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112 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 112.
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 13 and "Back-Panel Features and Indicators" on page 17 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 Serial port 2 (COM2 and COM4)
IRQ4 Serial port 1 (COM1 and COM3)
IRQ5 Remote access controller
IRQ6 Diskette drive controller
IRQ7 Reserved
IRQ8 Real-time clock
IRQ9 ACPI functions (used for power management)
IRQ10 Available
IRQ11 Available
IRQ12 PS/2 mouse port unless the mouse is disabled through the System Setup program
IRQ13 Math coprocessor
IRQ14 IDE CD drive controller
IRQ15 Available
Book.book Page 112 Friday, February 3, 2006 11:09 AM