Dell Latitude CP, Справочное и ремонтное руководство

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Troubleshooting Your Computer 3-23
Troubleshooting an External Keyboard
or External Keypad
During POST, the computer checks to see if an external
keyboard or keypad is connected. If an external keyboard
is connected, the computer recognizes both the built-in
and the external keyboards. If an external keypad is con-
nected, the computer recognizes the external keypad and
the built-in keyboard, but does not recognize the embed-
ded numeric keypad. If an attached external keyboard or
keypad does not work when you boot the computer, make a
copy of the Diagnostics Checklist found in Chapter 5 and fill
it out as you complete the following procedure.
NOTE: The computer’s PS/2 connector supports two
devices with the use of a PS/2 “Y” adapter.
1. Make sure the cable from the external keyboard
or keypad is firmly connected to the external key-
board/keypad/mouse connector on the back of the
computer. (See “Checking Connections” found
earlier in this chapter.)
2. If you are using a keyboard with various switch
settings, make sure the switch is set to PS/2,
Enhanced XT/AT, or PC/AT.
The switch settings are usually on the bottom of the
keyboard, sometimes behind a panel tab.
3. Reboot the computer. During the boot routine, do
the Num Lock, Caps Lock, and Scroll Lock indica-
tors on the external keyboard flash momentarily?
Yes. Continue to step 4.
No. You may have a defective keyboard port fuse.
Go to step 7.
4. Does the computer recognize the external key-
board or keypad?
Use the external keyboard or keypad to type some
characters. Do they appear on the display?
Yes. The problem is resolved.
No. Continue to step 5.
5. Turn off the computer, and disconnect the exter-
nal keyboard or keypad from the computer.
6. Reboot the computer. Is the computer recognizing
the built-in keyboard?
Allow one minute for the computer to initialize its
components. Then use the computer’s built-in
keyboard to type some characters. Do the characters
appear on the display?
Yes. The external keyboard may be defective. Run
the Keyboard test group in the Dell Diagnostics.
(See Chapter 4, “Running the Dell Diagnostics,” for
instructions.) If you cannot isolate the problem after
running the diagnostics, call Dell for technical assis-
tance. (See Chapter 5, “Getting Help,” for
instructions.)
No. The computer’s keyboard controller on the sys-
tem board may be defective. Run the Keyboard
Controller Test in the Dell Diagnostics. (See
Chapter 4, “Running the Dell Diagnostics,” for
instructions.) If you cannot isolate the problem after
running the diagnostics, call Dell for technical
assistance. (See Chapter 5, “Getting Help,” for
instructions.)
7. Call Dell for technical assistance.
See Chapter 5, “Getting Help,” for instructions.
Troubleshooting Memory
If the memory count displayed in the lower-right corner of
the System Setup program is less than the amount installed,
make a copy of the Diagnostics Checklist found in Chapter 5
and fill it out as you complete the following procedure.
NOTE: Before beginning this procedure, make sure a
memory module is installed in one of the memory module
sockets on the system board. The computer will not func-
tion unless there is at least one installed memory module.
1. Reboot the computer, and open the System
Setup program by pressing the <Fn><F1> key
combination. Does the memory total displayed
match the actual amount of memory installed in
the computer?
Yes. The computer needed to update the memory; the
memory check phase is now OK.
No. Continue to step 2.
2. Turn off the computer, and reseat (remove and
reinstall) any installed memory modules in your
computer.
Loose or disconnected memory modules may cause
intermittent memory problems. Removing and rein-
stalling, or reseating, memory modules often corrects
the problem.