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brainboard update - was (Re: Keyboard issues ...HELP!!!!!)

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On Apr 7, 4:27 am, Nama <forums6...@mac.com> wrote:
> On Apr 6, 9:31 pm, mwillegal <m...@willegal.net> wrote:
>
>
>
>
>
> > On Apr 6, 6:42 am, Nama <forums6...@mac.com> wrote:
>
> > > On Apr 6, 2:11 pm, Nama <forums6...@mac.com> wrote:
>
> > > > I recently got a Apple II+ keyboard from John Woodall. He couldn't
> > > > test it so it came with no guarantee. Well the keyboard arrived, and
> > > > the first thing I noticed was the traces on the back of the keyboard
> > > > were damaged, and it was obviously this keyboard would need some
> > > > jumper wires to get at least 4 keys working. So instead of complain to
> > > > John I decided to just jumper the broken traces with fine wire.
>
> > > > Before plugging in the keyboard to test it I decided to look at the
> > > > daughterboard just incase. The decoder chip was a NKBD-931 (8018 UX),
> > > > and one of the pins was obviously out of the socket. I bent it back
> > > > and put it back in the socket correctly. Plugged it all together and
> > > > fired up the machine. Most of the keys worked, but some didn't. I
> > > > shorted the back PCB on of the keys that didn't work to see if the
> > > > issue was the key mechanism or something else. Shorting the key pins
> > > > seemed to work and displayed the appropriate character on the screen,
> > > > so I figured the issue was with the key mechanism. I was able to get
> > > > some of the keys working by spraying some contact cleaner down the
> > > > shafts. Thats when things went terribly wrong. I don't know what
> > > > happened, but suddenly I started geting multiple characters on the
> > > > screen from one key press, some keys seemed to suddenly stop working,
> > > > and others when pressed produced anything from 2 character to a stream
> > > > of 20+ characters in repeating patterns on the screen. Crazy!
>
> > > > Well, thats where I'm at now. I've looked at the board and can't see
> > > > anything obviously bad, so I'm stumped.
> > > > I was also wondering if the pin on the decoder chip was out for a
> > > > reason. I can't see any reference to the NKBD-931 on the net.
>
> > > > I do have a spare MM5740 decoder chip from an original Apple II
> > > > keyboard (raised power lamp), but I'm very wary to try it as I'm not
> > > > sure if that chip works in the II+ keyboard, and I certainly don't
> > > > want to fry it.
>
> > > > Can anyone help?
>
> > > > Thanks in advance.
>
> > > > Phil
>
> > > Well, well, well.
> > > I came back to the machine after a couple of hours, but nothing much
> > > changed. So it left it again in frustration. Another few hours later I
> > > tried it again, and what do you know, It fixed itself. ALL the keys
> > > are working!
>
> > > Not sure what happened, maybe there was still some residual contact
> > > cleaner in the key mechanisms that was shorting something...who
> > > knows.
>
> > > Thanks anyway.
>
> > > Phil
>
> > residual contact cleaner is exactly what was happening - I normally
> > use 91% isopropyl alcohol when cleaning keyswitch
> > mechanisms because it seems to work as good or better than contact
> > cleaner and evaporates
> > very quickly leaving no residual agent to cause problems later.
>
> > Regards,
> > Mike Willegal
>
> Hi Mike,
> Yes, that sounds like a better solution (pun intended)...lesson
> learnt.
> Funny though, I was looking at your site for clues to fixing the
> keyboard and was using your image of the keyboard matrix to help.
>
> Hows sales of your brain board going...I was thinking to get one.
>
> Phil

I was busy with the initial Brain Board shipments for a couple of
weeks, but at this point, I'm largely caught up. I'm thinking that
you'll probably be able to get some impartial impressions from Brain
Board owners posted online in blogs or podcasts in the coming weeks.

Mike W.

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Keyboard issues ...HELP!!!!! Nama <forums6000@mac.com> - 2011-04-05 22:11 -0700
  Re: Keyboard issues ...HELP!!!!! Nama <forums6000@mac.com> - 2011-04-06 03:42 -0700
    Re: Keyboard issues ...HELP!!!!! mwillegal <mike@willegal.net> - 2011-04-06 05:31 -0700
      Re: Keyboard issues ...HELP!!!!! Nama <forums6000@mac.com> - 2011-04-07 01:27 -0700
        brainboard update - was (Re: Keyboard issues ...HELP!!!!!) mwillegal <mike@willegal.net> - 2011-04-07 05:18 -0700

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