Re: Some IIgs questions

["Mike Westerfield" <MikeW50@aol.com>]

----------
In article <37BC48DC.8B9@together.net>, MQSmith <livepoet@together.net>
wrote:


>It came with an expansion card in the third slot.  It has a large LEGO
>logo, and at the top it says in much smaller script, For Educator Use. 
>Below the logo there are large numbers, 9767.  I'm assuming that this is
>the model number.  Anyone have any idea what this is?

It's an interface to the Lego robotics box, allowing the computer to control
Lego projects built with specialized parts. They are really quite cool, but
the card is worthless without the software, the box that sits at the other
end of the card, and the specialized Logo parts it is designed to control.
If you don't have those, pull it out and put it with your other spare parts.

>There looks to be a chip or an IC or something missing, I'm not sure if
>it comes like that out of the factory or if it was removed.  There's a
>white plastic connector, it's either labeled J21 or GAME, I'm not sure
>which (J21 is to its immediate upper left, GAME is directly below it). 
>I think the J21 label might be for a circuit.  The plastic thing has
>holes in it, it looks like it could accept an IC, but there isn't one
>there.  Is this normal?

Very. It's the game paddle port, which is used for game paddles, joysticks
and other devices. This is the "old style" connector; there is another
connector for joysticks on the back panel. It drives most, but not all, of
the pins from the socket you noticed.

The socket actually gives you four simple analog to digital inputs that take
0 to 150 ohm resistance and convert it to a byte value of 0 to 255 that can
be read by a program. It also gives you 3 TTL inputs and 4 TTL outputs. (Or
was it 4 inputs and 3 outputs? I'd have to look.) There are several FAQs and
books that give specifics, if you're interested.

>Near the back of the case, near the expansion slots, there is a what
>appears to be a power hookup labeled 'FAN', with two pins extending out
>of a red plastic casing.  I'm assuming that this is a hookup for a fan
>(unless it's some acronym).  If it is, what's the voltage and where
>would I put the actual fan?

You can buy fans, but unless there are a lot of cards in the computer, you
don't need one. See http://www.allelec.com for one source of fans designed
to fit in the Apple IIGS.

>At the beginning of the motherboard, to the left of a power hookup (a
>wire runs from it underneath the motherboard to the speaker), there's
>something that looks like a larger power hookup.  It has a red casing
>the same color as the other ones, but it is larger and has seven pins,
>not just two.  What is this, and what is it for?

That one I don't recognize from your description. It _may_ be the input for
some simple sound digitizers. You may be able to get one from
http://www.allelec.com if you care to use the input.

>The mouse that the thing came with didn't have a mouse ball in it (the
>cover to secure it is there though).  Will a modern mouseball fit in
>there and be able to be used?  It looks the same size as the one I have
>in my PC's mouse, but I can't tell for sure.

If it fits, it will work. You can also replace the mouse with any Macintosh
ADB mouse or trackball.

>Is there a site I could go to that has schematics for all the stuff on
>the motherboard, explaining what each thing does?  I'd like to take a
>look at one if only to satisfy my curiosity.

Not that I know of. The Apple IIGS predates the web, and very little was
ever moved there. You can get the information you are after from the Apple
IIGS hardware reference. It's available as a reprint from
http://www.byteworks.org.

Mike Westerfield