Re: Turn on Apple to preserve it?

["Michael J. Mahon" <mjmahon@aol.com>]

Linards Ticmanis wrote:
> Mike Willegal wrote:
>
> > So what are the restrictions on the early Apple supplies.  I've been 
> > thinking about the implemenation of a USB-Disk II interface.  One of 
> > the issues is a power supply for a Disk II  (+5/-5/+12/-12).  One of 
> > easiest solutions would be an Apple II supply, but I'm not sure if 
> > there is enough current draw from an idle Disk II.  Any thoughts out 
> > there?
>
>
> -5 is not needed at all as far as I can tell from the schematic, and -12 
> only to bias the differentiator in the mc3470 amplifier, so current draw 
> should be tiny.
>
> Aren't there small components that can make -12 from +12?

Yes, that was the approach I used several years ago for this very
purpose.  I used a "brick on a rope"-style supply that put out +5v
and +12v, plus a little DC-to-DC "polarity inverter".

Thrift stores are great places to locate random power adapters.  ;-)

-michael

NadaPong: Network game demo for Apple II computers!
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