Re: Apple ][+ question

[nogard@cishollywood.com]

On Mar 17, 2:32 am, "Michael J. Mahon" <mjma...@aol.com> wrote:
> nog...@cishollywood.com wrote:
> > Just picked up another Apple ][+, and have a question.  There seems a
> > be a wire running from 74ls251 pin 16 (the right lowest pin with the
> > keyboard facing you) down to ??? (seems to have been dislodged over
> > time).  I was thinking this was the shift key mod, but it seems to be
> > connected the the chip below the game port.  Now somebody could of
> > have just attached it randomly, I have no idea.  I was just curious
> > where I would need to attach the other end?
> > Also if this helps, it seems to have the Applied Engineering Lower
> > Case Rom Chip (Rev LC 1.0).
>
>  > Sorry the grabbette is connected to pin 9 not 16 or 74LS251.
>
> The Lower Case ROM is a dead giveaway that the machine would
> be shift key modified.
>
> If by "lowest" pin, you mean closest to the keyboard, then the
> pin you describe is pin 1, which is the PB2 input--the usual
> place for the shift key mod to be connected.  The other end of
> the wire should go to the high (non-ground) side of the shift key,
> or pin 2 of U4 on the keyboard encoder board.
>
> There are spare wires/pins on the keyboard connector(s), and some
> people modified their encoder boards to pipe the high side of the
> shift key to an unused pin of the main board keyboard connector.
> This approach allows a "clean" shift key mod, without flying wires.
> (The connection to the game port or the '251 can be made with a wire
> under the board, for an even cleaner installation.)
>
> -michael
>
> NadaNet networking for Apple II computers!
> Home page:  http://members.aol.com/MJMahon/
>
> "The wastebasket is our most important design
> tool--and it's seriously underused."

Yes that was it, my confusion was in which pin was #1.  Now that I
found something on the web that actually described it the way you did,
it all made sense.


Thanks,
Chris