imsai 2 - test-drb@ccmp.vtda.org

17 Aug 1999

Eric wrote:
...
 Tim wrote:
> According to what I read from the web page, there's a PC-clone switching
> power supply followed by a "boost" switching circuit to get back to
> +8 and +/- 16.  That's not completely unreasonable, but it sounds a 
> little bit fishy to me in the sketchiness of the details. 
...
 It sounds a *lot* fishy. 
Well, I wasn't going to say so, but indeed it does sound something
like vaporware.

...
   For the required current, it would be more
expensive to try to use a standard PC supply with custom step-up converters
on the outputs than to simply:

1)  Hack a stanard switcher

2)  Build a custom switcher

3)  Have one of the switcher manufacturers build a slightly customized model 
But a standard PC-clone switching supply is so common that they're
almost free, so it may be the place to start.  Again, I think we may
be talking about vaporware, so perhaps a technical discussion about the
way something should/shouldn't be done is silly when it'll never be done
anyway.

...
 I've been thinking about replacing the power supply
in my IMSAI because
the transformer has shorted turns and is delaminating.  I've been looking
at stuff from Vicor.  Not cheap, but high quality and reliable. 
Certainly, there are many expensive high quality and reliable solutions
to getting 8V at tens of amps and +/- 16V at a few amps.  But I can't
think of any really cheap solutions that are high quality and
reliable.

-- 
 Tim Shoppa                        Email: shoppa(a)trailing-edge.com
 Trailing Edge Technology          WWW:   http://www.trailing-edge.com/
 7328 Bradley Blvd		   Voice: 301-767-5917
 Bethesda, MD, USA 20817           Fax:   301-767-5927