DELL 1950 User Manual

94

Troubleshooting Your System

Checking the Equipment

This section provides troubleshooting procedures for external devices attached to the system, such as the 
monitor, keyboard, or mouse. Before you perform any of the procedures, see "Troubleshooting External 
Connections" on page 94.

Troubleshooting IRQ Assignment Conflicts

Most PCI devices can share an IRQ with another device, but they cannot use an IRQ simultaneously. To 
avoid this type of conflict, see the documentation for each PCI device for specific IRQ requirements. 
Table 4-2 lists the IRQ assignments.

Troubleshooting External Connections

Loose or improperly connected cables are the most likely source of problems for the system, monitor, and 
other peripherals (such as a printer, keyboard, mouse, or other external device). Ensure that all external 
cables are securely attached to the external connectors on your system. See "Front-Panel Features and 
Indicators" on page 11 and "Back-Panel Features and Indicators" on page 14 for the front- and back-panel 
connectors on your system.

Table 4-2.

IRQ Assignment Defaults

IRQ Line

Assignment

IRQ0

System timer

IRQ1

Keyboard controller

IRQ2

Interrupt controller 1 to enable IRQ8 through IRQ15

IRQ3

IRQ4

Serial port 1 (COM1 and COM3)

IRQ5

Remote access controller

IRQ6

Reserved

IRQ7

Reserved

IRQ8

Real-time clock

IRQ9

ACPI functions (used for power management)

IRQ10

IRQ11

IRQ12

IRQ13

Math coprocessor

IRQ14

IDE CD drive controller

IRQ15