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Re: Apple ][+ keyboard
Nels Bruckner wrote:
I picked up a really nice looking ][+ last weekend from a local
computer recycler. Inside I found very minimal dust and everything
looks to be in good shape; however, the keyboard seems to have a
couple functional issues. I was wondering if these might ring a bell
for anyone -
First issue is there are 4 or 5 keys that don't register at all.
These are spread around the board and include the repeat key. Second
issue is that about 50% of the keys that do function are very 'bouncy'
- press the key once and you get 3-4 characters on the command line.
I disassembled and inspected everything, and the keyboard appears
visually to be in great shape. All the copper contacts on the blue
fiberglass board are corrosion free (though I cleaned them with
isopropal just to be sure), all the metal pads beneath the keys are
shiney and new looking, and all the keys function mechanically just
like new. Cleaned the pins on the encoder board, though it also
appears to be in like-new shape. I did not remove and reseat the big
socketed chip on the encoder board, because that sucker is IN THERE
really tight and I was afraid to pry on it too hard.
The micron-thin coating of insulating oxide that disrupts seldom-used
switches is often invisible.
You can either use the "indirect" method of cleaning the oxide layer
by pressing the keys hundreds+ times, with or without contact cleaner,
or you can use the "direct" method--disassemble the keyboard once more
and use a hard eraser ("pen" eraser is what they used to be called) to
burnish all the contact traces on the PC board and (harder) all the
metal pads under the keys.
When finished, wash again with alcohol, dry, and reassemble.
That should get everything working again.
To keep it working, use it regularly. An unused copper contact is
a place to grow oxide. ;-)
-michael
AppleCrate II: An Apple II "blade server"!
Home page: http://members.aol.com/MJMahon/
"The wastebasket is our most important design
tool--and it's seriously underused."