kevinla said:
I am receiving this error message when plugging in a keyboard:
"one of the usb devices attatched to this computer has malfunctioned, and
windows does not recognize it."
Here is the sequence of events that led to this message:
I am using XP Pro.
Does that message mean it won't recognize it in the future? Is it possible
the keyboard needs more time to dry? It has been about 15 hours since the
water went into the keyboard.
I tried the USB port on another computer and received the same message.
Is my keboard fried?
When you spill a beverage on a keyboard...
1) Shut down the computer and power it off. Disconnect the keyboard from the
computer. (Use a spare keyboard in the interim period. Do not be tempted
to "try" the damaged keyboard too soon.) *Do not* try to run the keyboard
for any length of time, while the foreign liquid is present. Mineral water
may have conductive salts present in it, which could dry in place.
2) Rinse the keyboard immediately, under tap water, for about ten minutes.
It is important, if the beverage has sugar or salts present, to flush as
much of them away as possible. After the initial rinse, disassemble the
keyboard. Some of them allow the rinse operation to be done thoroughly.
Others may make cleaning properly impossible.
3) Place the keyboard near a desk fan, something you might use to cool
an area in summer. Leave the keyboard parts in the open if possible,
so that you get thorough drying.
4) Reassemble the keyboard. Invert the keyboard, keys down, and give it a
shake. Did droplets of water fall on the table ? If so, your drying
operation is not complete. Repeat step 3. It may take a couple days
to dry the keyboard. Water can stay inside the key caps for a long
long time.
I've spilled coffee on two keyboards. The first keyboard cost $150.00
and that one, has steel rivets inside, holding the parts together.
Even after rinsing and drying, three keys were so sticky from the
sugar in the coffee, they no longer worked properly. I had to
replace that keyboard (yes, I was angry at the time).
The second keyboard was a membrane type. It has three plastic layers
in precise alignment inside. Since the keyboard can be disassembled
(7 or 8 screws), and the three plastic layers can be separated and
held apart, it was much easier to rinse everything. I allowed a couple
days to dry, and there were still traces of water in the keycaps.
Was the second keyboard recovery a success ? I'm typing on that keyboard
right now.
*******
The keys in the keyboard, are placed in a matrix. Keys are scanned
by an X/Y grid of wires. Page 58 here, shows an example of how
the keys in the keyboard are wired. When there is a problem with
a signal on the scan matrix, a set of keys may appear to fail
at the same time.
http://www.datasheetcatalog.org/datasheet/philips/ISP1130DL.pdf
The arrangement of keys in the keyboard, is not an orderly one.
The keys which share a wire for communications, may snake through
the keyboard. So you cannot make much sense, of the mapping
between failed keys, and the matrix itself. But suffice to say,
when a bunch fail, they may be sharing a common scan wire.
In that example datasheet, the matrix is 8 x 19. Only 27 total pins
are needed to monitor 107 keys. Using matrix scan makes
the keyboard chip, cheaper to make, since the cost of ICs
is dominated by the cost of the package they're in. Big IC
packages cost more money.
Paul
