Re: ID: Cards...

["Shaun Olson" <solson@kc.rr.com>]

Tony Diaz's site (apple2.org) already has a pretty good start for images....
check here

http://www.apple2.org/aboutimages.html

Shaun
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"Tony Cianfaglione" <ab616@chebucto.ns.ca> wrote in message
Pine.GSO.3.95.iB1.0.1030726175705.16339A-100000@halifax.chebucto.ns.ca">news:Pine.GSO.3.95.iB1.0.1030726175705.16339A-100000@halifax.chebucto.ns.ca...
>
> Wow!  You know your stuff.
>
> The DAC card, the Mockingboard and the Soundchaser are all in an
> unenhanced 64k IIe.  The person I got it from said the stuff was in ther
> when he got it and he never used it and didn't know what it was for.  I
> wonder what the original use for all 3 cards together was for; if, indeed,
> they were used together and not separately.
>
> It would be great if someone with some time on their hands created a
> reference website listing as many old A2 cards that could be identified
> including scans, for posterity sake.
>
> ----------------------------------------
>
> On 26 Jul 2003, Michael Black wrote:
>
> > Obviously, it's got some sort of digital to analog converter, with
> > speaker level output.
> >
> > The LM386 is a small audio amplifier.
> >
> > The LM3900 is a "quad norton amplifier", in other words, kind of like
> > op-amps and there are four of them in the package.
> >
> > My first thought about the "558" is that it's the quad timer IC, which
> > is used (I think) in the Apple II for the joystick controller (and in
> > the IBM's joystick controller).
> >
> > But that seems a bit off, and the "AD" prefix is Analog Devices;
> > not only did they not make timer ICs, but considering the labelling
> > of the board, that must be the DA converter.
> >
> > A websearch verifies this, it's an 8-bit digital to analog converter
> > intended for interfacing to a CPU bus.
> >
> > So it must be for generating sounds of some sort, be it music or
> > speech.  If those are the only ICs on the board, obviously it counts
> > on software to do much of the work.
> >
> > I suppose the LM3900 is being used as a low pass filter, between the
> > DAC and the audio amplifier.
> >
> >   Michael
> >
> >
> >
> > > -----------------------------
> > >
> > > On 25 Jul 2003, Michael J. Mahon wrote:
> > >
> > >> >MMI DSC Board (1982)
> > >>
> > >> Rings a bell, but I can't place it...  Could you describe it and its
chips?
> > >
> >
> >
> >
> >
>