Re: A plea: Looking for a working MM5740AAE/N for Apple II Keyboard

[rittwage <rittwage@gmail.com>]

On Dec 7, 2:49 am, "Michael J. Mahon" <mjma...@aol.com> wrote:
> rittwage wrote:
> > I have an old Apple II that I've fixed every other odd problem
> > (besides a broken Applesoft E0 ROM) except the keyboard!
>
> > I found some AAC/N chips, but no luck- the encoding is wrong.  I need
> > to see if any kind soul has any AAE/N encoder chips left to spare.
>
> > I really hate to convert to PS/2- I like the original keyboard.
> > Without that, I might as well use an emulator.  :)
>
> Pete, I'd recommend keeping this thread in csa2 and avoiding
> crossposting to marketplace and emulators.
>
> Are you sure that the problem is the encoder chip, and not
> one or more shorted keyswitches?  Failed encoders are not
> the most common keyboard problems.
>
> If it is the encoder, then you will have a hard time finding
> an equivalent replacement.  It would be possible to construct
> an equivalent that plugs into the original electrical "footprint",
> but it's not a simple project.
>
> Since the encoder presents parallel ASCII to the Apple II, it
> should not be too difficult to replace the keyboard with, say,
> a later Apple ][+ keyboard.  Those used to be pretty plentiful,
> depending on how authentically "Apple" it had to be...
>
> -michael

It's definitely the encoder- the original does nothing and the AAC
works, but has all wrong keys.  No switches are shorted, and I traced
to find no "stuck" bits.  It's just that the AAC, AAD, etc. send
different keystrokes to the AAE.

This is an early Datanetics keyboard without the separate encoder
board, so that modern encoder board replacement won't work.  Also, I
know I can replace the keyboard entirely with a PIC and a PS/2
keyboard, but... yuck.  I know I can also swap the whole keyboard for
another, but they are about as hard to find!

I do have extra IIe keyboards, but to my knowledge they can't be
converted.  Or can they?

-Pete