Dell Latitude LM - Manual (Page 44)

3-10 Dell Latitude LM Reference and Troubleshooting Guide
setting for each installed device. Then consult Table 3-4
to configure the device for one of the available IRQ lines.
NOTE: Installed devices cannot share the same COM
port address. The default address of the computer’s serial
port is COM1.
T
roubleshooting Procedures
This section provides troubleshooting procedures for
built-in components (such as the display) and for external
devices that connect to the computer (such as an external
monitor). Before performing any of the procedures in this
section, see “Basic Checks” found earlier in this chapter
and read the safety instructions at the front of this guide.
Then perform the appropriate troubleshooting procedure
for the component or equipment that is malfunctioning.
NOTE: When you see the question “Is the problem
resolved?” in a troubleshooting procedure, perform the
operation that caused the problem to see if the problem
still occurs.
Troubleshooting a Wet Computer
Liquids, spills and splashes, rain, and excessive humidity
can cause moisture damage to the computer. If the com-
puter gets wet or if condensation forms on the computer
because of humid conditions, use the following
procedure:
1. Turn off the computer, and disconnect it from the
AC adapter. Then disconnect the AC adapter
from AC power. Turn off any attached periph-
erals, and disconnect them from their power
sources and then from the computer.
2. Remove any installed batteries.
Wipe off each battery, and store it in a safe place to
dry.
3. If the options bay slot is wet, remove the device
from the bay. If the PC Card slot is wet, remove
the PC Cards. Put the device and cards in a safe
place to dry.
Table 3-4. IRQ Line Assignments
IRQ Line Used/Available
IRQ0 Generated by the system timer
IRQ1 Generated by the keyboard controller to sig-
nal that the keyboard output buffer is full
IRQ2 Cascade to second interrupt controller
IRQ3 Used by the infrared port (COM2)
IRQ4 Used by the serial port (COM1)
IRQ5 Used by the audio controller
IRQ6 Generated by the diskette drive controller
to indicate that the diskette drive requires
the attention of the microprocessor
IRQ7 Used by the parallel port
IRQ8 Generated by the system RTC
IRQ9 Software redirect to INT0A
IRQ10 Reserved
IRQ11 Reserved
IRQ12 Generated by the keyboard controller to indi-
cate that the output buffer of the integrated
touch pad or external PS/2 mouse is full
IRQ13 Used by the math coprocessor on the
microprocessor
IRQ14 Generated by the hard-disk drive to indi-
cate that the drive requires the attention of
the microprocessor
IRQ15 Reserved
NOTE: For the full name of an abbreviation or acronym used
in this table, see the Glossary in the online System User’s
Guide.
WARNING: Perform step 1 of the following proce-
dure only after you are certain that it is safe to do
so. If the computer is connected to an alternating
current (AC) power source, Dell recommends turn-
ing off AC power at the circuit breaker before
attempting to remove the power cables from AC
power. Use the utmost caution when removing wet
cables from live power.