Hi Michael,

Yeah, I thought about driving the 5 Volt regulator from regulated 12
Volts, but I figured that would put extra load on the 12 Volt
regulator.  At some point, when I get time, I've got to measure
current and see if I need to make any changes.  I know that
accidentally inverting the level of the stepper motor controls didn't
help with the 5 volt supply, so the heat issue may already have been
solved. I haven't thought about checking it after making that fix.  So
far, after many hours of operation, the power supply hasn't given any
sign of trouble.

I also thought about looking for a inexpensive switcher with the right
voltages.  I was even contemplating using a spare Apple II supply for
initial debug.  12 Volt wall warts are everywhere, dirt cheap and
don't take up much space.  In the end, adding a few power supply
components to the board really took less effort than messing around
with finding the right switcher and figuring out how to mount it.

This is definitely intended for a box.  Size and shape will probably
be driven by finding the best way to expose the 20 pin Disk II header
from a standard enclosure.

Regards,
Mike Willegal

On Feb 6, 4:49=A0pm, "Michael J. Mahon"  wrote:
> mwillegal wrote:
> > I'm pretty far along on a "smart" version for DIsk ][ drives,
> > formatted in DOS 3.3 format.
> >http://www.willegal.net/appleii/appleii-disk-int.htm.
>
> BTW, you can cool down your +5v regulator by running it from
> the *regulated* +12v instead of the unregulated.
>
> A small switching supply that outputs +12 and +5, and maybe
> even -12 and -5 (though that's less important), is probably
> available surplus for under $10. =A0(When I tried this--without
> the microcontroller, hoping the parallel port would work--
> I used a "brick on a rope" that supplied +12, +5, and -12.)
>
> (I'm assuming that eventually this will all go into a box
> anyway.)
>
> -michael
>
> ******** Note new website URL ********
>
> NadaNet and AppleCrate II for Apple II parallel computing!
> Home page: =A0http://home.comcast.net/~mjmahon/
>
> "The wastebasket is our most important design
> tool--and it's seriously underused."
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