Re: Apple ][+ keyboard

[Nama <forums6000@mac.com>]

On Sep 30, 4:49 pm, Nels Bruckner <ne...@comcast.net> 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 keyboard behaved identically when plugged into one of my spare ][+
> boards.
>
> I've got a Super Encoder on order from Briel, just in case it's an
> encoder issue.  Unfortunately I don't have another ][ keyboard to try
> swapping.
>
> --Nels

I've fixed a few Apple II and II+ keyboards that have exhibited
similar symptoms as you describe. Often continual pressing the keys
can bring them back to life (warning: some of the keys I fixed must
have taken hundreds (thousands?) of pushes to get them working again),
a bit of contact cleaner squirted down the shaft of the keyswitch
helps too. Sometimes the next day, the same keys will not work until I
cycle them a few more (hundred) times to get them running again.
Eventually, over time they consistently work.
Sometimes keys exhibit bounce, which means that two characters appear
with one keypress. Again, cycling the key seems to fix this most of
the time. Finally I found that some keys ultimately could not be fixed
and I had to replace the keyswitches which is a little bit of a
delicate soldering process...too much heat and the plastic melts.
If that isn't the problem, then I'm sorry I don't know what else it
could be. Maybe the encoder as you described.
Phil