Hardware Reference
In-Depth Information
as a test. If the system works properly with the known-good keyboard, you know the ori-
ginal keyboard or cable is defective. If the system still does not work normally, you might
have to replace the motherboard.
In many newer systems, the motherboard's keyboard and mouse connectors are protected
byafusethatyoucanreplace.Lookforanytypeoffuseonthemotherboardinthevicinity
ofthekeyboardormouseconnectors.Othersystemsmighthaveasocketedkeyboardcon-
troller chip (8042-type). In that case, you might be able to repair the motherboard key-
board circuit by replacing this chip. Because these chips have ROM code in them, you
should get the replacement from the motherboard or BIOS manufacturer. If the mother-
board uses a soldered keyboard controller chip or a chipset that integrates the keyboard
controller with other I/O chips, you need to replace the motherboard.
See the DVD included with this topic for a listing of the standard POST and diagnostic
keyboard error codes that some systems use.
Keyboard Disassembly
Although disassembling a keyboard is possible, most likely you won't need or want to do
that given how inexpensive new keyboards have become. If you do want to disassemble
your keyboard, see “
Keyboard Disassembly
” in the Technical Reference section of the
DVD accompanying this topic.
Cleaning a Keyboard
One of the best ways to keep a keyboard in top condition is periodic cleaning. As pre-
ventive maintenance, you should vacuum the keyboard weekly, or at least monthly. When
vacuuming, you should use a soft brush attachment to dislodge the dust. Also note that
some keyboards have keycaps that come off easily, so be careful when vacuuming; other-
wise you may have to dig the keys out of the vacuum cleaner. I recommend using a small,
handheld vacuum cleaner made for cleaning computers and sewing machines; these have
enough suction to get the job done with little risk of removing your keytops.
You also can use canned compressed air to blow the dust and dirt out instead of using a
vacuum. Before you dust a keyboard with the compressed air, however, turn the keyboard
upside down so that the particles of dirt and dust collected inside can fall out.
On all keyboards, each keycap is independently removable, which can be handy if a key
sticks or acts erratically. For example, a common problem is a key that does not work
every time you press it. This problem usually results from dirt collecting under the key.
An excellent tool for removing keycaps on almost any keyboard is the U-shaped chip
puller included in many computer tool kits. Simply slip the hooked ends of the tool un-
der the keycap, squeeze the ends together to grip the underside of the keycap, and lift up.
