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Re: Apple II plus keyboard repair
js@cimmeri.com wrote:
KPR wrote:
I just got an apple II plus and there are some keys that don't work.. I
cleand it the best I could.. wiping and blowing out the dust and dirt..
Wiping and blowing is worst way to clean a keyboard, or a computer..
but many people persist in using compressed air (which just recycles
all the dust back into the air where it gets re-drawn into other
equipment (such as your lungs), or it forces dust further into places
where it shouldn't be).
A small but powerful suction hose, perhaps with an attached brush,
would be perfect, but that's hard to find...
I usually wash the entire keyboard in hot water and a VERY mild soap
that I mix for the purpose, and try to avoid getting water into the
keys. However, I often do and the entire keyboard stops working even
after being allowed to dry a few days. Panic can settle in.
What restores the action is let the keyboard dry even longer over
something slightly warm.. such as a motherboard for instance. This
evaporates the humidity retained within each switch.
Wet washing is particularly effective in dealing with soluble
contaminants, like spilled beverages, etc.
Then, with the keyboard plugged in and computer on, I spray a little
CAIG Deoxit 5 into each keyswitch, and work every key until it
consistently will fill up two lines on the screen without a single
keypress miss. Sometimes, this takes 100's of keypresses... sometimes
I even have to flip something at the key to really smack it fast (seems
to jar something loose that's stuck).
The trick is to induce a little "wiping action" in the switch contacts
(which are normally self-cleaning). I have found that pushing the
switch at a 45-degree angle from various directions can also help.
However, using these methods, I've completely restored every keyboard
I've worked on... particularly the extremely sensitive to water IIc
keyboards.
Now, there are exceptions: sometimes -- especially on the earliest
keyboards -- the switches really are bad.. and you have to unsolder and
unscrew them.
A later keyboard comes apart nicely and is easy to work on, but has a
very poor touch feel so I don't like using it even though it can be
kept in service perpetually.
Even later keyboards are extremely difficult to service (would require
unsoldering ALL switches merely to replace one), but luckily, I've not
encountered a bad switch on one of these yet.
-michael
Music synthesis for 8-bit Apple II's!
Home page: http://members.aol.com/MJMahon/
"The wastebasket is our most important design
tool--and it is seriously underused."