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RE: [N8VEM-S100:558] Best place to start building S100 computer?

The only problem with that Jack is you have to remove/bypass regulators on
every board. A real pain if you are switching old/new S-100 boards in out
and essentially out of the question if you have as well an old IMSAI like
box. If you are doing this, watch out for Zenier diodes on some boards.
Honestly the modern switching supplies are easier and don't provide any home

John Monahan Ph.D

-----Original Message-----
From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On
Behalf Of Jack Rubin
Sent: Wednesday, December 21, 2011 4:51 AM
To: n8vem...@googlegroups.com
Subject: RE: [N8VEM-S100:558] Best place to start building S100 computer?

Why fight to drive uphill to just heat the room? Just eliminate the 78xx
regulators and run 5 and 12 volts on the rails! That's what Godbout and
Morrow did at the end - it's certified vintage and it's smart. 


> -----Original Message-----
> From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com]
> On Behalf Of Mike
> Sent: Wednesday, December 21, 2011 12:11 AM
> To: n8vem...@googlegroups.com
> Subject: Re: [N8VEM-S100:557] Best place to start building S100 
> computer?
> On 12/20/2011 02:49 PM, W3DRK wrote:
> [clip]
> >
> > I'd like to start by collecting the basic "core" parts such as a
> power
> > supply and motherboard and build up from there.
> >
> > Fortunatly I am friends with someone in the custom transformer field 
> > so getting a decent transformed sized just for this purpose should 
> > be pretty strait forward, and perhaps even less expensive then using 
> > 2
> or
> > 3 seperate SMPS units.  I already have heavy heatsink mounted 
> > rectifier diodes, filter caps, etc so that helps too.
> >
> [clip]
> > Thanks!
> > Dieter Kedrowitsch - W3DRK
> Hi Dieter,
> I'd agree with the others regarding the use of a switching power 
> supply.
> I got a 7.5V @42A supply from eBay that has a little bit of voltage 
> adjustment, but I'm leaving it at 7.5V so the 7805s will run a little 
> cooler.
> I also got, from eBay, a couple of 12V @5A switchers  to run the +/- 
> 16V rails, they will adjust to about 14.5V which will be fine.
> All together I don't think I spent more than about $80 on the power 
> supplies.
> PS. Sorry I've been slacking on the 68K work, guys, I've been just up 
> to my neck, it's getting closer to the front burner however.
> Mike Sharkey
> http://8bit.zapto.org
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