a key on the keyboard, move the mouse, or press the power button to resume normal operation.
If the power light is off, the computer is either turned off or is not receiving power.

Reseat the power cable into both the power connector on the back of the computer and the electrical outlet.
If the computer is plugged into a power strip, ensure that the power strip is plugged into an electrical outlet and that the power strip is turned on. Also bypass power protection devices, power strips, and power extension cables to verify that the computer turns on properly.
Ensure that the electrical outlet is working by testing it with another device, such as a lamp.
Ensure that the main power cable and front panel cable are securely connected to the system board.

If the power light is blinking amber, the computer is receiving electrical power, but an internal power problem might exist.

Ensure that the voltage selection switch is set to match the AC power at your location (if applicable).

If the power light is steady amber, a device might be malfunctioning or incorrectly installed.

Remove and then reinstall the memory modules.
Remove and then reinstall any cards.
Remove and then reinstall the graphics card, if applicable.
Ensure that all power cables are securely connected to the system board.

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 (see "Front View of the Computer"). 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 "off" condition or a possible pre-BIOS failure has occurred.

The diagnostic lights are not lit after the system successfully boots to the operating system.

Plug the computer into a working electrical outlet. Also see "Power Lights."

A possible processor failure has occurred.

Reinstall the processor and restart the computer.

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.

A possible graphics card failure has occurred.

If the computer has a graphics card, remove the card (see "Cards"), reinstall it, and then restart the computer.
If the problem still exists, install a graphics card that you know works and restart the computer.
If the problem persists, contact Dell.

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.

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.

A possible expansion card failure has occurred.

Determine if a conflict exists by removing a card (not a graphics 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 (see "Cards").
If the problem persists, contact Dell.

Another failure has occurred.

Ensure that the cables are properly connected to the system board from the hard drive, CD drive, and DVD drive (see "System Board Components").
If there is an error message on your screen identifying a problem with a device (such as the floppy drive or hard drive), check the device to make sure it is functioning properly.
The operating system is attempting to boot from a device (such as the floppy drive or hard drive); check system setup to make sure the boot sequence is correct for the devices installed on your computer.
If the problem persists, contact Dell.

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. The diagnostic lights are not lit after the system successfully boots to the operating system.	Plug the computer into a working electrical outlet. Also see "Power Lights."
	A possible processor failure has occurred.	Reinstall the processor and restart the computer.
	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.
	A possible graphics card failure has occurred.	If the computer has a graphics card, remove the card (see "Cards"), reinstall it, and then restart the computer. If the problem still exists, install a graphics card that you know works and restart the computer. If the problem persists, contact Dell.
	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.
	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.
	A possible expansion card failure has occurred.	Determine if a conflict exists by removing a card (not a graphics 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 (see "Cards"). If the problem persists, contact Dell.
	Another failure has occurred.	Ensure that the cables are properly connected to the system board from the hard drive, CD drive, and DVD drive (see "System Board Components"). If there is an error message on your screen identifying a problem with a device (such as the floppy drive or hard drive), check the device to make sure it is functioning properly. The operating system is attempting to boot from a device (such as the floppy drive or hard drive); check system setup to make sure the boot sequence is correct for the devices installed on your computer. If the problem persists, contact Dell.
	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

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 system setup 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 system setup 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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